CSC162 Manual [1]

CSC-162 Numerical Transmission Line Protection Equipment Manual

CAUTION1) This manual applies only to CSC-162 2) Please read the manual carefully and with the specification of the installation, adjustment, testing, operation and maintenance. 3) To prevent damage to equipment, dont plug-hot-plug any unit of the equipment, touching the chips and components in printed circuit board. 4) Please use the testing equipment and devices which comply with the relevant standards for test and detection. 5) If any abnormality occurred in the equipment or unusual maintenance needed, promptly contact with the agents or our service hotline. 6) The operation password is 8888.

WARNING1) During hot-line operation of equipment ,certain parts of this equipment are under high voltage. Severe personal injury or significant equipment damage could result from improper behavior. 2) Only qualified personnel should work on this equipment or in vicinity of the equipment. These persons must be familiar with warning & service procedure described in this manual, as well as with safety regulations. 3) Prerequisites to proper & safety operation of the equipment are proper storage, setup, installation, operation & maintenance of the equipment. 4) In particularly cases, the general rules & safety regulations according to relating standards(e.g. IEC, National standards or other International standards) for work with high voltage equipment must be observed.

COPYRIGHTAll rights reserved.

Registered trademark are registered trademark of Beijing Sifang automation co., ltd.

CONTENTS1. 1.1 1.2 1.3 2. 2.1 2.2 3. 3.1 3.2 4. 4.1 4.2 5. 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 6. 6.1 6.2 6.3 7. 7.1 7.2 7.3 7.4 7.5 7.6 7.7 8. 8.1 8.2 Introduction ................................................................................................................. 1 Application ................................................................................................................... 1 Features........................................................................................................................ 1 Functions ..................................................................................................................... 2 Design........................................................................................................................... 5 Mechanical structure .................................................................................................. 5 Dimensions .................................................................................................................. 6 Technical data.............................................................................................................. 7 General data................................................................................................................. 7 Function data ............................................................................................................. 11 Hardware functions................................................................................................... 13 Hardware arrangements ........................................................................................... 13 Operations of complete units .................................................................................. 13 Protection functions ................................................................................................. 16 Whole structure of protection program .................................................................. 16 The protection basic elements ................................................................................ 16 Monitoring function................................................................................................... 25 Other logic of pilot protection ................................................................................. 29 Pilot protection .......................................................................................................... 31 Four zones distance protection............................................................................... 35 Zero-current protection ............................................................................................ 38 Direction over current protection............................................................................ 40 Over voltage protection ............................................................................................ 41 Undervoltage protection ........................................................................................... 41 Breaker failure protection ........................................................................................ 42 Autoreclose................................................................................................................ 43 Broken Conductor Function..................................................................................... 46 Installation and commissioning .............................................................................. 48 Unpacking & repacking ............................................................................................ 48 Mounting .................................................................................................................... 48 Check before power on ............................................................................................ 48 Operation.................................................................................................................... 49 Safety precautions .................................................................................................... 49 Dialog with the equipment ....................................................................................... 50 Setting the functional parameters ........................................................................... 54 Annunciations ........................................................................................................... 63 Testing and commissioning..................................................................................... 66 Commissioning using primary tests....................................................................... 75 Putting the equipment into operation ..................................................................... 77 Maintenance............................................................................................................... 78 Routine checks.......................................................................................................... 78 Relacing the back-up battery ................................................................................... 78

8.3 8.4 8.5 8.6 8.7 8.8 8.9 8.10 9. 10. 10.1 10.2 10.3 11. A. B.

Fault tracing............................................................................................................... 78 Repairs ....................................................................................................................... 78 The notices during operation .................................................................................. 78 Manipulation after replacing software or CPU ....................................................... 79 Manipulation after replacing software or MASTER module ................................. 79 Manipulation after replacing input or output module ........................................... 79 Manipulation after replacing AC module ................................................................ 79 Several illuminations ................................................................................................ 80 Storage ....................................................................................................................... 81 Ordering.83 Selection and ordering data.84 Ordering data84 Accessories..85 Appendix .................................................................................................................... 85 Terminal diagram ....................................................................................................... 85 Communication Protocol Tables ............................................................................... 86


1. Introduction1.1 Application CSC-162 numerical transmission lines protection equipment applicable to 132kV and lower voltage transmission lines. The product consists of primary protection namely 4 zones distance protection, 1 stage Definite time and Inverse time zero current protection, 1 stage Definite time and Inverse time over-current protection, 2 stages over-voltage protection, 2 stages under-voltage protection, circuit breaker failure protection and three phase auto-re-close etc, as shown in Table.1-1. Table.1-1 Main function and arrangement Main function and arrangement Definite Definite Over Three 4 zones phases- time and voltage time and Type Circuit phase Phase distance and Inverse and inverse breaker Autoground distance time Under time over failure Re-close protection zero Seq voltage current current CSC-162 1.2 Features The equipment has characteristics as follows: The microprocessor combined 32 bits DSP with MCU, high performance hardware system ensures the parallel real-time calculation in all components of the equipment. Protective functions, man-machine interface and also communications functions are completely independent in equipment. This improves the reliability and makes debugging installation, maintenance easier. Internal module is designed in such a way that a comprehensive real-time selfmonitoring is performed. Dual A/D sampling in analog circuit, performing real time self-testing. Latest checking methods are used which can detect coil performance in

energized circuit. Therefore failure of the relay is identified easily The equipment provides periodical automatic testing. Disturbance recorder with larger capacity, (memory up to 4M bytes), can record more than 5 records. Optional event format or wave format is provided when the records need to be printed. Fault wave disturbance records can be easily

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extracted through serial port or Ethernet port and saved in COMTRADE format 1000 event records which are date and time tagged are stored in non volatile memory to ensure that the data are not lost when DC supply fails. The relay can record protection operating process, logic flow and various calculated values. Our CSPC software can be used for viewing the above and also the recorded fault data and for analyzing disturbance records via RS-232 serial port on the relay front fascia 2-channel high speed reliable electric Ethernet ports (optional optical fiber Ethernet ports), 2-channel Lon-Works ports, RS-485 port and series printing port are provided; the user can select any of these according to the requirements. The protocol supports IEC60870-5-103, IEC61850 or CSC-2000 of Sifang Company, for interface with substation automatization system and protection management information system. Liquid crystal display with backlit is provided to display various messages such as current, voltage, power, frequency, Strip State, setting zones etc. The menu is easy to operate. Four shortcut keys are set to finish operation with one key for local operator. 1.3 Functions Tele-Protection scheme (distance protection) Distance protection is the primary protection for transmission line. Relay is suitable for 2 types of channel aided schemes viz, permissive under reach mode and permissive over reach mode. It consists of directional distance element, directional zero-sequence and negative-sequence element. Directional distance element consists of directional phase to earth distance element and phase to phase distance element. Distance protection (Z) Both phase to phase distance protection and phase to earth distance protection are provided in CSC-162 Distance protection protects the transmission line and has a backup protection for the power system. This protection has four settable zones; in addition, every zone can be enabled or dis-enabled via binary settings. When VT fuse fails , distance scheme is blocked, thereby avoiding the maloperation.The distance characteristic is polygonal. Power swing blocking (PSB) In 150ms after the abrupt current startup element operates, or when power swing startup element or zero-current startup element operates, the executing program will directly go into the logic part of power swing blocking. For asymmetric faults detection element, Zero-sequence and negative-sequence current can distinguish fault from swing. The criterion is described as below. |I0|>m1|I1| or I2>m2|I1|2


For three-phase fault detection element, the method distinguishing fault from power swing: 1. Within time , if R < K RMin (1800, TZMAX, ) is satisfied, it is determined that fault occurs in power system. 2. Within time , if R K RMin (1800, TZMAX, ) is satisfied, it is determined that swing occurs in power system. Zero-current protection (3I0) This protection function is a backup protection for the transmission lines and the power system. The protection is one stage definite time 3I0>. The zero-current protection Function can be enabled via binary settings. Inverse time zero current protection (3I0_INV) The directional element of inverse time zero current protection can be enabled or disabled via binary settings. Its characteristic equation is as shown below;T= T 0 _ factor + T0_INV Id N0 ( ) 1 3I 0 _ INV

Id - fault current. T0_factor - Time factor of inverse time zero-current. N0 - Index of inverse time zero-current. 3I0_INV - current setting of inverse time zero current. T0_INV - delay time setting of inverse time zero current which can meet the requirement that inverse time zero current co-operates with different protection. Inverse curves can be obtained according to the following setting N0=0.02 and T0_factor=0.14 Standard inverse (IEC Standard) N0=1 and T0_factor=13.5 Very inverse N0=2 and T0_factor=80 Extremity inverse. Over current protection (OC) This protection function is a backup protection for the transmission lines and the power system. The protection is one stage definite time I>. The over-current protection Function can be enabled via binary settings. Inverse time over current protection (OC_INV) The directional element of inverse time over current protection can be enabled or disabled via binary settings. Its characteristic equation is as shown below;T= Toc _ factor + Toc_INV Id ( ) Noc 1 Ioc _ INV

Id - fault current. Toc_factor - Time factor of inverse time over current. Noc - Index of inverse time over current.

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Ioc_INV - current setting of inverse time over current. Toc_INV - delay time setting of inverse time over current which can meet the requirement that inverse time over current co-operates with different protection. Inverse curves can be obtained according to the following setting Noc=0.02 and Toc_factor=0.14 Standard inverse (IEC Standard) Noc=1 and Toc_factor=13.5 Very inverse Noc=2 and Toc_factor=80 Extremity inverse. Over voltage protection Uph-e> (OV) The protection comprises 2 stages Uph-e >. The phase voltage is measured directly at the VT. The overvoltage protection function can be enabled via binary settings. Under voltage protection Uph-e< (UV) The protection comprises 2 stages Uph-e .It can be started by internal protective tripping or external via binary input. Auto-reclose (AR) CSC-162 protection system has three-phase auto-reclose. For any fault on the line, all the three poles will be tripped, and all the three poles will be re-closed. This function can be enabled via binary settings. Broken Conductor CSC-162 relay has broken conductor function, if the necessary condition are satisfied, relay can give alarm and trip output. On-load measurement The on-load measured values generated in the unit such as current, voltage, phase angle, etc. can be displayed at the LCD or by means of a PC.

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2. Design2.1 Mechanical structure The enclosure for equipment is 19 inches in width and 4U in height according to IEC 60297-3. The equipment is flush mounting with panel cutout and cabinet. Connection terminals to other system on the rear. The front panel of equipment is aluminum alloy by founding in integer and overturn downward. LCD, LED and setting keys are mounted on the panel. There is a serial interface on the panel suitable for connecting a PC. Draw-out modules for serviceability are fixed by lock component. The modules can be combined through the bus on the rear board. Both the equipment and the other system can be combined through the rear interfaces.

Fig.2-1 CSC-162 protection equipment view

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2.2 Dimensions Dimension drawings for CSC-162 are shown in Fig.2-2.

Fig.2-2 flush-mounted enclosure of 162 with panel cutout (dimensions in mm)

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3. Technical data3.1 General dataAnalog input and output

Nominal Frequency 50 Hz Current Inputs Rated current IN 1 A or 5 A Current Overload Capability per Current Input Thermal (rms.) 2 IN continuously 10 x IN for 10s 70 x IN for 1s Voltage Inputs 110/3 Rated Voltage UN Voltage Overload Capability in Voltage Path per Input Thermal (rms.) 1.2 UN continuously 1.4 UN 10s 3.1.1 Power supply Voltage Supply ( to be mentioned before Purchase order) Rated auxiliary voltage UDC 110V DC 220V DC Permissible voltage ranges 88V~121V 176V~242V 3.1.2 Binary inputs and outputs Binary inputs Variant Quantity CSC-162 Rated voltage range Rated voltage range Binary outputs Variant CSC-162 Rated voltage range 8 Nos. of 110V/ 220V DC 3 Nos. of 24V DC

Trip contacts Quantity 24 NO contacts 110V/ 220V DC

Alarm contacts Quantity 18 NO & 1 NC contacts

3.1.3 Communications interfaces Operator Interface local Connection type Medium of connection Type of connector Type of data transfer Speed of communication Dielectric level

RS-232 Electric DB25 Serial 9600bps III

Ethernet Electric RJ45 Serial 10/100Mbps III

RS-485 electric twisted-pair serial 9600bps~38400bps III

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Maximum cable length

10m RS-232:Print Functions supported by setting, fault this port report, waveform report

110m See setting, fault report, waveform report

1.2km see setting, fault report, waveform report

Rear port for 2 Ethernet 2 RS-485 substation automation CSC2000 or IEC 60870-5- CSC2000 or IEC 60870Communication protocol 103 or IEC 61850 5-103 or IEC 61850 Medium of connection Either optics or electric Electric Type of connector RJ45 Twisted-pair Speed of 10/100Mbps 9600bps~38400bps communication Dielectric level III III Maximum cable length 110m 1.2km Note: Optical port is optional by order. 3.1.5 Other general data Other General data of the equipments see table 3. Table 3 General data of the equipments No. Item Class/rated According Note to standards 1 Environment conditions 1.1 Ambient temperature -10C~+55C 1.2 Extreme range of -25C~+70C IEC 60255ambient temperature 61988 (GB/T 1.3 Atmospheric pressure 80 -110kPa 14047-1993 1.4 Operative ranges of (80% -110% )UN IDT ) auxiliary energizing quantities 1.5 Relative humidity 75% 1.6 Storage temperature -10C ~ +40C 2 Rated parameters 2.1 Rated value of voltage 110V or 220V 2.2 Rated value of current 1A or 5A 2.3 Rated value of 50Hz frequency 3 Burden

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3.1

rated burden

AC current DL/T 478-2001 circuit 1VA AC voltage circuit 0.5A DC power supply circuit: 50W Specific rating defined by Manufacturer in IEC 60255-6 1988

4 Thermal property 4.1 Thermal of short and AC current circuit long time 2 In -continuously 10 x IN for10s 70 x IN for1s AC voltage circuit 1.2 UN-continuously 1.4 UN for10s 5 Electrical insulation 5.1 Insulation resistance 100M

DL/T 478-2001

5.2

Insulation resistance in 1.5M dry heat

IEC 60255-5 2000 (GB/T 14598.3 -2006,IDT) DL/T 478-2001 No defined in IEC602555 500V was defined for less then 63V in IEC 60255-5

5.3

Dielectric voltage

5.4

Impulse voltage

AC 2kV Ui63V IEC 60255-5 1kV Ui I_abrupt where i= || iK- iK-T|-| i K-T - iK-2T || means AB,BC or CA, K is the current sampling timingT=24 samples per cycle (K-T) is the sampling timing before one cycle from timing K, (K-2T) the sampling timing before two cycles from timing K, 3i0 is abrupt zero-current value, I_abrupt is the setting value of abrupt current. The abrupt current element operates when any phase-to-phase abrupt current i or zero-sequence abrupt current 3i0 continuously exceed the setting I_abrupt.

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5.2.1.2 Zero-sequence current startup element Besides abrupt current startup element, zero-sequence current element is also able to overcome the inadequate sensitivity problem of abrupt current startup element at faults with high resistance (up to 100 for 220kV, up to 300 for 500kV). As an auxiliary startup element, it operates with 30ms delay. Its criterion is as follows: 3I0 > 0.9*I0set Where 3I0 is three times zero-sequence current, I0set is the minimal value of the following values (1) The setting value of the zero-sequence current, (2) The setting value of inverse time zero current, 5.2.1.3 The static stability detector To ensure the proper operation during loss of static stability state, the loss of static stability detector is considered Its operating conditions are described as below. (1) All currents of phase A, B and C are bigger than the current setting of I_PS and the abrupt current elements have not operated. (2) All impedances of phase-to-phase AB, BC and CA enter into zone of distance relay, and the abrupt current elements have not operated. Any of the above conditions has been validated for 30ms, power system is regarded in the loss of static stability state, then, the startup element operates, the protection program is switched to power swing blocking module, at the same time, Z STARTUP or I_PS STARTUP and RELAY STARTUP are reported. 5.2.1.4 Lower voltage startup element (detailed in weak-source part) When one end of the protected line is weak-source system, lower voltage can be used to startup protection for permission mode. Its criterion: Single-phase voltage is less than 30V or phase-to-phase voltage is less than 50V and the relay receives signal. 5.2.1.5 Auto re-close startup element Protection tripping and the contacts of CB can cause autoreclose. Detailed in autoreclose part 5.16. 5.2.2 Phase selector Using integrated phase selector detect various fault types, phase selector can pick out the faulted phase for selective-phase tripping. Abrupt current phase selector is used at the beginning of fault after abrupt current startup, later; sequence fault components phase selector is used. Both abruptcurrent phase selector and sequence fault components phase selectors are not applicable to weak-source system and feeder terminal line where low voltage phase selector is employed.

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5.2.2.1 Abrupt current phase selector Abrupt current phase selector employs phase-to-phase differential current IAB, IBC and ICA to detect the faulted phase by comparing the value of these currents. The amplitude of phase-to-phase differential current IAB, IBC and ICA at different faults are shown in Tab.5-1 below. (Where + means the bigger one, ++ the biggest one, means the smaller one) Table.5-1 Phase Slected AB BC CA ABC A B C I + + ++ + + ++ IAB IBC ICA + + + + + + ++ + + ++ ++ ++

IAB, IBC and ICA can be sorted into the biggest, the bigger and the smaller, then the fault selection result can be implemented according to Tab.5-1. 5.2.2.2 Sequence current phase selector Steady state sequence current phase selector mainly uses the angle relation of zeroand negative- sequence current to detect the fault phase with an additional method based on phase-to-phase impedance. Theoretical analysis have demonstrated that, compared with phasor I0a, I2a locates at area of -30~+30when A-phase earth fault occurs or BC-phase earth fault does with a smaller resistance, furthermore, I2a lags behind I0a close to 90 with the resistance increasing. Six phasor areas can be divided according to the angle relation of I2a/I0a as shown in Fig.5-1.

I 0a

+30ABN

0

AN, BCN

- 30

0

BCN

+90

0

- 90CN, ABN BN, CAN0 0

0

+150

CAN

- 150

Fig.5-1 Phasor areas of steady state sequence phase selector 1. +30~ -30 conforms to AN or BCN 2. +90~ +30 conforms to ABN 3. +150~ +90 conforms to CN or ABN 4. -150~ +150 conforms to CAN 5. -90~ -150 conforms to BN or CAN 6. -30~ -90 conforms to BCN

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Corresponding phase-to-phase faults are affirmed directly in the above areas of (2), (4) and (6). On the other hand, in phasor areas of (1), (3) and (5), there are singlephase and phase-to-phase both fault types which are always independent to each other and can be differentiated by phase-to-phase impedance calculation. If phaseto-phase impedance is bigger than its setting, then phase-to-phase fault is impossible, single-phase-ground fault can be confirmed, otherwise phase-to-phase fault will be done. 5.2.2.3 Low voltage phase selector Low voltage phase selector mainly meets phase selection of the relay fixed at weaksource end where both of the above phase selectors can not select faulted phase. If VT circuit does not open, low voltage phase selector can be put into operation. Its criterion is as below. a) Any one of phase voltage is less than 30V and other two phases voltage are larger than 50V, then the single phase with lower voltage is decided. b) If phase-to-phase voltage is less than 30V phase-to-phase fault is decided. 5.2.3 Distance element Distance protection consists of measuring unit and directional unit. 5.2.3.1 Operating characteristics of distance element Every zone of the distance element is of the polygonal characteristics as shown in Fig.5-2. For 4 zones phase-to-phase distance relay, RSET and XSET of zone 1, 2,3 and 4 is respectively set to R1_pp, R2_pp, R3_pp, R4_pp, X1_pp, X2_pp, X3_pp and X4_pp. For 4 zones phase-to-ground distance relay, RSET and XSET of zone 1, 2, 3 and 4 is respectively set to R1_pe, R2_pe, R3_pe, R4_pe, X1_pe, X2_pe, X3_pe and X4_pe. Where XSET is set according to the protected range and RSET is set according to avoiding load impedance (under general instance), which meets different requirements to enhance the resistive tolerance to high path fault resistance for short line and to improve the ability of avoiding load impedance for long line. The reactance line of polygon is inclined to an obliquitous angle 7(as shown in Fig.5-2) to enhance the ability to prevent the relay from overreaching at forward external faults. When fault occurs after reclose or manual close, based on the characteristics shown in Fig.5-2, the impedance operating characteristics includes a small rectangle area at the center of coordinates as shown in Fig.5-3. This is called impedance-offset characteristics that can ensure that faults near the bus can be reliably cleared. Zone 3 of distance element has offset characteristics when three-phase fault occurs.

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Fig.5-2

Fig.5-3

Fig.5 operating characteristics of polygonal distance protection The values in the small rectangle operation area are shown in Tab.5-2. Tab.5-2 X is set as XSET/2, if XSET 1 Setting X is set to 0.5(In=5A) or 2.5 (In=1A), if XSET>1 Setting The minimum among 8 times the above X and RSET/4 Where XSET is the reactance setting of relevant elements, RSET is the resistance setting of relevant elements. 5.2.3.2 Measuring unit of distance element Based on differential equation arithmetic, measuring element calculates relevant circuit impedance value with real-time voltage and current. For single-phase-to-ground impedance: d ( I + K X 3I 0 ) +R *(I+Kr3I0), = A, B, C. U=L * dt dI + RI, =AB, BC, CA. For phase-to-phase impedance: U=L dt Where Kx = (X0-X1)/ (3X1), Kr = (R0-R1)/ (3R1). Measuring resistance R and reactance X (X =L=2fL) at relay location can be obtained by means of calculating the above differential equations. 5.2.3.3 Directional unit of distance element Special directional elements are set to resolve dead zone for distance protection when fault occurs near the bus. For symmetric fault, the memory voltage that is the pre-fault voltage is used to compare phasor with post-fault current to detect direction. For asymmetric fault near the bus, negative-sequence directional element is taken as directional element of distance relay. The operating conditions for distance relay are as below: The forward directional element operates, and measuring impedance lies within the setting polygon area.

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5.2.4 Zero-sequence directional unit Zero-sequence current directional unit is composed of forward and reverse directional elements whose operation areas are shown in Fig.5-4. The threshold of forward directional element can be set while that of reverse directional element can not, whose sensitivity is automatically higher than forward element, and threshold is 0.625 times that of the forward element. Area of forward directional element is 18 arg (3 I 0/3 U 0) 180 Area of reverse directional element is -162 arg (3 I 0/3 U 0) 0. .

.

.

lm

forward81 81 18

3U0

reverse

Fig.5-4 Operation area of zero-sequence current directional element a Criterion of forward directional element is as below. Directional element lies in the forward directional operation area and 3I0>3I0SET. Where 3I0SET are the setting of inverse time zero-sequence current, and the setting values of of zero-sequence current 3I0. b) Criterion of reverse directional element is as below. Directional element lies in the reverse directional operation area and 3I0>0.625*3I0SET. The zero-sequence directional element employs the 3U0 that is obtained by software summing three-phase voltage. 5.2.5 Negative-sequence directional element Negative-sequence directional element is taken as condition of enabling impedance directional element for asymmetric faults. Operation area is shown in Fig.5-5. Area of forward directional element is 18 arg (3 I 2/3 U 2) 180, Area of reverse directional element is -162 arg (3 I 2/3 U 2) 0.. . . .

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lm

forward81 81 18

3U2

reverse

Fig.5-5 Operation area of negative-sequence directional element 5.2.6 Opening element of power swing blocking Power system is impossible to begin swing within 150ms after sudden-charge current startup element operating, therefore, during this time, all distance relays are settled to take on action, and power swing block need not be enabled. After the setting of T_PS NO BLOCKING, all distance relays are settled to take on action, and power swing block need not be enabled. After 150ms or the protection startup by loss of static stability or zero-sequence current, the distance relay must be enabled by fault detector to prevent mistake trip during power swing. Fault detectors for power swing blocking are different for asymmetric faults and three-phase fault. 5.2.6.1 Asymmetric faults detection element Zero- and negative-sequence current can distinguish fault from swing. The criterion is described as below. |I0|>m1|I1| or I 2>m2|I 1| Where m1 and m2 ensure that, during power swing, the mal-operation of the distance protection is not caused when external fault occurs under the most disadvantageous conditions of power system but asymmetric faults detection element can be operates when internal asymmetric fault occurs. When power swing happens, I0 and I 2 are close to zero, it is impossible for the above formula to come into being. When power swing and external fault occur, the smaller fault component current at the relay location cant meet the above formula. When power swing and internal fault occur, I0 and I 2 will be big enough to meet the above formula. To keep the protection from mistake trip caused by the imbalance output of zero- and negative-sequence current when the external fault is removed, the protection has to operate in a certain short time delay.

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5.2.6.2 Three phase fault detection element a) During power swing, measuring resistance or measuring impedance at the relay location is continuously changing with time, and sometimes the change is slow, sometimes the change is intensive, the change rate is decided by swing period and the machine angle . Curve 1 and curve 2 in Fig.5-6-(a) are the trajectories of measuring resistance changing with time, where Rf is load resistance component and Tz is swing period. Whether the trajectory of measuring impedance is a line or a circular arc on R-X plane during power swing, is decided by electromotive force of both terminals equivalent system, as shown in Fig.5-6-(b).Rm t ) ( 1 Rf 2 jX

0

t0

Zm R

Tz b

a

(a) Measuring resistance Rm. changing with time (b) the track of measuring impedance on R-X plane Fig.5-6 The trajectory of measuring impedance during power swingRm t ) ( Rf Rk

O t1 t2 t3

t

Fig.5-7 The trajectory of pre- and post-fault measuring resistance changing with time b) When fault occurs on the protected line, resistance component of measuring impedance maybe changes due to electric arc elongated, but analysis and calculation show that changing rate of arc resistance is far less than that of resistance corresponding to the possibly biggest swing period noted up to the present. After short circuit, measuring resistance is resistance RK of short circuit, whose value hardly changes or almost keeps invariability, as shown in

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Fig.5-7. The rule of measuring impedance is also similar. Contrasting Fig.5-6 with Fig.5-7, it can be seen that power system is determined to be in the swing state if measuring resistance is always changing and exceeds a threshold value in a period of time. Therefore, the least change of resistance is looked over during power swing. It can be known from analyzing Fig.5-6 that the instance of the least change of measuring resistance occurs in the following conditions. (1) near =180 (2) the biggest swing period TZMAX. And then, enlarge this part track of resistance change to be shown in Fig.11.RmTZMAX swing curve

180

Rmin

/2

t

Fig.5-8The instance of the least change of measuring resistance It can be known from Fig.5-8 that a minimum changing resistance RMin (1800, TZMAX, ) is obtained corresponding to a time , in this way, for any swing period and any time period , all exist: R RMin (1800, TZMAX, ). Therefore, consider error and protection margin, take the following formula as criterion detecting swing. R KRMin (1800, TZMAX, ) (1) Reliable coefficient K is a less than 1. Surely, also consider equivalent system impedance Z S for (1). And, for a different regulated time , the corresponding RMin (1800, TZMAX, ) can be calculated. Concluding the above analysis, we can reason the method distinguishing fault from power swing: 1. Within time , if R < KRMin (1800, TZMAX, ) is satisfied, it is determined that fault occurs in power system. 2. Within time , if R KRMin (1800, TZMAX, ) is satisfied, it is determined that swing occurs in power system. When fault occurs, it is possible that formula (1) is satisfied due to time too small, however, can be increased to relax the restrained condition R < KRMin (1800, TZMAX, ), and to make use of it to identify fault gradually. c) When fault suddenly occurs on the protected line, if the angles between two sources do not reach 180, or three-phase fault occurs outside the swing center, the magnitude and angle of pre- or post-fault impedance must have great sudden change. Based on this characteristic, distance element can be enabled quickly when three-phase fault occurs in power system without serious swing or under the conditions that swing does not occur after protection pickup for 150ms.

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5.3 Monitoring function 5.3.1 Software monitoring

5.3.1.1 Loss of measure voltage detection Interruptions in the secondary circuits of voltage transformers is detected and reported by the device. Two criteria are set to detect VT circuit opened and both of them have delay time. Only under normal operation and without any element startup, they are put into operating. Hardly does the circuit-opened detector stop operating when any startup element operates, and it is not enabled until all system reset. Criterion a: The sum of three phase voltages is not equal to zero, U a + U b + U c >7V(r.m.s) This is used to detect one phase or two phases circuit open. Criterion b: When VT is connected to bus, if any phase voltage Ua, Ub or Uc is less than 8V, VT fuse fail is confirmed When VT is connected to line, if any phase voltage Ua, Ub or Uc is less than 8V, and any phase current is larger than 0.04In or circuit breaker (CB) is in the closed state, VT fuse fail is confirmed The additional current condition of criterion b is to avoid undesired alarms before CB is switched on when VT is on the line side. The additional condition which CB is in the closed state is to avoid that the system can be unable to give an alarm in case of loss of voltage for three phases when the line current is too small (for example, CB lying at another terminal of the line is off). When VT circuit is opened, VT Fail is reported, and all distance units, negative sequence directional unit, abrupt directional element, directional over current unit and zero current unit with direction are forbidden to operate. Measure voltage will be continuously supervised in order that each element can be automatically put into the operation again as soon as the voltage returns to the normal. VT Fail judge logic is shown below in Fig.5-9:. . .

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Relay startup

3U0 >7V& AND1

& AND2

VT FAIL

NO DI CB OPEN1 OR1

VT_bus

1 OR2

Relay test

& AND3

& AND5

Ia(b,c) > 0.04In

& AND4

Ua(b,c) < 8V

Fig.5-9 VT Fail judge logic

5.3.1.2 CT failure/current unbalance To prevent the relay from wrong trip, interruptions in the secondary circuits of current transformers is detected and reported by the device. When the zero-sequence current is always larger than the setting value of 3I0 for 12s, CT Fail will be reported and zero-sequence current protection will be blocked.

5.3.1.3 Check Phase-sequence for voltage and current In normal condition of power system, whether AC circuits of three phases are connected in right sequence or not can be distinguished by phasor comparison of three phases current and voltage. If they are in abnormal sequence, 3-PH SEQ Err will be reported.

26


5.3.1.4 Check 3I0 polarity By comparing value and phasor of calculation 3I0 (IA+ IB + IC) with that of 3I0 external connected, whether the polarity of external 3I0 is connected in reverse or not can be differentiated, if it is in reverse, 3I0 Reverse will be reported. 5.3.1.5 Check the third harmonic of voltage If the third harmonic voltage exceeds 4V, Harmonic Alarm will be reported with 10s delay time, but the protection is not blocked. 5.3.1.6 Line reference voltage check Under the auto-reclose condition of three-phase mode, if there is current through line or not, input of auxiliary tripping contact of CB, which indicates CB is in the close state. The following methods can check the line voltage in good condition. When AR_check Sync or AR_check low U is set for automatic reclosure modes, if the voltages between both sides of CB can not meet the setting synchronism condition, which is confirmed with 14s delay time, SYN Voltage Err is reported. The system supervises extractive voltage on real time. 5.3.1.7 Check auxiliary contact of circuit breaker (CB) If there is input signal of auxiliary contact of CB, and corresponding phase has current, which is confirmed with 2s-delay time, CB Open Err is reported.

5.3.1.8 Check for the illogicality of setting a) In function of pilot protection such as< POR mode > and < PUR mode >, if both modes are put into operation at the same time, Pilot FUNC Alarm is alarmed. b) In function of automatic recolsure of equipment, if any two kinds of modes are put into operation at the same time among < AR_No check >, < AR_check low U > and < AR_check Sync >, AR FUNC Alarm is alarmed. c) Choose VT mode, If two kinds of modes are put into operation at the same time < VT_line >and < VT_bus>, VT Choice Alarm is alarmed. If for < VT_line >and < VT_bus> is not put into operation, relay is put into operation for < VT_bus>. d) In function of distance protection, Z4 put into operation, if two kinds of modes are put into operation at the same time < Reverse_Z4 >and < Forward_Z4 >, Z4 Choice Alarm is alarmed. 5.3.1.9 Check of the CSC-162relay system a) CPU module check. CPU module performs self-testing to its memories, analog channels and program during power on, parts of the above are checked by itself in real time during the system running. If any of them is confirmed to be incorrect, alarm will be given, and the protection will be blocked.

27


b) The sampled data can be checked with each other in real time due to the redundancy of double A/D channel for one analog quality. If the difference between two channels exceeds the setting limit, one of the double channels is regarded as fault one. c) Each I/O module performs self-testing during power-up and real-time self-tests. Self-testing checks input channel, output channel, memories and code areas etc. Self-testing of input channel is performed by bit changing simulation. Self-testing of output channel includes coil tests and outer circuit tests. The tests are very thorough with wide range, if any failure is confirmed, alarm is given. d) Real-time self-testing of communication ports. CPU module and MASTER module perform real-time self-tests of communication among all kinds of function modules. When interrupt communication is detected, alarm is given. e) MASTER module performs self-testing at power-up and real-time self-testing that check memories, program areas and relevant communication with the outside. If any abnormal event is detected, alarm will be given. The setting and strap messages stored in this module are checked with each other. f) Real-time supervision for DC power supply. g) CRC checks for the setting etc. 5.3.2 switch-on-to-fault protection (SOTF) The input of auxiliary tripping contact of CB lasts 10s, later I operates, and then the system regards this condition as manual closure of the CB. If no fault is detected, 1s later, the whole system resets. If fault is detected, instantaneous trip function put into operation. Distance relay use impedance element to detect fault, zero-current relay operates with 100ms delay, when fault occurs during switch-on-to-fault. When switch-on-to-fault line occurs, if the binary setting of distance relay is enabled, the distance relay will accelerate to operate. Six loops of impedance will be calculated, if any of them is located in the area of operating characteristics with offset region, the distance relay trips with no delay time. 5.3.3 Tripping after automatic reclose If the fault still exists after automatic reclose, then the protective elements will re-trip the circuit breaker. The equipment requires three auxiliary tripping contacts of segregated phase respectively as three binary inputs. For 3/2 bus connection scheme, each phase tripping contacts of two breakers must be series at first, and then the series contacts of each phase are connected to the corresponding binary input of the equipment. When the equipment has detected CB opened, and any phase current is larger than 0.1In(three-phase reclose mode) or the input of auxiliary tripping contact disappears, the equipment thinks that line has reclosed.

28


5.3.4 The conditions of relay reset When all the following conditions have been meet for 5s, the whole relay resets from fault dealt program. a) Six loops of impedance are outside the 4 zone of impedance. b) Zero-current is less than the setting of zero-current startup value. c) All three-phase currents are less than the setting I_PS of loss of static stability. 5.4 Other logic of protection 5.4.1 Logic after tripping After tripping commands sent out, the current of tripping phase is in the supervision. When tripping phase has not current, the protection system considers that CB has been opened. If tripping phase always has current, the system output three-phase trip signal with 150ms delay. After this, if any phase current lasts 150ms, three-phase final tripping command is issued. Later, if CB still in close state lasts 5s, three-phase final tripping failure alarm will be sent out, and the whole relay will reset. Trip command will be withdrawal as soon as fault is cleared. To ensure that CB trips reliably, withdrawal command is impossible to be considered within 40ms after trip command sent out. When there is no current flowing through three phases for 12s after the output of three-phase trip command, the program routine jumps to the whole relay reset. The delay time of 12s is to believe that the most setting delay time for three-pole autoclosure is impossible larger than 10s. After tripping command output, the sending signal command (for permissive mode) does not return until tripping command has been withdrawal for 120ms in order to ensure the tele protection of both terminals to operate reliably.

5.4.2 Reverse directional elements Impedance directional element is set forward directional element. The threshold of forward directional element can be set while that of reverse directional element need not whose sensitivity is automatically higher than forward element. The usage of the reverse directional element is as follows. a) Tele protection sends signal with 40ms-delay time when the directional elements change from reverse direction to forward direction. It prevents relay wrong tripping when zero-sequence or negative-sequence power reversing flow during external faults cleared. b) In the protection logic for weak-source system, only all the forward and reverse directional elements do not operate, the send signal element using low-voltage could be put into operation.

29


5.4.3 Protection schemes for feeder If one side of the line is feeder, when forward fault for the relay at feeder side occurs, the fault characters are no longer same as that of two side source system. To perform selective tripping function for a line with feeder, feeder tripping of pilot protection must be put into operation. If feeder function is enabled, CSC-162can fit the following conditions. When internal faults occur, the local relay sends out permissive signal (permissive mode) in order that the relay at power source side trips quickly. The relay at weaksource side can correctly perform selective trip. Phase selector of the relay at weak-source end can meet the phase-selection requirements for line faults, and the relay can correctly perform selective trip. Even if faults occur on load terminal line, the relay can either send out tripping command quickly and exactly or select fault phase correctly. 5.4.4.1 Logic of low-voltage pickup When abrupt current startup element does not pick up, if feeder function is enabled, relay starts up under the following conditions. a) Voltage is lower than 30V. b) Receiving signal. After pickup, the feeder relay will send signal (for permissive mode) quickly, and extend the signal 120ms to ensure the relay at power source side to trip quickly. 5.4.4.2 The relay trip logic at feeder At feeder side, if the relay have picked up and the following conditions are satisfied, the relay of permissive mode sends permissive signal. If the setting of the relay at feeder is enabled, the relay can trip after confirming permissive signal. c) d) e) f) At least one phase voltage or phase-phase voltage is less than 30V. Both the forward and reverse directional elements do not operate. Pickup time is less than 200ms. Receiving permissive signal for 5ms.

5.5 Tele protection schemes for Distance protection It is applicable to two kinds of communication modes: permissive under reach mode (PUR) and permissive over reach mode (POR).

30


5.5.1 Pilot protection logic for permissive mode

5.5.1.1 Overreach permissive CSC-162pilot protection logic for overreach permissive mode is shown in Fig.5-10. When internal fault occurs, the startup elements and zone 2 can operate, permissive signal is sent out to the remote to permit the remote trip. If it is external fault that occurs on line, the forward directional element of one end of the line operates and does not receive permissive signal while that of another end of the line does not operate and receive permissive signal, therefore, both ends cant trip. a) Internal fault operates, relay trip for meeting following condition. 1) Instantaneous trip if Zone 1 Operation 2) Zone 2 + permission Signal from Remote end for 5ms. Zone 2 operates that permissive signal is sent out to the remote. b) External Fault Because the directional element near fault detects reverse direction, it does not send permissive signal to the remote. Although the remote relay can send signal, it cannot receive the remote permissive signal, therefore, both of two sides do not trip. c) Power flow reversing for external fault The method to resolve this problem for the relay is that the relay sends signal with 40ms delay time when the directional element operates from the reverse to the forward to avoid the period in which both sides are forward direction, and then both sides trip after sending signal is confirmed with 15ms delay when internal fault occurs again. d) Protection schemes for feeder The binary setting Feeder_FUNC is enabled. 1. For feeder end, abrupt current startup element cannot operates, the logic of the low voltage is startup: If the relay at feeder end receives the remote permissive signal and operates, relay startup. 2. For feeder end, abrupt current startup element operates, the operating logic of the relay is as below. Within 200ms after protection pickup, if operates, both the forward and reverse directional element at feeder end do not operate, and the permissive signal has been received for 5ms, (sending signal) lasted for 120ms to ensure the relay at power source end trips quickly, feeder end can also trip. e) The protection is not picked up, receives the remote signal < CARR RECEIVED > and there are < CB OPEN >, (send signal) can be done for 200ms to ensure the remote pilot protection operates reliably.

31

CSC-162 Numerical Transmission Line Protection Equipment ManualRelay startup Relay reset Zone 2 operation Delay time 5ms CARR Received Single fault Multiphase fault Three phase fault &Low voltageAND-9 |0 120|

&AND-1

&AND-4

OR-2

CARR Send signal

&AND-5

& &AND-3 AND-2

&AND-6

Trip three phase

&AND-7

Trip three phase Permenent trip

&AND-8

CB OPEN

OR-1

&AND11 |0 200|

Fig.5-10 CSC-162pilot protection for overreach permission mode logic

5.5.2.2 Under reach permissive CSC-162pilot protection logic for under reach permissive mode is shown in Fig.5-11. When internal fault occurs, the startup elements and zone 1 can operate, permissive signal is sent out to the remote to permit the remote trip. If it is external fault that occurs on line, the forward directional element of one end of the line operates and does not receive permissive signal while that of another end of the line does not operate and receive permissive signal, therefore, both ends cant trip. a) Internal fault operates, relay trip for meeting following condition. 1) Instantaneous trip if Zone 1 Operation 2) Zone 2 + permission Signal from Remote end for 5ms. Zone 1 operates that permissive signal is sent out to the remote.

32


b) External Fault Because the directional element near fault detects reverse direction, it does not send permissive signal to the remote. Although the remote relay can send signal, it cannot receive the remote permissive signal, therefore, both of two sides do not trip. c) Power flow reversing for external fault The method to resolve this problem for the relay is that the relay sends signal with 40ms delay time when the directional element operates from the reverse to the forward to avoid the period in which both sides are forward direction, and then both sides trip after sending signal is confirmed with 15ms delay when internal fault occurs again. d) Protection schemes for feeder The binary setting Feeder_FUNC is enabled. (1) For feeder end, abrupt current startup element cannot operates, the logic of the low voltage is startup: If the relay at feeder end receives the remote permissive signal and operates, relay startup. (2) For feeder end, abrupt current startup element operates, the operating logic of the relay is as below. Within 200ms after protection pickup, if operates, both the forward and reverse directional element at feeder end do not operate, and the permissive signal has been received for 5ms, (sending signal) lasted for 120ms to ensure the relay at power source end trips quickly. Feeder end can also trip. e) The protection is not picked up, receives the remote signal < CARR RECIEVED > and there are < CB OPEN >, (send signal) can be done for 200ms to ensure the remote pilot protection operates reliably.

33

CSC-162 Numerical Transmission Line Protection Equipment ManualRelay startup Relay reset Zone 1 operation Zone 2 operation Delay time 5ms CARR Received Single fault Multiphase fault Three phase fault &Low voltageAND-9 |0 120|

&AND-1

&AND-4

OR-2

CARR Send signal

&AND-5

& &AND-3 AND-2

&AND-6

Trip three phase

&AND-7

Trip three phase Permenent trip

&AND-8

CB OPEN

OR-1

&AND11 |0 200|

Fig.5-11 CSC-162pilot protections for under reach permission mode logic Pilot direct trip function The pilot protection has input of B/LBB OPTD, it will give output Direct trip send for 200ms. If it has input of Direct trip RECV, it will give output Direct trip RECV.Input Output

B/LBB OPTD Direct trip RECV

0

200

Direct trip send Direct trip RECV

34


5.6 Four zones distance protection The distance relay consists of 4 zones phase-to-phase and 4 zones phase-to-earth distance elements, which is applied to remove phase-to-phase fault and single phase-to-earth fault. Zone 1, zone 2, zone 3 and zone 4 of distance relay are controlled respectively to be on or off by the binary setting. Zone 4 of distance relay can be set to operate in forward or reverse direction.

5.6.1 Some introductions of the program logic of the distance protection

5.6.1.1 Power swing blocking After the abrupt current startup element operates, the protection switches the executing program to the fault processed part, the distance measurement element is instantaneously opened for 150ms. Within 150ms, zone 1, zone 2, zone 3 and zone 4 of distance relay are fixedly put into operation. The abrupt current startup element operates after 150ms , or when the loss of static stability startup element or zerocurrent startup element operates, before the setting of T_PS NOBLOCKING, the executing program will directly go into the logic part of power swing blocking. In this period, four zones of distance relay must be enabled by fault detector of power swing blocking, that is, asymmetry faults are detected by asymmetry fault detector, three phase fault is detected by the impedance change rate detector (dR/dt) Four zones of distance relay are controlled by the setting to be selected whether they are blocked during power swing. If the setting is set off, four zones of distance relay are put into operation without blocking all the time during power swing. During power swing, there is a special program module to detect whether power swing quiets down or not, that is, if all zero-current elements, Power swing current detection element and six impedances of four zones of distance relay dont operate, after 5s, the whole system resets.

5.6.1.2 Loss of Potential Measurement The distance relay exits after loss of measure voltage, and at the same time, the measure voltage of VT is monitored continually. Once the voltage comes to the normal, the distance relay will be automatically put into operation again.

35


5.6.2 Function of the distance relay as shown in Tab.5-4 Tab. 5-4 Item Zone Zone 1 Zone 2 Zone 3 Zone 4

binary setting Z_PS blocking Blocked unblocked Blocked unblocked Blocked unblocked Blocked unblocked

Trip mode / / / / Three phase trip Trip_no AR Trip_no AR Trip_no AR

trip control the setting Z1_FUNC the setting Z2_FUNC the setting Z3_FUNC the setting Z4_FUNC of of of of

5.6.3The scheme logic of distance protection The scheme logic of distance protection is shown in Fig.5-12. a) The measure element is enabled to operate for 150ms after abrupt current startup, if the calculated impedance lies in zone 1 of the distance relay: Whether zone 1 of the relay is blocked during power swing or not is controlled by the setting Z1_PS blocking. If the setting Z1_PS blocking is set to off, power swing blocking is disabled,. If the setting Z1_PS blocking is set to on, power swing blocking is enabled, distance relay are opened through detecting fault. Relay startup reclose after Zone 1 trip. b) If the calculated impedance lie in the operating area of zone 2: Whether zone 2 is blocked during power swing or not is controlled by the setting Z2_PS blocking. If the setting Z2_PS blocking is set to off, power swing blocking is disabled. If the setting Z2_PS blocking is set to on, power swing blocking is enabled. Relay dont startup reclose after Zone 2 trip with delay time. c) Fault occurs in the range of zone 3: Whether zone 3 is blocked during power swing or not is controlled by the setting Z3_PS blocking. If the setting Z3_PS blocking is set to off, power swing blocking is disabled. If the setting Z3_PS blocking is set to on, power swing blocking is enabled. Relay dont startup reclose after Zone 3 trip with delay time. d) Fault occurs in the range of zone 4: Whether zone 4 is blocked during power swing or not is controlled by the setting Z4_PS blocking. If the setting Z4_PS blocking is set to off, power swing blocking is disabled. If the setting Z4_PS blocking is set to on, power swing blocking is enabled. Relay dont startup reclose after Zone 4 trip with delay time. Zone 4 can be select Reverse_Z4 or Forward_Z4, Reverse_Z4 mainly apply to blocking mode.

36


Four zones distance relay dont consider power swing blocking after abrupt current startup for the setting T_PS NOBLOCKING. e) Permanent trip for three-phase fault: Relay will permanent trip for three-phase fault. f) Switch-on-to- fault: If any impedance lies in the area of zone 1, zone 2, zone 3, relay permanent trip immediately.

I_PS start up

Zerosequence current startup Current change startup Fault detect swing unblockingZ1(2,3,4)_PS blocking

OR-1

&AND-4 |150 0|

&AND-1

OR-3

&AND-2

OR-2

&AND-5

Forward direction VT fail

&AND-3

&AND-6

Trip three phase

SOTF

&AND-8

&AND12

OR-4

Zone 1 -pe Zone 1 fault Single -pp Three phase fault Zone 2 Zone 3 Zone 4|T2 0|

&AND-9

Trip three phase

&AND10

OR-7

|T3

0|

OR-6

&AND11

Permenent trip

|T4

0|

Fig.5-12 Distance protection logic

37


5.7 Zero-current protection 5.7.1 Configuration and principle One stage directional definite time and inverse time zero current protection are set during three-phase operation. Directional element of zero current protection is fixed. Zero current is controlled to be on or off by the setting of 3I0_FUNC, and inverse time zero current protection is controlled to be on or off by the setting of 3I0_INV FUNC, Directional element of inverse time zero current protection is controlled to be on or off by the setting of 3I0_INV DIR. 5.7.2 Inverse time zero current protection The directional element of inverse time zero current protection can be on or off via the setting of 3I0_INV FUNC. Its characteristic is written as below:

T=

T0_factor + T0_INV Id N0 ( ) 1 3I0_INV

Where: Id fault current. T0_factor time coefficient of inverse time zero current. N0 Index setting of inverse time zero current. 3I0_INV current setting of inverse time zero current. T0_INV delay time setting of inverse time zero current which can meet the requirement that inverse time zero current co-operates with different protection. Inverse curves can be obtained according to the following setting: N0 =0.02 and T0_factor =0.14 Standard inverse (IEC Standard) N0 =1 and T0_factor =13.5 Very inverse N0 =2 and T0_factor =80 Extremity inverse. 5.7.3 Some explain about the program of zero current protection a) The polarity of 3U0 The protection system employs the self-count 3U0 which is obtained by the sum of three phase voltages by means of software for the zero-sequence directional element to detect direction. If VT circuit is open, zero protection with directional element exits automatically. b) CT circuit open To prevent sensitive zero current from maloperation caused by CT circuit open, the character that the zero-sequence voltage is zero in case of CT open can be employed to block zero-current directional protection which may maloperate by zero- sequence directional element. Zero current will last for a long time as CT circuit is open, if zero current is larger than the setting of 3I0 continuously for 12s, CT Fail will be reported, and every stage of zero protection will be blocked.

38


5.7.4 Function of zero current protection as shown in Tab.5-5 Tab.5-5 Directional Tripping mode Output element controlled controlled by setting control by setting Definite time of the setting of fixed with direction Permanent trip zero current 3I0_FUNC the the setting of Inverse time of setting3I0_INV Permanent trip 3I0_INV zero current DIR is on or off FUNC Item stage 5.7.5The scheme logic of zero-current protection The scheme logic of zero-current protection is shown in Fig.5-13. After the abrupt current startup element or zero current assistant startup element operate, the protection system goes into the executing program to the fault processed. Definite time zero current and inverse time zero current are put into operation under three-phase operation.

SOTF

3I0 FUNC 3I 0> 3I 0 & 3I0_INV FUNC

| T0 |

OR-3

Permenent trip

3I0 3I0_INV DIR

|T_INV |

&

Forward direction & VT fail CT fail CT failALARM

&

|12s

0|

Fig.5-13 zero current protection logic

39


5.8 Direction over current protection 5.8.1 Configuration and principle This protection function is a backup protection for the transmission line and the power system. The protection comprises one stage definite time over current and inverse time over current. The over current protection function can be applied to via binary settings. Each phase current is compared with the setting value Ioc_pe after numerical filtering. Currents above the associated pickup value are detected and signaled. The protection is blocked by directional element. Directional element is 90 connection mode. Current of each phase is controlled by corresponding directional component. Following figure (Fig.5-14) is over current directional element(current lags and angle of voltage is positive). directional element

I IA IB ICforward

U UBC UCA UAB

A B C Forward -90 arg (U/I) 30

I

U30

Fig.5-14 over current directional After expiry of the associated time delays Toc_pea trip command is issued. The function can be operation via a binary setting OC_FUNC ,and inverse time over current protection is controlled to be on or off by the setting of OC_INV_FUNC, Directional element of inverse time over current protection is controlled to be on or off by the setting of OC_INV DIR.. The over current function is permanent trip. 5.8.2 Inverse time over current protection The directional element of inverse time over current protection can be on or off via the setting of OC_INV FUNC. Its characteristic is written as below-

40


T=

Toc _ factor + Toc_INV Id Noc ( ) 1 Ioc _ INV

Where-Id fault current. Toc_factor time coefficient of inverse time over current. Noc Index setting of inverse time over current. OC_INV current setting of inverse time over current. Toc_INV delay time setting of inverse time over current which can meet the requirement that inverse time over current co-operates with different protection. Inverse curves can be obtained according to the following settingNoc =0.02 and Toc_factor =0.14 Standard inverse (IEC Standard) Noc =1 and Toc_factor =13.5 Very inverse Noc =2 and Toc_factor =80 Extremity inverse. The following figure (Fig.5-15) shows the logic diagram for over current.

OC FUNC I > I oc_pe &| Toc

|

OC_INV FUNC I OC_INV DIR

Permenent trip

&

| T_INV |

Forward direction & VT fail &

Note: I is phase current of Ia, Ib, Ic. Fig.5-15 Over current logic

5.9 Over voltage protection The relay comprises 2 stages over voltage function. The phase voltage is measured directly at the VT. The over voltage Function can be applied to via binary settings. Each phase voltage is compared with the setting value OV1_pe after numerical filtering. Voltages above the associated pickup value are detected and signaled. After expiry of the associated time delays Tov1_pea trip command is issued. The following figure (Fig.5-16) shows the logic diagram for first stage over voltage. The stage can be operation via a binary setting OV1_FUNC. Two stages over voltage is permanent trip.

41


OV1_FUNC

U>OV1_pe

&

Tov1_pe

OV2_FUNC

&Tov2_pe

Permenent trip

U>OV2_pe

Note: U is phase voltage of Ua,Ub,Uc.

Fig.5-16 Over voltage logic 5.10 Under voltage protection The protection comprises 2 stages under voltage. The phase voltage is measured directly at the VT. The under voltage protection Function can be applied to via binary settings. Each phase voltage is compared with the setting value UV1_pe after numerical filtering. Voltages under the associated pickup value are detected and signaled. After expiry of the associated time delays Tuv1_pea trip command is issued. The following figure (Fig.5-17) shows the logic diagram for first stage under voltage. The stage can be operation via a binary setting UV1_FUNC. Two stages under voltage is permanent trip.U0.1In VT fail Initiate AR

& &

Tuv1_pe

& &Tuv2_pe

UV2_FUNC

Permenent trip

UI_CBF IB>I_CBF IC>I_CBF

&1

T_CBF

3P_CBF startup

Fig.5-18 Circuit Breaker Failure Protection logic Figure 5.12 Autoreclose 5.12.1 Autoreclose mode CSC-162protection system is provided with autoreclose whose performance is only to close the circuit breaker but not to select fault phase and trip. CSC-162protection system only have three phase autoreclose mode. In CSC162relay you can setup control word AR_3p modeto enable auto re-close. AR_3p mode-if three phase trip, and relay then reclose regardless of the fault types, whether single-phase fault or multi-phase fault. CSC-162have 4 checking modes of reclose : AR_No check, AR_check Sync, AR_check low U and AR_CB3, you can select any one of them by control word to enable it , if you select one checking mode ,conditions must be satisfied ,so autoreclose can perform. 5.12.2 Voltage and synchronism check When all three phases of the circuit breaker are open, three kinds of check mode are provided as below. a. Synchronism check: If the line voltages and bus bar voltages are larger than the value of have voltage setting, and meet the synchronous conditions, synchronizing reclose can be performed. b. Low voltage check: If the line voltages are checked to be less than the value of no-voltage setting, reclose can be performed. If the line voltages and bus bar voltages are all larger than the value of voltage setting, the check mode is automatically turned to synchronism check to reclose. c. No check: Whatever the line voltage and bus bar voltage are, autoreclose is

43


performed.when relay only enable AR_3p mode,and dont select any reclose mode of AR_No check, AR_check low U and AR_check Syn,then relay think it is in AR_No check mode . Note : (1)The threshold of low voltage check is 17V of rated voltage and that of voltage check is 40V of rated voltage, the angle of synchronism check can be set. (2)The voltage phases of synchronism check or low voltage check need not be set, as the protection system can automatically identify, that is to say, if autoreclose check mode is set to synchronism check or no-voltage check, the voltage phases is identified according to the voltage from the bus and line. When CB is closed, if the voltage phases whose voltage can be satisfied with synchronism check cant be found, SYN Voltage Err is alarmed, and A-phase voltage is regarded as the synchronism voltage. The voltages provided for the relays are always from the bus VT, so the reference voltage is referred to the voltage at terminal Ux for low voltage check or synchronism check. (3) When three check modes of autoreclose are all disenabled, the faceplate of LCD displays: check mode: No check. 5.12.3 Charge and discharge of autoreclose To avoid repetitious autoreclose, a special timer with charging interval for the setting T_Reclaim is set to perform the function of charge and discharge. Only after charge has been finished, autoreclose is enabled while charge is not finished, autoreclose is disenabled. a) The charge time counter starts when the following conditions are satisfied. (1) There is no input of CB OPEN. (2) The startup elements of autoreclose do not operate. (3) No input of blocking autoreclose. b) The charge time counter is reset when the following conditions are satisfied. (1) External signals of blocking reclose are received. (2) Discharge is performed when the reclose command is output. (3) There is no input of CB OPEN or INITIATE 3PH A/R when charge is not finished. (4)During autoreclose startup, the opened phase has current. 5.12.4 Autoreclosure pickup Two kinds of pickup mode are set by relay internal trip, digital input of other relay trip or the auxiliary contacts of CB. a) Auto re-close startup caused by other relay trip Input terminal INITIATE 3PH A/R. The relay must return immediately after a successful tripping and reclosure is started after the contacts return from the close position. b) Internal tripping signals have pick up autoreclose, therefore, the input terminal44


for INITIATE 3PH A/R which need not be connected again from external contacts. Only distance zone 1 and pilot relay operate to startup reclose. Other relays operate to block AR. c) Autoreclose shot caused by the auxiliary contacts of CB Autoreclose shot caused by the auxiliary contacts of CB is mainly considered for CB occasional mal-open. The CB occasional mal-open of three-phase can be set by the control word to decide whether to pick up reclose or not. In addition, no accelerated contacts are given after successful reclose caused by the auxiliary contacts of CB. 5.12.5 Reclose When autoreclose is picked up, the following functions are performed before reclose signal output. a) Continue to detect the digital input of A/R BLOCK. If it is received, time counter of charging will be cleared, and the program of autoreclose will be reset. b) Voltage check is performed according to the setting of voltage and synchronism check, if voltage condition is not satisfied, the counter of time delay of autoreclose is cleared. c) If reclose command is sent out, autoreclose module is reset in 4s. When autoreclose is picked up, the discharging conditions are satisfied, autoreclose module is reset immediately and reclose is disabled. If it is caused by unsatisfied synchronism conditions or the others that reclose can not be performed successfully, autoreclose model will be reset with a certain time delay. Under three-phase autoreclose mode, it is the setting delay of three-phase autoreclose +12s. The voltages provided for the CSC-162protection system are always from the bus VT, so the reference voltage is referred to the voltage at terminal Ux for novoltage check or synchronism check. If the line voltages and bus voltages are all larger than the value of voltage setting, the check mode is automatically turned to synchronism check. 5.12.6 Blocking AR condition Relay will block reclose when any conditions occur, at the same time, it gives output of AR Lockout Alarm. a) Distance zone 1 operates when equipment has digital input of CARRIER FAIL. b) Distance zone 1 or pilot operates when the fault occur again after reclosing . c) Distance zone 1 or pilot operates when equipment has digital input of A/R BLOCK .

45


5.12.8 Both series of autoreclose operating at the same time The CB closed state are detected according to trip and current, when two series of autoreclose are set for one breaker and both of them are put into operation, it is impossible for the second autoreclose to take place. 5.12.9The scheme logic of autoreclose The scheme logic of auto reclose is shown in Fig.5-19. AR_3p mode on , if the three-phase occasional mal-tripping occurs, whether starting the reclose or not is determined by the control word, that is the control word of AR_CB3,the AR_CB3 is setuped to 1 to enable autoreclose. The AR_CB3 is setuped to 0 to disenable autoreclose.

AR_CB3

&CB OPEN INITIATE 3PH A/R from 1 to 0

Distance trip

& AR_3p mode

T3p_AR

Reclose

AR_No check AR_check Syn Syn condition meet AR_check low U Low condition voltage

&

&

A/R BLOCK

Fig.5-19 CSC-162automatic re-close logic

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5.13 Broken Conductor Function This function can be enabled by control word of BROKEN COND_FUNC,if the function is enabled ,and relay will check several conditions to judge Broken Conductor ,the conditions as below : 1) |Ia-Ib|or|Ib-Ic|or|Ic-Ia| 0.15In 2) I2 > setting value of 3I2_BROKEN COND 3) T > setting value of T_BROKEN COND 4) no CB OEN digital input Broken Conductor function scheme logic is shown in Fig.5-20. BROKEN COND FUNC |Ia-Ib|or|Ib-Ic| or|Ic-Ia|>0.15In CB OPENI2> 3I2_BROEKN COND

&

T_BROKEN COND

Report&Alarm

Fig.5-20 Broken Conductor Function logic

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6. Installation and commissioning6.1 Unpacking & re-packing

When dispatched from the factory, the equipment is packed in accordance with the guidelines laid down in IEC 60255-21, which specifies the impact resistance of packaging. This packing shall be removed with care, without force to the equipment and without the use of inappropriate tools. The equipment should be visually checked to ensure that there are no external traces of damage. Verify that the conformity certificates, matched documents, accessories are consistent with the order requirements, and ensure that the type, nameplate, numbers of the equipments are perfect and consistent with encasement sheet. The transport packing can be re-used for further transport when applied in the same way. The storage packing of the individual equipments is not suited to transport. If alternative packing is used, this must also provide the same degree of protection against mechanical shock, as laid down in IEC 60255-21-1 class 2 and IEC 60255-21-2 class 1. Before initial energization with supply voltage, the equipment shall be situated in the operating area for at least two hours in order to ensure temperature equalization and to avoid humidity influences and condensation.

6.2 Mounting The equipment ought to be fixed on panel or cabinet, and every connection bolt of the equipment must be firmed. Using earthing coppery wires connect the equipment ground and panel (cabinet) ground with bus line and verify the earthing is reliably. Checking the connection The equipment wiring must meet the requirements of wiring scheme.

6.3 Check before power on

Pull out all the modules, check-up whether the mechanical structure accessory on the board becomes flexible or there are mechanical damages and whether the wiring is fastness. Check the man-machine interface is connected with faceplate reliable. Check the type tag of the equipment on faceplate, the lighting tag, backboard terminal figure, terminal number tag and nameplate label of the equipment is intact and right. Each module withdrawal and insertion are flexible, spaces between module and plug slot are suitable right, and the insertion depth is satisfied. Verify the lock-up is reliable. The slice of current connecter for short circuit ought to be opened reliably when module is inserted. Test insulation resistance in turn between analog circuits and ground, and the circuits to each others every resistance must not be less than 100 M .

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Check with power on Power supply check Testing of voltage output value and its stability: Every class output voltage must be maintained stably as shown in Tab.X when the input voltage of DC power supply is UN. Tab. Rating voltage +5 +12 12 +24 V Permissive range 4.85.2 1113 1113 2226

Give alarm after power off Energized DC power supply, the equipment for loss of power alarm ought to be excited reliably, and its contacts as X11-c16 and X11-a16 must be opened reliably. Cut off rating DC power supply, the relay for loss of power alarm ought to be lost magnetism reliably, and its contacts as X11-c16 and X11-a16 must be closed reliably.

7. Operation7.1 Safety precautions During the equipment tests and start-up, the general safety regulations applicable to electrical systems must be complied with. Failure to comply with these regulations might cause harm to the working staff and damage to property. All the inspections and tests must only be carried out by specially trained personnel. Check the enclosure shell has been grounded reliably and maintain electric continuity to earth. The general safety regulations applicable to equipments must be strictly complied with. Insert or pull out models must be strictly prohibited during the equipment tests and operation. During operation, nobody is allowed to press the keyboard on the panel optionally. During operation, nobody is allowed to operate the following commands: Test DO; Modification and write settings; Set up numbers of running CPU; Change setting zone; Change address used communication net.

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7.2 Dialog with the equipment Setting operation and interrogation of digital protection systems can be carried out via the integrated membrane keyboard and display panel located on the front plate. All the necessary operating parameters can be entered and all the information can be read out from here. For example display, main menu, debugging menu. Operation is, additionally, possible via interface socket by means of a personal computer or similar. 7.2.1 Front view of the relay Front panel adopts little arc streamline and beelines sculpt, and function keys for MMI are reasonably distributed in faceplate. Panel layout is shown in Figure 7-1.

C 162 SC -

R un O at i on per R ose ecl N U ot sed N U ot sed N U ot sed N U ot sed Al ar m

QIT U

SET

F1

F2

F3

F4

+

-

SI O

Figure 7-1 Panel layout of CSC-162 7.2.2 Member of keyboard and display panel The member of keyboard and display panel is externally arranged similar to a pocked calculator. Figure 7.1 illustrates the front view. The significance of the keys is explained in detail in the following.SET

QIT U

Confirmation key, used to setup or confirm

Press this key for loop display. Current screen can be fixed to be displayed (there is a key mark on the right corner of screen, viz. orientating current screen), press again to cancel orientating function. Press this key during menu operation to cancel current operation to return the upper menu. Press this key to return normal display state to operate other key.

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,

,

,

: Selecting key, used to select menu on display panel. Use to move cursor,and

and

: to change content.

R ESET : Used to reset LED of signal and output , return to loop display state.

Four shortcut keys and two function keys under LCD Press one time, prompt Print the latest event report? YES NO If select YES, prompt Format of printed record wave Graph Data to select graph format or data format to print. Another function of key Press to turn screen page downward to view set values. Press one time, prompt Print set values of current setting zone? Another function of key Press to turn screen page upward to view set values. Press one time, prompt Print sampled data? Press one time, prompt Print device information and status? Function key The number of setting group +1. Press one time, prompt Select setting zone to switch: Current setting zone:xx; Switch setting zone: xx. Function key, The number of setting group -1. Press one time, prompt Select setting zone to switch: Current setting zone:xx; Switch setting zone: xx. SIO jack: 9-pin jack to connect external PC is dedicated interface of debugging program CSPC. 7.2.3 LEDs Explanation LED of CSC-162is fixed. From up to down, the left side of LCD of CSC-162are < Run >, , , , , , , and light in turn. (1) < Run >: Lit green under normal operation, flash when protection startup.. (2) , Lit red LED after tripping. (3) , Only for auto re-closure of CSC-162, lit red after operation (4) (5) (6) (7) (8), This is not lit under normal operation. When alarm II (abnormal alarm) is issued, this light is lit constantly and only the corresponding protections are out of service, power supply for protection output is not blocked.

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When alarm I (serious alarm) is issued, this light flash and all protections are out of service, power supply for protection output is blocked. 7.2.4 Menu structure Loop display of screen panel in sequence is: year-month-day, hour: minute: second, Ia, Ib, Ic, 3I0, Ua, Ub, Uc,Ux, P, Q and phasor angle, enabled, current setting zone, channel state. Panel display includes loop display, main menu, debugging menu for leaving factory and window of initiative transporting report. Main menu has 10 terms in total as shown in Tab.7.1-1. Press SET to enter into main menu during loop display. Default operation password is 8888. Tab.7.1-1Main menu OpStatus Status Version Equipcod DI voltage of input 1, voltage of input 2, and output voltage Display device type and version of CPU Device type and version, factory, I/O, Master MMI and CPU RESET, CB OPEN, A/R BLOCK, INITIATE 3PH A/R, B/LBB OPTD, CARR RECEIVED, DIRECT TRIP RECV, CARRIER FAIL, START CBF 3-PH, REM ACCESS BLK, RELAY TEST Ia,Ib,Ic,3I0,IN,Ua,Ub,Uc,Ux IaR,IbR,IcR,3I0R Za ,Zb ,Zc ,Zab ,Zbc ,Zca Press SET select setting zone - press SET to display all setting Binary settings can set 1 or 0. System parameter BayName: Can input actual line name CommAddr Setup address of 485 series ports 10H ~ ABH Ethernet 1: Ethernet 2: Time Made Network mode, pulse mode,IRIGB 9600, 19200, 38400 Sub-menu 1 AI Sub-menu 2 Ia, Ib, Ic, 3I0,IN,Ua, Ub, Uc, Ux, IaR, IbR, IcR, 3I0R Explanation Select CPU number at first Display magnitude Provide for debug worker and engineer to view Display current state of inputs open or close Display magnitude and phasor Complex number, display magnitude Input password firstly NOT USED Setup with ISN or CSPC can not be set to 0, if connected with protocol of CSN, extension address of Ethernet 2 is: 10.10.6.124 Optional network mode, pulse based on GPS Use UP or DOWN to select

Measure Impen.Z Settings ProtSet ProtContWd EquipPara CommPara

BaudR485

52

CSC-162 Numerical Transmission Line Protection Equipment Manual Query Report EventRpt Latest Rpt Last 6 Rpts QueryRpt by Date Last 6 Rpts QueryRpt by Date Latest Rpt Last 6 Rpts QueryRpt by Date Last 6 Rpts QueryRpt by Date Manual Receive reset command to reset SOE Reset Automatic Receive reset command to reset SOE Reset automatically in 10s V1.20 Protocol V1.10 Protocol Press SET to view Press SET to view Ditto Ditto Ditto Ditto Ditto Ditto Ditto Ditto Reset mode can be selected CSC2000 used, This option need not be set if the relay communicates with IEC60870-5103 to be selected, not to be selected

AlarmRpt StartRpt

Log Setup SOEReset

Protocol

SetPrint

103Type ModifyPW ProtSet EquipPara Report Setup Status AI Version Equipcode DI PrtMeasure PrtSample Test DO

Setup for record print: Setup for analog quantities print, such as voltage and current. Setup for I/O print, such as trip and command etc. Print Print record automatically, print binary Mode setting, mode of record print Data or Graph Display current type: F2H Password can be modified Please select setting zone None EventRpt, StartRpt, AlarmRpt ,Log Print Equipment Setup Analog input, version, digital input, system state, system code, strap state Analog input CPU version Equipment code Digital input Print Measure Data Print Sampling Data, select CPU number at first ALARM I, ALARMII, 3-Phase Trip, Permanent Trip, Initiate 3PH A/R,CARR Send CH-1, Direct Trip Send, CARR Fail Alarm, AR TO Close CB, U/V_O/V-1, U/V_O/V-2, Start 3-PH CBF, AR Lockout Alarm, VT Fail, SOTF Alarm, CARR Received, Direct Trip RECV, Weak End Infeed, PSB Alarm Year month day hour minute sec Year month day hour minute sec

RecPrt Setup

Print

Set function coding of IEC60870-5-103 Password of leaving factory: 8888 Connect the printer

Input password at first

Set Time

Current Set

Modify with the key of UP DOWN LEFT RIGHT

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CSC-162 Numerical Transmission Line Protection Equipment Manual Contrast Testing SwSetGrp ViewDrift AdjDrift ViewScale AdjScale PrtSa

Documents

CSC162 Manual [1]