2008_harmonic Filter Web

8/9/2019 2008_harmonic Filter Web

http://slidepdf.com/reader/full/2008harmonic-filter-web 1/54

1

Application of Harmonic Filters Application of Harmonic Filters

JuneJune 20082008

Prepared by B. J. Park

PQ TECH INC.

2

IndexIndex

Design Considerations

Understanding Capacitors

(Construction, Process, Capacitor Types, Tests)

Filter Reactors

What is K factor?

Surge Arrestors

Switching Capacitors

Grounding versus Ungrounding

Banks Protections (Various Protection, Setting Philosophy)

Harmonic Filter Types

Bank Design

Steel Making Plant Harmonics

Case Study for Electrochemical Plant



2

3

Harmonic Filter Design ConsiderationsHarmonic Filter Design Considerations

Various Nonlinear Loads

Harmonic Voltage and or Current can cause damage to equipment

Voltage Current Distortion Guide Line

Harmonic Filter Locations

300

400 75

125

150 150

23kV

380V Bus 1

380V Bus 2

4

Key Filter Design ConsiderationsKey Filter Design Considerations

Reactive Power Requirements

Harmonic Limitations

Background Harmonics

Harmonic Filter Conditions (Ratings)

System Transient, abnormal conditions

Contingency Filter Conditions



3

5

Maximum and Minimum SizeMaximum and Minimum Size

The maximum bank size

a) Change in system voltage upon capacitor bank switching.

b) Switchgear continuous current limitations.

dV is limited in the range of 2%~3%, determined by load flow

The minimum bank sizea) Capacitor bank unbalance considerations

b) Fuse coordination

6

Construction of Capacitor ElementConstruction of Capacitor Element

ALUMINIUM FOIL

5um Edge Fold

Hazed Polypropylene Film

11- 15um



4

7

Air Shower Booth to Access W/R Air Shower Booth to Access W/R

8

RollRoll WindingWinding ProcessProcess



5

9

Extended Foil SolderingExtended Foil Soldering

10

Container TIG WeldingContainer TIG Welding



6

11

ImpregnationImpregnation FacilityFacility

12

ImpregnaImpregnanntt ,, JarylecJarylec C101C101

GoodGood performanceperformance in hin high temperatureigh temperatureLowLow dissipation factor dissipation factor

ExcellentExcellent absorbingabsorbing PDPD--characteristicscharacteristics

The fluid is non chlorineThe fluid is non chlorine biogradablebiogradable and contains no PCBsand contains no PCBs

CH2

CH3

CH2 CH2

CH3

Benzyltoluene 75% Dibenzyltoluene 25%



7

13

Impregnation, Under VacuumImpregnation, Under Vacuum 0.01 torrs0.01 torrs

Impregnant

Filling

Sealing

Drying

0

20

40

60

80

100

0 1 2 3 4

DAYS

T E M P o C

5

14

RoutinRoutinee Test,Test, IEC 60871IEC 60871



8

15

PD Test in Shield Room @ 2.15*UnPD Test in Shield Room @ 2.15*Un

16

Routine Test,Routine Test, IEC 60871IEC 60871

Each capacitor unit undergoes the foll owing:

Leakage test at 60 C for 24 hours

Partial Discharge Test at 2.15 Un

HV tests:

AC terminal t o terminal at 18kV for 10 sec

AC terminal t o case at 38kV for 10 secCapacitance and Dielectric loss angle at Un

Short circuit discharge test at 1.7Un

Internal discharge resistor test



9

17

All -fil m -Low dissipation, hazed, high

energy density

Folded foil – Good perf orm ance to the PD

and transients

Impregnation - Dribble penetration, extra

vacuum levels, long term filling.

Container -1.5mm 430 grade stainless steel,

can be supplied unpainted. TIG welding

Power Capacitor UnitsPower Capacitor Units

18

Harmonic FilterHarmonic Filter Capacitor Capacitor ss

D

Film

FoilExtended Foil

D

UE0



10

19

Between voltage gradient and failure rate, and assumed life can be described as

Assumed LifeVoltage Gradient

Failure rate

Where:L =Expected life

N = Number of elements

λ = Failure rate (0.01%/year)

Eo= Designed Voltage GradientE = Actual Voltage Gradient

α = Constant for Voltage Gradient (α = 6 ~17)

Capacitor Life ExpectancyCapacitor Life Expectancy

( )

-α

E o

E λ N L ⎥

⎦

⎤⎢⎣

⎡=

20

Many connection, fuses, more hands, degrade insulation, cost

Possible to continuing service after few fuses brownUnit rating around 10kV

Internally Fused Capacitor UnitInternally Fused Capacitor Unit



11

21

Unit rating 15~25kV

Externally Fused Capacitor UnitExternally Fused Capacitor Unit

22

All strings must be separated / simple process / good joint foil electrodes at dielectric fault

FuselessFuseless Capacitor UnitCapacitor Unit



12

23

Yes, but the is co ncern

the oil contamination

Europe

Less

Lower

No(hazard)

Smaller

6P12S

Higher

Impossible

Fuseless

Yes, but the is con cern

the oil contamination

Europe / Asia

No

Amer ica / A sia

Higher

Higher

yes

Higher

6P 12S

Lower

Easy to find

Externally

Fused

Less

Lower

No(hazard)

Smaller

12S 6P

Higher

Impossible

Internally Fused

Connection (example)

Replace cost

Visual check for faulty unit

Protection for terminal to c ase

fault

Popular using Area

Cost of protection

Sensitivity of unbalance

Continuing service of uni t at a

roll faulty

Delta C by faulty roll

Features & Types

Types of Capacitor UnitTypes of Capacitor Unit

24

Filter Capacitor Specification ExampleFilter Capacitor Specification Example

Rated voltage 9008 [V]

Rated curr ent 87.48 [A]

Rated output 788 [kVAr]

Type All film

Rated capacity 788 [kVAr]

Rated capacitan ce 30.91 [uF]

Rated frequency 50 [Hz]

Insulation level 30 [kVrms], 95 [kV BIL]

Number of phase Single Phase

Number of bushing 2

Dielectric Synthetic polypropylene filmElectrodes Fold/Laser cut aluminum foil

Impregnate with Non-PCB dielectric fluid

Protection method Internally fused

Painting color Munsell No. 5Y7 / 1

Painting method Vapor cure double layers Epoxy coated

Discharge device Built in resistors

Discharge time / unit <50V within 5 [min]

Standards IEC60871-1, 60871-2, 60871-4

Case material Stainless Steel 1.6 [mm]

Fixing hanger bracket 2 EA for both side

Continues allowable overvoltage 110 [%] Un

Maximum permissible kVAr 135 [%]

Tolerance of capacitance -0 ~ +15 [%] at 25 [

]



13

25

Probability of 2Probability of 2ndnd failure for Each Typesfailure for Each Types

IEEE summer meeting 1997IEEE summer meeting 1997

[1]>[2] 2nd Failure in the Same group

[1]>[11] 2nd Failure in the another group

26

24

26

6.40

6.20

λ

for [1]>[11]

“Random”

% / year

0.0150.4Fuseless

(Internal String)

132kV, 36 MVAr

Y-Y connection5

0.0452.6Fuseless

(conventional)

132kV, 36 MVAr

Y-Y connection4

0.0100.26Internally fused132kV, 36 MVAr

Y-Y connection3

0.0220.57Externally fused33 kV, 9 MVAr

Y-Y connection2

0.0100.26Internally fused33 kV, 9 MVAr

Y-Y connection1

Δ

c/c

%/ Year

λ

for [1]>[2]

“ Avalanche”

% / year

Capacitor TypeBankCase

26

Filter ReactorsFilter Reactors

Magnet wire is copper wire which has been coated (or enamelled) with a very thin layer of insulating material



14

27

Filter ReactorsFilter Reactors

28

10.1151.596

0.0160.0000.00525

0.0340.0000.00823

0.0160.0000.00621

0.0440.0000.01119

0.0940.0000.01817

0.0810.0000.01915

0.1060.0010.02513

0.3400.0030.05311

0.1570.0020.0449

0.7900.0160.1277

3.5530.1420.3775

3.8880.4320.6573

1.0001.0001.0001

I2 x h2I2Current (Pu)Harmonic

Ex)K factor = 6.34 PEC-R= 8% (Eddy current loss factor) I rms = 0.85 (pu)

2

2

h

h

I hK

I = ∑

∑

2

1

1

ECR

rms ECR

P I

KP

−+=

+´

What is K factor?What is K factor?

IEEE C57.110IEEE C57.110--19861986



15

29

Typical Air Core Dry Type Reactor Typical Air Core Dry Type Reactor

30

Magnetic ClearanceMagnetic Clearance



16

31

Filter Reactor Specification ExampleFilter Reactor Specification Example

Type Air Core, 6 [%]

System Voltage 132 [kV]

Rated Frequency 50 [Hz]

Rated Induc tance 59.0 [mH]

Rated Current 262.43 [A]

Insulation Level 275 / 650 [kV]

Number of Phase Single Phase

Temperature Rise 60.5 [

]

Color Munsell No. 5Y7 / 1

Standards IEC 289

Frame and Structure

Reactors shall have mechanical and electrical strength and it s hall be painted with Munsell No. 5Y7 / 1.

Installation Outdoor

Cooling Air-cooled with natural convection

Impedance calculation of the bank

Zf for Fundamental Frequency, Xcf = 308.94 Ohm, Xlf = 18.54 Ohm, Zf = 290.4 Ohm

Z5 for 5th harmo nic Fr equency, Xc5 = 61.79 Ohm, Xl5 = 92.7 Ohm, Z5 = 30.91 Ohm

Tests

The tests are carried out by manufactur er accordance with standard IEC 289.

The reports are attached herein.Routine tests

Measurement of windi ng resistance

Measurement of impedance at continuo us current

Separate source voltage with stand test

Induced over voltage withstand test

Type tests

Temperature ri se test

Lightning impulse test

Marking IEC 289.16

32

Surge ArrestorsSurge Arrestors



17

33

To prevent capacitor failures at a breaker restrike or failure.

To limit the risk of repeated breaker restrikes.

To prolong the service life of the capacitors by limiting high overvoltages.

To serve as an ”insurance” against unforeseen resonance conditions which otherwise

would lead to capacitor failures.

For overall limitation of transients related to capacitor bank switching which can be

transferred further in the system and cause disturbances in sensitive equipment.

For upgrading of capacitors by preventing high overvoltages and/or for increasing theservice voltage.

To serve as protection against lightning for capacitor banks connected to lines.

Using Surge ArrestorsUsing Surge Arrestors

34

Arrestor Positioning Arrestor Positioning

Continuous operating voltage

Rated voltage

Energy capability



18

35

Arrestor Positioning Arrestor Positioning

ExampleSystem voltage: 36 kV

Fault clearing time:10 s or lessSystem grounding: Ungrounded

Capacitor bank connection: Ungrounded wyeRated 3-phase power: 18 MVAr

Desired protective level : 2,4 p.u.

Summary of required arrester data for connection Phase-ground:

Rated voltage: 33 kV or moreProtective level at 3kA: 64,7 kV or less (switching surge)

Energy capability for capacitor discharges:2,8 kJ per kV rated voltage or more

Summary of required arrester data for connection Phase-neutral:Rated voltage: 33 kV or moreProtective level at 3kA: 69 kV or less (switching surge)

Energy capability for capacitor discharges:3,2 kJ per kV rated voltage or more

36

High duty-cycle

Most circuit breakers and protective devices operate a few times in their

entire life span.

Switch for capacitor bank gets to operate every day, sometimes several

operations per day.

Voltage spikeWhen capacito r swi tches do operate, they generate undesirable voltage

surges, which if unmitigated, can cause problems in Power Quality to the

users.

Re-strike

Common concern for older switching technologies.

Switching Capacitor BanksSwitching Capacitor Banks



19

37

Continuous current

ungrounded neutral banks – 1.25 times the nominal current

grounded neutral banks – 1.35 times the nominal currents

Inrush current dur ing energization

Nominal system voltage

Transient recovery voltage during de-energization

Switches must be capable of withstanding inrush current

Ipk = Peak of Inrush cur rent

Isc = available three phase fault current

I1 = capacitor bank current

141.1 I I I sc pk ⋅=

The Key Considerations for Switchgear The Key Considerations for Switchgear

38

Inrush current during back to back switching

Fs = system frequency in Hz

Ft = frequency of transient in kHz

Leq = total inductance between two banks in micro -henries

I1, I2 = being sw itched, already energized banks cur rents in A

VLL = line to line vol tage in kV

)(

)(1747

21

21

I I L

I I V I

eq

LL pk ⋅

⋅⋅=

)(

))()((5.9

21

21

I I L

I I V f f

eq

LLst ⋅

+⋅=




20

39

Several hundred meters between overhead capacitor banks is usually an adequate

separation distance to limit the inrush current to an acceptable level, but configurationswhere the banks are very close together may require inrush current limiting reactors.

When switching is done at nominal system voltage, the switch recovery voltage reaches 2.0

per unit for a grounded-wye-connected bank and 2.5 per unit for an ungrounded-wyebank.


Ec = Peak System Voltage

To = Beginning of Switching Opening

T1 = First Current Zero

T2 = 1/2 Cycle After First Current Zero

T3 = Switch Completely Opened

Switching Recovery Voltage

40

The 6% inductor to the capacitive reactance has been widely usedThe 6% inductor to the capacitive reactance has been widely used ,,

to reduce the inrush current less than 5 times the nominal curr eto reduce the inrush current less than 5 times the nominal curr entsnts

LC o

1=ω

LC Z Z =× 06.0

ω ω

1,11 =Ω== C C

Z C

)(sin t Z

V i o

o

o ω =

ω

ω ω

ω ×=

×

= 1.406.01

1o

ω

ω

06.0,06.0 =Ω== L L Z L




21

41

ITI CurveITI Curve

42

Synchronous Type Circuit Breaker Synchronous Type Circuit Breaker

P1 : Graphs

0.1825 0.1850 0.1875 0.1900 0.1925 0.1950 0.1975 0.2000 0.2025 0.2050

-200

-150

-100

-50

0

50

100

150

200

y

Ap

A

B

C

Switching Sequence_ Ungrounded Capacitor Banks



22

43


Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y

step1-Ia step1-Ib step1-Ic

-300

-200

-100

0

100

200

300

y

Ap

Without Series Reactor Without Series Reactor

44


With 6% Series Reactor With 6% Series Reactor

Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y


-300

-200

-100

0

100

200

300

y

Ap



23

45

Conventional Circuit Breaker Conventional Circuit Breaker

Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y


-300

-200

-100

0

100

200

300

y

Ap

kA

kV

Without Series Reactor Without Series Reactor

1.6 Per unit peak

65 kA peak

46

Conventional Circuit Breaker Conventional Circuit Breaker

Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y


-300

-200

-100

0

100

200

300

y

Ap

With 6% Series Reactor With 6% Series Reactor



24

47

General Control StrategyGeneral Control Strategy

grounded neutral, the three poles

should close in succession with a

time separation of 1/6 cycle

(3.3 ms at 50 Hz or 2.8 ms at 60 Hz).

ungrounded neutral, two poles

should close simul taneously at

phase - phase voltage zero,

and the last o ne 1/4 cyc le later (5ms at 50 Hz or 4.2 ms at 60 Hz).

48

The advantages of the grounded w ye compared to the ungrounded

Initial cost is lower, the neutral does not needed to ful l system B IL

Recovery voltages are reduced

Mechanical duties less severe for the structure

Low impedance path to ground for ligh ting gives self protection from sur ge

System & cap bank be grounded at 121kV above _ IEEE C37.99-2000

The disadvantages of the grounded wye compared to the ungrounded

Higher inr ush curr ent may occur i n ground, it is needed NGR

Zero sequence harmonic current may draw to the ground

Usually m akes current lim iting fuses due to l ine to ground fault

GroundedGrounded vsvs UngroundedUngrounded



25

49

SR Location and Insulation CostSR Location and Insulation Cost

2nd

0 . 0 9 2 8 [ H ]

A _ c ur r

0 .2 1 [ oh m ]

3 7 . 9 4 [ uF ]

A_

c a p_

u

0 . 0 1 [ oh m ]

0 . 0 1 [ oh m ]

0 . 0 1 [ oh m ]

1 [ohm]

A_rr

3 7 . 9 4 [ uF ]

A_

c a p_

d

2nd

0 . 0 9

2 8 [ H ]

B _ c ur r

0 .2 1 [ oh m ]

3 7 . 9 4 [ uF ]

e_s

0 . 0 1 [ oh m ]

0 . 0 1 [ oh m ]

0 . 0 1 [ oh m ]

1 [ohm]

B_rr

3 7 . 9 4 [ uF ]

B_

c a p_

d

B_

r

A_

n g

B_

n g

Main : Graphs

0.00 0.10 0.20 0.30 0.40 0.50

0.0

2.5k

5.0k

7.5k

10.0k

12.5k

15.0k

17.5k

20.0k

y

A cap u B r

Main: Graphs

0.00 0.10 0.20 0.30 0.40 0.50

0.0

1.0k

2.0k

3.0k

4.0k

5.0k

6.0k

7.0k

8.0k

9.0k

10.0k

y

A_cap_d B_cap_d

Main: Graphs

0.00 0.10 0.20 0.30 0.40 0.50

0.0

2.5k

5.0k

7.5k

10.0k

12.5k

15.0k

17.5k

20.0k

y

e_s A_cap_u

Reactor Bushing Potential

Capacitor Bushing Potential

Capacitor Bushing Potential

50

Unbalance detection means ;

An in ternal element fai ls

→

voltage distribution & current flow c hange within a bank

Magnitude of changes

externally fused > internally fused

Purpose of the unbalance protection ;

alarm or disconnect the entire capacitor bank when morethan 10% over vol tages across the healthy capacito rs

More consideration required for ;

Types of unbalance protection

Over currents

Over & under voltage

Protecting the Harmonic Filter BanksProtecting the Harmonic Filter Banks



26

51

Neutral current

Neutral voltage

Current unbalance between neutrals

Phase voltage unbalance

Voltage difference

Current unbalance in br idge connection

Types of Unbalance ProtectionTypes of Unbalance Protection

52

Sensing Neutral Current & VoltageSensing Neutral Current & Voltage

Neutral Current Neutral Voltage

Star Connection with Neutral Grounded

Through a Current Transformer

Star Connection with Voltage Transformer

Between Neutral and Ground



27

53

Sensing dV & Current UnbalanceSensing dV & Current Unbalance

Voltage Difference Current Unbalance in

Bridge Connection

Star Connection with Grounded Neutral

and Voltage Transformers Connected in

differential Measurement

Bridge Connection

54

Sensing Unbalance Current & VoltageSensing Unbalance Current & Voltage

Current Unbalance Between

Neutrals

Phase Voltage

Unbalance

Double Star Connection wi th Ungrounded

Neutral

Star Connection with Ungrounded Neutral

and Voltage Transformers Connected in an

Open Delta



28

55

Summary of Capacitor Protection Methods Reference IEEE C37.99

Various schemes used,

suitability depends on banks

arrangements

Unbalance sensing with cu rrents or

voltage relays

Instantaneous relay action

necessary to limit fault damage

Unbalance relaying

Over current relayRack faultRack fault

To reduce inrush current

required series reactor

Switched or fixed impedance in

series with cap. BankInrush currentInrush current

Proper bank design Limit

number of cap. Unit

Individual unit fuse

Proper bank designDischarge current fromDischarge current from

parallel connected unitparallel connected unit

Not suitable for unmanned

substation for system overvoltages

Visual inspection phase overvoltage

relay

Continuous capacitorContinuous capacitor

unit over voltageunit over voltage

Coordination provided by

manufacture

Individual unit fuses (Expulsion or

current limiting)Over current due to unitOver current due to unit

failurefailure

Grounded capacitor banks

partially reduce surge voltageSurge arrestersSystem surgeSystem surge

Conventional methods applySupply breaker with OVR Power

fusesBus faultBus fault

RemarksRemarksType of ProtectionType of ProtectionConditionCondition

Summary of the Capacitor Banks ProtectionSummary of the Capacitor Banks Protection

56

1.01.0 1010 100100 1,0001,000 10,00010,000

Currents in amperes (Currents in amperes (r.m.sr.m.s.).)

1,0001,000

100100

1010

1.01.0

0.10.1

0.010.01

Time in SecondsTime in Seconds

Low probabilityLow probability

of case ruptureof case rupture

High probabilityHigh probability

of case ruptureof case rupture

Paper or paperPaper or paper

film dielectricfilm dielectric

All fil m di elect ric All fil m di elec tri c

Case Volum e 30,000CmCase Volum e 30,000Cm33

Typical Case Rupture CurvesTypical Case Rupture Curves



29

57

Meters A, V, Var, MVA, MW, pf, Hz

SCADA - Var and Voltage contro l

Main Bus

Sub Bus

TC

CC

C / T * 3

Ground SW

Arr ester s

Capacitor S. W

60MVAr

Capacitor

Bank

4 Levels of Unbalance Protection

4 Levels of Instantaneous OCP

Reactor Over Load TD Protection

Under Currents TD protection

Measurements Last Trip Record

Remote Control for Trip & Closing

Reactors

Neutral

Resistor

ID for

Faulty

Phase

PT 3P

In- Sensitivity 0.005A

51Q, 51G, 51N - 3Vo, 3V1, 3V2, 3Io, 3I1, 3I2

Event Waveform Oscillogr aph

Breaker Failure Detection

Failure Target for Each phase Group

Meters and Indicators for Alarm

Battery Voltage Measurement

1 Serial ports

1 Front, 3 rear

- integrating

relays to SCADA

An example Protection Scheme An example Protection Scheme

58

Conventional

3CTs

2P + 2P

Balanced DY

665kVAr, 96EA

ID faulty side, to be

checked 48EA for a

side

Advanced prot ecti on

7 CTs (KEPCO)

2P+2P

Balanced SYDB

665kVar, 96EA

ID the faulty phase,

to be checked 32EA for

a phase

Advanced prot ecti on

6 CTs

2P+2P

Balanced SYDB

665kVar, 96EA

ID the faulty phase,

to be checked 32EA fora phase

Conventional

1 CT

2P(L) + 1P(R)

Unbalanced DY

887kVAr, 77EA

Fail only, to be

checked 77EA forwhole bank

Grounded YY (Single Y Double Br)Grounded YY (Single Y Double Br)Grounded YGrounded Y--Y (Double Y)Y (Double Y)

Ungrounded YY (Single Y Double Br)Ungrounded YY (Single Y Double Br)Ungrounded YUngrounded Y--Y (Double Y)Y (Double Y)

NGRNGR

Various ConfigurationsVarious Configurations



30

59

Filter Capacitor BankFilter Capacitor Bank

60

Overview of Capacitor Banks ProtectionOverview of Capacitor Banks Protection

Aim of Unbalance Protection (Alarm, Trip)Isolate faulty capacitor banks

To prevent any of healthy units exposed to over than 110% of Un

Inherent unbalance current, Sufficient delay time to override external disturbances.

Overload Protection is to Protect from (Alarm, Trip)

Overcurrent, harmonic current, OvervoltageThe trip stage is based on the IEEE Std. C37.99 IEC60871-1 inverse time characteristics

Overcurrent Earth Fault Protection, Should be ConsiderSwitching inrush current

Time delay to clear the fuseSingle phase numerical type, standard inverse time

Overvoltage Protection is to Protect from the System Power Frequency Overvoltage

Undervoltage Protection, to trip the bank loss of system voltage, should be considered

Reenergizing capacitor bank with a trapped chargeEnergizing a cap bank without parallel load through a previously unenergized transformer

Delay time to override external faults



31

61

List of Relay UsedList of Relay Used

SWITCHSYNC

E113 ABBF25-POWPoint on Wave device7

KVGC 202 ALSTOMF90-AVC Automatic Volt age

Controller 6

KVFG 142 AREVAF27=UVUnder-voltage Interlock Relay5

P 922S AREVAF27-UVUnder-voltage protection4

P 922S AREVAF59-OVOver-voltage pr otection3

SPAJ 160C ABBF51 –UB &

F49- OL

Capacitor Unbalance

&Over-load pr otection2

P 123 AREVAF50/51OCOver-current & Earth

Fault protection1

TypeManufacturer DesignationFunctionNo.

62

Protection Scheme & Coordination PlotProtection Scheme & Coordination Plot

Protection Scheme for 132kV 60MVAr



32

63

Features of Protection RelayFeatures of Protection Relay

Current Unbalance and Over Current Unbalance and Over --load Protection [ABB SPAJ 160C]load Protection [ABB SPAJ 160C]

Current Unbalance Relays (-F51UB)

The relay receive the signal through neutral current transformer.

Two stages of alarm provided. If any capacitor element fails, the relay shall set to

alarm (Stage 1) at appropriate value and to trip (Stage 2) the capacitor bank if the

110% rated voltage appears on any remaining units in the same unit.

Over-load Relays (-F49OL)

Both inverse time current characteristic and definite time characteristic are

provided.

Two stages of operation for alarm and tripping are also provided

64

Over Over --current and Earthcurrent and Earth--Fault Protection (F50/51OC) [AREVA P123]Fault Protection (F50/51OC) [AREVA P123]

Over-current Relays (-F50/51)

Relays are of the three-single phase numerical type with both definite time and

standard inverse time characteristic and with an independent measuring unit for

each phase.

Earth fault Relays (-F50N/51N)

Relays are single-phase numerical type with both definite time and standard

inverse time characteristic and with an independent measuring unit for each

phase




33

65

Over Over --volt age and Under volt age and Under --volt age Protection [AREVA P 922S]volt age Protection [AREVA P 922S]

Over-voltage Relays (-F59OV)

Time delay of both inverse time and definite characteristics types are provided.

The relay should be provided for tripping off the capacitor bank in case of

overvoltage condition occurring in the system such as due to sudden load loss.

Under-voltage Relays (-F27UV)

Voltage Input is taken from existing voltage selection scheme / busbar VT. If there

is no busbar VT then it is required that the voltage is taken from capacitor side VT,

with is supplemented with a blocking logic as below.

The relay should be provided for tripping off the capacitor bank in case of

temporary loss voltage such as during the line auto-reclosing, to prevent re-

closing of capacitor bank before the capacitor is fully discharged.


66

Setting PhilosophySetting Philosophy

Over Over --current and Earth Fault (current and Earth Fault (--F5l OCEF) [AREVA P123]F5l OCEF) [AREVA P123]

The -F51 OCEF relay shall be set to operate as fast as possible in the occurrences of short circuitin the capacitor bank feeder since down-stream coordination are not required.

Characteristics of the -F51 OCEF relays will be determine from coordination studies. Both definitetime (DT) characteristic and IDMT-Extremely Inverse Characteristic are used to protect thebank.

Time over-current relay (510C) - For a shunt capacitor bank, pickup setting 130% (IEEE std37.99-2000; the desirable minimum pickup is 135% of IN for grounded wye banks and 125% of INfor ungrounded banks) of rated current of the capacitor bank is proposed. Selection of time

delay characteristic is based on coordination study. Both definite time and inverse timecharacteristic with time multiplier setting (TMS) higher than their respective overloadcharacteristics is recommended.

Instantaneous over-current relay (50OC) - For shunt capacitor bank, pickup at least 1.15 timespeak inrush to override inrush transient. (IEEE std. C37.99-2000 clause 7.2.3)

Time over-current relay (51 EF) - The capacitor bank is not grounded hence sensitive EF shouldbe set to 20% pickup with the same operating time as OC elements to detect and to providefast clearing for ground faults.

Instantaneous over-current relay (50EF) - Same as 51 OC or defeated if setting range notavailable.



34

67

Unbalance and Overload (Unbalance and Overload (--F5l UB/F5l UB/--F49OL) [AB B SPAJ 160C]F49OL) [AB B SPAJ160C]

F49OL - This is a protection against over-voltages and harmonics current. Capacitor shall be able

to carry continuous over-load current of 130% the rated current including due to harmonic andmaximum voltage variations. The over-voltage trip start setting should be at 110% of capacitor

bank rating, utilizing overload curve (at 1.1 pu). The alarm setting shall be at 110% of overloadstart setting with a time delay of 60 seconds and trip 115% with time delay 0.2seconds

F5l UB - The time delay of the unbalance relay trip should be minimized to reduce damage from anarcing fault within the bank structure and prevent exposure of the remaining capacitor units to

over-voltage conditions beyond their permissible limits.

Setting shall be followed by Annex 4) which is analyzed that the unbalance neutral current, andbased on over-voltage limit (per capacitor unit) when the internal fuse has blown up to three

elements, the terminal voltage of the faulty unit capacitor is less than 103.1% of Un.

Setting shall also be confirmed / compensated with neutral unbalance current afterexercitation. (with measurement)


68


Characteristic of the overload curve is related to over-voltage characteristic of ANSI-

1990 and IEC 60871-1. 1997 as tabulated below.

ANSI 1036-19926 cycles0.102.20

ANSI 1036-199215 cycles0.272.00

ANSI 1036-19921.00 s0.901.70

ANSI 1036-199215.0 s13.51.40

ANSI 1036-199260.0 s54.01.30

IEC 60871-1. 1997300 s2701.20

IEC 60871-1. 19971800 s16201.15

Standard durationTime (s)Overload



35

69


Under & Over Under & Over --voltage (voltage (--F27UV/F27UV/--F59OV) [AREVA P922S]F59OV) [AREVA P922S]

F59OV - This protection as backup for the main protection. Inverse characteristic shall becoordinated with the allowable range as tabulated below. Alternatively, a definite time

characteristic can be used with pickup at the maximum system voltage limit (+10%). Operatingtime shall be coordinated wilt the AVR setting.

1min1.30

Voltage rise at light load5min1.20

System voltage regulation and fluctuation s30min in

every 24h1.15

System voltage regulation and fluctuation s8h in

every 24h1.10

Highest average value during any p eriod of

capacitor service.Continues1.00

Power Frequency

ObservationMaximum

Duration

Voltage factor

Un VrmsType

Capacitor allowable over-voltage range is as table 6 from IEC 60871-1. 1997 as follows

70

F27UV - Under voltage protection can be used to trip the capacitor bank and to block CB closingwhen its residual voltage is still high before being discharged after disconnection. The

tripping function may be required if loss of system voltage. VT source should be taken from

the busbar voltage selection to avoid blocking during normal closing if VT source fromcapacitor bank side.

Residual voltage allowable for capacitor discharging is less than 50Vdc from initial voltage of √2

of the rated voltage (Un). For this project, the bank is designed to reduce the residual voltageless then 50Vdc within 5 minutes. The manufacturer should provide discharge time to 50V inthe instruction manual or rating plate.




36

71

Au tom atic Volt age Control ( Au tom atic Volt age Control (--F90AVC)F90AVC)

System operations shall advise the bandwidth setting. The setting depends on the local system

condition. Typical operating system voltage is between 1.0 to 1.05 p.u. The AVR setting for132kv system is recommended to regulate the system voltage between the normal operating

range. Recommended time delay to be set is 30s.

As per the operating experience we recommend the programmable timer setting, the daily closingtime is at 08:00 and opening time is at 23:00, it shall be determined by the system operator.


72

Fault Level Calculation ExampleFault Level Calculation Example



37

73

Fault an AMPG Bus Under Peak LoadFault an AMPG Bus Under Peak Load

-79.625832.6TOTAL FAULT CURRENT (AMPS)NA

0.000.0TO SHUNT (AMPS)

999990.0049.35-82.404269.9 AMP/OHM213275.00 AMPG27588215

999990.0049.35-82.404269.9 AMP/OHM113275.00 AMPG27588215

5.91780.412.77-80.374319.4 AMP/OHM213132.00PMJU13288175

5.91780.412.77-80.374319.4 AMP/OHM113132.00PMJU13288175

4.20876.631.12-72.512692.9 AMP/OHM213132.00TWSA13288137

4.20876.631.12-72.512692.9 AMP/OHM113132.00TWSA13288137

5.91980.412.60-81.821661.4 AMP/OHM213132.00KLJTI13288121

5.91980.412.60-81.821661.4 AMP/OHM113132.00KLJTI13288121

APP X/R AN(Z+)/Z+/ AN(I+)/I+/I/ZCKT AREAX-----------FROM--------------X

THREE PHASE

FAULT

AT BUS 88120 AMPG132 132.00 Area 13 (kV L-G) V+: / 0.000/ 0.00

THEV. R, X, X/R : POSITIVE 0.00360 0.0168 4.605

PSSE/E SHORT CIRCUIT OUTPUT MON, MAY 16 2005 17:16 HOME BUS is 88120

2007 PEAK LOAD CASE AMPG 132.00

FAULTED BUS IS 88120 (AMPG132 132.00) 0 LEVELS AWAY

50 kA500kV

40/50* kA275kV

31.5 kA132kV

Short Circuit RatingVoltage Class TNB Planning criteriaTNB Planning criteria

74

Construction of the Unit Capacitor Construction of the Unit Capacitor Construction of t he Unit Capacitor

Rating : 9kV 1P 50Hz 591kvar, 23.18uF, 65.6A

Construction : 6Series x 10Para (60 Rolls)

Eco : 13.91uF Discharge Resistor : 375kΩ x 6 series =2.25MΩ

Fuse : 0.4Φ

Cupper Wire,Fuse Total length 20mΩ,

Fuse operating Length 13.5mΩ

Unit Capacitor

DischargeDischargeResistor Resistor

13.91uF

Unbalance CalculationUnbalance Calculation



38

75

Unbalance current and overvoltage characteristicsUnbalance current and overvoltage characteristics

99.612,971103.113,3141372,959357m3

99.812,888101.813,1501222,630214m2

99.912,901100.813,0201102,36993.8m1

100.012,912100.012,9121002,1522.76m0

Sound group

Unit % of Un

Sound group

unit VT-T[Vp]

Faulty Unit

% of Un

Faulty unit

VT-T[Vp]

Faulty Element

of Un

Faulty Element

Group [Vp]NCT [Ap]

No. of

faults

76

Typical Air Core Dry Type ReactorTypical Air Core Dry Type Reactor



39

77

Al lowable Overload Current for Reactor Al lowable Overload Current for Reactor

78

Typical Case Rupture Curve for ALL Film CapTypical Case Rupture Curve for ALL Film Cap

Typical case rupture curve for approximately 1800 cubic inchesTypical case rupture curve for approximately 1800 cubic inches-- case volume the dielectriccase volume the dielectric

material with Polypropylene film (ALL PP) quoted from IEEE Std.material with Polypropylene film (ALL PP) quoted from IEEE Std. 10361036--19921992

S’s typical clearing time of the internal fuse



40

79

Harmonic Filter TypesHarmonic Filter Types

80

Current Transformer

2:2A 20VA

R S T

Configurations of Single LineConfigurations of Single Line DwgDwg ..

9 Series / phase

4 Parallel / phase

9s x 4p x 3 = 108 Cans



41

81

Key Rating FactorsKey Rating Factors

/(1 )c pV V α = −

/ L c X X α =

2( / ) (1/(1 )) L eff

Xc V Q α = × −

/ 3P L

V V =

2(1/ ) L C X h X = ×

21/ hα =

L C X X α = ×

(1/(1 ))cphase pV V α = × −

/cunit cpha seV V Ns=/( /(1 ))

sr pV V α α = −

Three PhaseThree Phase -- Single PhaseSingle Phase

VLVsr

Vp

Vcphase

/(1 )cap eff

Q Q α = −

/capunit cap cap

Q Q N =

sr cap eff Q Q - Q=

82

Harmonic Filter designHarmonic Filter design

2

LLsys

eff

eff

kV X =

Q (Mvar)

2

21

C eff

h X X

h

⎛ ⎞= ⎜ ⎟−⎝ ⎠

2

C L

X X

h=

Xeff is the effective reactance of the harmonic filter,

Qeff is the effective reactive power (Mvar) of the harmonic filter,

VLLsys is the nominal system line-to-line voltage,XC is the capacitive reactance of the harmonic filter capacitor at the fundamental frequency,XL is the inductive reactance of the harmonic filter reactor at the fundamental frequency,

h is the harmonic number.



42

83

Numerical ExampleNumerical Example

A 30 MVA industrial load is supplied from a 34.5 kV bus.

The three-phase fault level at the bus is 10.0 kA rms symmetrical.

The load has a power factor of 0.85. It is desired that the power factor be raised to 0.95.

The load is a source of harmonic current.

The magnitude of the harmonic current suggests that the capacitor should be designed as a

harmonic filter.

Qeff (in kvar) = (multiplying factor)(load power in kilowatts)

Qeff = (0.291)(30 000 kVA)(.85) = 7420 kvar

84


Because of Phase shift of h component



43

85


86




44

87

Harmonic Current EstimationHarmonic Current Estimation

jXL Rs

-jXC Xs

Ih

88

Configurations of 132kV 60MVArConfigurations of 132kV 60MVAr

(Ungrounded Double Y) Side view(Ungrounded Double Y) Side view



45

89

Configurations of 132kV 60MVArConfigurations of 132kV 60MVAr

(Ungrounded Double Y) Front view(Ungrounded Double Y) Front view

90

Steel Making Plant HarmonicsSteel Making Plant Harmonics

Changing cycle by cycleInterharmonics

Design Filter is not traditional

Interharmonics ->torsional and mechanical resonance



46

91


92

Steel Making FacilitiesSteel Making Facilities

Important Categories

Characteristic harmonics

Derive loads in the rolling mill

Non-characteristic harmonics

Third harmonic component

Even harmonic components

Shorter duration than conventional but important

Interharmonics

Fluctuating EAF, Cycloconverter

Should be capable of measurement

Statistical characteristics of the harmonic levels



47

93

Steel Making FacilitiesSteel Making Facilities

Statistically evaluation for interharmonic

12 cycles sample, bin size of 5Hz

Cumulative probability distribution

Specific values can be determined the distortion levels

Vh95%

VTHD95%

Vh99%

VTHD99%

Ih95%

ITDD95%

Ih99%

ITDD99%

The harmonic filters should not magnify interharmonic components,resulting in excessive levels.

94


Example filter design for arc furnace installations.



48

95

Case Study for Electrochemical PlantCase Study for Electrochemical Plant

System Problems

The utility side transformer has excessive audio frequency noise and overheats.

Voltage THD on the 22 kV system is 7.7%, exceeding limits in IEEE Standard 519.

The rectifiers incur thyristor phase control malfunctions due to voltage sensing errors.

Utility and customer capacitor banks incur over currents and excessive noise.

Complaints are generated from adjacent customers due to device malfunctions, and in particular,standstill conditions created at a precision electrical facility

Increasing System Reliability Using Series TunedIncreasing System Reliability Using Series Tuned

Harmonic Filter Banks in a Chemical FacilityHarmonic Filter Banks in a Chemical Facility

16th Annual Power Quality Conference

October 25th -27th 2005

Baltimore Convention center

96


Utility Data

The normal Utility operating voltage is approximately 154 kV.

The Utility three-phase short circuit MVA is 1,400 MVA, with an X/R ratio of 10.

The 45 MVA supply transformer has a primary delta and secondary ungrounded wye windingarrangement, and a 5% impedance.

The incoming line distance from utility is indeed 0.75 km, composed with single core copperconductor 400 mm2.

22.9kV line has two sets of the capacitor banks 5MVAr, 6% SR



49

97


Ratings of Rectifier Converter

No.1 rectifier 5,810kW 3,210kVAr 6-pulse thyristor converter



No.4 rectifier 2,100kW 820kVAr 6-pulse thyristor converter

98


Plant System with 6% SL Capacitors

UTIL 1400MVA

D-Y

154/22.9kV

45/65MVA

Z=5%

D-D

22.9/6.6kV

9MVA, 7%

D-D

22.9/3.3kV

5MVA, 7%

3.7MW

950kVAr

3.7MW

950kVAr

300kVA

6.3Ohm

5MVAr

22.9kV

CU500mm2

500mCU400mm2

750m

PCC

KPC23kV

DSN

PKCOM23

300kVA

6.3Ohm

5MVAr

22.9kV

6% Series

Reactors

22.9kV

1400kVAr

22.9kV

1500kVAr

22.9kV

900kVAr

D-Y

22.9/0.22kV

7.5MVA, 7.5%

D-Y

22.9/0.22kV

8.6MVA, 10%

D-Y

22.9/0.22kV

7.5MVA, 10%

D-Y

22.9/0.22kV

2.3MVA, 5.5%

5.8MW

3.21MVAR

6.1MW

4.91MVAR

5.8MW

3.21MVAR

2.1MW

0.821MVAR

UTIL 1400MVA

D-Y

154/22.9kV

45/65MVA

Z=5%

D-D

22.9/6.6kV

9MVA, 7%

D-D

22.9/3.3kV

5MVA, 7%

3.7MW

950kVAr

3.7MW

950kVAr

300kVA

6.3Ohm

5MVAr

22.9kV

CU500mm2

500mCU400mm2

750m

PCC

KPC23kV

DSN

PKCOM23

300kVA

6.3Ohm

5MVAr

22.9kV

6% Series

Reactors

22.9kV

1400kVAr

22.9kV

1500kVAr

22.9kV

900kVAr

D-Y

22.9/0.22kV

7.5MVA, 7.5%

D-Y

22.9/0.22kV

8.6MVA, 10%

D-Y

22.9/0.22kV

7.5MVA, 10%

D-Y

22.9/0.22kV

2.3MVA, 5.5%

5.8MW

3.21MVAR

6.1MW

4.91MVAR

5.8MW

3.21MVAR

2.1MW

0.821MVAR



50

99


Impedance scan results and Harmonic spectrum

100

Passive Filter Passive Filter

Series Tuned Harmonic Filter

High voltage Class : 50 < Q < 150

Low voltage Class : 10 < Q < 50

LC

1

C

L

R

ω

C

L

RQ

1=

C ω

1 Lω

R

F Z

)(ω F Z



51

101

Passive Filter Passive Filter

Damped High Passive Filter (2nd Order)

LC

1

C

L

R

F Z

ω

C ω

1 Lω

R

)(ω F Z

b R

b R

C Rb

1

102

Without Filter: VTHD = 7.6%


Without Filter



52

103

Plant System with Harmonic Filter Banks


UTIL 1400MVAD-Y

154/22.9kV

45/65MVA

Z=5%

D-D

22.9/6.6kV

9MVA, 7%

D-D

22.9/3.3kV

5MVA, 7%

3.7MW

950kVAr

3.7MW

950kVAr

300kVA

6.3Ohm

5MVAr

22.9kV

CU500mm

500mCU400mm

750m

PCC

KPC23kV DSN

PKCOM23

300kVA

6.3Ohm

5MVAr

22.9kV

D-Y

22.9/0.22kV

7.5MVA, 7.5%

D-Y

22.9/0.22kV

8.6MVA, 10%

D-Y

22.9/0.22kV

7.5MVA, 10%

D-Y

22.9/0.22kV

2.3MVA, 5.5%

5.8MW

3.21MVAR

6.1MW

4.91MVAR

5.8MW

3.21MVAR

2.1MW

0.821MVAR5th_1, 11th_High, 5th HF, 7th HF, 11th HF

60.7 6.05 15.6 15.4 8.2 mH

1006kVAr, 1934kVAr, 3162kVAr, 2028kVAr, 1485kVAr

UTIL 1400MVAD-Y

154/22.9kV

45/65MVA

Z=5%

D-D

22.9/6.6kV

9MVA, 7%

D-D

22.9/3.3kV

5MVA, 7%

3.7MW

950kVAr

3.7MW

950kVAr

300kVA

6.3Ohm

5MVAr

22.9kV

CU500mm

500mCU400mm

750m

PCC

KPC23kV DSN

PKCOM23

300kVA

6.3Ohm

5MVAr

22.9kV

D-Y

22.9/0.22kV

7.5MVA, 7.5%

D-Y

22.9/0.22kV

8.6MVA, 10%

D-Y

22.9/0.22kV

7.5MVA, 10%

D-Y

22.9/0.22kV

2.3MVA, 5.5%

5.8MW

3.21MVAR

6.1MW

4.91MVAR

5.8MW

3.21MVAR

2.1MW


60.7 6.05 15.6 15.4 8.2 mH

UTIL 1400MVAD-Y

154/22.9kV

45/65MVA

Z=5%

D-D

22.9/6.6kV

9MVA, 7%

D-D

22.9/3.3kV

5MVA, 7%

3.7MW

950kVAr

3.7MW

950kVAr

300kVA

6.3Ohm

5MVAr

22.9kV

CU500mm

500mCU400mm

750m

PCC

KPC23kV DSN

PKCOM23

300kVA

6.3Ohm

5MVAr

22.9kV

D-Y

22.9/0.22kV

7.5MVA, 7.5%

D-Y

22.9/0.22kV

8.6MVA, 10%

D-Y

22.9/0.22kV

7.5MVA, 10%

D-Y

22.9/0.22kV

2.3MVA, 5.5%

5.8MW

3.21MVAR

6.1MW

4.91MVAR

5.8MW

3.21MVAR

2.1MW


60.7 6.05 15.6 15.4 8.2 mH

1006kVAr, 1934kVAr, 3162kVAr, 2028kVAr, 1485kVAr

104


Fr. scan results & modeling data TR / Filter



53

105

Name Type Comp IRMS kW Losses kVar Losses VSUM%

ADFL-5_1 Notch 59.589 4.134 1058.369 146.4%

ADFL-11A 2nd Ord R 2.081 4.807

L 55.943 0.290 82.018

C 55.990 110.5%

FL-5 Notch 95.393 1.204 490.719 116.6%

FL-7 Notch 65.681 0.473 265.355 114.5%

FL-11 Notch 46.222 0.201 94.608 111.9%


Filter data for design

106


5th, 7th, 11th, 11th Hi-pass filter currents



107


With Harmonic Filters

1.22.3K factor

0.7k0.76kCurrent Peak in Vp

19.1k20.9kVoltage Peak in Vp

471.9523.3Current Average in A

2.967.59~7.7Voltage Distortion %

6.73~7.0414.1~16.6Current Distortion %

0.980.88Power Factor

3,7009,870Power Q in kVAr

18,53018,440Power P in kW

18,90020,900Power S in kVA

Tuned Harmonic Filters6% SR CapacitorsDescription


Summary of before and after power characteristics

Documents

2008_harmonic Filter Web