2v73 Application

7/28/2019 2v73 Application

1/18

THE RELAY SPECIALISTS

relay monitoring systems pty ltd www.rmpl.com.au


2/18

2V73

High Impedance Differential Relay


3/18

2V73


The 2V73 relay provides high speeddifferential protection for various items of

power system plant including generators,busbars, motors & the individual windings ofpower transformers.

It is also suitable for restricted earth faultprotection applications.


4/18

2V73


The relay measuring element is basically anattracted armature unit of simple & rugged

construction powered from a bridge rectifier.

Relay stability can be set in steps (25-115V in 15Vsteps or 25-325V in 50V steps), by using the front

panel mounted selector switch. A capacitor isconnected in series with the operating coil to makethe relay insensitive to the DC component of faultcurrent.


5/18

External Fault

A DCB

2500A 4500A 3000A

5000A

10000A

F1

15 kA

5A 9A 6A 20A

No current

through

relay

EXTERNAL FAULT of 15 kA

RELAY CURRENT = 5 + 9 + 6 - 20 = 0A


6/18

External Fault Assuming

CT Not Saturated

10.2A 30.6A10.2A10.2A


7/18

External Fault Causing

CT Saturation

If CT saturation occurs it is most l ikely to affect

CT with heaviest loading.

Unbalance current caused by CT saturation wil l

flow through secy winding of saturated CT and

through relay.

To obtain a relay operating voltage in excess of

the resultant voltage the relay is required to be a

HIGH IMPEDANCE.

Note this is a relative term i.e. high impedance

relative to impedance of saturated CT path


8/18

Stability Setting

For CT Saturation Condition

10.2A

30.6A

10.2A10.2A

82.6V

RL

2 ohms

RCT

0.7 Ohm


9/18

Internal BUS Fault

A DCB

2500A 4500A 3000A 5000A

F215 kA

5A 9A 6A 10A

30A

through

relay

INTERNAL FAULT of 15 kA

Relay Current = 5 + 9 + 6 + 10 = 30A


10/18

2V73

Operating Current

The primary operating current is given by: I op = n ( IR + N I

)

IR = Relay operating current & Metrosil current at setting voltageas per the table below.

I

= CT magnetizing current at setting voltage (A)

n = CT turns ratioN = Number of connected CTs

The operating currents shown in the following tables are for both3 inch & 6 inch Metrosils connected to the 2V73 as per the wiringdiagram.

Range A(Volts)

25 75 125 175 225 275 325

Nominal(mA)

15 15 15 15 17 21 29

13 13 13 13 13 15 18

to to to to to to toLimits(mA)

16 17 17 20 27 39 61


11/18

2V73

Operating Current

Range B(Volts)

25 40 55 70 85 100 115

Nominal(mA)

14 14 14 14 14 14 14

13 13 13 13 13 13 13

to to to to to to toLimits

(mA) 16 16 16 17 17 17 17

Should the natural effective operating current after applying theabove formula be lower that desired, it can be raised to therequired level by adding a shunt resistor across the differentialrelay input circuit.


12/18

2V73

BUS Protection

(Single Phase Representation)

12

8

14

10

Flag resetvoltage free

contact

Magnetic flagoption only

Flag auxiliary

Flag auxiliary

28

24

22

26

Tripoutput 2

Tripoutput 1

5

6 Vs

L1 L2 NL3

P2P1

P2P1


13/18

2V73

Restricted Earth Fault Application

12

8

14

10

Magnetic flagoption only

Flag resetvoltage free

contact

Flag auxiliary

Flag auxiliary

28

24

22

26

Trip

output 2

Tripoutput 1

5

6 Vs

P2P1

P2

P1


14/18

2V73

Metrosil

An external Metrosil unit having a non-linear

resistance characteristic is required foreach phase element to limit the peakvoltage appearing across the secondarydifferential circuits under internal fault

conditions.


15/18

1M123

BUS Bar Protection Rack

3 x 2V73 Single phase high impedance differential relays1 x 2V75 3 phase Metrosil module1 x 2HSM High speed multi trip relay1 x 4M800 4U 19 inch sub rack frame


16/18

2V73

Metrosil Selection

Refer 2V75 Metrosil Module

Type Specification Rated Energy Part No.6 3 600A/S3/I/S887 33kJ 2105C58001

6 1 600A/S1/S887 33kJ 2105C58002

3 3 300A/S3/I/S3063 8kJ 2105C58006

3 1 300A/S1/S646 8kJ 2105C58004


17/18

Customer Generated Ordering Code

Generate the required ordering code as follows: e.g. 2V73 BAA

OrderCodeGeneral

Type1 2 3

2V73 -

1 SETTING RANGE

A 25-325V AC in 50V stepsB 25-115V AC in 15V steps

2 RATED FREQUENCY

A 50 HzB 60 Hz

3 FLAG TRIP INDICATION

A Mechanical flag no flag auxiliary requiredB Magnetic flag 24 to 150V DC auxiliaryC Magnetic flag 140 to 300 V DC auxiliary


18/18

2V73

Additional Information

Technical Bulletin User Guide Software downloads

Auto Cad Mounting Drawings Price & Availability

www.rmspl.com.au/2V73.htm

Test Manuals

www.rmspl.com.au/search.asp

Other Products

www.rmspl.com.au/Products.htm

Documents

2v73 Application