Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Earth fault protection of generator rotor in connection with

current injection unit PIZ 50V and protection REJ 521

Document No: Issued: November Revision:

1MCZ300045-EN 2004 D

© Copyright Petr Dohnálek 2004

ISO 9001:2000

1MCZ300045 EN rev.D

1

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Content

Content .................................................................................................................................................................................... 2 Basic characteristic ................................................................................................................................................................ 3 Current injection source PIZ 50V......................................................................................................................................... 4 Range of application ............................................................................................................................................................ 4 Operation principle .............................................................................................................................................................. 4 Technical data ...................................................................................................................................................................... 4 Testing instructions.............................................................................................................................................................. 7 Size and assembly instructions ............................................................................................................................................ 8 Earth-fault relay REJ 521 ................................................................................................................................................... 10 Features.............................................................................................................................................................................. 10 Application......................................................................................................................................................................... 10 Design ................................................................................................................................................................................ 10 Technical data .................................................................................................................................................................... 12 Ordering ............................................................................................................................................................................. 14

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1MCZ300045 EN, rev.D

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Basic characteristic •

Current injecting source is designed for earth fault protection of generator rotor.

•

Earth fault protection of generator rotor is made by connection with overcurrent protection REJ 521, (injecting source can also be used for multifunctional protections SPAJ, REJ, REM, REG, etc.).

•

The source can be used for all types of synchronous machines, that enable access to periphery of rotor.

•

The box of source has small dimensions. It is designed for panel assembly.

1MCZ300045 EN rev.D

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Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Current injection source PIZ 50V Range of application Current injection source PIZ 50V is source of auxiliary feeding. Together with overcurrent protection REJ makes up for double level earth fault protection of synchronous machine rotor.

Operation principle Current injection source is supplied by alternating voltage of 230 V, 130 V, and 100 V resp. 50/60Hz. Current injection unit transforms the supplying voltage to alternating voltage of 50 V. The alternating voltage is connected to machine rotor and to earth potential. Earth failure can arise between the earth potential and periphery of rotor. If an earth failure arises in periphery of the rotor, small failure current starts to leak through condensators of current injection unit to failed locality of the rotor. Earth conductor and sensitive earth-fault relay (sensitive earth fault protection) close the return current leak. The maximum failure current I1 is 16 mA. Once the earthfault current exceeds the set start current, the protection unit starts and after the set start time operates. The sensitive earth fault protection should be insensitive to harmonic frequency of failure current. It is possible to use the protection of this type: REJ, SPAJ, REM, REG. Regarding to rotor capacity towards earth, the permanent current of range of miliamper leaks through the circuit in unfailure state. Setting of the current value of the earth fault protection is defined by connection of resistance of 2000 Ω between rotor periphery and earth potential.

Technical data Supply (input) voltage Output voltage Voltage withstand from terminals 1, 2, 4, 5 to terminal 10 Current carrying capacity

230 V, 130 V or 100 V alter + 10... -15 %, 50 / 60 Hz 50 V alter 1000 V direct Permanent short circuit between clamps 1,2,4,5 and clamp 10 allowed 2 x 0,5 µF; 2,5 kV

Condensator capacity Short circuit current between connected clamps 1,2,4,5 against clamp 10 I1 = 16 mA Maximum current of protection unit (claims 19-20) I2 ≤ 600 mA Consumption ≤ 5,5 W Maximum circuit resistance of protection unit (claim19-20) RSM = 3 Ω Voltage of insulation test, input to both outputs, output to output and all to earth - by IEC 60255-5 5 kV, 50 Hz, 1 min Impuls test by IEC 60255-5 5 kV; 1,2/50s; 0,5 J Cycle humidity heat by IEC 60068-2-48 -40 - +70 °C Stage of cover of unit case IP 40 Unit mass ~ 1,0 kg IEC 60068-2-30 (12+12 h cycle) +25..+50 °C, humidity > 93 %, 6 cycles Operating temperature range by IEC 60068-2-1,-2-2 -10... +55 °C Storage temperature range by IEC 60068-2-48 - 40... +70 °C EMC – emission: correspond to ČSN EN 61000-6-4, class A, group 1 by ČSN EN 55011 EMC – immunity: correspond to ČSN EN 61000-6-2, supply – level 4 by ČSN EN 61000-4-4 – level 4 by ČSN EN 61000-4-5

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1MCZ300045 EN, rev.D

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521 PIZ 50V

Protection current dependence on earth-fault resistance RZ for circuit resistance Rsm = 0,1 Ω

Ranges of setting for various capacity of exciting system CZ = 0 µF; 0,2 µF; 0,5 µF; 0,7 µF; 1µF

600

I2 [mA] 560 520 480 440 400 360 320 Cz = 1µ F 280 Cz = 0,7µ F 240 Cz = 0,5µ F 200 160

Cz = 0,2µ F

120 Cz = 0µ F

80 40 0 0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

RZ [Ω Ω]

Cz

– capacity of exciting system

Rz

– resistance of line to-earth fault

I2

– current of protection unit

The values given here are informative only, they can vary by about 15 % depending on the internal resistance of input current transformers and type of protection unit.

1MCZ300045 EN rev.D

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Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

PIZ 50V

Protection current dependence on earth-fault resistance RZ for circuit resistance Rsm = 3 Ω

Ranges of setting for various capacity of exciting system CZ = 0 µF; 0,2 µF; 0,5 µF; 0,7 µF; 1µF

340

I2 [mA]

320 300 280 260 240 Cz = 1µ F

220 200

Cz = 0,7µ F

180

Cz = 0,5µ F

160 140 Cz = 0,2µ F

120 100

Cz = 0µ F

80 60 40 20 0 0

1

2

3

4

5

8

Cz

– capacity of exciting system

Rz

– resistance of line to-earth fault

I2

– current of protection unit

9

10

11

12

13

14

15

16

17

18

19

20

21

22

RZ [Ω Ω]

The values given here are informative only, they can vary by about 15 % depending on the internal resistance of input current transformers and type of protection unit.

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1MCZ300045 EN, rev.D

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Testing instructions

REJ 521

Circuit for testing of rotor earth fault protection is shown in fig. 1. Clamps 1,2 and 4,5 are wired and connected to earth potential bundle 10 through testing breaker S and testing resistor R. Protection settings are described in section. "Technical data" The protection itself should be tested according to instructions for this protection.

1MCZ300045 EN rev.D

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Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Size and assembly instructions The current injection source is installed inside a metallic case. The case can be assembled in arbitrary position to plane panel. The connection can be done via Cu or Al conductors. Maximum conductor cross-section is 2,5 mm2 in the case of 2 wires in one clamp or 4 mm2 in the case of one wire in one clamp.

Fig. 2:

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1MCZ300045 EN, rev.D

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Fig. 3: Single-line connection

REJ 521

Fig. 4: Double-line connection

REJ 521

1MCZ300045 EN rev.D

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Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Earth-fault relay REJ 521 Features


Low-set non-directional earth-fault stage with definite time or inverse definite minimum time (IDMT) characteristic




High-set non-directional earth-fault stage with instantaneous or definite time characteristic




Circuit-breaker failure protection unit (CBFP)




Disturbance recorder




Relay settings are modified via HMI or via a personal computer (free software available)




The relay settings are stored in a non-volatile memory




Two normally open power output contacts




Two change-over type signal output contacts




Accurate current input




Galvanically isolated binary input with a wide input voltage range




Output contact functions freely configurable for the desired operation




Optical PC connector for two-way data communication




Continuous self-supervision of hardware and software. At a permanent fault all stages and outputs are blocked




User-selectable rated frequency 50/60 Hz

Application The earth-fault relay REJ 521 is a secondary relay that is connected to the current transformers of the object to be protected. The earth-fault unit continuously measures the detection of a fault, the relay starts, trips the circuit breaker, provides alarms and records fault data in accordance with the application and the relay functions configured.

Design The relay consists of a high-set and a low-set earth-fault unit and a circuit-breaker failure protection unit. Further, the relay includes a self-supervision system and a disturbance recorder unit. Earth-fault unit Once the earth-fault current exceeds the set start current of the low-set stage I 0 >, the earth-fault unit starts and, after the preset start time of ~60 ms, it delivers a start signal. After the set operate time, at definite time operation, or the calculated operate time, at inverse time operation, the earth-fault unit operates. In the same way, the high-set stage I 0 >> of the earth-fault unit starts when the set start current is exceeded, and delivers a start signal after the preset ~40 ms start time. When the set operate time elapses, the earth-fault unit operates. The low-set stage of the earth-fault unit may be given a definite time or an inverse definite minimum time (IDMT) characteristic. When the IDMT characteristic is used, six time/current curve groups are available. Four of the curves comply with the standards BS 142 and IEC 255, and are called “normal inverse“, “very inverse”, “extremely inverse” and “long time inverse”. The two additional inverse time curves are called “RI” and “RD”. 10

1MCZ300045 EN, rev.D

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

The inverse time function of stage I 0 > can be inhibited by the start of stage I 0 >>. Then the operate time is determined by stage I 0 >>. If not needed, the I 0 >> stage can be set out of operation. This situation is indicated by “999” when the set start current value is read via the serial communication. The set start current value I 0 >>/I n of stage I 0 >> can be automatically doubled in a start situation, i.e. when the object to be protected is connected to the network. Thus the start current of the overcurrent stage I 0 >> can be set below the connection inrush current level. A start situation is defined as the situation where the phase current rises from a value below 0.12 x I 0 > to a value above 1.5 x I 0 > in less than 60 ms. The start situation ends when the current falls below 1.25 x I 0 >. CBFP unit The relay incorporates a circuit breaker failure protection (CBFP) unit. The CBFP unit generates a trip signal via output PO2 after the set operate time of 0.1…1 s, provided the fault has not been cleared by that time. Normally, the CBFP unit controls the upstream circuit breaker. It can also be used for tripping via redundant trip circuits of the same circuit breaker, if the circuit breaker is provided with two trip coils. The circuit-breaker failure protection unit is activated via a software switch. Disturbance recorder unit The relay includes an internal disturbance recorder, which records momentary values, internal logic and external control signals. The disturbance recorder can be set to be triggered by the operation of the protection stages or by an external trigger signal, either on the falling or rising edge. Self-supervision unit The relay is provided with a self-supervision system for monitoring internal faults. Once the self-supervision system detects an internal relay fault, the ready indication LED starts blinking. At the same time, the normally operated self-supervision alarm relay drops off and a fault code can be read from the relay. This fault code identifies the fault that has been detected. Communication capabilities Relay data, such as events, input data, setting values and recorded information can be read via the optical PC interface. The relay communicates over the SPA bus protocol, data transfer rate 4.8 or 9.6 kbps. For the connection of a PC, an optical connection cable type 1MKC950001-1 is needed. Auxiliary supply For its operation the relay requires a secured auxiliary voltage supply. The internal power supply of the relay forms the voltages required by the relay electronics. The power supply is galvanically isolated. A green LED indicator “READY” on the front panel is lit when the power supply module is operating. Rated voltage ranges:


AC range 80…265 V ac, rated 110/120/220/240 V




DC range 38…265V dc, rated 48/60/110/125/220 V

The primary side of the power supply is protected with a fuse located on the printed circuit board of the relay. The fuse size is 2.5 A (slow).

1MCZ300045 EN rev.D

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Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Technical data Table 1: Energizing inputs Rated current In Thermal withstand capability

0,2 A

1A

continuously

1,5 A

4A

for 1 s

20 A

100 A

Dynamic current withstand, half-wave value

50 A

250 A

Input impedance

< 750 mΩ

< 100 mΩ

Rated frequency fn

50 Hz / 60 Hz ± 5 Hz

Table 2: Measuring ranges Earth-fault current as a multiple of the rated current In of the energizing input

0…8 x In

Table 3: Output contact ratings for power outputs (PO1 and PO2) Terminals

X2, 1/3-4, X2, 1/5-6

Rated voltage

250 V ac/dc

Continuous carry

5A

Make and carry for 0.5 s

30 A

Make and carry for 3.0 s

15 A

Breaking capacity for dc, when the trip circuit time constant L/R ≤ 40 ms, at 48/ 110/ 220 V dc

5 A/ 3 A / 1 A

Contact material

AgCdO2

Table 4: Output contact ratings for signal outputs and self-supervision output (SO1, SO2 and IRF) Terminals

X2, 1/7-8-9, X2, 1/10-11-12, X2, 1/13-14-15

Rated voltage

250 V ac/dc

Continuous carry

5A

Make and carry for 0.5 s

10 A

Make and carry for 3.0 s

8A

Breaking capacity for dc, when the trip circuit time L/R ≤ 40 ms, at 48/ 110/ 220 V dc

1A/ 0,25 A/ 0,15 A

Contact material

AgCdO2

Table 5: External binary input External control rated voltage level

Un = 24/ 48/ 60/ 110/ 220 V dc

Operative range

18…265 V dc

Typical control current of input circuit

2…25 mA

Table 6: Auxiliary voltage Rated voltage

Un = 110/ 120/ 220/ 240 V ac Un = 48/ 60/ 110/ 125/ 220 V dc

Operative range

80…265 V ac 38…265 V dc

Power consumption

4…10 W

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1MCZ300045 EN, rev.D

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Table 7: Data transmission Transmission mode

Optical PC interface RER 103

Protocol - rear panel

SPA bus or IEC 608 70 – 5 – 103

Selectable data transfer rates

4,8 nebo 9,6 kbps

Optical connection cable – front panel

1MKC 950001-1

SPA bus protocol

Table 8: Dielectric tests Insulation test according to IEC 60255-5

2,0 kV, 50 Hz, 1 min.

Impulse test according to IEC 60255-5

5 kV, 1,2/50 µs, 0,5 J

Insulation resistance test according to IEC 60255-5

>100 MΩ, 500 V dc

Table 9: Electromagnetic compatibility tests The EMC immunity test level fulfils the requirements specified in the generic standard EN 50082-2 1 MHz burst disturbance test, class III (IEC 60255-22-1) Electrostatic discharge test, class III (IEC 61000-4-2) Radio frequency interference test

Fast transient disturbance test (IEC 60255-22-4 and IEC 610004-4) Surge immunity test (IEC 61000-4-5)

common mode

2,5 kV

differential mode

1,0 kV

for contact discharge

6 kV

for air discharge

8 kV

conducted, common mode (IEC 61000-4-6)

10 V (rms), f = 150 kHz….80 MHz

radiated, amplitude-modulated (IEC 61000-4-3)

10 V/m (rms), f = 80…1000 MHz

radiated, amplitude-modulated (ENV 50204)

10 V/m, f = 900 MHz

radiated, test with a portable (IEC 60255-22-3, method C)

f = 77,2 MHz, P = 6 W; f = 172,25 MHz, P = 5 W

ac/dc ports

4 kV

binary contacts

2 kV

power supply, ac/dc ports

4 kV, common mode 2 kV, differential mode

I/O ports

2 kV, common mode 1 kV, differential mode

Electromagnetic emission tests (EN 55011 a EN 50081-2)

conducted RF emission (mains terminal)

EN 55011, class A

radiated RF emission

EN 55011, class A

CE approval

Complies with the EMC directive 89/336/EEC and the LV directive 73/23/EEC

Table 10: Mechanical tests Vibration test (IEC 60255-21-1)

class I

Shock/bump test (IEC 60255-21-2)

class I

Table 11: Environmental conditions Climatic environmental tests

Dry cold test

according to IEC 60068-2-1

Dry heat test

according to IEC 60068-2-2

Damp heat test

according to IEC 60068-2-30

Degree of protection by enclosure of the device case according to IEC 529, when the relay is panel-mounted Weight of the relay 1MCZ300045 EN rev.D

IP54 2,8 kg 13

Earth protection of generator rotor in connection with current injection unit PIZ 50V and protection REJ 521

Ordering The order number identifies the hardware as described below.. This number is labelled on the marking strip on the front panel. REJ521 B 413 B A A Analogue interface type A: Only matching transformers included Digital input voltage range A: Digital input voltage range Ur = 24/48/60/110/220 V dc Auxiliary voltage range of power supply B: Ur = 110/120/220/240 V st; 48/60/110/125/220 V ss Hardware number Revision Earth-fault relay

When ordering, please specify: Ordering information

Ordering example

Type designation and quantity

REJ 521, 5 pieces

Order number

REJ 521B 413-BAA

Optical connection cable

1 piece (1 MKC 950001-1)

Relay setting tool

1 piece (CAP 501)

Order numbers Optical connection cable Relay setting tool

1 MKC 950001-1 CAP 501

The supplier of current injection unit PIZ 50 V, service measurement and cooperative protections settings is DOHNÁLEK - ochrany pro energetiku Úpská 132 542 23 Mladé Buky Czech Republic Telefon: Fax:

+420 439 873 443 +420 439 873 442

E-mail: [email protected] Website: www.dohnalek.cz

The supplier of cooperative protection series SPAJ, REJ, REM, REG etc. is ABB s.r.o Division Power Technologies Komenského 821 541 70 TRUTNOV Czech Republic Tel.: +420 439 808 111 Fax: +420 439 808 501 http://www.abb.cz

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1MCZ300045 EN, rev.D