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Alternator Protection List

This document lists 14 protection functions for a VAMP 210 relay and 2 protection functions for a VAMP 265 relay used in an alternator protection list (RLPCL). It also lists protection for alternator winding temperature and bearing temperature monitored by a PLC. The protections include overcurrent, overvoltage, undervoltage, loss of excitation, reverse power, overfrequency, underfrequency, voltage transformer and current transformer supervision. Differential current protection is also listed for the VAMP 265 relay for generator stator winding protection.

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Fahad Parvez
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220 views3 pages

Alternator Protection List

This document lists 14 protection functions for a VAMP 210 relay and 2 protection functions for a VAMP 265 relay used in an alternator protection list (RLPCL). It also lists protection for alternator winding temperature and bearing temperature monitored by a PLC. The protections include overcurrent, overvoltage, undervoltage, loss of excitation, reverse power, overfrequency, underfrequency, voltage transformer and current transformer supervision. Differential current protection is also listed for the VAMP 265 relay for generator stator winding protection.

Uploaded by

Fahad Parvez
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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AVK ALTERNATOR PROTECTION LIST (RLPCL)

VAMP 210 RELAY

1. AC Inverse Time Overcurrent

ANSI (American National Standards Institute) Code=51


In (585A) *1.2=703A/Time Delay=0.2s

2.Instantaneous Overcurrent

ANSI Code=50
In (585A) *2.5=1464A/Time Delay=0.6s

3.Reverse-phase/Phase-Balance Current Relay/Unbalance Load

ANSI Code=46
In (585A) *0.08=47A/Time Delay=20s

4.Directional Earth Fault relay/ Directional Residual Current

ANSI Code=67N
CT Primary Current (50) *0.04=2A/Time Delay=0.3s

5.Ac Inverse Time Earth Overcurrent Relay (Residual Method)/ Residual Current

ANSI Code=51N
CT Primary Current (50) *0.04=2A/Time Delay=1s
Residual Current Stage >> 51N
CT Primary Current (50) *0.15=7.5A /Time Delay=0.3s

6.Neutral Voltage Displacement /Earth Fault

ANSI Code= 59N


Uon (6350V) *0.1(10%)=635V /Time Delay=2s
Earth Fault Stage U0>> 59N
Uon (6350V) *0.2(20%)=1270V /Time Delay=1s

7.Overvoltage

ANSI Code= 59
Overvoltage Stage U> 59
Un(11000V) *1.12(112%)=12320V /Time Delay=4s
Overvoltage Stage U>> 59
Un(11000V) *1.4(140%)=15400V/ Time Delay=0.5s

8.Undervoltage

ANSI Code= 27
Un(11000V) *0.8(80%)=8800V/ Time Delay=20s

9.Loss of Excitation / Under Excitation

ANSI Code= 40
Sn (11155kVA) *0.3(-30%)=-3347kVAr /Time Delay=2s

10.Reverse Power

ANSI Code= 32
Pn (8924kW) *0.04(-4%)=357kW /Time Delay=2s

11.Overfrequency

ANSI Code= 81O


Fn (50Hz) *1.15(15%)=57.5Hz /Time Delay=3s

12.Underfrequency

ANSI Code= 81U


Fn (50Hz) *0.95(5%)=47.5Hz /Time Delay=4s

13.VT Supervision

The voltage transformer supervision (VTS) feature is used to detect failure of the ac voltage inputs to the
relay. This may be caused by internal voltage transformer faults, overloading, or faults on the interconnecting
wiring to relays. This usually results in one or more VT fuses blowing. Following a failure of the ac voltage
input there would be a misrepresentation of the phase voltages on the power as measured by the relay, which
may result in maloperation.
ANSI Code= 60
Un(11000V) *0.7(70%)=>7700V
In(585A) *0.1(10%)=<59A
Time Delay=0.2s

14.CT Supervision (Ctsup)

The current transformer supervision feature is used to detect failure of one or more of the ac phase current
inputs to the relay. Failure of a phase CT or an open circuit of the interconnecting wiring can result in
incorrect operation of any current operated element. Additionally, interruption in the ac current circuits risks
dangerous CT secondary voltages being generated.
ANSI Code= 60
In(585A) *0.2(20%)= 117A (Imax)/In(585A) *0.1(10%)= 59A (Imin)/Time Delay=2s
VAMP 265 RELAY

Differential Current Relay

Protection for generator stator windings-(Phase to Ground, Phase to Phase, Turn to Turn Fault).
ANSI Code= 87
Stage I> 87
I> pick-up (Ibias < 0.5Ign)
In(585A) *0.25(25%)=146A
Slope 1=25%
Ibias for start of slope 2
In(585A) *3=1756A
Slope 2=100%
Stage I>> 87
In(585A) *5=2927A

PLC

1.Alternator Winding Temperature

Alarm -140C
Trip -150C

2. DE & NDE Bearing Temperature

Alarm -105C
Trip -110C

Md. Ruhul Amin


EE, RLPCL

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