Application Possibilities; Inadvertent Generator Energization - ABB Relion 670 Series Applications Manual

1MRK 511 358-UUS A
10.1.2.3

Application possibilities

Due to its flexibility the general current and voltage protection (CVGAPC) function can be used,
with appropriate settings and configuration in many different applications. Some of possible
examples are given below:
1. Transformer and line applications:
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2. Generator protection
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10.1.2.4

Inadvertent generator energization

When the generator is taken out of service, and stand-still, there is a risk that the generator circuit
breaker is closed by mistake.
Three-phase energizing of a generator, which is at standstill or on turning gear, causes it to
behave and accelerate similarly to an induction motor. The machine, at this point, essentially
represents the subtransient reactance to the system and it can be expected to draw from one to
four per unit current, depending on the equivalent system impedance. Machine terminal voltage
can range from 20% to 70% of rated voltage, again, depending on the system equivalent
impedance (including the block transformer). Higher quantities of machine current and voltage (3
to 4 per unit current and 50% to 70% rated voltage) can be expected if the generator is connected
Application manual
Underimpedance protection (circular, non-directional characteristic) (21)
Underimpedance protection (circular mho characteristic) (21)
Voltage Controlled/Restrained Overcurrent protection (51C, 51V)
Phase or Negative/Positive/Zero Sequence (Non-Directional or Directional) Overcurrent
protection (50, 51, 46, 67, 67N, 67Q)
Phase or phase-to-phase or Negative/Positive/Zero Sequence over/under voltage
protection (27, 59, 47)
Special thermal overload protection (49)
Open Phase protection
Unbalance protection
80-95% Stator earth fault protection (measured or calculated 3Vo) (59GN)
Rotor earth fault protection (with external COMBIFLEX RXTTE4 injection unit) (64F)
Underimpedance protection (21)
Voltage Controlled/Restrained Overcurrent protection (51C, 51V)
Turn-to-Turn & Differential Backup protection (directional Negative Sequence.
Overcurrent protection connected to generator HV terminal CTs looking into generator)
(67Q)
Stator Overload protection (49S)
Rotor Overload protection (49R)
Loss of Excitation protection (directional pos. seq. OC protection) (40)
Reverse power/Low forward power protection (directional pos. seq. OC protection, 2%
sensitivity) (32)
Dead-Machine/Inadvertent-Energizing protection (51/27)
Breaker head flashover protection
Improper synchronizing detection
Sensitive negative sequence generator over current protection and alarm (46)
Phase or phase-to-phase or Negative/Positive/Zero Sequence over/under voltage
protection (27x, 59x, 47)
Generator out-of-step detection (based on directional pos. seq. OC) (78)
Inadvertent generator energizing
Section 10
Multipurpose protection
SEMOD53443-136 v2
SEMOD151947-4 v2
229