Overpower Logic; Application Notes; Forward Overpower Setting Guidelines; Reverse Power Considerations - GE MiCOM P40 Agile Technical Manual

P14x
2.2

OVERPOWER LOGIC

P(A, B, or C)
Power>1 1 Ph Watt
Power>1 1 Ph VAR
Power>1 Mode
Active
-1
Reactive
P(3 phase )
Power>1 3 Ph Watt
Power>1 3 Ph VAR
Power>1 Mode
Active
-1
Reactive
Power>1Direction
Forward
Reverse
Power>1 Status
Enabled
VTS Slow Block
V00900

Figure 137: Overpower logic

2.3

APPLICATION NOTES

2.3.1

FORWARD OVERPOWER SETTING GUIDELINES

The relevant power threshold settings should be set greater than the full load rated power.
The operating mode should be set to Forward.
A time delay setting (Power>(n) TimeDelay) should be applied. This setting is dependant on the application, but
would typically be around 5 seconds. The delay on the reset timer (Power>(n) tRESET), would normally be set to
zero.
2.3.2

REVERSE POWER CONSIDERATIONS

A generator is expected to supply power to the connected system in normal operation. If the generator prime
mover fails, it will begin to motor (if the power system to which it is connected has other generating sources). The
consequences of generator motoring and the level of power drawn from the power system will be dependent on
the type of prime mover.
Typical levels of motoring power and possible motoring damage that could occur for various types of generating
plant are given in the following table.
Prime mover
Diesel Engine
Motoring level depends on compression ratio and cylinder bore stiffness. Rapid disconnection is required to limit power loss
and risk of damage.
P14xEd1-TM-EN-1
&
X &
&
X &
Motoring power
5% - 25%
Chapter 12 - Power Protection Functions
DT
1 &
Power>1TimeDelay
DT
1 &
Power>1TimeDelay
Possible damage (percentage rating)
Risk of fire or explosion from unburned fuel
Power>1 Start
Power>1 Trip
Power>1 3 PhStart
Power>1 3Ph Trip
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