Settings - ABB RELION 670 Series Applications Manual

Section 9
Voltage protection
RESET: OEXPVPH has a thermal memory, which can take a long time to reset. Activation of the
RESET input will reset the function instantaneously.
Recommendations for Output signals
Please see the default factory configuration for examples of configuration.
ERROR: The output indicates a measuring error. The reason, for example, can be configuration
problems where analogue signals are missing.
START: The START output indicates that the level V/Hz>> has been reached. It can be used to
initiate time measurement.
TRIP: The TRIP output is activated after the operate time for the U/f level has expired. TRIP
signal is used to trip the circuit breaker(s).
ALARM: The output is activated when the alarm level has been reached and the alarm timer has
elapsed. When the system voltage is high this output sends an alarm to the operator.
9.4.3.2

Settings

GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ),
UBase ) and ( SBase ).
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Operation : The operation of the Overexcitation protection OEXPVPH can be set to On / Off .
MeasuredU : The phases involved in the measurement are set here. Normally the three phase
measurement measuring the positive sequence voltage should be used but when only
individual VT's are used a single phase-to-phase can be used.
MeasuredI: The phases involved in the measurement are set here. MeasuredI: must be in
accordance with
V/Hz> : Operating level for the inverse characteristic, IEEE or tailor made. The operation is
based on the relation between rated voltage and rated frequency and set as a percentage
factor. Normal setting is around 108-110% depending of the capability curve for the
transformer/generator.
V/Hz>> : Operating level for the tMin definite time delay used at high overvoltages. The
operation is based on the relation between rated voltage and rated frequency and set as a
percentage factor. Normal setting is around 110-180% depending of the capability curve of the
transformer/generator. Setting should be above the knee-point when the characteristic starts
to be straight on the high side.
Lower V/Hz limit is always set value V/Hz> in %. Upper V/Hz limit for the inverse time
characteristic is taken as greater value among the following two values in %:
• 1.10 x V/Hz>
• V/Hz>>
The reason behind this is to prevent loss of accuracy of the inverse time characteristic when
the difference between V/Hz> and V/Hz>> set values is too small.
XLeak : The transformer leakage reactance on which the compensation of voltage
measurement with load current is based. The setting shall be the transformer leak reactance in
primary ohms. If no current compensation is used (mostly the case) the setting is not used.
TrPulse : The length of the trip pulse. Normally the final trip pulse is decided by the trip function
block. A typical pulse length can be 50 ms.
478
MeasuredU .
1MRK 504 152-UEN B
M6496-84 v7
M6496-91 v8
Application manual