Excitation performance evaluation – Basler Electric DECS-400 User Manual

Page 157

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9369700990 Rev R

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Excitation Performance Evaluation

In the following performance evaluation, temporary settings will enable you to test excitation performance
without stressing the machine or exceeding ancillary protection devices. Procedures are provided that will
allow you to set your final operating values. This evaluation is a continuation of the previous tests.

Off-Line Excitation Limiter Operation

In this test, with the generator set below the rated voltage output, you will set the AVR setpoint above the
maximum setting and the system should alarm. If the system does not alarm, the OEL gain (Ki and Kg)
may be set too low. If the system doe alarm and oscillates, Ki and Kg may be set too high.

Enable the off-line OEL ......................................................................................................... ________

Determine the field current required to reach 105% of the rated generator voltage. ............ ________

Set the off-line OEL for a value equal to the no-load field current. ....................................... ________

Lower the terminal voltage to 10% below rated. ................................................................... ________

To speed performance in the following test, you may increase the OEL gain (Ki and Kg).

Using the AVR/FCR tab of the BESTCOMS Setting Adjustment screen, set the AVR
setpoint to 110% of the rated output. (The AVR Max setting should remain at 105%.) ........ ________

If an output relay is programmed to alarm, the output, the front panel HMI,
BESTCOMS, and any remote devices should annunciate the alarm. ................................... ________

Return (set) the AVR setpoint to the rated output. ................................................................ ________

Limit and Protection Check

In this test, the generator overvoltage, generator undervoltage, field overvoltage, and field overcurrent
protection functions will be tested.

Review the generator overvoltage protection settings on the General Protection tab of
the BESTCOMS Protection screen. ...................................................................................... ________

Lower the generator overvoltage setting to the operating setpoint. ...................................... ________

Verify that all alarms and annunciations function as programmed. ....................................... ________

Reset the generator overvoltage setpoint to the final value. ................................................. ________

Raise the generator undervoltage setting to the alarm threshold. ........................................ ________

Verify that all alarm and annunciations function as programmed. ........................................ ________

Reset the generator undervoltage setpoint to the final value. ............................................... ________

Lower the field overvoltage setting to the operating setpoint. ............................................... ________

Verify that all alarms and annunciations function as programmed. ....................................... ________

Reset the field overvoltage setpoint to the final value. .......................................................... ________

Lower the field overcurrent setting to the operating setpoint. ............................................... ________

Verify that all alarms and annunciations function as programmed. ....................................... ________

Reset the field overcurrent setting to the operating setpoint. ................................................ ________

Parallel Operation, Generator On-Line

In this test, the generator will be connected to the bus and the phase relationship between the current and
sensed voltage will be checked. If the CT polarity is incorrect, a shorting terminal block can be used to
reverse the polarity. If the sensed voltage has the wrong phasing, the generator breaker must be opened
and the generator must be shut down in order to reverse the voltage sensing polarity. After the phase
relationship is verified as correct, the overexcitation and underexcitation protection will be exercised. Also,
var and power factor performance evaluations will be conducted at values that will not stress the machine.

Phase Relationship Test

Transfer to FCR mode. .......................................................................................................... ________

DECS-400

Commissioning

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