GE KVGC 202 - 9.7.3 Overcurrent Detector (IL) Testing

K
VCG202/EN M/H11
Technical
Manual
KVGC202
Slowly increase the applied voltage and measure the voltage at which the over voltage
contact ‘V>’ closes.
Check the measured voltage is within (V>) +2% of setting.
Check the ‘Raise volts’ contacts remained open and the ‘Lower volts’ contacts remained
closed
[Restore the following settings:
- initial time delay setting (tINIT),
- intertap delay (tINTER),
- undervoltage setting (V>)].
9.7.3 Overcurrent Detector (
IL)
The relay should be commissioned with the settings calculated for the application.
This test will check if both the ‘Raise’ and ‘Lower’ operations of the relay are blocked by
the operation of the internal relay when the load current
IL exceeds the threshold setting
if logic link LOG3 is set to ‘1’.
[Before making the following changes note the settings for: logic link LOG3, initial time
delay setting (tINIT), intertrip delay (tINTER), load current (
IL)].
Set the:
- logic link LOG3 to ‘0’,
- initial time delay setting (tINIT) to 0 seconds,
- intertap delay (tINTER) to 0 seconds,
- load current (
IL) to 0.5In].
Set the relay mask to operate ‘
IL>’ and ‘Blocked’ relay output contacts. Both contacts
should be open.
Connect a current source to load current input (terminals 27 & 28).
Apply voltage equivalent to the system voltage setting (Vs) to system voltage input
terminals 17 & 18.
Slowly increase the load current from zero and measure the current at which the ‘
IL>’
relay contact closes. The text on the LCD display should indicate excessive load current
detected.
Check the measured current is in the range 0.475
In to 0.525In (i.e. (IL) ±5%). Reduce
the load current to zero.
Set logic link LOG3 to ‘1’, to prevent tap change operation.
Slowly increase the load current from zero until the ‘
IL>’ contact closes.
The ‘CONTROL’ LED should now be lit permanently. The ‘Blocked’ relay contact should
be closed and both ‘Raise volts’ and ‘Lower volts’ contacts should be open to indicate tap
change.
Reduce the load current below the threshold setting, the ‘
IL>’ and ‘Blocked’ relay
contacts should open and the text ‘
IL>’ on the LCD should clear. The ‘CONTROL’ LED
should be extinguished.
[Restore the following settings:
- logic link LOG3,
- initial time delay setting (tINIT),