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KVCG202/EN M/H11
9.6
Control functions
Reference should be made to Appendix 3 for the application diagram used for the
following tests. The relay should be commissioned with the settings calculated for the
application.
9.6.1
Regulated Voltage setting V
The relay should be commissioned with the settings calculated for the application.
This test checks the function of the transformer tap change control.
continuously monitors the system voltage and compares it with the reference voltage Vs.
If the regulated voltage moves outside the deadband limits the relay actuates the tap
changer mechanism to 'Raise' or 'Lower' the voltage to bring it back within the set
deadband limits after the initial set time has elapsed.
[Before making the following changes note the settings for: Initial time delay (tINIT), inter-
tap delay (tINTER) setting, and Initial time characteristic.
Set the initial time delay (tINIT) and the inter-tap delay (tINTER) to 0 seconds for
continuous tap change.
Set the definite/inverse time characteristic to 'definite time'].
Monitor 'Raise volts', 'Lower volts' and 'Blocked' relay contacts.
Energise the auxiliary voltage supply and check that 'Blocked' is displayed on the LCD
and 'Blocked' relay contact is closed.
Apply the system voltage and adjust the voltage equivalent to the system voltage setting
(Vs) to (terminals 17 and 18).
raise/lower volts relay contacts should become open.
Slowly increase the supply voltage and record the voltage (V
volts' contacts closes.
voltage until 'CONTROL' LED extinguishes again.
Slowly reduce the voltage further and record the voltage (V
contacts 'Raise volts' closes. The 'CONTROL' LED should illuminate.
Using the values recorded for V
the actual deadband as follows:
Vreg = (V
HIGH
The value of Vreg should be (Vs ±0.5%) and the deadband should (dVs ±0.5% of Vs).
[Restore all settings changed i.e. the initial time delay, the inter-tap delay, and the initial
time characteristic.]
9.6.2
Load shedding/boosting
The relay should be commissioned with the settings calculated for the application only
check for the settings levels used for this application.
The purpose of this test is to ensure that the level of load shedding function is working.
The system voltage setting (Vs) can be raised or lowered by means of load shedding
option.
[Before making the following changes note the setting for: input masks, inter-tap delay
(tINTER) setting.
Set the inter-tap delay (tINTER) to 0 seconds
For this test ensure that the input masks are set to operate the following opto inputs
[0707, 0708, 0709 INPUT MASKS]:
For test 1 and 4 connect L0 OPTO (terminal 46) to switch S1.
For test 2 and 5 connect L1 OPTO (terminal 48) to switch S1.
and Dead Band dV
S
The 'CONTROL' LED should extinguish, and the
The 'CONTROL' LED should illuminate. Reduce the supply
HIGH
+ V
)/2
dVs
LOW
actual
S
LOW
and V
, calculate the regulated value Vreg and
LOW
= (V
– V
)
HIGH
LOW
Technical Manual
KVGC202
The relay
) at which the 'Lower
HIGH
) at which the raise volts
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