Mounting and Commissioning
3.3 Commissioning
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
445
Calibrating the Reverse Power Protection
If a generator is connected with the network, reverse power can be caused by
• closing of the regulating valves,
• closing of the stop valve
Because of possible leakages in the valves, the reverse power test should – if possible – be performed for both
cases.
In order to confirm the correct settings, repeat the reverse power measurement again. For this, the reverse
power protection (address 3101) is set to Block relay in order to check its effectiveness (using the indica-
tions).
Start up generator and synchronize with network. Close regulating valves.
From the operational measured value for the active power, the motoring power measured with the protection
device can be derived. 50% of that value should be taken as the setting for the reverse power protection.
Increase driving power.
In a further test, check the stop valve criterion . It is assumed that the binary input „>SV tripped“ is allo-
cated correctly and is controlled by the stop valve criterion (by a pressure switch or a limit switch at the stop
valve).
Close stop valve.
From the operational measured value for the active power, the motoring power measured with the protection
device can be derived.
If that value should be found to be unexpectedly less than the reverse power with the stop valves closed, 50%
of that value should be taken as the setting for the reverse power protection.
Shut down the generator by activating the reverse power protection.
Switch ON the reverse power protection (address 3101) and - if used - the forward power supervision (address
3201).
Checking the Under-excitation Protection
The angle error correction value W0 determined and configured with regard to reverse power protection under
address 204 also applies for the underexcitation protection.
In this section, the measured values of the reactive power have been read out, and thus a plausibility check of
that measured value with directional check has been carried out. No further checks are required.
If nevertheless by an additional load level measurement a directional check is to be performed, proceed as de-
scribed in the following.
Caution!
Under-excitation may cause the generator to fall out of step, in particular with increased active power!
Nonobservance of the following procedures can result in minor injury or material damage.
Operation with underexcitation is admissible only for a short period
For checking under load , set the underexcitation protection (address 3001) to Block relay.
The proper functioning is checked by approaching freely selected load levels under overexcited and then un-
derexcited conditions. The plausibility check is carried out by reading out the relevant operational measured
values from the protection device and comparing them with the measured values obtained from the control and
instrumentation system.
Set the underexcitation protection to 3001 (address ON).
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