Mounting and Commissioning
3.3 Commissioning
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
428
If there are deviations, connection errors are normally assumed (see margin title „Primary test with generator“)
• Disconnect test source and protected object
• Check and correct connections and test setup
• Repeat measurement
Checking the Zero Voltage Release
If the zero voltage release is used, it must be checked during the test of the stator earth fault protection. In the
presence of an earth fault, the indication 5841 „REF U0> releas.“ must appear. When performing the test,
keep in mind that the zero voltage is calculated from the three phase voltages and converted on the secondary
side to the phase-to-phase voltage (equivalent to √3
U0). The value thus obtained is the same as for a broken
delta winding.
Blocking by Overcurrent
If the above measurements have been successfully performed, and the measured phase currents were plau-
sible, it can be assumed that the current measurement works correctly. You only need to check the correct
setting in the protection function (address 2102 = REF I> BLOCK).
The pickup values are checked by injecting a current using secondary test equipment (CTs need not be dis-
connected).
• After completion of the tests, disconnect the test source and the protected object (shut down generator)
• If parameter settings have been changed for the tests, reset them to the values necessary for operation.
• After completion of the earth fault protection tests, activate the earth current differential protection.
3.3.15 Checking the Voltage Circuits
General
The voltage circuits of the machine are checked to ensure the correct cabling, polarity, phase sequence, trans-
former ratio etc. of the voltage transformers - not to check individual protection functions of the device.
Earthing of the Voltage Transformers
When checking the voltage transformers, particular attention should be paid to the broken delta windings
because these windings may only be earthed in one phase.
Preparation
Set the overvoltage protection function to about 110 % of the rated generator voltage with trip on excitation.
Switch frequency protection (address 4201) and overexcitation protection (address 4301) to Block relay.
Already in the unexcited condition of the machine make sure, with the help of remanent voltages, that all short-
circuit bridges are removed.
Test Instruction
The checks of all voltage transformer circuits (protection, measuring, metering etc.) are carried out with about
30 % of the rated transformer voltage. Tests with generator voltages of more than 30 % rated voltage are only
required when the idle characteristic is measured for the first time.
The measuring circuit supervision of the rotor earth fault protection (see below) can be checked when testing
the voltage circuits, or after the synchronization.
To Next Page
Loading...
Need help?
General
