Siemens Siprotec 7UM611, Руководство пользователя

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3 Mounting and Commissioning
274
7UM61 Manual
C53000-G1176-C127-3
In secondary values:
with
N
CTR
- Current transformer ratio
N
VTR
- Voltage transf. transform. ratio
If substantial deviations or wrong the sign occur, then the voltage transformer connec-
tions are incorrect.
After shutdown and de-excitation of the generator, and removal of the short-circuit
bridge, the short-circuit tests are completed.
No further tests are required for unbal-
anced load protection, overcurrent time protection, thermal overload protection
and impedance protection.
Activate the overcurrent time protection and the impedance protection (address
1201
:
O/C I>
=
ON
or address
1401 O/C Ip
=
ON
, address
3301
:
IMPEDANCE PROT.
=
ON
) and it works immediately as a short-circuit protection for all subsequent tests. If
used, address
1301 O/C I>>
=
ON
, the thermal overload protection (address
1601
:
Ther. OVER LOAD
=
ON
), the unbalanced load protection (address
1701
:
UNBALANCE LOAD
=
ON
) can be activated. Otherwise, they are set to
Off
.
3.3.9 Checking the Voltage Circuits
General The voltage circuits of the machine are checked to ensure the correct cabling, polarity,
phase sequence, transformer ratio etc. of the voltage transformers - not to check indi-
vidual protection functions of the device.
Earthing of the
Voltage Transform-
ers 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
.
Check in the unexcited condition of the machine 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.
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