12.4.16.1
Testing
SEMOD158692-13 v2
The protection function uses injection of an ac voltage to the generator field circuit. The
COMBIFLEX voltage injection unit RXTTE4, Part No 1MRK 002 108-AB contains a voltage
transformer with a primary winding for connection to 120 or 230 V, 50 or 60 Hz supply voltage.
From the secondary winding of this internal voltage transformer approximately 40 V AC is
injected via series capacitors and resistors into the rotor circuit. The injected voltage is fed to
a voltage input of the REG670 IED. The current caused by the injection is fed to a current input
of the REG670 IED via a current transformer, which is amplifying the current ten times, as
shown in figure
en06000498.vsd
REG 670
RXTTE 4
I
U
230 V AC
120 V AC
0
Generator rotor winding
G
313
314
315
421
428
324
325
221 222
Optional
external resistor
Connection to be done
by the panel builder
IEC06000498 V1 EN-US
Figure 55: Ten times amplification of current via a current transformer
can be done with the generator at stand-still situations.
Procedure
1.
The test should be prepared with a switch connected between the output of RXTTE4
(221) and the station earth. Initially this switch is open.
2.
First the 120 (230) V input to RXTTE4 is disconnected. This should give a signal from
REG670 that the injection voltage is low.
3.
Reconnect the 120 (230) V input and check that the low injection voltage signal resets.
1MRK 502 067-UEN B
Section 12
Testing functionality by secondary injection
153
Commissioning manual
