ABB RELION REF615R, Техническое руководство

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polarity of the input voltage is reversed (180°). In this case, the protection relay permits
the circuit breaker closing in a situation where the voltages are in opposite phases. This can
damage the electrical devices in the primary circuit. Therefore, it is extremely important
that the wiring from the voltage transformers to the terminals on the rear of the protection
relay is consistent regarding the energizing inputs
V_BUS
(bus voltage) and
V_LINE
(line voltage).
The wiring should be verified by checking the reading of the phase difference measured
between the
V_BUS
and
V_LINE
voltages. The phase difference measured by the
protection relay has to be close to zero within the permitted accuracy tolerances. The
measured phase differences are indicated in the LHMI. At the same time, it is
recommended to check the voltage difference and the frequency differences presented in
the monitored data view. These values should be within the permitted tolerances, that is,
close to zero.
Figure 268 shows an example where the synchrocheck is used for the circuit breaker
closing between a busbar and a line. The phase-to-phase voltages are measured from the
busbar and also one phase-to-phase voltage from the line is measured.
GUID-8C044A41-24DE-44D0-AAB4-E52D6BD61BC5 V1 EN
Figure 268: Connection of voltages for the protection relay and signals used in
synchrocheck
1MRS240050-IB C
Section 9
Control functions
REF615R 507
Technical Manual