Verifying The Settings - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
11.4.12.1
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
Two current channels I3P1 and I3P2 are available in OOSPPAM function to allow
the direct connection of two groups of three-phase currents; that may be needed for
very powerful generators, with stator windings split into two groups per phase,
when each group is equipped with current transformers. The protection function
performs a simple summation of the currents of the two channels I3P1 and I3P2.

Verifying the settings

The test of the out-of-step protection function is made to verify that the trip is
issued if the following events happen.
• the impedance, seen by the function, enters the lens characteristic from one
side and leaves it from the opposite side
• the trip is issued according to the settings TripAngle and tBreaker
The tripping zone needs to be detected and confirmed. The test may be performed
by taking into account the following key points that are shown in Figure 40:
• the point RE (RE = Receiving End)
• the intersection between the line segment SE-RE and the X-line, which is
defined through the setting ReachZ1
• the point SE (SE = Sending End)
IEC10000141 V2 EN-US
Figure 40: Trajectory of the impedance Z(R, X) for the injected current with
two components: a 50 Hz component and a 49.5 Hz current
component
The test of the out-of-step protection function requires the injection of the analog
quantities for a quite long time. The rating of the analogue channels is considered
in order to avoid any hardware damage. The test current is lower than the
continuous permissive overload current I
the transformer module.
I = I(50 Hz) + I(49.5 Hz)
of the protection current channels of
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