9171300990 Rev R
BE1-87T Installation
4-25
CAUTION
Assigning 30° Phase Shift Compensation requires disassembly of the relay, and must be
done when the relay has been taken out of service. Access to the 30° Phase Shift
jumpers requires the removal of the Analog #2 Board, shown in Figure 4-27. To avoid
personal injury or equipment damage, do
NOT
proceed unless thoroughly familiar with
the instructions in the sections on
RELAY OPERATING PRECAUTIONS
and
RELAY
DISASSEMBLY: Precautions
.
30° Phase Shift Compensation Adjustment Procedure
The position of a set of movable jumpers on Analog Board #2 determines the state of the internal
compensation. To gain access to these jumpers, it is necessary to remove Analog Board #2. Refer to the
topic
RELAY DISASSEMBLY
for instructions on gaining access to the circuit board then adjust the
jumpers shown in Figure 4-27 as follows:
•
In cases where no phase shift is wanted, all three jumpers (
φ
A,
φ
B, and
φ
C) shown in Figure 4-
27 are in the
WYE-WYE
position. (Relays are shipped with all jumpers in this position.)
•
If one of the inputs requires a shift in phase, the jumpers for all three phases are moved as
follows:
1. The
Δ
2 position develops A-B, B-C, C-A.
2. The
Δ
1 position develops A-C, B-A, C-B.
NOTE
The result of each of these vector differences has a magnitude of the square root of three
times each component.
The internal phase shift compensation is performed electronically as shown in the chart of Figure 4-27.
The internal compensation can apply to any power transformer with any combination of wye, delta or
autotransformer winding connections.
A procedure to check the differential balance is described later in this section,
CHECKING THE RELAY
SETTINGS AND SYSTEM INPUTS.
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