6–114 339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION CHAPTER 6: SETPOINTS
Directional power (32)
The Directional Power element responds to three-phase directional power and is designed
for reverse power (32REV) and low forward power (32FWD) applications for synchronous
machines or interconnections involving co-generation. The relay measures the three-
phase power from either a full set of wye-connected VTs or a full-set of delta-connected
VTs. In the latter case, the two-wattmeter method is used. The function has two
independent elements; typically one element is used for alarming and the other stage for
tripping.
The element has an adjustable characteristic angle and minimum operating power as
shown in the Directional Power characteristic diagram. The element responds to the
following condition:
Where:
P and Q are active and reactive powers
angle theta is the element characteristic (RCA) angles
SMIN is the minimum operating power.
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