4.140
SEL-700G Relay
Instruction Manual
Date Code 20170814
Protection and Logic Functions
Group Settings (SET Command)
Figure 4.97
Power Elements Operation in the Real/Reactive Power Plane
The power element type settings are made in reference to the load convention:
➤
+WATTS: positive or forward real power
➤
–WATTS: negative or reverse real power
➤
+VARS: positive or forward reactive power
➤
–VARS: negative or reverse reactive power
The four power element time delay settings ((PWRm1D–PWRm4D)) can be
set to have no intentional delay for testing purposes. For protection
applications involving the power element Relay Word bits, SEL recommends
a minimum time delay setting of 0.1 second for general applications. The
classical power calculation is a product of voltage and current, to determine
the real and reactive power quantities. During a system disturbance, because
of the high sensitivity of the power elements, the changing system phase
angles and/or frequency shifts may cause transient errors in the power
calculation.
For antimotoring protection of the generator, calculate the prime mover rated
motoring power. To ensure that the element securely detects this level of
Reverse
(Leading)
3PWR2
3PWR1
Forward
(Lagging)
Reactive
Power
Real
Power
3PWRY2P
(pickup)
3PWRY1P
(pickup)
PWRY1T =
+VARS
(type)
PWRY2T =
—VARS (type)
3PWR2
3PWR1
Reverse
Forward
Reactive
Power
Real
Power
3PWRX1P
(pickup)
3PWRX2P
(pickup)
PWRX2T =
—WATTS
(type)
PWRX1T =
+WATTS
(type)
Note: Highlighted area represents pickup region
R
Utility
Tie
IX
VX
IY
VY
SEL-700GT
52T
52G
X-Side Set as Real Power Elements
Y-Side Set as Reactive Power Elements
Summary of Contents for SEL-700G Series
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