3.59
Date Code 20080103 Instruction Manual SEL-351S Relay
Overcurrent, Voltage, Synchronism Check, Frequency, and Power Elements
Power Elements (Available in Firmware Version 7)
Power Elements (Available in Firmware Version 7)
Four independent power elements are available. For wye-connected systems,
either single-phase power elements or three-phase power elements may be
enabled (but not both). For delta-connected systems, only three-phase power
elements may be enabled. The group setting EPWR setting determines how
many (and what type of) power elements are enabled:
EPWR = N (none), 1, 2, 3, 4 (single-phase); 3P1, 3P2, 3P3, 3P4
(three-phase) {wye-connected voltages}
EPWR = N (none), 3P1, 3P2, 3P3, 3P4 (three-phase) {delta-connected
voltages}
Each enabled power element can be set to detect real power or reactive power.
With SEL
OGIC control equations, the power elements provide a wide variety
of protection and control applications. Typical applications are:
➤ Overpower and/or underpower protection/control
➤ Reverse power protection/control
➤ VAR control for capacitor banks
Power Elements
Settings
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 (lagging)
–VARS: negative or reverse reactive power (leading)
Table 3.14 Single-Phase Power Element Settings and Setting Ranges
(EPWR = 1, 2, 3, or 4)
Settings Definition Range
PWR1P, PWR2P,
PWR3P, PWR4P
Power element
pickup
OFF, 0.33–13000.00 VA secondary,
single-phase (5 A nominal phase current
inputs, IA, IB, IC)
OFF, 0.07–2600.00 VA secondary,
single-phase (1 A nominal phase current
inputs, IA, IB, IC)
PWR1T, PWR2T,
PWR3T, PWR4T
Power element type +WATTS, –WATTS,
+VARS, –VARS
PWR1D, PWR2D,
PWR3D, PWR4D
Power element time
delay
0.00–16000 cycles, in 0.25-cycle steps
Table 3.15 Three-Phase Power Element Settings and Setting Ranges
(EPWR = 3P1, 3P2, 3P3, or 3P4)
Settings Definition Range
3PWR1P, 3PWR2P,
3PWR3P, 3PWR4P
Power element
pickup
OFF, 1.00–39000.00 VA secondary,
three-phase (5 A nominal phase current
inputs, IA, IB, IC)
OFF, 0.20–7800.00 VA secondary,
three-phase (1A nominal phase current
inputs, IA, IB, IC)
PWR1T, PWR2T,
PWR3T, PWR4T
Power element type +WATTS, –WATTS,
+VARS, –VARS
PWR1D, PWR2D,
PWR3D, PWR4D
Power element time
delay
0.00–16000 cycles, in 0.25-cycle steps
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