Schweitzer Engineering SEL-387-0, Инструкция по эксплуатации

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3.50
SEL-387-0, -5, -6 Relay Instruction Manual Date Code 20170601
Differential, Restricted Earth Fault, Thermal, and Overcurrent Elements
Overcurrent Element
Figure 3.18 50Pn1 Phase Definite-Time O/C Element, Torque Controlled
50Pn2–Phase Instantaneous Element
Figure 3.19 shows the logic for the 50P n 2 element. The 50P n 2 element logic
compares magnitudes of phase input currents IAW n , IBW n , and ICW n to
pickup setting 50P n 2P. If one or more current magnitudes exceed the pickup
level, a logic 1 asserts at one input to the AND gate. The torque-control
SEL
OGIC
control equation 50P n 2TC determines the other AND input. If
50P n 2TC is true, Relay Word bit 50P n 2 asserts.
Figure 3.19 50Pn2 Phase Instantaneous O/C Element, Torque Controlled
50Pn3 and 50Pn4–Phase Instantaneous Element
Figure 3.20 shows the logic for the two nontorque-controlled phase
instantaneous elements. The two elements find application primarily in level
detection or phase identification. The logic compares magnitudes of phase
input currents IAWn, IBWn, and ICWn to pickup setting 50P
n 3P(4P). Any
phase current exceeding the pickup level will assert the appropriate phase-
specific Relay Word bit, 50A
n 3(4), 50B n 3(4), or 50C n 3(4). These bits enter
an OR gate to assert Relay Word bit 50P n 3(4), indicating “any phase” pickup.
Figure 3.20 50Pn3 and 50Pn4 Phase Instantaneous O/C Element,
Nontorque Controlled
+
–
D
0
50Pn1T
–
+
+
–
50Pn1
D = 50Pn1D
(n = Winding 1, 2, 3, or 4)
|IAWn|
|IBWn|
|ICWn|
50Pn1P
Relay
Word
Bit
Relay
Word
Bit
50Pn1TC (SEL
OGIC
control equation TRUE)
+
–
–
+
+
–
50Pn2
(n = Winding 1, 2, 3, or 4)
|
IAWn
|
|
IBWn
|
|
ICWn
|
50Pn2P
Relay
Word
Bit
50Pn2TC (SEL
OGIC
control equation TRUE)
+
–
–
+
+
–
50Pn3(4)
(n = Winding 1, 2, 3, or 4)
|
IAWn
|
|
IBWn
|
|
ICWn
|
50Pn3P
(4P)
50An3(4)
50Bn3(4)
50Cn3(4)
Relay
Word
Bits
Relay
Word
Bits