Relay Element Settings 2-43
SEL-300G Instruction Manual Date Code 20020206
Residual Time-Overcurrent Settings
Residual Time-O/C Pickup (OFF, 0.5–16.0 A) 51GP = 8.0
Residual Time-O/C Curve (U1–U5, C1–C5) 51GC = U2
Residual Time-O/C Time-Dial (0.50–15.00, U curves) 51GTD = 3.00
(0.05–1.00, C curves)
Residual Time-O/C EM Reset (Y, N) 51GRS = Y
51G Torque-Control Setting 51GTC = 1
The SEL-300G Relay provides inverse-time overcurrent elements for neutral and
residual current. Each of the elements includes a settable pickup, curve shape, and
time-dial. Ten curve shapes are available. Curves U1–U5 emulate the popular North
American induction disk relays. Curves C1–C5 emulate popular European analog
time-overcurrent relay operation. Operating characteristics of the available curves are
shown in Figure 2.27 to Figure 2.36.
When you select Y to enable electromechanical reset emulation, the relay provides a
slow reset that is dependent on the amount of current measured, similar to an induction
disk relay reset. When you select N, the relay fully resets the time-overcurrent element
one cycle after current drops below the pickup setting, similar to analog and many
microprocessor-based time-overcurrent relays. Select Y or N to match the operating
characteristic of other time-overcurrent protection protecting this generator.
Each of the inverse-time overcurrent elements is also equipped with a torque-control
setting. When the equation result is logical 1, the element is permitted to operate.
When the result is logical 0, the element is not permitted to operate. Use other
protection elements, logic conditions, or control inputs to supervise these elements if
desired.
Relay Word Bits
Relay Word Bit
Function Description Typical Applications
50P1
Level 1 Phase O/C Pickup Indication, Control
50P1T
Level 1 Phase O/C With Definite-Time
Delay
Indication, Control, Event
Triggering, SER Triggering
50P2
Level 2 Phase O/C Pickup Indication, Control
50P2T
Level 2 Phase O/C With Definite-Time
Delay
Indication, Control, Event
Triggering, SER Triggering
50N1
Level 1 Neutral O/C Pickup Indication, Control
50N1T
Level 1 Neutral With O/C Definite-Time
Delay
Indication, Control, Event
Triggering, SER Triggering
50N2
Level 2 Neutral O/C Pickup Indication, Control
50N2T
Level 2 Neutral O/C With Definite-Time
Delay
Indication, Control, Event
Triggering, SER Triggering
50G1
Level 1 Residual O/C Pickup Indication, Control
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