Sel SEL-421 - Trip Logic Enable Options

R.2.26
SEL-421 Relay Reference Manual Date Code 20111215
Auto-Reclosing and Synchronism Check
Two-Circuit-Breaker Auto-Reclosing
EXAMPLE 2.1 Conditional Three-Pole Tripping for Circuit Breaker
BK2
Your system reclosing requirement is that Circuit Breaker BK2 always
three-pole trips, unless Circuit Breaker BK2 is the leader. (This occurs
when Circuit Breaker BK1 is out of service.) Program SEL
OGIC control
equation ESPR2 as follows:
ESPR2 := LEADBK2 AND BK1LO Single-Pole Reclose Enable—BK2 (SELOGIC Equa-
tion)
Trip Logic and
Reclose Sources
Internal Recloser
Program the SEL-421 recloser function to drive the trip logic with Relay Word
bits R3PTE (Recloser Three-Pole Trip Enable), R3PTE1 (Circuit Breaker
BK1 Recloser Three-Pole Trip Enable) and R3PTE2 (Circuit Breaker BK2
Recloser Three-Pole Trip Enable) as follows:
E3PT := R3PTE Three-Pole Trip Enable (SELOGIC Equation)
E3PT1 := R3PTE1 Breaker 1 Three-Pole Trip (SELOGIC Equation)
E3PT2 := R3PTE2 Breaker 2 Three-Pole Trip (SELOGIC Equation)
These settings connect the internal SEL-421 recloser for both three-pole
reclosing and single-pole reclosing.
Enter enable settings ESPR1 and E3PR1 as appropriate for your application.
The SEL-421 is a single-pole tripping relay; that is, if E3PT is logical 0 and
E3PT1 equals logical 0, the relay can single-pole trip Circuit Breaker BK1. If
E3PT1 equals logical 1, the relay can only three-pole trip Circuit Breaker 1.
The same conditions apply to setting E3PT2 and Circuit Breaker BK2.
Tab le 2.23 summarizes the relay trip logic enable options.
Relay Word bits R3PTE1 and R3PTE2 both equal logical 1 for any of the
following conditions when Global setting NUMBK (Number of Breakers in
Scheme) is 2 and SPLSHT (Single-Pole Last Shot) is asserted (see
Figure 2.8):
➤ BK1TYP and BK2TYP equal 3 (Circuit Breaker 1 and Circuit
Breaker 2 Trip Type)
➤ NSPSHOT := N (Number of Single-Pole Reclosures)
Table 2.23 Trip Logic Enable Options
Enable Condition Circuit Breaker BK1 Circuit Breaker BK2
E3PT E3PT1 E3PT2
Single-
Pole Trip
Three-
Pole Trip
Single-
Pole Trip
Three-
Pole Trip
000x x
001x x
010 xx
011xx
100xx
101xx
110xx
111xx