Date Code 20171006 Instruction Manual SEL-400 Series Relays
Instruction Manual
SECTION 6
Autoreclosing
This section describes the operation of autoreclose logic in SEL-4XX relays that
include an autorecloser. This section covers the following topics:
➤ Autoreclosing States on page 6.2
➤ One-Circuit-Breaker Autoreclosing on page 6.4
➤ Two-Circuit-Breaker Autoreclosing on page 6.10
➤ Autoreclose Logic Diagrams on page 6.26
➤ Manual Closing on page 6.40
➤ Voltage Checks for Autoreclosing and Manual Closing on page 6.43
➤ Settings and Relay Word Bits for Autoreclosing and Manual Closing
on page 6.45
The relay autoreclose function provides complete control for single circuit
breaker and two circuit breaker reclosing schemes. The autoreclose function
accommodates both single-pole and three-pole reclosing. Some SEL-400 series
relays only support three-pole operations. See the Features subsection in
Section 1: Introduction and Specifications in the product-specific instruction
manual to determine the reclosing capability of each relay. Relays that support
single-pole breaker operations can be set for a total of two single-pole reclose
shots. Three-pole breaker operations can be set for as many as four three-pole
reclose shots.
You can designate the leader and follower circuit breakers in a two-circuit
breaker configuration. The relay recloser can dynamically change leader and fol-
lower designations based on settings and operating conditions.
You can program the autoreclose logic to perform one shot of high-speed three-
pole reclose. This high-speed three-pole shot replaces one of the four delayed
time three-pole shots. There is no difference between a shot of high-speed three-
pole reclose and a shot of delayed three-pole autoreclose; simply select the open
interval time accordingly.
NOTE: The relay voltage check
elements (for bus and line voltages)
may be used without the synchronism
check feature, however, for certain
voltage connections, some of the
synchronism check settings need to
be entered to ensure that the correct
voltages are used.
Two autoreclose modes are available when using the relay to control two circuit
breakers:
➤ Combined two-breaker mode (setting E79 := Y)—both circuit
breakers must trip before any reclosing can occur.
➤ Independent two-breaker mode (setting E79 := Y1)—the follower
circuit breaker can trip and reclose even when the lead breaker has
not operated. This is useful on both ring bus and breaker-and-a-half
schemes, where the follower breaker is a tie breaker that can be
tripped by protection on either side.
For single circuit breaker applications, use setting E79 := Y.
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