Reclosing is a type of relay protection

Yes, reclosing is considered a form of relay protection, specifically an automatic reclosing function integrated with protective relays to restore power after transient faults.

Overview of Reclosing

Reclosing, often implemented as Automatic Reclosing (ARC), is a protection strategy in power systems where a circuit breaker is automatically reclosed after a fault is detected and cleared. It is designed to handle transient faults—such as lightning strikes, tree contacts, or temporary line surges—that resolve themselves without permanent damage, allowing the system to restore service quickly without manual intervention .

How Reclosing Works

1. Fault Detection & Trip: Protective relays (e.g., overcurrent or distance relays) detect abnormal current or voltage and trigger the circuit breaker to trip, isolating the faulted section .
2. Dead Time Delay: A short delay (typically 0.3–1 second for overhead lines) allows the fault arc to dissipate .
3. Reclosing Attempt: The reclosing relay issues a command to reclose the breaker. If the fault has cleared, normal operation resumes; if not, the breaker trips again .
4. Lockout Decision: After a predefined number of unsuccessful attempts (usually 1–4), the ARC locks out to prevent repeated stress on equipment .

Reclosing as Relay Protection

Reclosing is integrated with protective relays and is considered part of the relay protection scheme because it relies on relay logic to detect faults, control breaker operations, and determine whether faults are transient or permanent. It complements traditional protective relays by reducing unnecessary outages and improving system reliability, especially in overhead distribution networks where transient faults are common .

Standards and Implementation

Reclosers and reclosing relays are governed by standards such as IEC 62271-111, IEEE C37.60, and ANSI 79, which define operational limits, timing, and the number of reclose attempts . They are often integrated into rated circuit breakers with current and voltage sensors, making them both a switching device and a protection asset .

Key Takeaway

While reclosing is not a protective relay in the traditional sense (like overcurrent or distance relays), it functions as a protection relay feature that automatically restores service after transient faults. It is an essential part of modern power system protection schemes, enhancing reliability and minimizing downtime .