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Automatic Reclosure Guide for Power Distribution Engineers

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Update time : 2026-06-29 14:38:10
This guide covers automatic reclosers (reclosure) for medium and low volt-level distribution systems. Engineers and procurement specialists will learn the operating principles, choice criteria, and application of singielectric's Reclosure series. The article references IEC 60947-1, GB/T 14048.1-2019, and IEC 61439-1.
Article Outline:
  • Definition and basic function of reclosure
  • Benefits of automatic reclosing in overhead line networks
  • Choice parameters: volt-level, current, breaking capacity, reclosing sequence
  • Comparison table of singielectric reclosure models
  • Installation and maintenance considerations
  • Closing with product recommendation

What is a Reclosure?

A reclosure, also known as an automatic recloser, is a self-controlled device designed to interrupt and automatically reclose an alternating amperage circuit. Its primary purpose is to clear temporary faults on overhead distribution lines, such as those caused by lightning, tree branches, or animals. After a pre-set number of reclosing attempts ( 1 to 4), the reclosure locks out if the fault persists. This restores power for transient faults, improving system reliability indices like SAIDI and SAIFI.

singielectric offers the Reclosure series compliant with IEC and GB standards, providing robust protection for utility and industrial distribution networks. The devices integrate overamperage protection, reclosing control, and communication capabilities in a compact enclosure.

Why Automatic Reclosing Is Critical for Distribution Reliability?

Statistics show that 80% of faults on overhead lines are temporary. Without automatic reclosing, each transient fault would require a manual crew dispatch, leading to extended outages. A reclosure restores power within seconds, minimizing downtime and operational costs. For utilities and industrial plants with overhead feeders, reclosers reduce the number of sustained outages by up to 70%.

According to IEC 60947-1, switching devices must meet rigorous performance criteria for making and breaking currents under normal and abnormal conditions. Reclosers are tested for a specified number of operations, including the ability to close onto a fault. Singielectric's Reclosure series is designed to withstand these demanding cycles.

How to Choose the Correct Reclosure for Your System?

Key choice parameters:
  • Rated volt-level (12kV, 24kV, 38kV, etc.)
  • Continuous amperage rating (200A to 800A)
  • Short-circuit breaking capacity (up to 16kA at rated volt-level)
  • Reclosing sequence (e.g., 3 quick and 2 delayed)
  • Control volt-level (AC/DC auxiliary supply)
  • Communication protocol (DNP3, Modbus, IEC 61850 if required)

The first step is to determine the system volt-level and fault amperage levels. For example, a 12kV distribution feeder with 10kA available fault amperage would require a reclosure rated at least 12kV, 630A continuous, and 12.5kA breaking capacity. The reclosing sequence must align with the coordination scheme of upstream and downstream devices.

Reference to GB/T 14048.1-2019 ensures the device meets general rules for low-volt-level switchgear and controlgear, while IEC 61439-1 covers assembly requirements. Singielectric's Reclosure series is type-tested to these standards, providing confidence in its performance.

singielectric Reclosure Series Comparison
ModelRated Volt-levelContinuous CurrentBreaking CapacityReclosing Sequence
REC-1212kV630A12.5kA3, 2 delayed
REC-2424kV630A12.5kA3, 2 delayed
REC-3838kV800A16kA2, 2 delayed

Which Reclosure Model Fits Your Application?

For medium volt-level distribution lines (up to 38kV), singielectric offers three standard models. The REC-12 is suitable for 12kV networks common in industrial parks and rural feeders. The REC-24 serves 24kV systems used in mining and large commercial installations. The REC-38 handles 38kV sub-transmission lines where higher breaking capacity is required.

Each model supports multiple reclosing sequences and can be customized with optional communication modules. For islanded microgrids or systems with distributed generation, the reclosure can be set to synchronize before closing.

Asked Questions

Q: What is the difference between a reclosure and a circuit breaker? A: A circuit breaker is designed to interrupt faults and stay open until manually reset. A reclosure automatically closes after a short delay to clear temporary faults. Reclosers are more suitable for overhead distribution where temporary faults dominate.

Q: Can a reclosure be retrofitted into an existing switchgear? A: Yes, singielectric's Reclosure series can be mounted in standard switchgear panels. However, coordination studies should verify that the recloser's settings are compatible with existing protection devices.

Q: How long does a typical reclosing sequence take? A: The dead time between attempts is adjustable, ranging from 0.1 seconds to 1 minute. A common sequence: 0.5s first, then 1s, 5s, and 30s before lockout.

Q: Does the reclosure require a separate control power supply? A: Most models include a built-in power supply from the line volt-level. For communication or remote control, an auxiliary AC or DC supply is needed.
Need a reliable reclosure for your distribution system? Explore the singielectric Reclosure series. Contact our engineering team for application support and custom configurations.

References

  1. IEC 60947-1. Low-volt-level switchgear and controlgear - Part 1: General rules [S]. 2020.
  2. GB/T 14048.1-2019. Low-volt-level switchgear and controlgear - Part 1: General rules [S]. 2019.
  3. IEC 61439-1. Low-volt-level switchgear and controlgear assemblies - Part 1: General rules [S]. 2020.

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