Is Your Anti-Pumping Circuit Truly Reliable?

TonyZhang
Jan 5
5 min read

Anti-Pumping: A “Must-Have” That Still Goes Wrong in Practice

In high-voltage circuit breaker control circuits, anti-pumping (anti-reclose on an active command) is not optional. It is written into relay protection and anti-misoperation guidelines as a hard requirement:

Before a breaker has completed one open–close–open sequence, the close coil must not receive another effective close command.

Yet in real projects, two recurring issues still appear:

Misuse of the breaker open/close auxiliary contacts, leading to so-called “anti-pumping” that does not actually block repeat closing.
Operate time of the auxiliary relay cannot keep up with a modern high-speed breaker, so the anti-pumping logic does not assert in time.

Both issues have the same root cause: the anti-pumping circuit is assembled with generic interposing relays and ad-hoc wiring, rather than using a purpose-built anti-pumping relay with defined logic and timing.

ODES has developed anti-pumping relay families specifically for this application, used in primary control cubicles and secondary protection panels across tens of thousands of bays. More details on these solutions are available at www.odes-electric.com.

1. Where Anti-Pumping Really Matters: Three Typical Scenarios

1.1 Circuit Breaker Close / Trip Control Circuits

In the breaker closing circuit, if the close command contact (local control switch or automatic reclose output) sticks or fails to return to its “off” position, and the anti-pumping circuit is ineffective or missing, the breaker can be driven into repeated close–open–close sequences.

The consequences are:

Severe electrical and mechanical stress on the breaker poles and operating mechanism.
Possible miscoordination with protection and interlocking schemes.
Reduced reliability and shortened maintenance intervals.

A properly engineered anti-pumping circuit ensures that one sustained close command produces at most one closing operation, regardless of how long the command contact remains operated.

1.2 Primary Control Cubicles – Local / Remote Switching

In primary control cubicles and bay control cabinets, anti-pumping logic must often coexist with:

Local / remote selector switch
Local close and trip pushbuttons
Close circuit supervision and blocking logic

When the circuit is assembled from multiple generic auxiliary relays, the wiring quickly becomes complex:

Contact allocation is inconsistent across panels.
Commissioning engineers must reconstruct the logic from drawings.
Long-term reliability depends heavily on wiring quality and documentation.

Dedicated anti-pumping relays simplify this picture by embedding the logic inside one device, with clearly defined NO/NC contact groups for the anti-pumping function.

1.3 Coordination with Protection and Automatic Reclosing

On the secondary side, anti-pumping must coordinate with:

Protection output contacts
Automatic reclosing logic
Close circuit supervision and interlocks

Here, operate time, contact synchronism and EMC immunity of the anti-pumping relay directly influence system behaviour. A slow or inconsistent relay can:

Allow a second close command before the breaker has fully opened, or
Interfere with complex reclosing sequences that rely on precise timing.

For high-speed GIS/HGIS and EHV breakers, the margin between “safe” and “too late” is only a few milliseconds, so relay performance becomes critical.

2. Why Anti-Pumping Circuits Must Be Purpose-Designed

From a relay protection standpoint, the goal of anti-pumping is simple to state:

As long as the breaker has not completed its current operation, no new close command is allowed to energize the close coil.

To guarantee this in real installations, three engineering conditions must be satisfied:

Deterministic logic
Fixed and documented contact grouping
Operate time matched to the breaker

If a control circuit is assembled from ordinary auxiliary relays without these constraints, typical errors include:

Wrong choice between N.O. and N.C. contacts
Contact groups wired in the wrong order, creating logic gaps
Relay operate time too slow for the breaker type

This is why more and more projects now specify dedicated anti-pumping relays instead of “generic relays plus custom wiring” for this function.

3. Engineering Configurations for Anti-Pumping Relays

For most projects, there are two practical configuration philosophies.

3.1 Integrated Anti-Pumping Relay – Embedded Logic

In the first approach, a dedicated anti-pumping relay integrates the logic inside the device:

The internal contact arrangement and coil logic implement the anti-pumping function.
External wiring is reduced to a few standard terminals.
NO/NC contacts are pre-grouped for typical breaker control and monitoring circuits.

This approach is well suited for:

Primary control cubicles in AIS/GIS bays
Conventional breakers with standard operating times
Projects aiming for consistent bay-to-bay wiring and simplified commissioning

For design engineers, the integrated relay allows anti-pumping to be treated as a standard symbol in the schematic rather than a small bespoke logic network built from several interposing relays.

3.2 High-Speed UEG Anti-Pumping Relay – For Fast Breakers

For high-speed breakers, especially modern GIS / HGIS equipment and systems with strict reclosing performance requirements, standard relay operate times may not provide enough margin.

The UEG series high-speed anti-pumping relay is optimized for these cases:

Typical operate time ≤ 7 ms
Contact sets arranged specifically for anti-pumping and close circuit supervision
Suitable for use in high-voltage GIS/HGIS and rapid auto-reclose schemes

Engineering benefits include:

Sufficient timing margin to establish anti-pumping before a fast breaker completes its stroke.
Clear separation of anti-pumping contacts and monitoring contacts, reducing wiring errors.
A single family of relays that can be specified wherever high-speed anti-pumping is required.

4. Reliability Requirements for Anti-Pumping Relays

Anti-pumping relays are placed in the critical path of the close circuit. When they are required to operate, they must do so correctly, under the same environmental and electrical stresses as the primary equipment.

A hydropower or transmission-grade anti-pumping relay must therefore address three areas.

4.1 Standards and Application Scope

The design philosophy is aligned with:

Relay protection and anti-misoperation guidelines such as DL/T 478.
Low-voltage switchgear and controlgear standards such as GB/T 14048.5 or corresponding IEC standards for control circuit devices.

This ensures that the relay is developed as a power system control component, not just as a modified industrial relay.

4.2 Electrical and Environmental Robustness

Typical target parameters for a dedicated anti-pumping relay include:

Insulation resistance ≥ 100 MΩ
Dielectric withstand around AC 2 kV for 1 min between coil and contacts
Operating temperature from −25 °C to +70 °C for use in outdoor switchyards and unconditioned rooms
Flammability of insulating materials at UL94 V-0 level

These values map directly to the reality of high-voltage switchgear and protection panel environments, where temperature, humidity and transient stress are more demanding than in generic industrial control panels.

4.3 Proven Field Performance

For a function as fundamental as anti-pumping, field data matters as much as laboratory tests. Over two decades, ODES anti-pumping relays have been deployed in:

Primary high-voltage switchgear close circuits
Substation secondary protection and control panels
Mixed AIS/GIS installations and retrofit projects

With hundreds of thousands of units operating in service, their behaviour has been validated across a wide spectrum of system voltages, breaker types and environmental conditions, giving design engineers the confidence to adopt them as standard parts in bay control designs.

Conclusion: Anti-Pumping as a Standardised Protection Function, Not a Wiring Trick

Anti-pumping is more than a couple of contacts around a breaker close coil. It is a defined protection and anti-misoperation function that must be engineered with:

Deterministic logic independent of operator behaviour
Fixed, documented contact groupings tailored to breaker control circuits
Operate times matched to modern high-speed breakers
Electrical and environmental robustness proven over long-term service

By adopting dedicated anti-pumping relays—both integrated logic types and high-speed variants—owners and integrators can transform anti-pumping from a custom wiring exercise into a repeatable, verifiable design pattern across primary and secondary systems.

For more on ODES anti-pumping relay families and auxiliary control solutions, visit https://www.odes-electric.com/sales-page

If you are reviewing breaker control circuits or updating bay standards, ODES can help you consult on anti-pumping architectures, request typical UEG anti-pumping relay wiring schemes, and learn how to standardise these relays across primary control cubicles and secondary protection panels.