Relay protection device anti-pumping relay

An anti-pumping relay prevents a circuit breaker from repeatedly closing under continuous close commands, ensuring safe operation and protecting equipment from damage.

Function and Purpose

The anti-pumping relay is a protective auxiliary device used in circuit breaker systems to prevent multiple or repeated closing operations, commonly referred to as "pumping" ( ). Pumping occurs when a continuous close command is applied while a fault persists, causing the breaker to open and close repeatedly. This can damage the breaker mechanism, trip coils, and associated equipment, and may create unsafe electrical conditions ( ). The device ensures that only one close operation is allowed per close command, even if the operator or control system continues to send a closing signal ( ).

Working Principle

The anti-pumping relay typically uses circuit breaker auxiliary contacts and operates as a Normally Open (NO) contact:

• When the circuit breaker is closed, the relay is in the NO state, preventing current from flowing to the closing coil if another close command is issued ( ).
• When the circuit breaker is open, the relay is in the Normally Closed (NC) state, allowing the breaker to close when a command is given ( ). The sequence of operation is as follows ( ):

1. Normal Close Command: The breaker receives a close command and closes.
2. Relay Seals Itself In: The anti-pumping relay coil energizes, changing its contact state.
3. Opens the Close Circuit: The NC contact opens, disconnecting the closing coil from the control circuit.
4. Reset Condition: After the breaker operates and the fault is cleared, the relay resets, ready for the next close command. This logic ensures that even if the close button is held down or a continuous signal is present, the breaker will not repeatedly close.

Wiring and Application

• The anti-pumping relay is wired in series with the circuit breaker closing coil ( ).
• It is commonly used in generator/alternator breakers, grid breakers, and other high-voltage auxiliary breakers ( ).
• The relay can be implemented as a dedicated relay or a high-speed contactor, depending on manufacturer design ( ).
• It does not require additional auxiliary relays; the breaker's own contacts or multiplier relays can be used for connection ( ).

Importance

Using an anti-pumping device is mandatory for all types of circuit breaker closing circuits. It protects the breaker from mechanical damage, prevents abnormal voltage and current conditions, and ensures safe operation of the electrical system ( ). In summary, the anti-pumping relay is a critical interlock in breaker closing circuits, providing a simple yet effective method to prevent repeated closing and maintain system safety.