Introduction to the Basics of Automatic Circuit Recloser

Definition of Automatic Circuit Recloser

Automatic circuit recloser is a facility where, following a circuit breaker tripping due to some fault, the breaker is automatically reset using a mechanical device or relay automatic device.

Classification of Automatic Circuit Recloser

According to different features, it is commonly classified into the following types:

According to the type of action of the automatic circuit recloser, it can be divided into mechanical and electrical types.
According to the way automatic circuit recloser acts on the circuit breaker, it can be divided into three-phase, single-phase, and comprehensive reclosing.
According to the number of actions, it can be divided into single-action and double-action (multiple-action).
According to the usage conditions of automatic circuit recloser, it can be classified into single-side power reclosing and double-side power reclosing. Double-side power reclosing can be further divided into no-voltage check and synchronized reclosing, as well as asynchronous reclosing.

Principles for the Selection of Automatic Circuit Recloser

The reclosing method must be determined based on the specific system structure and operating conditions after analysis.
If a simple three-phase reclosing method can meet the actual needs of the specific system, then three-phase reclosing should be selected for the line. Particularly, for those lines in a dense ring network in a centralized power supply area that can still operate stably without reclosing after a trip, it is more appropriate to use a three-phase reclosing with an appropriately set time. For such ring network lines, quickly removing faults is the primary important issue.
When a single-phase ground fault occurs, if using three-phase reclosing cannot ensure system stability, or if a large area power outage in the regional system, or affects important load power outage on the line, single-phase or comprehensive reclosing method should be selected.
Three-phase reclosing is generally not used at large unit exits.

Measures for the Lockout of Reclosing Devices

When the reclosing method is deactivated, the automatic circuit recloser is directly locked.
When manually tripping, the automatic circuit recloser is directly locked.
When tripping without passing through automatic circuit recloser protection, the automatic circuit recloser is locked.
When using single-phase reclosing, if the circuit breaker trips three times, the automatic circuit recloser is locked by the position switch contacts; when tripping through comprehensive reclosing three times, the reclosing is locked.
When the pressure or hydraulic pressure of the circuit breaker drops to a level not allowing automatic circuit recloser, the automatic circuit recloser is locked.