Automatic reclosing function and requirements - News - Global IC Trade Starts Here Free Products

First, the role of automatic reclosing in the power system Overhead line faults are mostly "instantaneous" faults. After the line is relayed by the relay protection and the action breaker is disconnected, the insulation level of the fault point can be recovered by itself, and the fault disappears. . At this time, if the disconnected line breaker is reclosed, normal power supply can be restored. In addition, there are also "permanent faults". After the line is disconnected, they still exist. Even if the power is turned on, normal power cannot be restored. Therefore, an automatic reclosing device is adopted in the power system, that is, a device that can automatically control the circuit breaker to be reclosed after the circuit breaker is tripped by relay protection action or other non-manual operation. Second, the role of reclosing in the power system

• Greatly improve the reliability of power supply and reduce the number of power outages.
• The use of reclosing on the high-voltage transmission line can improve the stability of the parallel operation of the power system.
• The use of reclosing on overhead lines can suspend the installation of double-circuit lines to save investment.
• False tripping caused by the malfunction of the circuit breaker itself or the malfunction of the relay protection can also play a corrective role.

However, when it coincides with a permanent fault, it will also have some adverse effects, such as: (1) causing the power system to be hit again by the fault; (2) because the circuit breaker is continuous in a short period of time The short-circuit current is cut off twice, making the working conditions worse. Third, the basic requirements for automatic reclosing devices

• In normal operation, the automatic reclosing device shall operate when the circuit breaker is tripped by relay protection action or other reasons.
• When the circuit breaker is manually operated by the operator or disconnected by the remote control device, the automatic reclosing should not be started.
• After the relay protection action is removed, the automatic reclosing device should issue a reclosing pulse as soon as possible.
• The number of automatic reclosing devices should be in accordance with the previous regulations.
• The automatic reclosing device should have the possibility of accelerating the relay protection before or after the reclosing to accelerate the removal of the fault.
• When reclosing is performed on the line of the double-side power supply, the reclosing should meet the synchronous closing condition.
• When the circuit breaker is in an abnormal state and the reclosing is not allowed, the automatic reclosing device should be blocked.