Recloser

Automatic reclosing (AR ) or short interruption ( KU) is a term used in electrical power engineering. It is usually used to operated with high voltage power lines, since in this case the cause of the error as the one on the overhead line of fallen branch, lightning, etc. often goes away by itself or is removed by the arc.

Expiration

If, on an overhead line to a short circuit, often cause an arcing fault, which is not extinguished by itself. Since by the arc the cause of the error is often eliminated (ie, a branch that has fallen on the line, burns ), it performs an automatic reclosing. Here, the relevant circuit breaker trips due to an excitation of the line protection, but soon turns ( " pause " ) again automatically: for single-phase faults after about 0.5 to 3 seconds (variable part ), for three -phase faults after 0.2 to 0.5 sec.

If there is no more after restarting the error, one speaks of a successful AWE (AWE with success: AWE E. m. ). If the error still, one speaks of an unsuccessful (AWE AWE without success: AWE o E. ). In this case, the circuit breaker trips and remains switched off again.

The times given here are only a rough guide only and will depend on the voltage level and the network conditions and other factors. There are also several AWE successive cycles possible if the protection devices and circuit breakers are designed for this.

Requirements

Thus, a circuit breaker can perform AWE, it must be specifically designed for this: the drive (usually stored energy drive, now rarely compressed air and others) has the energy for at least three switching operations ( off-on - off) available in a short time from the memory have. If the circuit breaker with the ability to AWE line can turn on, which is usually the case, even the power for up to four switching operations needed ( on-off - on-off ). The control signals come here from a device in the field of power system protection. The device, which detects the error (eg, a distance protection relay), this is the trip command to the circuit breaker and after a set time ( " pause " ) to a command. If this relay after still detects an error switching on a final trip command can be carried out or start the cycle all over again.

Confines

At high-voltage cables no AR is performed usually. Error in cable networks have a destruction to the insulation, and often as a cause, eg by construction work. The damaged section of cable must first be located using cable fault location and then replaced.

Also in other parts of the plant such as power transformers and chokes AWE is performed. These system components are often permanently damaged by error, the error and the consequences must be dealt with first.