SE7710465L - DEVICE FOR AUTOMATIC RECONNECTION OF POWER SWITCHES - Google Patents

Abstract

This network protection device for very high-voltage networks whose star point is earthed and which are equipped with line protection devices (Sch) which, at the line ends, are allocated to the respective junction or are common to all the junctions of one or more stations and cause the power circuit breaker (LS) to switch off on the basis of detected disturbance criteria, has a logic gating circuit in addition to each line protection device (Sch), or which is common to all the line protection devices. This gating circuit has circuits (1) for identifying the operating state and defective state, data collection and identification, a circuit (2) for initiating a single-pole or three-pole brief interruption, a circuit (3) for influencing the sequence of disturbances and a circuit (4), which is known per se, for automatically switching the power circuit breaker (LS) on again. A standby protection circuit (5) is additionally provided for tripping the power circuit breaker if a protection failure occurs. By means of this network protection device, on the one hand the behaviour of any line disturbance is monitored without delay and, in the event of an abnormal behaviour, steps are taken in this way to limit the extent of the disturbance to a minimum; on the other hand, a line disconnection which is necessitated by a defect is maintained only as long as said disconnection is absolutely necessary to overcome the defect in order that the required transportation path is available again after the shortest possible interruption. In the event of a failure of the line protection, the standby protection circuit causes the power circuit breaker to trip at the right time and avoids serious consequences of disturbances. <IMAGE>