New Concept Of High-Voltage Switchgear On-line Monitoring System

In power system, one of the key element is high voltage switchgear. Switchgear contains numerous types of high-voltage equipment: circuit-breakers, disconnectors, earthing switches, current and voltage transformers and surge arresters. On-line monitoring of high voltage switchgear provides: insight into real-time switchgear condition, condition based maintenance, incipient fault detection, prevention and reduction of fault consequences (cost reductions), continuous information on switchgear condition, information about high voltage switchgear operating conditions (loads at switching operations, assessment of the residual life), increased availability and fault cause analysis. In this paper a new concept of a bay monitoring system (BMS) is described. A various operational quantities of high voltage apparatuses in a 400 kV switchgear bay are on-line monitored. For example the following circuit breaker data are available: close coil current, trip coil current, hydraulic pressure, pressure drop, recharging time, inter locks, heaters control, SF6 pressure at 20 0C, SF6 temperature, SF6 dew point, SF6 density, variations of SF6 pressure at various operations, close trigger, open trigger, motor trigger, motor current, motor operation time, spring status, circuit breaker open/closed, Joule-integral, I2t, operating times (closing time, opening time, arcing time, break time, close-open time), contact velocity, contact travel etc. Main features and benefits of BMS are simple Ethernet-based communication which means simple LAN connectivity with other systems in a switchgear, reliable data collection, reliable controller operation, reliable power supply, quick access to data and a quick and simple retrieval of stored data via graphic user interface (wave shapes, measured values). If an application on the controller fails due to power failure, it will automatically start again when the normal power supply is re-established.