Experience of disturbance recorders in an island power system

Northern Ireland Electricity´s total system load varies from 1450 MW (winter peak) to 300 MW (summer). Main transmission is 275 kV and sub transmission is 110 kV. There are four power stations and sixteen 275 kV circuits. Close monitoring of equipment performance during system faults is essential since low reliability of power lines or protection could result in system shutdown under storm conditions. Here, the authors describe how Northern Ireland Electricity has had an active role in the development and use of microcomputer based power system disturbance recorders, since the first trials conducted in 1978