INTRODUCTION

Recently, LINEGEAR 2000 has been able to add load break capability to its TRISEC automatic sectionaliser, and this has now led to the development of a lower cost fuse-switch combination which does not require an ARC operation to cause isolation.

Non-automatic load break switches (TRILINK, TRISWITCH) and the automatic sectionaliser (TRISEC) for network control though the latter does need to operate in conjunction with an auto-reclosing circuit breaker (ARC). This widely used concept gives a tremendous improvement to network performance in many ways, but it does mean in terms of quality of supply that all consumers on the faulted feeder circuit must endure operations of the ARC prior to the disconnection of the actual fault. The load-break TRISEC is normally caused to open by signals from the CT operated logic circuitry and a DC trip coil powered from a lithium battery, but it has now been devised to trip by operation of the drop-out fuse as well.