Introduction: Sub.net is a substation based multifunction disturbance recorder, which monitors various aspects of the power network. It is connected to protection VTs and CTs and auxiliary contacts from protection relays and switchgear. Sub.net process the information at site and sends formatted reports of events detected on the network directly to individual users by email.

It is possible to capture an event and distribute the processed data in around three minutes to the parties that can take the appropriate action. Monitors should be able to aid early indication of 11kV fault location, confirm that overhead line protection or automation schemes are functioning properly and determine if circuit breaker operating times are within acceptable limits, in addition to covering the full range of Power Quality phenomenon.

Objectives: There is a continuing business need to improve system performance. By processing data in as near real time as possible and disseminating necessary information to the appropriate staff, corrective action can be taken in the most expedient manner.