The unreliability and instability of Loss of Mains (LoM) protection is a well know problem. This protection is designed for avoiding any embedded station being islanded but they are often triggered unnecessarily due to disconnection of generation under large system disturbance conditions (e.g. large loss of infeed or generation). This could be a risk to system security. As the volume of embedded plant has increased to over 6 GW and is expected to continue to increase, the risk on the system could become unmanageable. It is therefore important to improve the reliability performance of this type of protection. The proposed project is to explore an alternative way of using up-to-date technology for LoM protection without jeopardising system security.

Objectives

This research project will investigate the potential for further improvement of the stability of DG connections during system-wide events by taking advantage of existing and emerging communication technologies such as satellite and/or internet. Satellite communications may form a particularly viable solution for remote and offshore locations (where many wind farms are, or will be, installed); whereas internet could preferably be used in urban areas. Satellite communications have not been widely applied in protection systems due to the assumed limited (or rather unknown) reliability of this medium. Therefore, it is believed that in addition to the development of novel LoM methods, the key to the successful deployment of such technologies in the protection domain is the rigorous assessment of the reliability of the communication media.