Investigation into the implementation of auto reclosing scheme in distribution networks with high penetration of DGs

Abstract

Renewable energy driven distributed generators (DGs) are mostly connected to radial distribution network with overhead feeders. It is estimated that 80% of network faults are temporary single phase to ground faults and therefore automatic restoration is required. A combination of automatic re-closer devices, circuit breaker, sectionalizer and fuse is applied to clear the temporary fault and isolate the permanent fault in order to optimise the service continuity to customers. Investigation into the sustainability of different DG technologies during temporary faults on overhead network should be carried out to (i) assess the possibility of preserving DG in services as far as possible to optimise the electric supply continuity and (ii) identify the requirements of automatic restoration in distribution networks with high penetration of DGs. On the other hand, it has been reported that future distribution networks are very likely to be operated in ring mode in order to maximise the installed capacity of distributed generation. The ring network operation mode will need special considerations in network feeder protection compared to radial network operation mode in the context of DG. Thus the implementation of auto reclosing in ring network with DG will also need further investigation. This paper reports an investigation into the impact of different wind power based distributed generations on auto reclosing schemes in MV overhead distribution networks that are operated in radial and ring modes. The paper is divided into two parts; the first part present literature survey on the development of system protection schemes in power distribution network with high penetration of DG. The second part present results of dynamic simulation studies on the operation of auto reclosing scheme in network with DGs when operated in different operating modes. A particular emphasis is placed on examining the application of single pole auto reclosing scheme in the distribution network.