Application of single pole auto reclosing in distributaion networks with high pentration of DGS

Due to continued penetration of DG into existing distribution network, the tripping of DG during network fault condition may affect the network stability and reliability. Operation of DG should be remain during network temporary fault as far as possible in order to maximise the benefits of interconnection of DG and increase reliability of power supply service to consumers. Conventional three pole auto recloser in distribution network become incompatible with the presence of DG because it interrupts the operation of DG during network temporary single phase to earth fault event and cause unnecessary disconnection of DG. Therefore the application of single pole auto reclosing scheme (SPAR) which is widely used in transmission network should be considered in distribution network with DG. Literature survey shows that no investigation has been carried out for the application of fault identification and phase selection techniques to single pole auto reclosing scheme in distribution networks with high penetration of DG. This paper presents the development of an adaptive fault identification and phase selection scheme to be used in the implementation of SPAR in power distribution network with DG. The proposed method uses only three line current measurements at the relay point. The value of line current during prefault condition and transient period of fault condition is processed using condition rules with IF-THEN in order to determine the faulty phase and to initiate single pole auto reclosure. The analysis of the proposed method is performed using PSCAD/EMTDC power system software. Test results show that the proposed method can correctly detect the faulty phase within one cycle. The validity of the proposed method has been tested for different fault locations and network operating modes.