Differential protection of microgrids over a WiMAX network

Abstract

One of the widely used methods for protecting power system elements is the Line Current Differential Protection (LCDP) schemes that works by comparing the vector difference between the measured currents at two or more line-terminals. Communications network plays a vital role in such schemes since the local and the remote line-terminals must exchange their current elements to perform the differential calculation. This paper investigates the use of an IEEE 802.16/WiMAX based wide-area wireless communications network to support LCDP schemes in the smart microgrids. The possible use of the WiMAX network as a synchronization source to the differential relays is also proposed. Using theoretical capacity analysis, the paper examines the use of advanced WiMAX features such as persistent scheduling, robust header compression and grant synchronization to efficiently support such a scheme. In addition, simulations were conducted using an OPNET simulation model to analyze the communications performance of the scheme in terms of packet-loss and delay. The results indicate that a WiMAX network along with its advanced features is particularly well-suited to meet the challenging requirements of a differential protection scheme.