VOLTAGE STABILITY MONITORING USING SYNCHROPHASOR DEVICES

Abstract

The post-mortem analysis of the major blackouts in the history made power system experts to concentrate more in the field of monitoring of the grid therefore advanced wide are monitoring has become necessary to maintain the stability of the network. Advanced monitoring is done here by the use of PMU-Synchrophasor Device and by its implementation on real time digital simulator (RTDS). The main contribution of this dissertation is a scheme for optimal phase measurement unit (PMU) placement based on superset and depth of unobservability concept. PMU placement is done in various phases by ensuring that the set of the placed PMUs in the next phase will be a superset of the previous phase. The proposed scheme is modification of spanning tree method with additional constraints. This scheme is verified by placing PMUs on various locations equal in nos. placed in spanning tree method in standard IEEE 14 bus test system. By the complete knowledge of states of the system, stability prediction of the buses is possible by the use of stability indices in any complex power system network. The outputs of the PMUs are utilized directly for determining the stability index. After getting optimum resultant locations of PMUs, the measurements received from the placed PMUs are used to determine the fast voltage stability index (FVSI) for further monitoring of the power system network. Testing of PMUs is very much necessary for its applications and further process of data for simple visualization of any complex network. To validate all the objectives, the complete scheme has been implemented on RTDS to achieve the values of the index at very high data rate. Successful placement of PMUs at optimal locations of the IEEE 14 bus test system on real time simulation test bed will show values of the states at sampling rate of 48 samples per second. So, the values of FVSI getting after PMU measurements will be extremely dynamic and it is possible to predict the voltage stability of the buses more accurately or to maintain complete network stability.