Impact of PMU in dynamic state estimation of power systems

Energy Management Systems (EMS) play the all important role of monitoring and control of the power systems and state estimation forms its backbone. In these days of increased operation of power system near to its limits and the tendency to utilize the grid to its full potential, monitoring and control with high level of accuracy becomes a boon. Dynamic state estimation (DSE) techniques with their unique ability to predict the state vector one time stamp ahead have the potential to foresee potential contingencies and security risks. Any improvement in its ability to predict or estimate would definitely go a long way in reducing the security risks in the modern day power system. One important factor affecting the quality of estimation is the measurement accuracy. Phasor Measurement Units (PMU) have revolutionized the way state estimation is being performed. Their unique ability to measure the voltage and current phasors (magnitude and phase angle) with very high accuracy makes them extremely useful in modern day energy management systems. This paper presents a PMU based DSE algorithm and studies the impact of PMUs on a dynamic state estimation technique. The paper explores the effect of the number of PMUs, their location, and the weightage given to their measurements on the accuracy of dynamic state estimation. With increasing usage of PMUs by the utilities, the PMU based dynamic state estimators will be of extreme importance in the modern day EMS.