ABSTRACT
Flexible AC Transmission System (FACTS) is a progressive technology that has allowed power system utilities to make the most out of the existing grid and control the governing parameters that affect the power flow and/or stability of the transmission and power system broadly. One of the most important FACTS devices is Unified Power Flow Controller (UPFC) which provides fast-acting reactive power compensation on high-voltage electricity transmission networks. The aim of this paper is to discuss in detail the dynamic model of UPFC. It is integrated to a Single Machine Infinite Bus system (SMIB) for state estimation. Power system State Estimation is important for efficient control and operation the system. State Estimator is a computer program which processes the available measurements to obtain the best values of state variables. Conventional State Estimation is static in nature. Static state estimation takes system snap-shots and hence the dynamics of system are not captured efficiently. Thus Dynamic State Estimation (DSE) is becoming more appropriate. It efficiently processes the data captured at smaller sampling time to obtain state vectors. Using the information about state vector at time instant k, a Dynamic State Estimator can predict the state vector at next time stamp k+1. In the present work, results for estimation of system dynamic states as well as UPFC dynamic states are presented using the Extended Kalman filter method.
