A NEW CLUSTERING TECHNIQUE FOR POWER-SYSTEM VOLTAGE STABILITY ANALYSIS

Bus clusters are usually formed by forming groups of PQ and PV buses w hich are coherent. All the buses in a cluster behave in a coherent man ner and therefore a bus can be taken as representative of a group of b uses in a cluster. Bus clusters are useful in voltage stability analys is because they not only can be used to identify the weak and strong a reas in a network but also help to speed up the control actions taken to improve voltage stability. This paper presents an LQPN method which uses the line stability factors to identify the weak lines in a netwo rk. The weak lines are eliminated and the bus clusters are formed base d on the coherent nature of buses in a cluster. The LQPN method is com pared with an earlier method developed by Schlueter which forms voltag e control areas or bus clusters. The results of the bus clusters forme d by the two methods are found to be in close agreement.