A NEW CLUSTERING TECHNIQUE FOR POWER-SYSTEM VOLTAGE STABILITY ANALYSIS

Bus clusters are usually formed by forming groups of PQ and PV buses which are coherent. All the buses in a cluster behave in a coherent manner and therefore a bus can be taken as representative of a group of buses in a cluster. Bus clusters are useful in voltage stability analysis because they not only can be used to identify the weak and strong areas 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 network. The weak lines are eliminated and the bus clusters are formed based on the coherent nature of buses in a cluster. The LQPN method is compared with an earlier method developed by Schlueter which forms voltage control areas or bus clusters. The results of the bus clusters formed by the two methods are found to be in close agreement.