This paper presents a novel approach for reactive power planning of a connected power network. Reactive power planning is nothing but the optimal usage of all reactive power sources i.e., transformer tap setting arrangements, reactive generations of generators and shunt VAR compensators installed at weak nodes. Shunt VAR compensator placement positions are determined by a FVSI (Fast Voltage Stability Index) method. Optimal setting of all reactive power reserves are determined by a GA (genetic algorithm) based optimization method. The effectiveness of the detection of the weak nodes by the FVSI method is validated by comparing the result with two other wellknown methods of weak node detection like Modal analysis and the L-index method. Finally, FVSI based allocation of VAR sources emerges as the most suitable method for reactive power planning. Key words: active power loss, FVSI method, genetic algorithm, operating cost, reactive power planning, weak nodes
IntroductionReactive power planning has been one of the most challenging problem to the power system engineers. Expansion of a transmission network is not always possible because of several reasons like cost, right of way etc. Again maintaining good quality of voltage for distribution of power to the consumer is also an important aspect. Sometimes a situation of system collapse is observed even with the slight increase in reactive power demand. Hence, it becomes absolutely necessary for the proper co-ordination and planning of all reactive power sources present in the network. In this paper, main concerns are proper planning and coordination of control variables like transformer tap changers, shunt VAR compensators, generators reactive VAR in an interconnected power system for minimum active power loss as well as minimum operating cost.A linear programming based optimization method is presented in [1] for optimal reactive power generation of large scale electric power networks. The solution of the reactive power problem by optimal placement of a capacitor is discussed in [2]. A modal analysis technique is described in [3] for the determination of weak nodes of a connected power network. The reactive power problem is solved in [4] by injecting reactive power at weak buses of a connected power system. Application of evolutionary programming in reactive power planning is discussed in [5]. A hybrid expert system and simulated annealing based algorithm for the planning of reactive power sources is presented in [6]. A technique for the determination of reactive margin is presented in [7]. Heuristic modal for secured operation of a power system is developed in [8]. A binary search technique and special heuristics are applied for optimal VAR planning in the case of a large scale power system in [9]. Static security constraints and nonprobabilistic uncertainties in load values are considered for optimal reactive power planning in [10]. Two rule based modules are used for voltage profile improvement to alleviate voltage limit violations and for minimization of ...