Technique for optimal capacitor placement in power distribution network

Abstract

Transfer of electric energy from the source of generation to the customer via the transmission and distribution networks is accompanied by losses. The majority of these losses occur in the distribution system. It is widely recognized that placement of shunt capacitors on the distribution system can lead to a reduction in power losses.

Reduction of I2R loss in distribution systems is very essential to improve the overall efficiency of power delivery. The voltage at different buses/sections of a distribution network improves significantly due to appropriate placement of shunt capacitors. The I2R loss can be separated into two parts based on the active and reactive components of branch currents. This thesis work presents a method of improving voltage profile and minimizing the loss associated with the reactive component of branch currents by placing shunt capacitors.

This method first determines a sequence of nodes to be compensated by capacitors. The size of the optimal capacitor at the compensated nodes is then determined by optimizing the loss saving with respect to the cost of investment. The performance of the proposed method is investigated on distribution systems consisting of IEEE 9 bus, IEEE 15 bus and IEEE 34 bus radial network. It is found that voltage at each nodes can be maintained within ±10 % of rated voltage and a significant loss saving can be achieved by placing optimal capacitors in the system.

The changing load condition in different seasons of the year is considered. The variable loading condition scenario is implemented considering winter off peak as the minimum loading and summer peak as the maximum loading condition. Comparison with other reported techniques show that the proposed technique obtains a better performance.