Sizing and Locating Shunt Capacitors in a Voltage Constrained South African Distribution Network

Abstract

Voltage-constrained networks cannot integrate additional load without compromising the voltage quality. Resolving voltage-constraints requires solutions that can be implemented within a short time period so additional load can be integrated. As a result, there is a need to develop methodologies that can be used to solve voltage-constraints in networks. This paper presents a methodology to size and locate shunt capacitors in a voltage-constrained network. The methodology aims to maximise network capacity while minimising capital expenditure (CAPEX). The methodology is applied to a voltage-constrained 132 kV network in South Africa. The network has a peak demand of 155 MW but is found to have the capacity to supply demand of 91 MW during contingencies. To create adequate capacity that enables the network to supply the peak demand with the least CAPEX, the study found that 24 MVAR shunt capacitors should be located at two of the buses experiencing voltage instability.