Evaluation of Three-phase Bus-bar Breaking Capacity for Voltage Profile Improvement Using Static Var Compensator (SVC: A Case Study of the Nigerian 330-KV Power System

Abstract

Bus-bar is a crucial component in power system networks, connecting various branches and requiring proper design and protection for reliable electricity supply.  In this article, the breaking capacity of a three-phase bus-bar was determined via the evaluation of the short-circuit fault current using Electrical Transient Analyzer Program (ETAP) software, and the formulated power flow equations. The formulated power flow equations were modified via the inclusion of Static Synchronous Compensator (SVC). The program was tested on IEEE 14-bus system and Nigerian 30-bus 330-kV, power transmission network. Three-phase short circuit faults were introduced into each of the 30-bus, sequentially. The short circuit and the breaking capacity of each bus-bar were determined on a normal power load condition and under a modified power flow condition respectively. The simulation results revealed that before modification, six buses experienced voltage magnitudes that are lower than the limit of the statutory operational voltage range of 0.95 to 1.05 p.u. But the inclusion of SVC improved the overall voltage magnitudes of the test system with no bus voltage violations observed. The breaking capacities for each of the buses were improved for the network with modification compared with no modification case scenario. The bus-bar breaking capacity ranges from 1.841 MVA to 30.830 MVA for the network without modification while it ranges from 1.830 MVA to 28.714 MVA in the case of network with modification. Therefore, the short circuit analysis of network incorporated with SVC enhances reliable and resilience operation of power system network.