Evaluation of 11kV Distribution Network for Improved Power Quality using Static Synchronous Compensator (STATCOM)

Abstract

The paper evaluated the existing GRA Phase 2 distribution network with the incorporation of a STATCOM. Electricity is supplied to the network from the Rumuola injection substation, which in turn receives power from the Port Harcourt mains transmission system. Modelling and simulation of the network were carried out using the Electrical Transient Analyzer Program (ETAP 20). Within GRA Phase 2, the system is exposed to various operational disturbances, particularly low-voltage conditions and excessive power demand. These issues were due mainly to power transformers operating very close to their rated capacity. Such persistent constraints have adversely affected both households and commercial users, many of whom now rely on alternative energy sources to satisfy their routine electricity requirements. The Newton–Raphson load flow approach was applied to determine the network’s voltage profile, power distribution, and associated line losses. Results from the initial (base case) simulation indicated that Bus 5 at 93.25%, Bus 10 at 92.77%, and Bus 13 at 93.50% were the weakest voltage points, as each fell outside the acceptable operating range of 0.95 to 1.05 pu. These buses were therefore selected for sensitivity studies aimed at identifying the most effective STATCOM placement. Based on V–Q sensitivity outcomes, Bus 10 emerged as the best location for reactive power compensation within the GRA Phase 2 system. For the base case, the total network power loss amounted to 59.32 kW + j78.91 kVAr. After installing a 6.25 MVAr STATCOM, losses decreased substantially to 34.89 kW + j43.69 kVAr, representing a reduction of 24.43 kW and 35.22 kVAr. This confirms that the STATCOM provided a marked improvement in system performance. When benchmarked against an SVC and other FACTS technologies, the STATCOM demonstrated superior behaviour, particularly in rapid dynamic response and its ability to both supply and absorb reactive power. The analysis further revealed that the most suitable position for a STATCOM is not constant but varies depending on where a disturbance or fault occurs within the network.