International Journal of Science and Engineering Applications Volume 12-Issue 09, 163 - 168, 2023, ISSN:- 2319 - 7560 DOI: 10.7753/IJSEA1209.1048 www.ijsea.com 163 Power Flow Analysis of 33/11kV, 15MVA Borokiri Injection Substation Ogbonna, Bartholomew Odinaka Dept of Electrical Electronic Engineering University of Port Harcourt Rivers State, Nigeria Oniyeburutan, Ebakumo Thomas Dept of Electrical Electronic Engineering University of Port Harcourt Rivers State, Nigeria Abstract: When an electrical power network undergoes a non-steady state condition or when been subjected to an unbalance power condition, the need for a complete electrical solution arise in which load flow analysis become a key tool. This paper examined the power flow status of Borokiri 33/11kV, 15MVA injection substation of the Port Harcourt Electricity Distribution Company to ascertain its steady state operating condition for improved performance. The Newton Raphson Load Flow Techniques was used to analyze the network in Electrical Transient Analyser Program (ETAP) Software to determine the various bus operating voltages, active and reactive power flow at generator bus and voltage phase angles at specified bus bars. It was observed from the base-case simulation that Harold Wilson 11kV feeder was overloaded and was operating under a critical under voltage condition while New Road 11kV feeder was marginally under voltage. Both cases were resolved by the application of transformer load tap changing (LTC) mechanism and the introduction of appropriate shunt capacitor bank at strategic point of Harold Wilson feeder. The Voltage profile of Harold Wilson and New Road feeder were improved from 89.22% to 95.37% and 94.49% to 99.01% respectively. However, it was recommended that bifurcation of Harold Wilson 11kV feeder should be conducted to reduce the overloading condition of the network. Keywords: Distribution Network, Power Flow, Newton Raphson Technique, Load Tap Changing, Optimal Capacitor Placement, Voltage Profile. 1.0 INTRODUCTION Power flow analysis also known as load flow analysis is one of the major tools of power system analysis. When a power network goes through a non-steady state condition or when it is subjected to an unbalance power condition, there is a need for a complete electrical solution in which this analysis is the key tool. Power flow analysis is a systematical mathematical approach used in the determination of various bus voltages, active and reactive power flow through different branches, phase angle, generators and loads under steady-state condition of an electric power system. Power flow calculations are very essential for power system operation, economic scheduling and planning. The results of power flow analysis are used in the studies of the normal operating condition, outage security assessment, contingency analysis and optimal dispatching and stability of power system network [1]. The main objective of the power flow analysis is to determine potential problems, such as overloading of facilities, unacceptable voltage conditions, decreasing reliability, or any failure of the transmission or distribution system to meet performance criteria. After the analysis, the Engineer or power system specialist develops alternative plans or approaches that will not only prevent the foreseen problems but also will best meet the long-term objectives of system reliability and economy. Load flow analysis is the main requirement for planning and designing a new power system. Also, extension of existing power system for increasing demand [2]. For distribution system the power flow analysis is a very important and fundamental tool. Its results play the major role in the operational stage of any power system, its control and economic schedule, as well as the design and expansion stage. The purpose of any load flow analysis is to calculate accurate steady-state voltages of all buses in the network, phase angles, the real and reactive power flows into all buses and transformer, under the assumption of known generation and load. The load flow solution also gives the initial conditions of the system when the transient behavior of the system is to be studied. In actual practice, it will be required to carry out numerous power flow solutions under a variety of conditions. A power (load) flow study is done on a power system to ensure that generation supplies the demand (load) plus losses, bus voltage magnitudes remain close to rated values, generation operates within specified real and reactive power limits and transmission lines and transformers are not overloaded [1]. The inadequate power supply and the incessant power failure from the central generating stations down to the final consumers suffers a lot of sets back; hence researchers and technologist, have resort to other means of managing this setback. In literatures, different methods have been implemented to provide an effective solution in regards to reliable power generation, transmission and delivery. In recent time, the impact of distributed generation linked to the distribution networks are on course. Distributed generation units have several benefits such as reliability, stability and economy; but it suffers some critical setbacks that may disturb these benefits as seen in [3]. Nigeria power grid network generating voltage falls within the range of 10.5kV – 16kV with operating frequency of 50Hz. It is step up to 330/132kV as primary/secondary transmission. Primary distribution voltage is 33kV to various injection substations for further distribution while secondary distribution voltage is 11kV to various consumers on point load and consumers down the road and streets through overhead lines