© FEB 2022 | IRE Journals | Volume 5 Issue 8 | ISSN: 2456-8880 IRE 1703209 ICONIC RESEARCH AND ENGINEERING JOURNALS 172 Enhancing Transient Stability of Nigeria 330kv Transmission Grid Using a High Voltage Direct Current (HVDC) UMEOZULU ADA S. 1 , ENEH I. I. 2 , ANEKE JUDE. I. 3 1 Transmission Company of Nigeria, Enugu, Nigeria 2 Enugu State University of Science and Technology, Enugu, Nigeria 3 Nnamdi Azikiwe University, Awka, Nigeria Abstract- The Nigerian power network over the years has suffered incessant power interruptions caused by inadequacies in power generation capacity, inadequate transmission, distribution facilities and poor maintenance culture and other disturbances. Therefore, this paper presents the application of a VSC-HVDC system for the improvement of the transient stability of the Nigeria 330kV transmission network. First, the buses that are marginally unstable (critical buses) in the network were determined through eigen value analysis of the system buses. Then, a balanced 3-phase fault was applied to the few critical buses and lines of the transmission network. By observing the dynamic response of the generators in the Nigeria 330kV grid, the existing transient stability situation was determined. The finding obtained vividly revealed that buses Olorunsogbo and Omotosho are the two most critical buses while transmission lines from Ikeja West - Olorunshogo Generating Station (GS) and Omotosho - Benin TS within the network are the most critical transmission lines. Also, when the balanced 3-phase fault was applied to these mentioned critical buses and lines, the network loses synchronism. To solve the problem, VSC-HVDC was installed at the identified lines that are marginally unstable. The conventional PI method was used to control the parameters of the VSC-HVDC converter and the converter in MATLAB/PSAT environment. The results obtained showed that the fault critical clearing time (CCT) was increased from 300milli- seconds to 400milli-seconds which is 33.33% increment. Also, the oscillations were quickly damped. I. INTRODUCTION Power system researchers in the past decades have faced a major challenge with the enhancement of the dynamic response of generators within a power system, when subjected to different disturbances. These different disturbances have resulted in frequent transient instability on the grid network (Rani and Arul, 2013). The effect of this, in long-run, is frequent power failures, long outage durations, poor availability and sustained blackouts and system collapse. The negative impact of poor availability and sustained blackouts are high on power system operators and consumers of electricity. It results in high operation costs for operators, causes drop in quality of life of electricity consumers, increases cost of living, shuts down industries, causes loss of jobs, increases production cost and in general results in down turn in national economy. Resolving the challenge of frequent transient instability on our power networks will resolve the above stated problem and its consequences (Sagar, Pavan and Rajalakshmi, 2016). In this work, HVDC controlled by the conventional PID is proposed as a technique for improving the transient stability of the Nigerian 40 bus network. The proposed method will enhance the transient stability of the network by intelligently controlling active and reactive power balance in the network and allowing bulk power transfer of power where it is mostly needed. Recently, the demand for electricity has radically increased and a modern power system becomes a difficult network of transmission lines interconnecting the generating stations to the major load centers in the overall power system in order to support the high demand of consumers. Transmission networks being