Enhancing Voltage Profile Problems in High-Voltage Transmission Lines Using Battery Supported STATCOM (A Case Study of the Adama 132 KV Substation Electric Supply System)

Abstract

This thesis focuses on enhancing the voltage profiles of Ethiopia's Adama substation electric supply system, a critical hub in the country's power infrastructure. The Adama substation receives power from multiple sources, including the Koka hydroelectric plant, Adama I wind generation, and the Awash 7-kilo substation via a 132 kV transmission line. However, outages on the primary Koka line lead to significant voltage drops and reliability issues. These drops put additional strain on the Awash 7-kilo line, causing further voltage decreases and forcing load shedding.Several substations impact the Adama substation's high-voltage transmission line electricity supply system, particularly the A7KSS. These substations include the Adama new substation (ADNSS), Metehra substation (MTSS), Awash 7 kilo substation (A7KSS), Awash Traction substation (ATSS), Asebe Tefri substation (ASTSS), and Sirba Ounkur substation (SOSS). The Adama I wind farm faces interruptions due to under-voltage protection, which requires the voltage to be 0.9 p.u. or above to maintain generation. During normal and peak conditions, the system voltage ranges between 132 kV (1 p.u.) and 122.2 kV (0.925 p.u.) but can drop to as low as 0.85 p.u. (113 kV) during emergencies or Koka line outages. From January 30, 2023, to December 29, 2023, the Adama I wind farm lost 206,266 kWh of energy due to these outages, and due to the Koka outage, the overall lost energy resulted in 1,049,436.5 kWh of unsold energy over the year 2023.The primary objective of this thesis is to use a battery- supported STATCOM to address these voltage issues. Using Particle Swarm Optimization (PSO), a 15 MVAR battery-supported STATCOM was optimally placed at the A7KSS bus. Power flow analysis under the Koka contingency scenario showed significant voltage improvements across the network. Initially, during a 0.4 to 0.7-second simulation, the system voltage at various buses dropped to 0.68 p.u., 0.86 p.u., 0.7 p.u., 0.7 p.u., 0.7 p.u., 0.68 p.u., 0.68 p.u., 0.7 p.u., and 0.68 p.u., respectively. After installing the 15 MVAR STATCOM, the voltage profiles improved to 1 p.u., 1.02 p.u., 0.978 p.u., 1 p.u., 1 p.u., 0.98 p.u., 0.976 p.u., 1.02 p.u., and 0.977 p.u., respectively. These enhancements prevent voltage-related interruptions at the Adama wind farm and reduce load shedding across the network. Matlab 2021a was used for system implementation, analysis, and simulation.