Published Paper Details:

This study aimed to diagnose power quality issues and develop a corrective scheme for the 13.2 kV/7.62 kV Feeder-5 distribution line system connected to the Mabiga Substation of Pampanga II Electric Cooperative, Inc. in Mabalacat City, Pampanga, Philippines. The research specifically investigated recurring problems of low voltage and harmonic distortion affecting residential, commercial, industrial, and irrigation consumers supplied by the feeder. A descriptive-analytical quantitative research design was employed and supported by qualitative validation from utility personnel. Primary data were collected through continuous monitoring using a Class A power quality analyzer installed at critical locations of the feeder, including the transformer tapping point and selected end-of-line areas. Monitoring was conducted for at least seven days to capture variations in load profiles and operational conditions. Measured parameters included balanced voltage magnitude, voltage imbalance, total harmonic distortion of voltage (THDv), and total harmonic distortion of current (THDi). These measurements were statistically analyzed and compared with international power quality standards such as IEEE 519-2022 and IEC 61000. Results revealed persistent undervoltage conditions across several segments of the feeder and elevated harmonic distortion levels, particularly during peak loading periods and in areas with significant nonlinear loads. Industrial and commercial load profiles exhibited the highest harmonic distortion levels, while residential areas generally maintained more stable voltage conditions. Further analysis showed that feeder loading, nonlinear equipment, load imbalance, and aging distribution infrastructure contributed significantly to the observed disturbances. Two corrective scheme proposals were developed and evaluated through load flow and harmonic simulations combined with technical economic comparison. Simulation results indicated that the recommended scheme improved voltage stability, reduced harmonic distortion, enhanced feeder reliability, and minimized system losses. The study provides a practical framework for diagnosing power quality problems and designing effective mitigation strategies in medium-voltage distribution systems, offering valuable guidance for electric cooperatives seeking improved operational performance and regulatory compliance.