POWER QUALITY MANAGEMENT IN HYBRID MICRO GRIDS: HARMONIC DISTORTION ANALYSIS AND MITIGATION FOR A 8.75MW PV-DOMINANT CAMPUS SYSTEM USING ETAP

Abstract

Large institutional campuses are increasingly faced with a dual challenge of guaranteeing high energy reliability while meeting their sustainability mandates. This work presents a design, modelling, and comprehensive performance analysis of the solar-dominant hybrid AC/DC micro grid tailored to the 8.75 MW demand of the University Campus Peshawar. The proposed system architecture integrates a portfolio of distributed energy resources comprising large-scale solar photovoltaic arrays, wind turbine generators, and diesel-powered backup generators interfacing with the local utility grid. A dedicated DC subsystem featuring an 875 Ah battery energy storage system was designed to feed 15 kW of critical loads with 8-hour autonomy, thus enhancing overall system resilience. A suite of simulation studies using the Electrical Transient and Analyser Program (ETAP) was conducted to validate the operational viability of the system. The AC/DC load flow analysis shows stable steady-state operation, and the system is capable of meeting the full campus demand and hence can export surplus power. The short-circuit study verifies the adequacy of the protection scheme, as the fault currents at all buses remain within the interrupting capacity of the selected protective devices. However, a critical power quality problem was revealed, where the THD at the points of common coupling for the PV arrays was exceeding the IEEE 519 standard of 5%. This problem was resolved through strategic placement of passive harmonic filters, which reduces THD to well below the acceptable limits. Results obtained collectively establish that the proposed hybrid micro grid is robust, reliable, and technically feasible to improve energy security and promote sustainable power infrastructures in a large-scale institutional setting.