Proposed Grounding System for A Solar-Powered Building Design at A State University in Pampanga

Abstract

As PV systems age, grounding concerns arise, posing a risk to system safety, among these hazards include incorrect electrical connections, improper design and installation of grounding systems, and the resulting from non-system installations. A grounding system provides the necessary safety for the user and the equipment of the solar PV system. This research is intended to propose a solar PV grounding system for the Admin Building at DHVSU Main Campus by determining the appropriate size of wires, breakers, and electrodes through manual computation; and providing a Single Line Diagram for a PV System that is focused on the integration of a grounding system. The proponents collected the Electrical System data of the Admin Building from DHVSU and the Solar PV System data from the existing feasibility study by Edgardo Santos in 2019. The study displayed the components comprising the on-grid solar system, but a grounding system was not included. Subsequently, the sizing of the DC Overcurrent Protective Device and Inverter AC Circuit Breaker were manually computed. DC and AC Equipment Grounding Conductor were sized, and Grounding Electrode System was determined under Philippine Electrical Code (PEC). For the canvassing of the price of significant components, bill of materials for consumables, grounding (bill of materials specific), manpower cost for installation, operation & maintenance cost, delivery of materials, and net-metering application cost, the researchers consulted a registered electrical engineer working at Transnational Uyeno Solar Corporation (TUSC). The Payback Period was calculated by dividing the total cost by the total savings. In modelling the grounding system, significant standards were used in finding the corresponding DC & AC overcurrent protective device, DC & AC equipment grounding conductor, and grounding electrode conductor. After completing all the information needed, the proponents came up with the following results: OCPD Rating = 20 AMP, PV Cable = 2-6mm² 90-degree Celsius wire with XLPE Insulation, DC Grounding wire = 1-5.5mm² THHN, AC OCPD Rating = 150AT 3P MCCB, main wire of the AC system = 4-60mm² THHN/THWN, AC Grounding Conductor Sizing = 1-14mm² THHN/THWN. The total estimated contract cost amounted to ₱3,039,120. On the other hand, the total contract cost amounted to ₱3,401,680 since the maintenance cost for a PV system without grounding is more expensive. Consequently, the payback period is extended for the PV system without grounding. A total of 3 years, 2 months and 23 days of payback period was computed considering the integration of the grounding system. The grounding system single-line diagram is presented in the study.