Abstract
One primary reason for Nigeria economic underdevelopment is the inconsistency of power supply, and as a result of this fact, immediate attention is required. The criticality of an uninterrupted power supply cannot be overemphasised. Therefore, is this work, a new approach is applied to switch power from a three-phase source to another without human interference. This work presents an automatic three (3) phase power changeover circuit with an alarm that turns power supply from Power Holding Company of Nigeria (PHCN) to a power generator at an instant of interruption or outage from PHCN. The signal is introduced to notify the user of the restoration of the PHCN supply and automatically carries out this process. This process is achieved by using logic control circuits, three-phase sequence monitors, phase(s) failure monitor, overload relay, and contacting relays for practical switching which takes approximate 30 seconds.
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