The Development and Performance Evaluation of Integrated Voltage Protection System for Single-phase Air-conditioning Units

Voltage instability, particularly undervoltage and overvoltage conditions, can adversely affect the performance, energy efficiency, and service life of single-phase air-conditioning units by increasing compressor stress, power consumption, and operating temperature. This study aimed to design, develop, and evaluate an Integrated Voltage Protection System (IVPS) capable of accurately detecting abnormal voltage conditions and automatically disconnecting and reconnecting the load to enhance equipment protection, electrical safety, and operational reliability. A Research and Development (R&D) approach with experimental validation was employed. The prototype integrated a voltage protection relay, magnetic contactor, timer relay, overload relay, measuring instruments, and control circuitry into a coordinated relay-based protection system. Simulation was performed using SimuRelay and MATLAB, followed by laboratory testing under normal (230 V), undervoltage (185 V), and overvoltage (255 V) conditions. System performance was evaluated based on voltage detection accuracy, response time, protection success rate, current, active power consumption, compressor operating temperature, and expert and end-user assessments. Results showed that the IVPS accurately detected abnormal voltage conditions with percentage errors below 0.20%, responded within an average of 0.82 s, and achieved a 100% protection success rate. Overvoltage significantly increased current, active power consumption, and compressor operating temperature (p