Transformer Energization and Power Quality Solutions

This technical report discusses the implementation of a controlled switching solution at Southern Peru Copper Corporation to address issues related to transformer energization. The report outlines the challenges faced due to a malfunctioning control device that caused high currents and voltage drops, impacting sensitive loads such as rock-crushing mills. To mitigate these issues, the company evaluated the SEL-352 Breaker Failure Relay, which utilizes point-on-wave switching technology. The report details the testing process conducted with the SEL-T400L Line Protection Relay to determine optimal closing times for the circuit breaker. Results indicated a significant reduction in inrush current from 2.5 per unit (pu) to less than 1 pu, with voltage drops remaining within acceptable limits. The successful implementation of this technology has improved power quality, ensuring the continuous operation of the rock-crushing mills and preventing potential production losses. The report emphasizes the importance of maintaining power quality in mining operations.