A methodology for parallel loading of distribution transformers with different impedance voltages

Abstract This paper introduces a new approach for parallel loading of distribution transformers with different impedance voltages and power ratings while considering all other relevant paralleling conditions. This approach is constructed to assist design and maintenance engineers in making informed decisions when a required transformer with specific impedance, voltage, and power rating is unavailable. The primary objective of this paper is to minimize partial stoppages and energy supply shortages resulting from the unavailability of appropriate transformers. Additionally, the study aims to enhance operational reliability in the event of unexpected failures in one or more transformers operating in parallel. The proposed approach optimizes new load sharing for transformers when a new or temporary unit replaces a failed one. The analysis aims to balance the costs of production losses and lifestyle disruptions resulting from energy shortages. These impacts are evaluated against the reduction in total transformer capacity and the operational constraints introduced by the newly installed transformer with a different impedance voltage. The proposed method’s effectiveness is demonstrated through a numerical example involving four different scenarios. The paper concludes with results, conclusions, and recommendations based on the proposed approach.