Transformer and tap changer (TC) maintenance is crucial for ensuring the reliable operation of electrical power systems. Regular maintenance of transformers involves comprehensive inspections, testing, and servicing to identify and address any issues promptly. This includes checking insulation resistance, winding resistance, and oil quality, as well as performing diagnostic tests such as Dissolved Gas Analysis (DGA) to detect potential faults. Tap changers, which regulate voltage levels in transformers, also require routine inspection and lubrication to prevent arcing and ensure smooth operation. By implementing a proactive maintenance program for transformers and tap changers, utilities and industrial facilities can minimize downtime, extend equipment lifespan, and enhance overall system reliability.