Transformers represent a substantial investment within the electricity supply chain. Hence, monitoring their health is pivotal for extending their lifespan and minimizing maintenance and repair costs. Effective health monitoring can be achieved by establishing measurable indicators. The Transformer Health Index (THI) is a method used to evaluate various transformer components on a measurable scale. By measuring THI, maintenance, testing, and replacement budgets can be more accurately allocated. Correctly chosen components for these indicators allow transformers to be ranked and analyzed statistically. Key components might include gas analysis in oil, oil quality analysis, transformer age, and various tests and inspections. Arya Transfo’s after-sales service company is well-prepared to provide accurate indicators for monitoring the health of network transformers. This monitoring facilitates the development of preventive or corrective maintenance plans.