Transformers
Transformers are frequently heavy, custom-built and slow to replace, making them key links in energy supply whose failure through insulation faults, overloading or inadequate cooling can trigger substantial property and business interruption losses.
Criticality
Large power transformers are custom-built, with lead times ranging from several months to more than a year, and many operators run them with little or no redundancy. A total loss therefore rarely stops at repair cost; it typically causes a multi-month business interruption because replacement units are scarce on the market. Typical loss causes include oil insulation ageing, winding faults, overvoltages, cooling failures and external short circuits.
Protection concept
The protection concept includes electrical protection relays (differential, overcurrent and earth-fault protection), mechanical safety devices such as Buchholz relays and pressure relief, and regular diagnostics: dissolved gas analysis (DGA) of the insulating oil, insulation resistance testing and thermographic inspection of terminals and bushings. Structural measures such as oil containment, fire separation distances or fixed suppression systems limit the impact of a transformer fire on neighbouring plant.
Insurance relevance
For machinery and business interruption insurance, replacement lead time is the decisive question: without a documented spare parts strategy, a standby transformer or contractually secured delivery times, the realistic indemnity period is often underestimated. Insurers therefore treat the age, condition data and redundancy concept of transformers as a distinct risk factor.