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Construction Operation & Maintenance


TEPCO have 1577 substations in 2005. We have built a variety of substations depending on their purpose, supplying voltage, installing cost, and its supplying area. 500kV large-scale underground type substation has been built for stable and efficient supply for Tokyo metropolitan area.
Even though we operate a variety of substations and machineries, We have achieved very low annual average electricity interrupting time. For stable supply, we have introduced many up-to-date techniques. And we have organized quality management system for substation design and construction (e.g. Guidelines for installation of SF6 Gas Insulated Switchgears.). And we have developed effective diagnostic/maintenance techniques for every machinery (e.g. dissolved gas analysis and circuit breaker operation monitoring are employed).
We can offer the best solutions for substation construction/operation from our technical experience. Dissolved Gas Analysis for Transformer
Analysis of dissolved gases in insulation oil enables identification of electrical fault (partial discharge, core overheating, or arcing) in transformers.

An Example of the Partial Discharge in a Transformer

The air and effects of DGA
  1. To be applied for early detection of incipient fault in transformers.
  2. DGA result history produces useful information RCM program.
  3. No outage and complex procedures are required.
  4. Effective for reliability management of equipment & total cost suppression.


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