Construction
	
	Operation & Maintenance
	
Substation 
	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
	
	  - To be applied for early detection of incipient fault in transformers. 
 
	  - DGA result history produces useful information RCM program. 
 
	  - No outage and complex procedures are required. 
 
	  - Effective for reliability management of equipment & total cost suppression. 
 
	
	