Hitachi, Ltd.

Shikoku Electric Power Co., Inc.

Ichitaro Tani

Katuo Sugawara

Hideo Tsukioka

Shigeo Shiono

Etsunori Mori

Etsuo Ohe

Seiichi Sakai

Toshihiko Gange

Method and apparatus for diagnosing abnormality of an oil-filled electric apparatus is disclosed. Presence or absence of abnormality is determined by comparing contents of plural predetermined components contained in gas extracted from the oil of the electric apparatus with respective predetermined reference values. The type of abnormality is determined on the basis of at least one set of two specific components selected from the plural components.

Method and apparatus for diagnosing oil-filled electric apparatus

A system for monitoring an abnormality of an oil-filled electric device by detecting the components of the gas dissolved in the insulating oil. A gas-in-oil separator which separates the gas from the insulating oil, a gas reservoir where the separated gas is collected, an air feeder which supplies air for delivering out the gas in said gas reservoir, a separating column packed with a gas separating filler whereby the gas supplied from the gas reservoir is separated into the components, a combustible gas detector element disposed in a case which connects at its one end to the outlet of said separating column, and a change-over valve disposed at a location connecting said gas reservoir, are provided. The air feeder and said separating column are adapted to switch a route passing the air from the air feeder into the separating column along with the gas via the gas reservoir to or from a route passing the air directly into the separating column. This system is capable of easily detecting the components in the gas in the insulating oil to allow monitoring of an abnormality with high reliability. Also, according to the system of this invention, at least the components CH.sub. 4 and H.sub.2 in the separated gas are measured separately, and in case it is judged that an abnormality is present, the type of such abnormality is judged from the ratio of said components.

System for monitoring abnormality of oil-filled electric devices

Growing community of inventors

Kitaibaraki, Japan

Ichitaro Tani