Method and apparatus for diagnosing oil-filled electric apparatus
AssigneesHitachi, Ltd., Shikoku Electric Power Co., Inc.
InventorsSeiichi Sakai, Toshihiko Gange, Hideo Tsukioka, Katuo Sugawara, Ichitaro Tani, Etsunori Mori, Shigeo Shiono
Life of this patent
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Abstract
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.
Claims25
A method of diagnosing an oil-filled electric apparatus as to abnormality, comprising steps of:
- detecting contents of a plurality of predetermined components contained in gas extracted from oil of said electric apparatus, said components bearing relevance to abnormality of said electric apparatus due to electric discharge and overheat;
- determining the presence or absence of abnormality due to electric discharge or overheat by comparing the contents of said gas components with respective reference values;
- determining the ratio of contents for at least one set of two selected components among those detected, when the presence of abnormality has been determined, and determining on the basis of the value of said ratio whether said abnormality is due to overheat or discharge;
- and
- further including a step of arithmetically determining the temperature of overheat, if the abnormality is due to overheat, on the basis of ratio of the contents of selected two of said components.
An apparatus for diagnosing an oil-filled electric apparatus as to abnormality, comprising:
- first means receiving signals representing contents of a plurality of predetermined components contained in gas extracted from oil of said electric apparatus, said components bearing relevance to abnormality of said electric apparatus due to electric discharge and overheat;
- second means for determining the presence or absence of abnormality due to discharge or overheat by comparing the contents of said gas components with respective reference values;
- third means for obtaining ratio of contents for at least one set of two specific components among said components, when the presence of abnormality has been determined, thereby to determine on the basis of the value of the ratio whether said abnormality is due to overheat or discharge;
- and
- further including means for arithmetically determining the temperature of the overheat, if determined to be present, on the basis of ratio of contents of selected two of said components.
Dependencies are inferred from the claim text.