The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 03, 1982
Filed:
May. 23, 1980
Takaaki Kai, Zushi, JP;
Kabushiki Kaisha Meidensha, , JP;
Abstract
The present invention discloses a grounding protective relay which compensates for zero phase circulation current between lines and zero phase vertical voltage drops generated by induction in a common suspension multiline system. The grounding protective relay comprises, substantially, a current detector which detects the inter-line differential currents, a filter which eliminates the positive phase component from the inter-line differential current of each pair of phases, calculating sections calculate the zero phase component, the ratio of the magnitudes and the phase difference, an grounded phase detector, and a selection section which selects, according to the phase which is grounded, a deriveration result from a calculating section, characterized in that, when a grounded fault occurs, the zero phase circulation current is selected and is compensated.