Patent ID: 8599883
Filing Date: 2013-12-03
Classification: H02H,H04J

Abstract:
1. A transit time fixation device which is used for protecting a power transmission line, comprising: a protective relay provided at each of a plurality to terminals of the power transmission line, based on information about electric current from each terminal, and which makes a sampling synchronization between the terminals via a network using a repeater to control transmission delay time between the terminals; a frame type judgment part which judges as to whether a frame is synchronous frame in the relation between a transmitter terminal and a destination terminal when the frame passes through the repeater, wherein the frame has been transmitted from each terminal and is composed of various information including information about electric current of the transmitter terminal; and a specific time delay part which performs a delay process of adding a specific time delay to transit time in which a synchronous frame judged by the frame type judgment part passes through the repeater, wherein the specific time is fixed in advance based on a maximum frame length under frame standards of the frame transmitted from each terminal and the transmission rate of the repeater, and further comprising: a delay frame judgment part which judges as to whether there is a synchronous frame to which a delay process is in progress by the specific time delay part; and a general frame delay part which adds a delay to a general frame that has been judged not a synchronous frame by the frame type judgment part only when the delay frame judgment part has judged that there is a synchronous frame to which a delay process is in progress.