In the field of protective relay, a dream which is unable to be realized by analogue technology has come true with the advance of computer technology. However, there is still room for the development of high functional protective system, which makes the most of a merit of digital processing because the present digital relay uses the same principle as analogue one. The points of proposed theory are that firstly it uses a lot of data of fault, secondly uses the First and Second Kirch-Hoffs laws at the same time which are the starting point of electric circuit theory, and thirdly calculates both fault lacation and resistance by solving non-linear simultaneous equations.
In this paper, high speed calculation for protective relays is achieved by solving a compact matrix using Newton-Raphson method.
The matrix consists of two sorts of variables (fault location, fault resistance), and the non-linear simultaneous equation is reduced by definition of new variables.
As a result of applying this theory to some real faults, we testified that the fault location error was within 0.1%, and the calculation time was less than 5 ms.
Therefore we think that this theory has been already on a practical stage.
The ultimate goal of this theory is the integration of various algorithms on protective relay, fault locater, and fault restoration operation.
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