Adaptive Distance Measuring Unit of Phase-To-Ground Fault Protection

Microprocessor distance measuring units with adaptive tripping characteristic upper boundary to load conditions are developed in this article. The analysis of the impedance measured during the phase-to-ground faults is carried out and mathematical functions for upper line of tripping characteristic are obtained. The experimental comparison of adaptive and static characteristics on the basis of numerical experiment was carried out. The results show that functioning effectiveness of distance measuring units with the adaptive characteristics is higher than with static ones

The Distance Measuring Units Algorithm Synthesis on the Basis of the Earth Fault Specified Model

The distance protection is the most common protection of the electric power transmission lines. However, the distance measuring units operation during the earth fault through the fault resistance is not always effective. This paper presents the new earth fault distance protection measuring units algorithm, which is based on the precise model of the protective object during the earth fault. It is obtained the estimations of the operation effectiveness of new and classical algorithms for the distance protection in the different earth fault regimes with different values of fault resistance

The Effective Earth Faults Distance Protection Algorithm for Tapped Lines

One of the main problems with distance protection of tapped lines is related to zero sequence infeed from an earthed tap-transformer. For the solution of this problem the distance measuring units algorithms for the tapped lines are developed. The new earth-faults distance protection algorithms are based on the use of numerical optimization methods and the objective function adaptation of to the network configurations. The estimations of new and classical algorithms operation in different earth fault conditions at the end of first protective zone are obtained. It is shown that the effectiveness of the developed earth-fault distance protection algorithms operation during different fault conditions on the tapped lines are higher then effectiveness of the classic algorithms