Non-synchronous sampling double-ended fault location method for double-circuit lines based on Jacobian matrix

Abstract

The invention discloses a double-circuit line non-synchronous sampling double-end fault distance detection method based on a jacobian matrix. The double-circuit line non-synchronous sampling double-end fault distance detection method includes the steps of measuring homonymous direction zero sequence currents at the two ends of a double-circuit line, selecting a fault distance initial value xk and a non-synchronous angle initial value deltak, calculating elements of the jacobian matrix, then calculating fault distance correction amount delta-xk and non-synchronous angle correction amount delta-deltak, judging whether the fault distance correction amount delta-xk and the non-synchronous angle correction amount delta-deltak are smaller than a setting threshold xi at the same time or not, finishing iterative computation if the fault distance correction amount delta-xk and the non-synchronous angle correction amount delta-deltak are smaller than the setting threshold xi at the same time, if the fault distance correction amount delta-xk and the non-synchronous angle correction amount delta-deltak are not smaller than the setting threshold xi at the same time, correcting the fault distance xk through the fault distance correction amount delta-xk, correcting the non-synchronous angle deltak through the non-synchronous angle correction amount delta-deltak, carrying out re-computation till the iteration condition is met, and finishing the iteration computation. According to the double-circuit line non-synchronous sampling double-end fault distance detection method, double-circuit line double-end fault accurate distance detection can be achieved through the jacobian matrix, the distance detection accuracy is not influenced by the factors such as double-circuit line fault types, transition resistance, a load current and inter-wire zero sequence mutual inductance, and the high distance detection accuracy is achieved.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a Jacobian matrix-based non-synchronous sampling double-terminal fault distance measurement method for double-circuit lines. Background technique [0002] Divided from the electrical quantity used for distance measurement, fault location methods can be divided into two categories: single-ended distance measurement and double-ended distance measurement. The single-ended ranging method is a method that only uses the voltage and current data at one end of the transmission line to determine the fault location of the transmission line. Since the voltage and current data on the opposite side of the transmission line cannot be obtained, there are few valid data available, and its algorithm is inevitably affected by power in principle. The system operation mode, load current and transition resistance are seriously affected. When a single-phase high-resistan...

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Problems solved by technology

This method takes into account the influence of distributed capacitive current, which helps to improve the accuracy of fault location, but it needs to involve complex exponential calculations and solving problems of hyperbolic functions, and it is difficult to implement the computer code, so it is impossible to apply this algorithm to the computer program. poor performance

Moreover, the double-terminal fault location method of transmission lines based on the distributed parameter model is still complex in algorithm, difficult to solve the equation, and requires a large amount of calculation. from failure

[0004] There is a strong zero-sequence mutual inductance between the double-circuit lines on the same pole. Due to the influence of the zero-sequence mutual inductance between the lines, there is a large error in the ranging accuracy of the double-ended fault location algorithm.

Many existing double-ended fault location algorithms are based on strict synchronous sampling of double-ended data on double-circuit lines. Due to the influence of optical fiber communication delay and optical signal transmission speed in the optical fiber by the line operating environment, the accuracy of the double-ended fault location algorithm Severely affected by asynchronous sampling

Due to the comprehensive influence of double-circuit line fault types, transition resistance, load current, and zero-sequence mutual inductance between lines, the existing double-ended fault location algorithms often exceed the full length of the line or have no ranging results, and cannot provide accurate fault locations. information, which leads to difficulties in line fault inspection, which is not conducive to line fault removal and line power supply recovery, and is not conducive to the safe and stable operation of the power grid

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