CN-122017461-A - Distribution line fault distance measurement method and system for capacitive node delay compensation

Abstract

The invention discloses a distribution line fault location method and system with capacity node delay compensation, wherein the system comprises a fault signal acquisition module, a fault signal processing module and a fault location analysis module, wherein the fault location analysis module is based on a formula And obtaining a distribution line fault distance measurement result. The distribution line fault distance measurement method and system for the capacitive node delay compensation are easy to implement and high in distance measurement precision.

Inventors

• LIU LIANG
• DENG MINGGAO
• ZHU PEIDONG
• WAN WANGLONG
• ZHANG ZHUXIAN

Assignees

• 长沙学院
• 湖南湘能智能电器股份有限公司

Dates

Publication Date

20260512

Application Date

20260303

Claims (5)

1. 1. A distribution line fault distance measurement method for capacitive node delay compensation is characterized in that: monitoring and fault ranging are carried out on one feeder line in the distribution line: The m1 distribution transformers are connected in parallel in the feeder line, a secondary side installation monitoring terminal of the n1 distribution transformer is selected as a monitoring point, and fault traveling wave monitoring and ranging are carried out; the network fault ranging formula based on double-end ranging is as follows:
2. 2. Wherein: L MiNj is the shortest line distance from the monitoring point M i to the monitoring point N j through the fault line; l MF is the distance from the monitoring point M to the fault point F; l MiM is the shortest distance between the monitoring point M i and the line of the monitoring point M; T Mi 、T Nj , the time when the fault initial traveling wave reaches the line monitoring point M i 、N j respectively; z is the wave impedance of the distribution line; c k equivalent inlet capacitances of n distribution transformers from the fault point F to the monitoring point M i ; C p equivalent inlet capacitances of m distribution transformers from the fault point F to the monitoring point N j ; v, traveling wave speed; And calculating double-end traveling wave ranging results between all two monitoring points, removing the result that the deviation L MF is larger than a preset calculation error lambda, and taking the result of arithmetic average as the final ranging result of network traveling wave ranging.
3. 3. The method for fault location of a distribution line with delay compensation of capacitive nodes according to claim 1, wherein: The traveling wave speed of the distribution overhead line is 2.8x10 8 m/s, and the traveling wave speed of the distribution cable line is 1.6x10 8 m/s.
4. 4. The method for measuring fault distance of distribution line with capacity node delay compensation according to claim 1 or 2, wherein the calculated error lambda is 300m.
5. 5. The distribution line fault distance measurement system with the capacity node delay compensation is characterized by comprising a fault signal acquisition module, a fault signal processing module and a fault distance measurement analysis module; The fault signal acquisition module is used for directly connecting the monitoring terminal into a voltage signal of a low-voltage side of the distribution transformer and a secondary signal of a current transformer of the low-voltage side, acquiring a fault traveling wave signal of a grounding wire of the distribution transformer by using a sensor, and sending the fault traveling wave signal to the fault signal processing module; The fault signal processing module is used for amplifying, AD converting and calibrating time processing of the travelling wave signals of the fault voltage travelling wave, the current travelling wave and the zero-mode travelling wave on the distribution transformer grounding line of the fault signal acquisition module, acquiring fault travelling wave data comprising the voltage travelling wave, the current travelling wave and the zero-mode travelling wave in real time, forming a travelling wave recording file when the fault travelling wave data meets a set recording threshold value, storing the travelling wave recording file and uploading the travelling wave recording file to the fault ranging analysis module; the fault ranging analysis module is used for calculating a final ranging result of the network traveling wave ranging by adopting the method of any one of claims 1-3, and realizing the fault ranging.

Description

Distribution line fault distance measurement method and system for capacitive node delay compensation Technical Field The invention relates to a distribution line fault location method and system for capacitive node delay compensation. Background The distribution network is used as an important component of a novel power system, the topological structure is changed from a traditional tree-shaped radiation type into a complex network with multiple branches, overhead-cable mixing and ring network connection, the distribution line is connected with a plurality of distribution transformers in parallel, under the action of high-frequency signals, the distribution transformers are equivalent to capacitors, so that the fault traveling wave transmission mechanism is changed, and the defects of the traditional fault diagnosis method in the scene of the distribution network are revealed (1) the problem that the traditional fault diagnosis method lacks of quantitative consideration of the accumulated time delay of a capacitive distribution transformer group, namely the influence of the accumulated effect of the transmission time delay when traveling waves pass through a plurality of parallel distribution transformer nodes cannot be completely described by the existing theory. (2) The fault accurate identification and ranging capability is insufficient, namely, the existing FTU traveling wave positioning module, the distribution network distributed fault monitoring device and the fault indicator can only monitor a main distribution network line and a large branch distribution network line, can not monitor small branch distribution network lines or tail ends of the distribution network lines, can not effectively conduct full-coverage fault ranging on the distribution network lines, and the like. Therefore, it is necessary to design a new fault location method and system. Disclosure of Invention The invention aims to provide a distribution line fault location method and system for capacitive node delay compensation, so as to improve fault location precision and speed. A fault ranging method for a distribution line with capacity node delay compensation is used for monitoring and fault ranging a feeder line in the distribution line: the feeder line is connected with m1 distribution transformers in parallel, a secondary side installation monitoring terminal of the n1 distribution transformer is selected as a monitoring point to monitor fault traveling wave, and m1 is greater than n1 The network fault ranging formula based on double-end positioning is as follows: ; wherein: L MiNj is the shortest line distance from the monitoring point M i to the monitoring point N j through the fault line; L MF is the distance from the monitoring point M to the fault point F, and is the line distance from the designated monitoring point M (such as the first monitoring point M 1 closest to the outgoing line of the transformer substation) to the fault point. L MiM is the shortest distance between the monitoring point M i and the line of the monitoring point M; T Mi、TNj , the time when the fault initial traveling wave reaches the line monitoring point M i、Nj respectively; T Mi、TNj is a traveling wave head wave time point in the waveform of the fault traveling wave record file recorded by the monitoring terminal of the M i monitoring point and the monitoring terminal of the N j monitoring point respectively (for example, a time point corresponding to 10% of the amplitude of the head wave in the waveform of the fault traveling wave record file recorded by the monitoring terminals of the M i monitoring point and the N j monitoring point). The wave impedance of the distribution line is the inherent traveling wave impedance value of the distribution line, the distribution overhead line is about 300 ohms, and the distribution network cable line is about 160 ohms. The method comprises the steps of C k, calculating a preliminary distance by using a double-end positioning formula under the condition of not considering distribution delay, determining the position of an approximate fault point, and measuring the inlet capacitance C k of the distribution transformers with different capacities by using n distribution transformers connected in parallel between the approximate fault point and the monitoring point M i. The method comprises the steps of C p, calculating a preliminary distance by using a double-end positioning formula under the condition of not considering distribution delay, determining the position of an approximate fault point, and measuring the inlet capacitance C p of the distribution transformers with different capacities firstly by using m distribution transformers connected in parallel between the approximate fault point and the monitoring point N j again. V is the traveling wave velocity, which means the traveling wave velocity, for a fixed line, is substantially constant, the distribution overhead line is about 2.8 x 10 8 m/s, and