Working method of real-time data acquisition and fault location system for distribution network

Abstract

The invention provides a real-time data collecting and fault positioning system of a power distribution network and a working method thereof. The real-time data collecting and fault positioning system comprises transformer substation voltage collecting units, a plurality of line units, a real-time data server, a background monitoring computer and a handheld terminal, wherein each transformer substation is provided with one transformer substation voltage collecting unit; each transformer substation voltage collecting unit comprises one intelligent voltage detection terminal; each line unit comprises three fault positioning and data collecting sensors and one communication and calculation terminal; the intelligent voltage detection terminal, the communication and calculation terminal and the handheld terminal are in wireless communication with the real-time data server; the three fault positioning and data collecting sensors of the same line unit are in short-distance wireless communication with the communication and calculation terminal. The working method mainly comprises the step of carrying out real-time data collection and fault judgment. The information precision of power transmission line data which is collected in real time is high, short circuit and grounding faults are rapidly and accurately judged, the time of powering off and overhauling is shortened, the quantity of fault line patrolling workers is reduced and manpower and material resources are saved.

Description

technical field [0001] The invention relates to the technical field of power grids, in particular to a real-time data acquisition and fault location system and a working method thereof during the operation of a distribution network. Background technique [0002] The fault location of the distribution network is mainly the fault location of the single-phase grounding of the overhead line and the fault location of the phase-to-phase short circuit. The voltage level of medium-voltage distribution lines is mainly 10KV, and most of them are ungrounded transformer neutral points or grounded through arc suppression coils. Such overhead lines are prone to faults, and more than 90% of them are single-phase ground faults. The reason is that such lines The single-phase ground current (capacitive current) is extremely small, and it is difficult to distinguish it from the unbalanced current in the normal operation of the line. The common sampling equipment for distribution network fault...

AI Technical Summary

Problems solved by technology

However, this method has flaws in principle, because the actual ground fault does not necessarily occur at the moment when the phase voltage is close to the peak value, resulting in low accuracy of fault location based on the principle of the half-wave method; the other is to use the principle of signal injection method , the method is to install a high-voltage signal source device on each bus section of the substation. When a ground fault occurs, the open triangle voltage change of the busbar of the substation is used as a starting signal, and the high-voltage contactor is closed to send a high-frequency signal to the line. On the ground point of the faulty line, a circuit is formed, and the fault indicator of this faulty line section is lit to judge the faulty section

When this method encounters high-impedance grounding (according to statistics, more than 50% of single-phase grounding faults are high-impedance grounding), it is difficult to accurately detect and identify the fault point due to the weak signal. It is also difficult to judge where the ground fault occurs

[0003] In addition, the methods used by existing equipment generally can only measure the fault current at a specific point of a line (phase), and cannot conduct comprehensive analysis and judgment based on the corresponding changes in the current of other phases and other points. Therefore, when the line current encounters When there is a large disturbance (such as the moment of disturbance when a large motor or transformer is put into operation), it is difficult to distinguish the line surge current from the single-phase ground fault current

In addition, at present, the functions of similar equipment are relatively simple, some can only perform fault location, and some can only monitor the operating status (current, temperature), and have not realized the integration of functions

Images