Distribution cable line live working measurement method

Abstract

The invention relates to a live-line working measurement method of cable lines of distribution network, which comprises the following steps of: connecting primary-side leads of a current transformer and a capacitive voltage divider with three phases of cable lines with different lengths and conductive cross section parameters of a distributed network to be measured respectively in series and in parallel and connecting secondary-side leads with a wave recorder; jump-connecting cable heads by using connection lines with an insulation rod and serial connection lines with a bodhisattva jumper, unfastening the cable heads, respectively disconnecting and lapping cable lines of each phase for a plurality of times, measuring and recording the waveforms of transient or stable current and voltage; respectively extracting transient voltage, stable voltage, transient current peak value, stable current value and arcing time for operations of the connection lines and the bodhisattva jumper, and selecting the ratio of the transient voltage to the stable voltage as an overvoltage multiple; and obtaining the corresponding relationship among a transient current peak value, the arcing time, the overvoltage multiple and different cable line parameters for operations of the connection lines and the bodhisattva jumper as the safety evaluation basis for selection of live-line working tools of the cable line of the distribution network.

Description

technical field [0001] The invention relates to a measurement method for live operation of distribution network cable lines, and belongs to the technical field of distribution network live operation. Background technique [0002] With the rapid development of the national economy, society is increasingly dependent on electricity, and the reliability of power supply is increasingly demanding. Sometimes even a short-term power outage disturbance will often cause unrest in urban society. and large economic losses. Live work is a kind of operation technology developed for the safe and economical operation of the power grid. The use of live work can enable faulty equipment to be repaired without power failure. It can effectively ensure the stable operation of power and improve the quality of power supply. It is convenient for people to produce, life and avoid huge economic losses due to power outages. At present, in the process of live work in distribution network, not only a s...

AI Technical Summary

Problems solved by technology

Live operating tools are one of the most critical parts of live work, because when the cable head is disconnected and connected with electricity on the distribution network cable line, the instantaneous capacitive current and voltage on the cable line will change greatly, and the large capacitive current It is easy to cause breaking failure, a long arc is likely to cause phase-to-ground or phase-to-phase short-circuit faults, and a high overvoltage is likely to cause equipment insulation breakdown, which endangers the safety of personal equipment. When the line is connected, the transient process when the line is connected should be fully considered

[0004] At present, in the live work of distribution network cable lines, the selection of working tools is not unified. The "Regulations" stipulate that when the steady-state capacitive current of the line reaches 1A, the arc suppression rope cannot be used as a tool for breaking the line.

In practice, most of them are determined by sensory experience, some are selected according to the length of the cable, some are selected by measuring the steady-state capacitance current of the line, and some are directly operated by the safest method regardless of the line condition. Unreasonable selection method, not both safety and economy

Images