CN105866608A - Power distribution network fault line selection method based on unique through-flow characteristic of resistive current - Google Patents

Abstract

The invention discloses a power distribution network fault line selection method based on a unique through-flow characteristic of a resistive current. The method comprises the steps: firstly measuring a zero sequence voltage of a bus of a power distribution network and a zero sequence current of each feed line in the power distribution network; carrying out the switching of a parallel resistor after fixed time delay if the amplitude value of the zero sequence voltage of the bus of the power distribution network is greater than 15% of the amplitude value of a phase voltage of the power distribution network during normal operation; measuring the zero sequence voltage of the bus of the power distribution network and the zero sequence current of each feed line in the power distribution network again; respectively calculating the resistive current of each feed line in the power distribution network, and selecting the feed line, corresponding to the maximum amplitude value of the resistive current, in the power distribution network as the fault feed line. The method achieves the fault line selection of the power distribution network through the characteristic that there is only one resistive current passing through the fault feed line, and the result of line selection is not affected by a transition resistor, the position of a single-phase grounding fault point, line parameters and a line length. The method is simple in principle of line selection, is accurate and reliable in line selection result, and is high in practicality.

Description

Distribution network fault line selection method based on the through-flow unique trait of current in resistance property

Technical field

The present invention relates to system for distribution network of power failure line selection technical field, concretely relate to a kind of based on the through-flow unique trait of current in resistance property join Electric network fault selection method.

Background technology

After the power distribution network lead-out wire generation single-phase fault of neutral by arc extinction coil grounding, the inductance current that arc suppression coil provides compensate for fault wire ground connection Point capacity current, fault wire earth fault electric current is the least, may be less than non-fault line zero-sequence current so that distribution based on zero sequence drying method Net fault-line selecting method (lift a sail, " small current earthing wire-selecting new criterion based on zero-sequence current transient state maximum " that Pan Zhencun and Zhang Huifen etc. delivers) Route selection result reliability is not enough.Due to arc suppression coil compensation effect, the most delayed residual voltage of faulty line zero-sequence current 90 ° so that based on zero sequence Current power direction method (" the online fault location of isolated neutral system based on zero sequence power direction " that Zhang Li, Yang Peng and Si Dongmei etc. deliver " portable study than phase power distribution network Earth design " delivered with Zhang Li, Yang Yihan and Yang Xiuyuan) it is not suitable for neutral point and connects through arc suppression coil The power distribution network lead-out wire single-phase fault route selection on ground.The small current neutral grounding system of " based on zero sequence compensated admittance " that Lin Xiangning, high gorgeous and Liu Pei etc. deliver Single-phase fault new protective method " and application number 201010260614.5 patent of invention " earthing protecting method of a kind of small current neutral grounding system " by sentencing Whether whether disconnected zero sequence compensation admittance magnitude meet operation condition carry out failure line selection more than threshold values and zero sequence compensated admittance phase angle.The method utilizes fault Rear circuit zero sequence admittance deducts being tested by single-phase earthing of prestoring or circuit zero sequence admittance that route parameter calculation obtains is led to calculate zero sequence compensation Receive, there is the factors such as pollution due to running and cause line insulation level to decline the line making to be tested by single-phase earthing or route parameter calculation obtains Road zero sequence admittance can not the zero sequence admittance of actual response line fault previous moment circuit, be likely to be due to the contaminated degree of circuit and seriously cause circuit zero sequence Admittance generation large change, the zero sequence compensated admittance amplitude thus calculated and phase angle still meet route selection condition to be caused protecting mistake excision regular link, Therefore the method practicality andreliabiliry is the highest.Application number 200910230433.5 patent of invention " a kind of novel fault selection method in small current neutral grounding system " Propose to carry out failure line selection based on 5 neutral harmonic current methods, owing to 5 order harmonic components in zero sequence current signal after singlephase earth fault are the least, Sensitivity is restricted, and the method cannot practical.Ma Jia, Yu Wenhui and car big raise etc. deliver " based on improving S injection method moral novel tree-like Detecting fault line for un-ground neutral power system " and Sang Zhong, Zhang Huifen and Pan Zhencun etc. deliver " realize small current grounding system single-phase grounding selecting with injection method Protection " propose to utilize S injection method to carry out failure line selection, the method practicality is relatively strong, but is easily affected by earth resistance and line distribution capacitance. Owing to transient process is of short duration, being affected by line parameter circuit value and transition resistance etc., (application number 00114452.9 invention is special to utilize transient algorithm failure line selection Profit " earthing protection method for small current earthing system ") also do not arrive practical level.Yan Feng, Yang Qixun and Qi Zheng etc. deliver " based on theory of travelling wave The research of electrical power distribution network fault location method " and in containing nanmu, Bao Hai and Yang Yihan delivers " practical approach of distribution network line fault location " and proposes profit Realize power distribution network off-line fault location with theory of travelling wave, reach practical level.But some user is the highest to power supply reliability in actual application, Wish to realize online failure line selection.Traveling wave method (application number 201010214355.2 patent of invention " single-phase grounded malfunction in grounded system of low current route selection side Method ") estimate fault distance two-way time for the first time according to fault wave between trouble point and monitoring point.But in small current neutral grounding system fault-signal is very Weak, the fault wave head of fault waveform is difficult to, and causes difficulty to traveling wave method practicality online.

Summary of the invention

It is an object of the invention to the deficiency overcoming prior art to exist, it is provided that a kind of distribution network fault line selection based on the through-flow unique trait of current in resistance property Method.The method utilizes current in resistance property uniquely to flow through this characteristic of fault feeder and realizes distribution network fault line selection, and route selection result is correctly reliable, not by Cross the impact of resistance, single-phase grounding fault point position, line parameter circuit value and line length.

The present invention adopts the following technical scheme that

Distribution network fault line selection method based on the through-flow unique trait of current in resistance property, it is characterised in that include following sequential steps:

(1) power distribution network bus residual voltage is measuredIfMeasure the 1st, 2 the most respectively ..., n-1, n bar power distribution network The zero-sequence current that feeder line flows throughWherein, n is distribution feeder number；For power distribution network time properly functioning Bus phase voltage；

(2) through set time T_sAfter time delay, parallel resistance R being connected in parallel with arc suppression coil on electrical structure sends switching order, and switching is also Connection resistance R, measures power distribution network bus residual voltage againMeasure the 1st, 2 respectively ..., the zero sequence that n-1, n bar distribution feeder flows through Electric currentWherein, n is distribution feeder number；

(3) the 1st, 2 is calculated respectively ..., the current in resistance property amplitude of n-1, n bar distribution feeder Choose the distribution feeder of current in resistance property amplitude maximum For fault feeder；Wherein, n is distribution feeder number.

The present invention compared with prior art, has a following positive achievement:

The inventive method utilizes current in resistance property uniquely to flow through this characteristic of fault feeder and realizes distribution network fault line selection, and route selection result is correctly reliable, is not subject to The impact of transition resistance, single-phase grounding fault point position, line parameter circuit value and line length.

Accompanying drawing explanation

Fig. 1 is the one-phase earthing failure in electric distribution network zero sequence sequence diagrams before the parallel resistance switching of application the inventive method.

Fig. 2 is the one-phase earthing failure in electric distribution network zero sequence sequence diagrams after the parallel resistance switching of application the inventive method.

Detailed description of the invention

Below according to Figure of description, technical scheme is expressed in further detail.

Fig. 1 is the one-phase earthing failure in electric distribution network zero sequence sequence diagrams before the parallel resistance switching of application the inventive method.The present embodiment with neutral point through disappearing Technical solution of the present invention is expanded on further as a example by the power distribution network nth bar feeder line generation singlephase earth fault of arc coil ground connection.First this enforcement measure distribution Net bus residual voltageIfMeasure the 1st, 2 the most respectively ..., the zero sequence electricity that n-1, n bar distribution feeder flows through StreamWherein, n is distribution feeder number；For power distribution network bus phase voltage time properly functioning.

Through set time T_sAfter time delay, parallel resistance R being connected in parallel with arc suppression coil on electrical structure sends switching order, switching parallel resistance R, Fig. 2 are the one-phase earthing failure in electric distribution network zero sequence sequence diagrams after the parallel resistance switching of application the inventive method.Again measure power distribution network bus zero Sequence voltageMeasure the 1st, 2 respectively ..., the zero-sequence current that n-1, n bar distribution feeder flows through

Calculate the 1st, 2 respectively ..., the current in resistance property amplitude of n-1, n bar distribution feeder:

${\mathrm{\ΔI}}_{01}=|{\stackrel{\·}{I}}_{01}^1-\frac{{\stackrel{\·}{U}}_0^1}{{\stackrel{\·}{U}}_0^2}{\stackrel{\·}{I}}_{01}^2|=|{\stackrel{\·}{U}}_0^1{Y}_{01}-{\stackrel{\·}{U}}_0^1{Y}_{01}|=0$

${\mathrm{\ΔI}}_{02}=|{\stackrel{\·}{I}}_{02}^1-\frac{{\stackrel{\·}{U}}_0^1}{{\stackrel{\·}{U}}_0^2}{\stackrel{\·}{I}}_{02}^2|=|{\stackrel{\·}{U}}_0^1{Y}_{02}-{\stackrel{\·}{U}}_0^1{Y}_{02}|=0$

……

${\mathrm{\ΔI}}_{0n-1}=|{\stackrel{\·}{I}}_{0n-1}^1-\frac{{\stackrel{\·}{U}}_0^1}{{\stackrel{\·}{U}}_0^2}{\stackrel{\·}{I}}_{0n-1}^2|=|{\stackrel{\·}{U}}_0^1{Y}_{0n-1}-{\stackrel{\·}{U}}_0^1{Y}_{0n-1}|=0$

Wherein, Y₀₁、Y₀₂、…、Y_0n-1It is respectively the 1st, 2 ..., the admittance over the ground of n-1 bar distribution feeder.

$\begin{array}{c}{\mathrm{\ΔI}}_{0n}=|{\stackrel{\·}{I}}_{0n}^1-\frac{{\stackrel{\·}{U}}_0^1}{{\stackrel{\·}{U}}_0^2}{\stackrel{\·}{I}}_{0n}^2|\\ =|{\stackrel{\·}{U}}_0^1(-Y_{01}-Y_{02}-\mathrm{...}-Y_{0n-1}-\frac{1}{h\mathrm{\ω}L})-\frac{{\stackrel{\·}{U}}_0^1}{{\stackrel{\·}{U}}_0^2}{\stackrel{\·}{U}}_0^2(-Y_{01}-Y_{02}-\mathrm{...}-Y_{0n-1}-\frac{1}{j\mathrm{\ω}L}-\frac{1}{R})|\\ =\left|\frac{{\stackrel{\·}{U}}_0^1}{R}\right|>{\mathrm{\ΔI}}_{0n-1}=\mathrm{...}={\mathrm{\ΔI}}_{02}={\mathrm{\ΔI}}_{01}\end{array}---\left(1\right)$

Wherein, ω is power system angular frequency；L is the reactance parameter of arc suppression coil.

From formula (1), current in resistance property can uniquely flow through fault feeder without flow through normal feeder line, current in resistance property, and flow through the resistive of fault feeder Current amplitude and parallel resistance R and power distribution network bus residual voltageRelevant, unrelated with other parameters.Therefore, the inventive method utilizes resistive Electric current uniquely flows through this characteristic of fault feeder and realizes distribution network fault line selection, and route selection result is not by transition resistance, single-phase grounding fault point position, line LUSHEN number and the impact of line length, location design is simple, and route selection result is correctly reliable, practical.

The foregoing is only the preferred embodiment of the present invention, but protection scope of the present invention is not limited thereto, any be familiar with the art Technical staff in the technical scope that the invention discloses, the change that can readily occur in or replacement, all should contain within protection scope of the present invention.

Claims (1)

1. distribution network fault line selection method based on the through-flow unique trait of current in resistance property, including following sequential steps:

(1) power distribution network bus residual voltage is measuredIfMeasure the 1st, 2 the most respectively ..., n-1, n bar power distribution network The zero-sequence current that feeder line flows throughWherein, n is distribution feeder number；For power distribution network time properly functioning Bus phase voltage；

(2) through set time T_sAfter time delay, parallel resistance R being connected in parallel with arc suppression coil on electrical structure sends switching order, and switching is also Connection resistance R, measures power distribution network bus residual voltage againMeasure the 1st, 2 respectively ..., the zero sequence that n-1, n bar distribution feeder flows through Electric currentWherein, n is distribution feeder number；

(3) the 1st, 2 is calculated respectively ..., the current in resistance property amplitude of n-1, n bar distribution feeder Choose the distribution feeder of current in resistance property amplitude maximum For fault feeder；Wherein, n is distribution feeder number.