CN103293384A - Online cable resistance tuning method for power distribution network - Google Patents

Abstract

The invention relates to the technical field of operation of the power system, in particular to an online cable resistance tuning method for the power distribution network. For a section of a cable of the power distribution network to mount a wide range measuring device, the online cable resistance tuning method includes: setting a voltage drop equivalent calculating model of the cable, analyzing and calculating coefficient of the voltage drop equivalent calculating model by a mathematic method according to high-density voltage and current information in a cycle at two ends of the cable, wherein the information is collected by the wide-range measuring device, and online identifying the resistance of the cable, wherein the resistance of the cable is the coefficient corresponding to the current of an acquiring point. Parameters of the resistance of the cable can be online identified by means of high-density data in a cycle, calculation is simple, and the online cable resistance tuning method is applicable to most cables provided with the wide range measuring devices. The online cable resistance tuning method is free of affection from arrangement way and operating environment of the cables, overcomes defects of conventional calculation methods, and is accurate and reliable in calculation results.

Description

A kind of power distribution network cable line resistance on-line tuning method

Technical field

The present invention relates to the Operation Technique of Electric Systems field, be specifically related to a kind of power distribution network cable line resistance on-line tuning method.

Background technology

The power distribution network line parameter circuit value is the important component part of power distribution network basic data, and its accuracy directly influences the validity of state of electric distribution network estimation, trend calculating, Risk-warning, fault diagnosis and On-line Control and decision-making.Along with the quickening of Urbanization in China, cable line more and more is applied to urban distribution network and some economic flourishing rural areas electrical networks.Because it is underground that cable line is embedded in, and influenced by multiple external cause, line parameter circuit value also can correspondingly change, and is difficult for discovering.If continue to adopt line design value or theoretical value to carry out the various analytical calculations of power distribution network, will directly influence operational decisions level and the power supply quality of power distribution network.Therefore, research power distribution network cable-line parameter discrimination method is significant.

At present, the power distribution network cable-line parameter obtained following three kinds of methods: (1) is directly calculated according to the line parameter circuit value computing formula or is inquired about from eelctrical engineering handbook or products catalogue according to the circuit model and obtain.The line parameter circuit value that these class methods obtain is theoretical value or design load, is changeless, can not in time reflect the variation of line parameter circuit value.(2) adopt instrument or device measuring line impedance.These class methods can obtain real line parameter circuit value, but must implement after circuit puts into operation, complicated operation, and can not frequently measure.(3) calculate by the Equivalent Model of setting up circuit.These class methods adopt multi-period data to calculate usually, can not reflect in real time that line parameter circuit value changes.

In recent years, along with the intelligent power distribution net is development, power distribution network design, operation and control are had higher requirement to line parameter circuit value.Especially cable line is embedded in underground, be subjected to various external causes to influence line parameter circuit value and change, be difficult for discovering, and the variation that Traditional calculating methods can not the real-time identification line parameter circuit value, can not satisfy the needs that modern power systems is analyzed, must the new line parameter circuit value computing method of research.

Wide area measurement system (Wide Area Measurement System, WAMS) be based on synchronous vector measurement technology, detect, analyze and be controlled to be the real-time monitoring system of target with dynamic process of electrical power system, have strange land high-precise synchronization vector measurement, high-speed communication and technical characterstic such as reflection fast.In recent years, the wide area measurement system development is rapid, and is gradually improved, and the instantaneous value that obtains high-density acquisition in cable line voltage, cycle of electric current in real time becomes possibility.

Summary of the invention

At the deficiencies in the prior art, the purpose of this invention is to provide a kind of power distribution network cable line resistance on-line tuning method, this method is at first set up the voltage drop Equivalent Calculation Model of this cable line, highdensity voltage, current information in the cycle in these cable line two ends that collects according to the wide area measurement device, adopt the coefficient of mathematical method analytical calculation voltage drop Equivalent Calculation Model then, the coefficient of current collection point electric current correspondence namely is the resistance of this cable line, thereby realizes the on-line identification of cable line resistance.This method is calculated simple, and real-time is good.

The objective of the invention is to adopt following technical proposals to realize:

A kind of power distribution network cable line resistance on-line tuning method, its improvements are, described method is based on the wide area measurement device information, described wide area measurement device image data ultimate principle in power distribution network is: gps receiver provides the 1pps signal, phase-locked oscilaltor is divided at least one impulse sampling with it, AC signal after filtering is handled quantizes through analog to digital converter, and microprocessor is calculated phasor according to the recursive discrete Fourier transformation principle, transmits by data channel and carries out data output;

Described method comprises the steps:

(1) sets up cable line voltage drop Equivalent Calculation Model;

(2) gather a cycle interior voltage, current information;

(3) determine cable line resistance;

(4) output cable circuit resistance result.

Preferably, in the described step (1), described cable line voltage drop is by cable resistance and reactance acting in conjunction, and cable line is represented with following formula in collection point t voltage drop:

$\mathrm{\&Delta;U}\left(t\right)=U_1\left(t\right)-U_2\left(t\right)=R\&CenterDot;I\left(t\right)+L\&CenterDot;\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}---<1>;$

In the formula: Δ U (t)---collection point t cable line head, terminal voltage are poor;

U ₁(t)---collection point t cable line head end voltage;

U ₂(t)---collection point t cable line terminal voltage;

R---cable line resistance;

I (t)---the electric current that collection point t cable line flows through;

The inductance of L---cable line;

When the data volume that collects as each data collection cycle T of wide area measurement device is n,

$\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=\underset{\mathrm{\&Delta;t}\&RightArrow;0}{\lim }\frac{I(t+\mathrm{\&Delta;t})-I\left(t\right)}{\mathrm{\&Delta;t}}\&ap;\frac{I(t+\frac{T}{n})-I\left(t\right)}{\frac{T}{n}}---<2>;$

In the formula:

Be the collection point

The electric current that cable line flows through;

N is the number of data points that collects in the data collection period T;

Δ t is sampling time interval.

By formula＜1〉and＜2 set up cable line voltage drop Equivalent Calculation Model and be:

$\mathrm{\&Delta;U}\left(t\right)=R\&CenterDot;I\left(t\right)+L\left(t\right)\&CenterDot;\frac{I(t+\frac{T}{n})-I\left(t\right)}{\frac{T}{n}}---<3>.$

Preferably, in the described step (2), based on cable line head, terminal voltage and the cable line electric current in data collection period of wide area measurement device information collection.

Preferably, in the described step (3), adopt following method to determine cable line resistance:

In a data collection period T, the note 0～T time period in high-density acquisition to n data point head, terminal voltage and electric current be respectively:

$U_1=\left[\begin{array}{c}{U}_1^A\\ U_1^B\\ U_1^C\end{array}\right]=\left[\begin{array}{ccccc}{U}_{11}^A& U_{11}^A& U_{13}^A& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^A\\ U_{11}^B& U_{12}^B& U_{13}^B& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^B\\ U_{11}^C& U_{12}^C& U_{13}^C& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^C\end{array}\right]---<4>;$

${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00003168171200012.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\left[\begin{array}{c}{U}_2^A\\ U_2^B\\ U_2^C\end{array}\right]=\left[\begin{array}{ccccc}{U}_{21}^A& U_{22}^A& U_{23}^A& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^A\\ U_{21}^B& U_{22}^B& U_{23}^B& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^B\\ U_{21}^C& U_{22}^C& U_{23}^C& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^C\end{array}\right]---<5>;$

$I=\left[\begin{array}{c}{I}^A\\ I^B\\ I^C\end{array}\right]=\left[\begin{array}{ccccc}{I}_1^A& I_2^A& I_3^A& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^A\\ I_1^B& I_2^B& I_3^B& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^B\\ I_1^C& I_2^C& I_3^C& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^C\end{array}\right]---<6>;$

In the formula:

The expression voltage U _iThe numerical value that collects at collection point j of p; I=1 wherein, 2; J=1,2,3 ..., n, p represent a certain phase among A, B, the C;

The numerical value that collects at collection point k of p of expression electric current I, k=1 wherein, 2,3 ..., n;

$\frac{\mathrm{dI}}{\mathrm{dt}}=\left[\begin{array}{c}\frac{{\mathrm{dI}}^A}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^B}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^C}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{cccc}\frac{I_2^A-I_1^A}{T/n}& \frac{I_3^A-I_2^A}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^A-I_n^A}{T/n}\\ \frac{I_2^B-I_1^B}{T/n}& \frac{I_3^B-I_2^B}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^B-I_n^B}{T/n}\\ \frac{I_2^C-I_1^C}{T/n}& \frac{I_3^C-I_2^C}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^C-I_n^C}{T/n}\end{array}\right]---<7>;$

Because line current is cyclical variation,

Then following formula is rewritten as:

$\frac{\mathrm{dI}}{\mathrm{dt}}=\left[\begin{array}{c}\frac{{\mathrm{dI}}^A}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^B}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^C}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{cccc}\frac{I_2^A-I_1^A}{T/n}& \frac{I_3^A-I_2^A}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^A-I_n^A}{T/n}\\ \frac{I_2^B-I_1^B}{T/n}& \frac{I_3^B-I_2^B}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^B-I_n^B}{T/n}\\ \frac{I_2^C-I_1^C}{T/n}& \frac{I_3^C-I_2^C}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^C-I_n^C}{T/n}\end{array}\right]---<8>;$

Order:

$\stackrel{\&OverBar;}{x_1^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p---<9>;$

$\stackrel{\&OverBar;}{x_2^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<10>;$

$\stackrel{\&OverBar;}{y^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<11>;$

$s_{11}^{\left(p\right)}=\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(I_t^p-\stackrel{\&OverBar;}{x_1^p})}^2---<12>;$

$s_{12}^p=s_{21}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(I_t^p-\stackrel{\&OverBar;}{x_1^p})(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})---<13>;$

$s_{22}^p=\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})}^2---<14>;$

$s_{1y}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(I_t^p-\stackrel{\&OverBar;}{x_1^p})((U_{1t}^p-U_{2t}^p)-\stackrel{\&OverBar;}{y^p})---<15>;$

$s_{2y}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})((U_{1t}^p-U_{2t}^p)-\stackrel{\&OverBar;}{y^p})---<16>;$

Wherein: With

Be the intermediate variable that convenience of calculation is introduced, i=1 wherein, 2, j=1,2;

Get following system of equations:

$\left\{\begin{array}{c}{s}_{11}^p{R}^p+S_{12}^p{L}^p=s_{1y}^p\\ s_{21}^p{R}^p+s_{22}^p{L}^p=s_{2y}^p\end{array}\right.---<17>;$

Wherein: R ^pBe cable line p phase resistance;

L ^pP phase inductance for cable line;

Separating above system of equations gets:

$R^p=\frac{s_{22}^p{s}_{1y}^p-s_{12}^p{s}_{2y}^p}{s_{11}^p{s}_{22}^p-s_{12}^p{s}_{21}^p}---<18>;$

Namely obtain p phase cable line resistance R ^p

Preferably, in the described step (3), adopt following method to determine cable line resistance:

The slope of each collection point is cyclical variation:

$\underset{t=1}{\overset{T/2}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=-\underset{l=T/2}{\overset{T}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(l\right)}{\mathrm{dl}}---<19>;$

For a certain phase p of circuit:

$\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)=R^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p+L^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=R^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p---<20>;$

Namely get p phase cable line resistance expression formula:

$R^p=\frac{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)}{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p}---<21>.$

Preferably, in the described step (3), adopt following method to determine cable line resistance:

Get N group cable line voltage, current data, wherein N be less than

Natural number, calculate the mean value of its p phase:

${\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}{I}_t^p---<22>;$

${\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<23>;$

${\left(\stackrel{\&OverBar;}{y^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<24>;$

Wherein:

Mean value for circuit p phase N group current data;

Mean value for circuit p phase N group electric current derivative;

Mean value for circuit p phase N group voltage difference data;

Get N group cable line p phase voltage, current data again, calculate its mean value:

${\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}{I}_t^p---<25>;$

${\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<26>;$

${\left(\stackrel{\&OverBar;}{y^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<27>;$

Wherein:

Mean value for another N group current data of circuit p phase;

Mean value for another N group electric current derivative of circuit p phase;

Mean value for another N group voltage difference data of circuit p phase;

Set up system of equations, as follows:

$\left\{\begin{array}{c}{\left(\stackrel{\&OverBar;}{y^p}\right)}_1={\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1{R}^p+{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1{L}^p\\ {\left(\stackrel{\&OverBar;}{y^p}\right)}_2={\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2{R}^p+{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2{L}^p\end{array}\right.---<28>;$

Separating above-mentioned system of equations, to get cable line p phase resistance as follows:

$R^{\left(p\right)}=\frac{{\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2-{\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1}{{\left(\stackrel{\&OverBar;}{y^p}\right)}_1{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2-{\left(\stackrel{\&OverBar;}{y^p}\right)}_2{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1}---<29>.$

Preferably, in the described step (3), adopt following method to determine cable line resistance:

Mean value falls in first, terminal p phase voltage

Computing method are as follows:

${\mathrm{\&Delta;U}}_{\mathrm{avg}}^p\widetilde{\&OverBar;}\frac{1}{n}(\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_1^p\left(t\right)-\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_2^p\left(t\right))---<30>;$

Circuit p phase current mean value Computing method are as follows:

$I_{\mathrm{avg}}^p\widetilde{\&OverBar;}\frac{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}^p\left(t\right)}{n}---<31>;$

First, terminal p phase voltage is fallen and circuit p phase current phase angle difference The mean value calculation method is as follows:

In the formula: θ _U1(t)---collection point t circuit head end p phase voltage phase angle;

θ _U2(t)---collection point t line end p phase voltage phase angle;

θ _I(t)---collection point t circuit p phase current phase angle;

Cable line resistance p phase expression formula is:

Compared with the prior art, the beneficial effect that reaches of the present invention is:

(1) along with the quickening of China's level of the productive forces and process of industrialization, cable line more and more is applied in the power distribution network.Its line parameter circuit value is the important component part of power distribution network basic data, and its accuracy directly influences the validity of state of electric distribution network estimation, trend calculating, Risk-warning, fault diagnosis and On-line Control and decision-making.The interior highdensity data of the cycle that the present invention can adopt the wide area measurement device to collect, the parameter identification of realization power distribution network cable line resistance is for distribution system analysis, control and decision-making provide foundation.

(2) along with the development of intelligent grid, the wide area measurement device will more and more be applied to power distribution network, for this invention provides Data Source.The present invention calculates simply, and computing velocity is fast, is applicable to all cable lines that the wide area measurement device is installed.

(3) the present invention is not influenced by cable installation mode, running environment, has remedied the deficiency of Traditional calculating methods, and result of calculation accurately, reliably.

Description of drawings

Fig. 1 is power distribution network cable line synoptic diagram provided by the invention;

Fig. 2 is a cycle image data of power distribution network provided by the invention synoptic diagram;

Fig. 3 is cable line voltage provided by the invention, current vector synoptic diagram;

Fig. 4 is power distribution network cable line resistance on-line tuning overview flow chart provided by the invention;

Fig. 5 is wide area measurement device image data schematic diagram provided by the invention.

Embodiment

Below in conjunction with accompanying drawing the specific embodiment of the present invention is described in further detail.

The invention provides a kind of power distribution network cable line resistance on-line tuning method of the instantaneous value based on high-density acquisition in the cable line voltage that obtains, cycle of electric current.Power distribution network cable line synoptic diagram provided by the invention as shown in Figure 1.

For the one section power distribution network cable line that is equipped with the wide area measurement device, set up the voltage drop Equivalent Calculation Model of this cable line, voltage, current information according to high-density acquisition in cycle in these circuit two ends of wide area measurement device collection, adopt the coefficient of mathematical method analytical calculation voltage drop Equivalent Calculation Model, the coefficient of current collection point electric current correspondence namely is the resistance of this cable line, thereby realizes the on-line identification of cable line resistance.This method is only used the image data of a cycle, can calculate line resistance in real time, realizes the identification of cable-line parameter.

Wide area measurement device image data schematic diagram provided by the invention as shown in Figure 5.(Wide Area Measurement System is based on synchronous vector measurement technology WAMS) to wide area measurement system, for dynamic process of electrical power system is monitored in real time, analyzed and control provides the information support.In recent years, have technical characterstics such as strange land high-precise synchronization vector measurement, high-speed communication and quick reflection because of the wide area measurement device, in power transmission network, obtained extensive application, also begin in power distribution network, to use simultaneously.Wide area measurement device image data ultimate principle in power distribution network is: gps receiver provides 1pps(1 pulse per second) signal, phase-locked oscilaltor is divided into the impulse sampling of some with it, AC signal after filtering is handled quantizes through analog to digital converter, and microprocessor is calculated phasor according to the recursive discrete Fourier transformation principle.For the three-phase phasor, microprocessor adopts symmetrical component method to calculate positive-sequence component, transmits by designated lane and carries out data output.

Power distribution network cable line resistance on-line tuning overview flow chart provided by the invention as shown in Figure 4, described method comprises the steps: based on the wide area measurement device information

(1) set up cable line voltage drop Equivalent Calculation Model:

The voltage drop of cable line is the coefficient effect of cable resistance and reactance, and cable line in the voltage drop computing formula of collection point t is:

$\mathrm{\&Delta;U}\left(t\right)=U_1\left(t\right)-U_2\left(t\right)=R\&CenterDot;I\left(t\right)+L\&CenterDot;\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}---<1>;$

In the formula: Δ U (t)---collection point t cable line head, terminal voltage are poor;

U ₁(t)---collection point t cable line head end voltage;

U ₂(t)---collection point t cable line terminal voltage;

R---cable line resistance;

I (t)---the electric current that collection point t cable line flows through;

The inductance of L---cable line;

When the data volume that collects as each data collection cycle T of wide area measurement device is n,

$\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=\underset{\mathrm{\&Delta;t}\&RightArrow;0}{\lim }\frac{I(t+\mathrm{\&Delta;t})-I\left(t\right)}{\mathrm{\&Delta;t}}\&ap;\frac{I(t+\frac{T}{n})-I\left(t\right)}{\frac{T}{n}}---<2>;$

In the formula:

Be the collection point

The electric current that cable line flows through;

N is the number of data points that collects in the data collection period T;

Δ t is sampling time interval.

By formula＜1〉and＜2 set up cable line voltage drop Equivalent Calculation Model and be:

$\mathrm{\&Delta;U}\left(t\right)=R\&CenterDot;I\left(t\right)+L\left(t\right)\&CenterDot;\frac{I(t+\frac{T}{n})-I\left(t\right)}{\frac{T}{n}}---<3>.$

By cable line voltage drop Equivalent Calculation Model as can be known, the cable line voltage drop is made up of two parts.First's voltage drop is that current collection point electric current causes at line resistance, and second portion is the voltage drop that the slope of current collection point electric current produces at the inductance of circuit.Owing to be subjected to the variation of cable line institute connected load, current collection point electric current slope is also in continuous variation, so the second portion voltage drop is constantly to change.But for a large amount of line voltage distributions and current data, this part voltage drop is tending towards its mathematical expectation, and there are linear relationship in this part voltage drop and current collection point electric current slope.

(2) gather a cycle interior voltage, current information: based on cable line head, terminal voltage and the cable line electric current in data collection period of wide area measurement device information collection.A cycle image data of power distribution network provided by the invention synoptic diagram as shown in Figure 2.Cable line voltage provided by the invention, current vector synoptic diagram are as shown in Figure 3.

(3) determine cable line resistance:

Adopt following four kinds of methods to determine cable line resistance, detailed process is as follows:

Method one:

In a data collection period T, the note 0～T time period in high-density acquisition to n data point head, terminal voltage and electric current be respectively:

$U_1=\left[\begin{array}{c}{U}_1^A\\ U_1^B\\ U_1^C\end{array}\right]=\left[\begin{array}{ccccc}{U}_{11}^A& U_{11}^A& U_{13}^A& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^A\\ U_{11}^B& U_{12}^B& U_{13}^B& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^B\\ U_{11}^C& U_{12}^C& U_{13}^C& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^C\end{array}\right]---<4>;$

${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA00003168171200012.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\left[\begin{array}{c}{U}_2^A\\ U_2^B\\ U_2^C\end{array}\right]=\left[\begin{array}{ccccc}{U}_{21}^A& U_{22}^A& U_{23}^A& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^A\\ U_{21}^B& U_{22}^B& U_{23}^B& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^B\\ U_{21}^C& U_{22}^C& U_{23}^C& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^C\end{array}\right]---<5>;$

$I=\left[\begin{array}{c}{I}^A\\ I^B\\ I^C\end{array}\right]=\left[\begin{array}{ccccc}{I}_1^A& I_2^A& I_3^A& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^A\\ I_1^B& I_2^B& I_3^B& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^B\\ I_1^C& I_2^C& I_3^C& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^C\end{array}\right]---<6>;$

In the formula:

The expression voltage U _iThe numerical value that collects at collection point j of p; I=1 wherein, 2; J=1,2,3 ..., n, p represent a certain phase among A, B, the C;

The numerical value that collects at collection point k of p of expression electric current I, k=1 wherein, 2,3 ..., n.

$\frac{\mathrm{dI}}{\mathrm{dt}}=\left[\begin{array}{c}\frac{{\mathrm{dI}}^A}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^B}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^C}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{cccc}\frac{I_2^A-I_1^A}{T/n}& \frac{I_3^A-I_2^A}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^A-I_n^A}{T/n}\\ \frac{I_2^B-I_1^B}{T/n}& \frac{I_3^B-I_2^B}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^B-I_n^B}{T/n}\\ \frac{I_2^C-I_1^C}{T/n}& \frac{I_3^C-I_2^C}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^C-I_n^C}{T/n}\end{array}\right]---<7>;$

Because line current is cyclical variation,

Then following formula is rewritten as:

$\frac{\mathrm{dI}}{\mathrm{dt}}=\left[\begin{array}{c}\frac{{\mathrm{dI}}^A}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^B}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^C}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{cccc}\frac{I_2^A-I_1^A}{T/n}& \frac{I_3^A-I_2^A}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^A-I_n^A}{T/n}\\ \frac{I_2^B-I_1^B}{T/n}& \frac{I_3^B-I_2^B}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^B-I_n^B}{T/n}\\ \frac{I_2^C-I_1^C}{T/n}& \frac{I_3^C-I_2^C}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^C-I_n^C}{T/n}\end{array}\right]---<8>;$

In order to express easily, the impedance of a computational scheme p phase.Order:

$\stackrel{\&OverBar;}{x_1^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p---<9>;$

$\stackrel{\&OverBar;}{x_2^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<10>;$

$\stackrel{\&OverBar;}{y^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<11>;$

$s_{11}^{\left(p\right)}=\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(I_t^p-\stackrel{\&OverBar;}{x_1^p})}^2---<12>;$

$s_{12}^p=s_{21}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(I_t^p-\stackrel{\&OverBar;}{x_1^p})(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})---<13>;$

$s_{22}^p=\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})}^2---<14>;$

$s_{1y}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(I_t^p-\stackrel{\&OverBar;}{x_1^p})((U_{1t}^p-U_{2t}^p)-\stackrel{\&OverBar;}{y^p})---<15>;$

$s_{2y}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})((U_{1t}^p-U_{2t}^p)-\stackrel{\&OverBar;}{y^p})---<16>;$

Wherein: With

Be the intermediate variable that convenience of calculation is introduced, i=1 wherein, 2, j=1,2;

Get following system of equations:

$\left\{\begin{array}{c}{s}_{11}^p{R}^p+S_{12}^p{L}^p=s_{1y}^p\\ s_{21}^p{R}^p+s_{22}^p{L}^p=s_{2y}^p\end{array}\right.---<17>;$

Wherein: R ^pBe cable line p phase resistance;

L ^pP phase inductance for cable line.

Separating above system of equations gets:

$R^p=\frac{s_{22}^p{s}_{1y}^p-s_{12}^p{s}_{2y}^p}{s_{11}^p{s}_{22}^p-s_{12}^p{s}_{21}^p}---<18>;$

Namely obtain p phase cable line resistance R ^p

Method two:

Because current waveform is cyclical variation, the slope of each collection point also is cyclical variation:

$\underset{t=1}{\overset{T/2}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=-\underset{l=T/2}{\overset{T}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(l\right)}{\mathrm{dl}}---<19>;$

For a certain phase p of circuit:

$\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)=R^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p+L^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=R^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p---<20>;$

Namely get p phase cable line resistance expression formula:

$R^p=\frac{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)}{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p}---<21>.$

Method three:

Under the less situation of image data error, get N group cable line voltage, current data, wherein N be less than

Natural number, calculate the mean value of its p phase:

${\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}{I}_t^p---<22>;$

${\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<23>;$

${\left(\stackrel{\&OverBar;}{y^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<24>;$

Wherein:

Mean value for circuit p phase N group current data;

Mean value for circuit p phase N group electric current derivative;

Mean value for circuit p phase N group voltage difference data.

Get N group cable line p phase voltage, current data again, calculate its mean value:

${\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}{I}_1^p---<25>;$

${\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<26>;$

${\left(\stackrel{\&OverBar;}{y^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<27>;$

Wherein:

Mean value for another N group current data of circuit p phase;

Mean value for another N group electric current derivative of circuit p phase;

Mean value for another N group voltage difference data of circuit p phase.

Set up system of equations, as follows:

$\left\{\begin{array}{c}{\left(\stackrel{\&OverBar;}{y^p}\right)}_1={\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1{R}^p+{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1{L}^p\\ {\left(\stackrel{\&OverBar;}{y^p}\right)}_2={\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2{R}^p+{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2{L}^p\end{array}\right.---<28>;$

Separating above-mentioned system of equations, to get cable line p phase resistance as follows:

$R^{\left(p\right)}=\frac{{\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2-{\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1}{{\left(\stackrel{\&OverBar;}{y^p}\right)}_1{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2-{\left(\stackrel{\&OverBar;}{y^p}\right)}_2{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1}---<29>.$

Method four:

Mean value falls in first, terminal p phase voltage Computing method are as follows:

${\mathrm{\&Delta;U}}_{\mathrm{avg}}^p\widetilde{\&OverBar;}\frac{1}{n}(\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_1^p\left(t\right)-\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_2^p\left(t\right))---<30>;$

Circuit p phase current mean value

Computing method are as follows:

$I_{\mathrm{avg}}^p\widetilde{\&OverBar;}\frac{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}^p\left(t\right)}{n}---<31>;$

First, terminal p phase voltage is fallen and circuit p phase current phase angle difference

The mean value calculation method is as follows:

In the formula: θ _U1(t)---collection point t circuit head end p phase voltage phase angle;

θ _U2(t)---collection point t line end p phase voltage phase angle;

θ _I(t)---collection point t circuit p phase current phase angle.

Cable line resistance p phase expression formula is:

Error calculated is analyzed:

Because the power distribution network data are more, equipment level is uneven, exists the image data mistake to cause problems such as the big and data collection cycle of Acquisition Error is asynchronous, influences result of calculation.And, each data collection cycle T mining height density collection to the difference of data volume n also can influence result of calculation.It is as shown in table 1 specifically to influence situation.

The influenced analytical table of each method error of calculation of table 1

Method	Acquisition Error	Data collection cycle is asynchronous	The data volume n that collection period T collects
				Method one	Influence less	Unaffected (unless sudden load change takes place)	N is more big, and the error of calculation is more little
Method two	Unaffected	Unaffected	Unaffected
				Method three	Influence bigger	Influence less	Influence less
Method four	Influence less	Influence less	Influence less

(4) output cable circuit resistance result.

The present invention can realize the parameter identification of power distribution network cable line resistance only with highdensity data in the cycle.Calculate simply, be applicable to the cable lines of great majority installation wide area measurement devices.The present invention is not influenced by cable installation mode, running environment, has remedied the deficiency of Traditional calculating methods, and result of calculation accurately, reliably.

Should be noted that at last: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can make amendment or be equal to replacement the specific embodiment of the present invention, and do not break away from any modification of spirit and scope of the invention or be equal to replacement, it all should be encompassed in the middle of the claim scope of the present invention.

Claims (7)

1. power distribution network cable line resistance on-line tuning method, it is characterized in that, described method is based on the wide area measurement device information, described wide area measurement device image data ultimate principle in power distribution network is: gps receiver provides the 1pps signal, phase-locked oscilaltor is divided at least one impulse sampling with it, AC signal after filtering is handled quantizes through analog to digital converter, microprocessor is calculated three-phase voltage and electric current phasor according to the recursive discrete Fourier transformation principle, transmits by data channel and carries out data output;

Described method comprises the steps:

(1) sets up cable line voltage drop Equivalent Calculation Model;

(2) gather a cycle interior voltage, current information;

(3) determine cable line resistance;

(4) output cable circuit resistance result.

2. power distribution network cable line resistance on-line tuning method as claimed in claim 1, it is characterized in that, in the described step (1), described cable line voltage drop is produced by cable resistance and reactance acting in conjunction, and cable line is represented with following formula in the voltage drop of collection point t:

$\mathrm{\&Delta;U}\left(t\right)=U_1\left(t\right)-U_2\left(t\right)=R\&CenterDot;I\left(t\right)+L\&CenterDot;\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}---<1>;$

In the formula: Δ U (t)---collection point t cable line head, terminal voltage are poor;

U ₁(t)---collection point t cable line head end voltage;

U ₂(t)---collection point t cable line terminal voltage;

R---cable line resistance;

I (t)---the electric current that collection point t cable line flows through;

The inductance of L---cable line;

When the data volume that collects as each data collection cycle T of wide area measurement device is n,

$\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=\underset{\mathrm{\&Delta;t}\&RightArrow;0}{\lim }\frac{I(t+\mathrm{\&Delta;t})-I\left(t\right)}{\mathrm{\&Delta;t}}\&ap;\frac{I(t+\frac{T}{n})-I\left(t\right)}{\frac{T}{n}}---<2>;$

In the formula:

Be the collection point

The electric current that cable line flows through;

N is the number of data points that collects in the data collection period T;

Δ t is sampling time interval.

By formula＜1〉and＜2 set up cable line voltage drop Equivalent Calculation Model and be:

$\mathrm{\&Delta;U}\left(t\right)=R\&CenterDot;I\left(t\right)+L\left(t\right)\&CenterDot;\frac{I(t+\frac{T}{n})-I\left(t\right)}{\frac{T}{n}}---<3>.$

3. power distribution network cable line resistance on-line tuning method as claimed in claim 1 is characterized in that, in the described step (2), based on cable line head, terminal voltage and the cable line electric current in data collection period of wide area measurement device information collection.

4. power distribution network cable line resistance on-line tuning method as claimed in claim 1 is characterized in that, in the described step (3), adopts following method to determine cable line resistance:

In a data collection period T, the note 0～T time period in high-density acquisition to n data point head, terminal voltage and electric current be respectively:

$U_1=\left[\begin{array}{c}{U}_1^A\\ U_1^B\\ U_1^C\end{array}\right]=\left[\begin{array}{ccccc}{U}_{11}^A& U_{11}^A& U_{13}^A& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^A\\ U_{11}^B& U_{12}^B& U_{13}^B& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^B\\ U_{11}^C& U_{12}^C& U_{13}^C& \&CenterDot;\&CenterDot;\&CenterDot;& U_{1n}^C\end{array}\right]---<4>;$

$U_2=\left[\begin{array}{c}{U}_2^A\\ U_2^B\\ U_2^C\end{array}\right]=\left[\begin{array}{ccccc}{U}_{21}^A& U_{22}^A& U_{23}^A& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^A\\ U_{21}^B& U_{22}^B& U_{23}^B& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^B\\ U_{21}^C& U_{22}^C& U_{23}^C& \&CenterDot;\&CenterDot;\&CenterDot;& U_{2n}^C\end{array}\right]---<5>;$

$I=\left[\begin{array}{c}{I}^A\\ I^B\\ I^C\end{array}\right]=\left[\begin{array}{ccccc}{I}_1^A& I_2^A& I_3^A& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^A\\ I_1^B& I_2^B& I_3^B& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^B\\ I_1^C& I_2^C& I_3^C& \&CenterDot;\&CenterDot;\&CenterDot;& I_n^C\end{array}\right]---<6>;$

In the formula:

The expression voltage U _iThe numerical value that collects at collection point j of p; I=1 wherein, 2; J=1,2,3 ..., n, p represent a certain phase among A, B, the C;

The numerical value that collects at collection point k of p of expression electric current I, k=1 wherein, 2,3 ..., n;

$\frac{\mathrm{dI}}{\mathrm{dt}}=\left[\begin{array}{c}\frac{{\mathrm{dI}}^A}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^B}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^C}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{cccc}\frac{I_2^A-I_1^A}{T/n}& \frac{I_3^A-I_2^A}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^A-I_n^A}{T/n}\\ \frac{I_2^B-I_1^B}{T/n}& \frac{I_3^B-I_2^B}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^B-I_n^B}{T/n}\\ \frac{I_2^C-I_1^C}{T/n}& \frac{I_3^C-I_2^C}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_{n+1}^C-I_n^C}{T/n}\end{array}\right]---<7>;$

Because line current is cyclical variation,

Then following formula is rewritten as:

$\frac{\mathrm{dI}}{\mathrm{dt}}=\left[\begin{array}{c}\frac{{\mathrm{dI}}^A}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^B}{\mathrm{dt}}\\ \frac{{\mathrm{dI}}^C}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{cccc}\frac{I_2^A-I_1^A}{T/n}& \frac{I_3^A-I_2^A}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^A-I_n^A}{T/n}\\ \frac{I_2^B-I_1^B}{T/n}& \frac{I_3^B-I_2^B}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^B-I_n^B}{T/n}\\ \frac{I_2^C-I_1^C}{T/n}& \frac{I_3^C-I_2^C}{T/n}& \&CenterDot;\&CenterDot;\&CenterDot;& \frac{I_1^C-I_n^C}{T/n}\end{array}\right]---<8>;$

Order:

$\stackrel{\&OverBar;}{x_1^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p---<9>;$

$\stackrel{\&OverBar;}{x_2^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<10>;$

$\stackrel{\&OverBar;}{y^p}=\frac{1}{n}\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<11>;$

$s_{11}^{\left(p\right)}=\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(I_t^p-\stackrel{\&OverBar;}{x_1^p})}^2---<12>;$

$s_{12}^p=s_{21}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(I_t^p-\stackrel{\&OverBar;}{x_1^p})(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})---<13>;$

$s_{22}^p=\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})}^2---<14>;$

$s_{1y}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(I_t^p-\stackrel{\&OverBar;}{x_1^p})((U_{1t}^p-U_{2t}^p)-\stackrel{\&OverBar;}{y^p})---<15>;$

$s_{2y}^p=\underset{k=1}{\overset{M}{\mathrm{\&Sigma;}}}(\frac{I_{t+1}^p-I_t^p}{T/n}-\stackrel{\&OverBar;}{x_2^p})((U_{1t}^p-U_{2t}^p)-\stackrel{\&OverBar;}{y^p})---<16>;$

Wherein: With

Be intermediate variable, i=1 wherein, 2, j=1,2;

Get following system of equations:

$\left\{\begin{array}{c}{s}_{11}^p{R}^p+S_{12}^p{L}^p=s_{1y}^p\\ s_{21}^p{R}^p+s_{22}^p{L}^p=s_{2y}^p\end{array}\right.---<17>;$

Wherein: R ^pBe cable line p phase resistance;

L ^pP phase inductance for cable line;

Separating above system of equations gets:

$R^p=\frac{s_{22}^p{s}_{1y}^p-s_{12}^p{s}_{2y}^p}{s_{11}^p{s}_{22}^p-s_{12}^p{s}_{21}^p}---<18>;$

Namely obtain p phase cable line resistance R ^p

5. power distribution network cable line resistance on-line tuning method as claimed in claim 1 is characterized in that, in the described step (3), adopts following method to determine cable line resistance:

The slope of each collection point is cyclical variation:

$\underset{t=1}{\overset{T/2}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=-\underset{l=T/2}{\overset{T}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(l\right)}{\mathrm{dl}}---<19>;$

For a certain phase p of circuit:

$\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)=R^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p+L^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}\frac{\mathrm{dI}\left(t\right)}{\mathrm{dt}}=R^p\&CenterDot;\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p---<20>;$

Namely get p phase cable line resistance expression formula:

$R^p=\frac{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)}{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^p}---<21>.$

6. power distribution network cable line resistance on-line tuning method as claimed in claim 1 is characterized in that, in the described step (3), adopts following method to determine cable line resistance:

Get N group cable line voltage, current data, wherein N be less than Natural number, calculate the mean value of its p phase:

${\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}{I}_t^p---<22>;$

${\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<23>;$

${\left(\stackrel{\&OverBar;}{y^p}\right)}_1=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<24>;$

Wherein:

Mean value for circuit p phase N group current data;

Mean value for circuit p phase N group electric current derivative;

Mean value for circuit p phase N group voltage difference data;

Get N group cable line p phase voltage, current data again, calculate its mean value:

${\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}{I}_t^p---<25>;$

${\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}\frac{I_{t+1}^p-I_t^p}{T/n}---<26>;$

${\left(\stackrel{\&OverBar;}{y^p}\right)}_2=\frac{1}{N}\underset{t=1}{\overset{N}{\mathrm{\&Sigma;}}}(U_{1t}^p-U_{2t}^p)---<27>;$

Wherein:

Mean value for another N group current data of circuit p phase;

Mean value for another N group electric current derivative of circuit p phase;

Mean value for another N group voltage difference data of circuit p phase;

Set up system of equations, as follows:

$\left\{\begin{array}{c}{\left(\stackrel{\&OverBar;}{y^p}\right)}_1={\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1{R}^p+{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1{L}^p\\ {\left(\stackrel{\&OverBar;}{y^p}\right)}_2={\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2{R}^p+{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2{L}^p\end{array}\right.---<28>;$

Separating above-mentioned system of equations, to get cable line p phase resistance as follows:

$R^{\left(p\right)}=\frac{{\left(\stackrel{\&OverBar;}{x_1^p}\right)}_1{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2-{\left(\stackrel{\&OverBar;}{x_1^p}\right)}_2{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1}{{\left(\stackrel{\&OverBar;}{y^p}\right)}_1{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_2-{\left(\stackrel{\&OverBar;}{y^p}\right)}_2{\left(\stackrel{\&OverBar;}{x_2^p}\right)}_1}---<29>.$

7. power distribution network cable line resistance on-line tuning method as claimed in claim 1 is characterized in that, in the described step (3), adopts following method to determine cable line resistance:

Mean value falls in first, terminal p phase voltage

Computing method are as follows:

${\mathrm{\&Delta;U}}_{\mathrm{avg}}^p\widetilde{\&OverBar;}\frac{1}{n}(\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_1^p\left(t\right)-\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{U}_2^p\left(t\right))---<30>;$

Circuit p phase current mean value

Computing method are as follows:

$I_{\mathrm{avg}}^p\widetilde{\&OverBar;}\frac{\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}^p\left(t\right)}{n}---<31>;$

First, terminal p phase voltage is fallen and circuit p phase current phase angle difference

The mean value calculation method is as follows:

In the formula: θ _U1(t)---collection point t circuit head end p phase voltage phase angle;

θ _U2(t)---collection point t line end p phase voltage phase angle;

θ _I(t)---collection point t circuit p phase current phase angle;

Cable line resistance p phase expression formula is:

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