CN104297628A - Method for detecting and positioning section faults of power distribution network containing DGs (distributed generators) - Google Patents

Abstract

The invention relates to a method for detecting and positioning section faults of a power distribution network containing DGs (distributed generators). The method is characterized in that three-phase current information acquired by protection device installation points at two end nodes of a section is utilized, Clark transformation is adopted, three-phase current is transformed into Clark alpha-mode current and Clark beta-mode current, the Clark alpha-mode current and the Clark beta-mode current are subjected to Fourier transformation to acquire a phase angle of the Clark alpha-mode current and a phase angle of the Clark beta-mode current, data of the phase angles is uploaded to a relay protection control center, the relay protection control center can detect a fault and find out the section in which a fault point is located when the fault occurs in an electric power system through calculating the phase angle difference of the Clark alpha-mode current and the Clark beta-mode current of each section and through comparing a relation between an absolute value of the phase angle difference of the Clark alpha-mode current and the Clark beta-mode current of each section and a threshold value, and remove the fault section timely so as to complete a protection action. The method provided by the invention can be applied to detecting and positioning the section faults of the power distribution network containing the DGs under high permeability.

Description

Containing the section fault detection and location method of the power distribution network of DG

Technical field

The present invention relates to a kind of fault detection and location method of the power distribution network containing DG.

Background technology

The fault detection and location of power distribution network is the important component part of power distribution network relay protection of power system; the safe operation of power distribution network is had great significance; it is the important guarantee realizing power distribution network self-healing; after power distribution network breaks down, fault zone can be excised timely, make whole system be subject to the scope of fault effects minimum.Along with the development of distributed generation technology; increasing distributed power source (Distributed Generators; DG) power distribution network is accessed; cause the change of power distribution network network structure and the change in fault current amplitudes and direction; problems are brought to the relay protection of power distribution network; as there is the check frequency of fault, relay protection cannot cooperation etc., and the over-current protection method making power distribution network traditional can not meet the requirement of relay protection.

Chinese invention patent 201210532103.3 disclose a kind of based on impedance model short trouble feature containing the interval decision method of DG distribution network failure, set up containing DG power distribution network asymmetrical three-phase impedance model, analyze and extract containing the short-circuit current fault signature under DG distribution impedance model as the index judging fault section, the accuracy that the method carries out localization of fault is subject to electric network composition and changes the impact causing system equiva lent impedance to change, not there is adaptivity, the development trend of intelligent distribution network can not be catered to.

Chinese invention patent 201310579589.0 discloses a kind of power distribution network 10kV feeder fault location method based on matrix operation, the method relies on feeder terminal unit (the Feeder Terminal Unit being positioned at Nodes, FTU) current information is gathered, computing and correction are carried out to the path matrix of electric system, obtain fault judgment matrix, fault zone is judged, but it is according to short-circuit current value that the method carries out fault verification, the dead band of fault detect is easily formed under high DG permeability, DG switching in electrical network may cause the erroneous judgement of fault, the method is higher to communicating requirement, the method may be caused to make mistakes when communicating and error code or fault occurring even to lose efficacy.

N.Perera, the people such as A.D.Rajapakse " IEEE TRANSACTIONS ON POWER DELIVERY " the 23rd volume the 4th phase in 2008 show " Isolation of Faults in Distribution Networks With Distributed Generators " and adopt the method comparing wavelet coefficient signs to carry out detection and positioning to fault, although adopt Wavelet Transform carry out multiscale analysis can obtain good fault detection sensitivity and accurately section location, but employing the method cannot avoid the POWER SYSTEM STATE in non-faulting situation to change the impact brought fault detect accuracy, in addition, the tediously long complexity of wavelet algorithm, require high to the sampling rate of hardware, deployment cost is very high, not easily realize.

Mostly the domestic and international detection & localization for the electric power system fault containing distributed power source is the voltage, the current information that utilize each Nodes measurement point to obtain at present, the judgement information of the amplitude amount based on node is obtained after processing further, by contrasting with the threshold value of setting, carry out the judgement of fault and the location of section, the impact adopting these class methods cannot avoid the temporal variations in electric system non-faulting situation to produce fault detecting and positioning method, does not have good adaptivity; Carry out based on traditional over-current protection method improving the electrical power distribution network fault location method containing DG obtained, with strong points, not there is versatility and adaptivity widely, once electric network composition or state change, the inefficacy of fault location algorithm may be caused; Although adopt differential current protection method to have certain effect, actual disposition cost is high, and the current information of communications is vector, comprises amplitude and the direction of electric current, requires higher for relay protection communication bandwidth.

In sum, in the face of the generating of distributed power source large-scale grid connection and intelligent grid realize the actual demand of complete self-healing, still need one more fast and effective fault detect and localization method.

Summary of the invention

The object of the invention is to the problem of the adaptivity deficiency existed for the fault detection and location of the existing power distribution network containing distributed power source, propose a kind of section fault detection and location method of the power distribution network containing DG.The present invention can make the power distribution network containing distributed power source under multiple running status, as: the switching of distributed power source, the change of load, quick, the reliable section fault detect of realization and accurately localization of fault, thus excision fault section, ensure that the safe and stable operation of electric system.

The technical solution used in the present invention is:

The present invention, containing the section fault detection and location method of the power distribution network of DG, adopts Clarke transform, three-phase current is become Clarke α, β mould electric current.By respectively to the Clarke α of electric system section, the analysis of phase angle difference in non-faulting situation and failure condition of β mould electric current, draw under electric system is the condition of non-purely resistive system, in conjunction with the phase angle difference of Clarke α, β mould electric current, various types of electric power system fault can be detected rapidly, reliably: singlephase earth fault, two-phase phase-to phase fault, double earthfault, three-phase phase-to phase fault, three-phase ground fault, and fault section can be found out accurately.Judgment basis is: when the absolute value of the Clarke α of electric system section, the phase angle difference of β mould electric current is 0 °, then judge do not have fault in this section; In the phase angle difference of the Clarke α of electric system section, β mould electric current, the absolute value of any one is greater than 0 °, then judge to break down in this section, and trouble spot is positioned at this section.The present invention can detect fault in electric system section fast and effectively and can localizing faults section accurately.

The present invention proposes the definition of the phase angle difference of electric current containing the section fault detection and location method of power distribution network of DG.For electric system, any one electric system all can be at random divided into n+1 part by n node, wherein, and n>0 and n is integer.Any two parts not between same node point in electric system are made to be called the electric system section between these two nodes.If the current phase angle at node x place is θ (x), wherein x=1,2 ..., n, if n →+∞, can think the current phase angle function that θ (x) is electric system, and be upwards continuous in this electric system central diameter.Therefore, the phase angle difference of the electric current of the electric system section between arbitrary two not identical node i, j may be defined as the difference of current phase angle at node i, j place, and its expression formula is: Δ θ (i, j)=θ (i)-θ (j), in formula: i, j are two not identical nodes, i>0, j>i, and i, j are integer, θ (x) is the current phase angle at node x place, x=1,2,, n.

Make the three-phase current of Nodes for:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_A=\sqrt{2}{I}_A\sin (\mathrm{\ωt}+{\mathrm{\θ}}_A)=I_A\∠{\mathrm{\θ}}_A\\ {\stackrel{\·}{I}}_B=\sqrt{2}{I}_B\sin (\mathrm{\ωt}+{\mathrm{\θ}}_B)=I_B\∠{\mathrm{\θ}}_B\\ {\stackrel{\·}{I}}_C=\sqrt{2}{I}_C\sin (\mathrm{\ωt}+{\mathrm{\θ}}_C)=I_C\∠{\mathrm{\θ}}_C\end{array}\right.$

Clarke transform mathematic(al) representation is:

$\left[\begin{array}{c}{\stackrel{\·}{I}}_0\\ {\stackrel{\·}{I}}_{\mathrm{\α}}\\ {\stackrel{\·}{I}}_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{ccc}\frac{1}{3}& \frac{1}{3}& \frac{1}{3}\\ \frac{2}{3}& -\frac{1}{3}& -\frac{1}{3}\\ 0& \frac{\sqrt{3}}{3}& -\frac{\sqrt{3}}{3}\end{array}\right]\·\left[\begin{array}{c}{\stackrel{\·}{I}}_A\\ {\stackrel{\·}{I}}_B\\ {\stackrel{\·}{I}}_C\end{array}\right]$

Therefore, Clarke transform is done to the three-phase current information that Nodes collects, obtain Clarke α, β mould electric current have:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}=\frac{2}{3}{\stackrel{\·}{I}}_A-\frac{1}{3}{\stackrel{\·}{I}}_B-\frac{1}{3}{\stackrel{\·}{I}}_C\\ {\stackrel{\·}{I}}_{\mathrm{\β}}=\frac{\sqrt{3}}{3}({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)\end{array}\right.$

If crane clarke α, β mould electric current be expressed as:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}=\sqrt{2}{I}_{\mathrm{\α}}\sin (\mathrm{\ωt}+{\mathrm{\θ}}_{\mathrm{\α}})=I_{\mathrm{\α}}\∠{\mathrm{\θ}}_{\mathrm{\α}}\\ {\stackrel{\·}{I}}_{\mathrm{\β}}=\sqrt{2}{I}_{\mathrm{\β}}\sin (\mathrm{\ωt}+{\mathrm{\θ}}_{\mathrm{\β}})=I_{\mathrm{\β}}\∠{\mathrm{\θ}}_{\mathrm{\β}}\end{array}\right.$

Then there is equation:

$\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\α}}=I_{\mathrm{\α}}\∠{\mathrm{\θ}}_{\mathrm{\α}}=I_{\mathrm{\α}}\cos {\mathrm{\θ}}_{\mathrm{\α}}+j{I}_{\mathrm{\α}}\sin {\mathrm{\θ}}_{\mathrm{\α}}\\ =(\frac{2}{3}{I}_A\cos {\mathrm{\θ}}_A-\frac{1}{3}{I}_B\cos {\mathrm{\θ}}_B-\frac{1}{3}{I}_C\cos {\mathrm{\θ}}_C)\\ +j(\frac{2}{3}{I}_A\sin {\mathrm{\θ}}_A-\frac{1}{3}{I}_B\sin {\mathrm{\θ}}_B-\frac{1}{3}{I}_C\sin {\mathrm{\θ}}_C)\\ =\frac{2}{3}{\stackrel{\·}{I}}_A-\frac{1}{3}{\stackrel{\·}{I}}_B-\frac{1}{3}{\stackrel{\·}{I}}_C\end{array}$

$\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{\β}}=I_{\mathrm{\β}}\∠{\mathrm{\θ}}_{\mathrm{\β}}=I_{\mathrm{\β}}\cos {\mathrm{\θ}}_{\mathrm{\β}}+j{I}_{\mathrm{\β}}\sin {\mathrm{\θ}}_{\mathrm{\β}}\\ =(\frac{\sqrt{3}}{3}{I}_B\cos {\mathrm{\θ}}_B-\frac{\sqrt{3}}{3}{I}_C\cos {\mathrm{\θ}}_C)+j(\frac{\sqrt{3}}{3}{I}_B\sin {\mathrm{\θ}}_B-\frac{\sqrt{3}}{3}{I}_C\sin {\mathrm{\θ}}_C)\\ =\frac{\sqrt{3}}{3}{\stackrel{\·}{I}}_B-\frac{\sqrt{3}}{3}{\stackrel{\·}{I}}_C\end{array}$

Clarke α, β mould electric current can be drawn by above two equatioies corresponding phase angle theta _α, θ _βexpression formula:

$\begin{array}{c}{\mathrm{\θ}}_{\mathrm{\α}}=\arctan \left(\frac{\frac{2}{3}{I}_A\sin {\mathrm{\θ}}_A-\frac{1}{3}{I}_B\sin {\mathrm{\θ}}_B-\frac{1}{3}{I}_C\sin {\mathrm{\θ}}_C}{\frac{2}{3}{I}_A\cos {\mathrm{\θ}}_A-\frac{1}{3}{I}_B\cos {\mathrm{\θ}}_B-\frac{1}{3}{I}_C\cos {\mathrm{\θ}}_C}\right)\\ {\mathrm{\θ}}_{\mathrm{\β}}=\arctan \left(\frac{I_B\sin {\mathrm{\θ}}_B-I_C\sin {\mathrm{\θ}}_C}{I_B\cos {\mathrm{\θ}}_B-I_C\cos {\mathrm{\θ}}_C}\right)\end{array}$

To Clarke α mould electric current phase angle theta _αanalyze, under electric system is three-phase equilibrium state, have ${\stackrel{\·}{I}}_A+{\stackrel{\·}{I}}_B+{\stackrel{\·}{I}}_C=\stackrel{\·}{0},$ Therefore have:

$\begin{array}{c}{\mathrm{\θ}}_{\mathrm{\α}}=\arctan \left(\frac{\frac{2}{3}{I}_A\sin {\mathrm{\θ}}_A-\frac{1}{3}{I}_B\sin {\mathrm{\θ}}_B-\frac{1}{3}{I}_C\sin {\mathrm{\θ}}_C}{\frac{2}{3}{I}_A\cos {\mathrm{\θ}}_A-\frac{1}{3}{I}_B\cos {\mathrm{\θ}}_B-\frac{1}{3}{I}_C\cos {\mathrm{\θ}}_C}\right)\\ =\arctan \left(\frac{\frac{2}{3}{I}_A\sin {\mathrm{\θ}}_A+\frac{1}{3}{I}_A\sin {\mathrm{\θ}}_A}{\frac{2}{3}{I}_A\sin {\mathrm{\θ}}_A+\frac{1}{3}{I}_A\sin {\mathrm{\θ}}_A}\right)=\arctan \left(\frac{I_A\sin {\mathrm{\θ}}_A}{I_A\cos {\mathrm{\θ}}_A}\right)\\ =\arctan \left(\tan {\mathrm{\θ}}_A\right)={\mathrm{\θ}}_A\end{array}$

Therefore, under three-phase equilibrium state, no matter electric power system fault whether, has θ _α=θ _aset up, that is: under three-phase equilibrium state, Clarke α mould current phase angle is equal with A phase current phase angle.

When electric system is non-purely resistive system, i.e. when the equivalent reactance value of electric system is 0, respectively to the Clarke α of electric system section, the phase angle difference of β mould electric current, in non-faulting situation and failure condition, be analyzed as follows:

Under non-faulting state, for Clarke α mould electric current there is the phase angle difference DELTA θ of the Clarke α mould electric current of electric system section _α=0 ° of establishment; If A phase fault, then the current amplitude I of A phase _aand phase angle theta _acan change, by phase angle theta _αexpression formula known, the phase angle theta of Clarke α mould electric current during fault _{α F}≠ θ _α, and the phase angle difference DELTA θ of the Clarke α mould electric current of electric system section when having fault _{α F}≠ Δ θ _α=0 °; If only have B phase or C phase singlephase earth fault, or when B, C double earthfault occurs, then B phase current magnitude I _b, phase angle theta _bwith C phase current magnitude I _c, phase angle theta _ccan correspondingly change, by phase angle theta _αexpression formula known, the phase angle theta of Clarke α mould electric current during fault _{α F}≠ θ _α, and the phase angle difference DELTA θ of the Clarke α mould electric current of electric system section when having fault _{α F}≠ Δ θ _α=0 °.If B, C two-phase generation phase-to phase fault, be analyzed as follows: equivalent analysis is carried out to three-phase electrical power system, utilize Dai Weining equivalence principle, by each equivalent source that be mutually all equivalent to voltage source and impedance cascade of analyzed section upstream with the three-phase electrical power system in downstream, the three-phase voltage at node i place is respectively ${\stackrel{\·}{U}}_{\mathrm{Ai}}=U_{\mathrm{Ai}}\∠{\mathrm{\θ}}_{\mathrm{Ai}},{\stackrel{\·}{U}}_{\mathrm{Bi}}=U_{\mathrm{Bi}}\∠{\mathrm{\θ}}_{\mathrm{Bi}},{\stackrel{\·}{U}}_{\mathrm{Ci}}=U_{\mathrm{Ci}}\∠{\mathrm{\θ}}_{\mathrm{Ci}},$ The voltage at node j place is ${\stackrel{\·}{U}}_{\mathrm{Aj}}=U_{\mathrm{Aj}}\∠{\mathrm{\θ}}_{\mathrm{Aj}},$ ${\stackrel{\·}{U}}_{\mathrm{Bj}}=U_{\mathrm{Bj}}\∠{\mathrm{\θ}}_{\mathrm{Bj}},{\stackrel{\·}{U}}_{\mathrm{Cj}}=U_{\mathrm{Cj}}\∠{\mathrm{\θ}}_{\mathrm{Cj}},$ In analyzed section, the equiva lent impedance of each phase is ${\stackrel{\·}{Z}}_s=R_s+j{X}_s,$ In formula: R _sfor the equivalent resistance of analyzed section, X _sfor the equivalent reactance of analyzed section, B, C phase in this section is divided into two parts by trouble spot: with and have fault point simultaneously between B, C phase is used carry out the equivalent short-circuit impedance that B, C phase fault occurs.If before fault occurs, node i, each phase current in j place are:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{Ai}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Ai}}-{\stackrel{\·}{U}}_{\mathrm{Aj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Aj}}={\stackrel{\·}{I}}_A\\ {\stackrel{\·}{I}}_{\mathrm{Bi}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Bi}}-{\stackrel{\·}{U}}_{\mathrm{Bj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Bj}}\\ {\stackrel{\·}{I}}_{\mathrm{Ci}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Ci}}-{\stackrel{\·}{U}}_{\mathrm{Cj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Cj}}\end{array}\right.$

After fault occurs, each phase current in node i place is:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{AFi}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Ai}}={\stackrel{\·}{I}}_A\\ {\stackrel{\·}{I}}_{\mathrm{BFi}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Bi}}-{\stackrel{\·}{U}}_{\mathrm{Cj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Bi}}-{\stackrel{\·}{U}}_{\mathrm{Ci}}}{2{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f}\\ {\stackrel{\·}{I}}_{\mathrm{CFi}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Ci}}-{\stackrel{\·}{U}}_{\mathrm{Bj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Ci}}-{\stackrel{\·}{U}}_{\mathrm{Bi}}}{2{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f}\end{array}\right.$

After fault occurs, each phase current in node j place is:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{AFj}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Aj}}={\stackrel{\·}{I}}_A\\ {\stackrel{\·}{I}}_{\mathrm{BFj}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Ci}}-{\stackrel{\·}{U}}_{\mathrm{Bj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Cj}}-{\stackrel{\·}{U}}_{\mathrm{Bj}}}{2{\stackrel{\·}{Z}}_{\mathrm{sj}}+{\stackrel{\·}{Z}}_f}\\ {\stackrel{\·}{I}}_{\mathrm{CFj}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Bi}}-{\stackrel{\·}{U}}_{\mathrm{Cj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Bj}}-{\stackrel{\·}{U}}_{\mathrm{Cj}}}{2{\stackrel{\·}{Z}}_{\mathrm{sj}}+{\stackrel{\·}{Z}}_f}\end{array}\right.$

If the electric system of analyzed section upstream and downstream is three-phase systems of balance, then have:

$\left\{\begin{array}{c}{\stackrel{\·}{U}}_{\mathrm{Ai}}+{\stackrel{\·}{U}}_{\mathrm{Bi}}+{\stackrel{\·}{U}}_{\mathrm{Ci}}=\stackrel{\·}{0}\\ {\stackrel{\·}{U}}_{\mathrm{Aj}}+{\stackrel{\·}{U}}_{\mathrm{Bj}}+{\stackrel{\·}{U}}_{\mathrm{Cj}}=\stackrel{\·}{0}\end{array}\right.$

Can draw:

$\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{BFi}}+{\stackrel{\·}{I}}_{\mathrm{CFi}}={\stackrel{\·}{I}}_{\mathrm{BFj}}+{\stackrel{\·}{I}}_{\mathrm{CFj}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B+\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B+\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}}\\ =-(\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}})=-({\stackrel{\·}{I}}_A+\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{sj}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}})\end{array}$

Therefore, the Clarke α mould electric current after can being out of order according to above formula:

${\stackrel{\·}{I}}_{\mathrm{\αFi}}={\stackrel{\·}{I}}_{\mathrm{\αFj}}={\stackrel{\·}{I}}_A+\frac{1}{3}\·\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_f+{\stackrel{\·}{Z}}_{\mathrm{sj}}}$

If phase fault impedance then can ignore phase fault impedance, above formula can abbreviation be further:

${\stackrel{\·}{I}}_{\mathrm{\αFi}}={\stackrel{\·}{I}}_{\mathrm{\αFj}}={\stackrel{\·}{I}}_A+\frac{1}{3}\·\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{4}{3}{\stackrel{\·}{I}}_A$

That is: when there is B, C phase fault in the electric system of three-phase equilibrium, Clarke α mould electric current phase angle theta _αcan not change, and with A phase current phase angle theta _aequal.Due to the phase angle difference DELTA θ that A phase is not fault phase, the A phase current of electric system section _a=0 °, the phase angle difference DELTA θ of the Clarke α mould electric current of electric system section can be drawn further _α=Δ θ _a=0 °.Therefore, when B, C phase fault occurs electric system section, the phase angle difference DELTA θ of the Clarke α mould electric current of section is adopted _αcannot detect fault, this kind of failure mode is the fault detect blind area of this detection method.

To Clarke β mould electric current phase angle theta _βanalyze, by phase angle theta _βexpression formula can draw: all can cause θ with B phase or the related Arbitrary Fault form of C phase _βchange, and have the phase angle difference DELTA θ of the Clarke β mould electric current of electric system section _β≠ 0 °.There is not with B phase or C phase the fault associated is A phase earth fault, be analyzed as follows: equivalent analysis is carried out to three-phase electrical power system, utilize Dai Weining equivalence principle, by each equivalent source that be mutually all equivalent to voltage source and impedance cascade of analyzed section upstream with the three-phase electrical power system in downstream, the three-phase voltage at node i place is respectively ${\stackrel{\·}{U}}_{\mathrm{Bi}}=U_{\mathrm{Bi}}\∠{\mathrm{\θ}}_{\mathrm{Bi}},{\stackrel{\·}{U}}_{\mathrm{Ci}}=U_{\mathrm{Ci}}\∠{\mathrm{\θ}}_{\mathrm{Ci}},$ The voltage at node j place is ${\stackrel{\·}{U}}_{\mathrm{Aj}}=U_{\mathrm{Aj}}\∠{\mathrm{\θ}}_{\mathrm{Aj}},{\stackrel{\·}{U}}_{\mathrm{Bj}}=U_{\mathrm{Bj}}\∠{\mathrm{\θ}}_{\mathrm{Bj}},$ in analyzed section, the equiva lent impedance of each phase is in formula: R _sfor the equivalent resistance of analyzed section, X _sfor the equivalent reactance of analyzed section, the A phase in section is divided into two parts by trouble spot: with and have use in the fault point of A phase simultaneously carry out the impedance ground of equivalent generation A phase ground short circuit fault.If before fault occurs, node i, each phase current in j place are:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{Ai}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Ai}}-{\stackrel{\·}{U}}_{\mathrm{Aj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Aj}}\\ {\stackrel{\·}{I}}_{\mathrm{Bi}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Bi}}-{\stackrel{\·}{U}}_{\mathrm{Bj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Bj}}={\stackrel{\·}{I}}_B\\ {\stackrel{\·}{I}}_{\mathrm{Ci}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Ci}}-{\stackrel{\·}{U}}_{\mathrm{Cj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_{\mathrm{Cj}}={\stackrel{\·}{I}}_C\end{array}\right.$

After fault occurs, node i, each phase current in j place are:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{AFi}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}+\frac{{\stackrel{\·}{U}}_{\mathrm{Ai}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_g}\\ {\stackrel{\·}{I}}_{\mathrm{AFj}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_A}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}-\frac{{\stackrel{\·}{U}}_{\mathrm{Aj}}}{{\stackrel{\·}{Z}}_g+{\stackrel{\·}{Z}}_{\mathrm{sj}}}\\ {\stackrel{\·}{I}}_{\mathrm{BFi}}={\stackrel{\·}{I}}_{\mathrm{BFj}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Bi}}-{\stackrel{\·}{U}}_{\mathrm{Bj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_B}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_B\\ {\stackrel{\·}{I}}_{\mathrm{CFi}}={\stackrel{\·}{I}}_{\mathrm{CFj}}=\frac{{\stackrel{\·}{U}}_{\mathrm{Ci}}-{\stackrel{\·}{U}}_{\mathrm{Cj}}}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}=\frac{\mathrm{\Δ}{\stackrel{\·}{U}}_C}{{\stackrel{\·}{Z}}_{\mathrm{si}}+{\stackrel{\·}{Z}}_{\mathrm{sj}}}={\stackrel{\·}{I}}_C\end{array}\right.$

Therefore, the Clarke β mould electric current after can being out of order:

${\stackrel{\·}{I}}_{\mathrm{\βFi}}={\stackrel{\·}{I}}_{\mathrm{\βFj}}=\frac{\sqrt{3}}{3}({\stackrel{\·}{I}}_B-{\stackrel{\·}{I}}_C)$

That is: when there is A phase ground short circuit in electric system, Clarke β mould electric current phase angle theta _βcan not change.Because B phase and C phase are not fault phase, have and have the phase angle difference DELTA θ of B, C phase current of electric system section _b=Δ θ _c=0 °, the phase angle difference DELTA θ of the Clarke β mould electric current of electric system section can be drawn further _β=0 °.Therefore, when A phase earth fault occurs electric system section, the phase angle difference DELTA θ of the Clarke β mould electric current of section is adopted _βcannot detect fault, this kind of failure mode is the fault detect blind area of this detection method.

In sum: be under the condition of non-purely resistive system in electric system, in conjunction with the phase angle difference of Clarke α, β mould electric current, various types of electric power system fault can be detected rapidly, reliably: singlephase earth fault, two-phase phase-to phase fault, double earthfault, three-phase phase-to phase fault, three-phase ground fault, and fault section can be found out accurately, judgment basis is: when the absolute value of the Clarke α of electric system section, the phase angle difference of β mould electric current is 0 °, then judge do not have fault in this section; In the phase angle difference of the Clarke α of electric system section, β mould electric current, the absolute value of any one is greater than 0 °, then judge to break down in this section, and trouble spot is positioned at this section.

In actual applications, can by arranging threshold k _{Δ θ}, wherein K _{Δ θ}> 0, to carry out the judgement of fault, that is: when the absolute value of the Clarke α of electric system section, the phase angle difference of β mould electric current is all less than or equal to threshold k _{Δ θ}time, judge there is no fault in this section; In the phase angle difference of the Clarke α of electric system section, β mould electric current, any one absolute value is greater than threshold k _{Δ θ}time, judge to break down in this section, and trouble spot is positioned at this section.

The present invention proposes a kind of section fault detection and location method of the power distribution network containing DG based on Clarke electric current modulus phase angle difference value, compared with prior art, the good effect that the method can produce is: first, the present invention can be used for the section fault detection and location of the power distribution network containing distributed power source, can be quick, reliable detection and accurately localizing faults, be applicable to various fault: singlephase earth fault, two-phase phase-to phase fault, double earthfault, three-phase phase-to phase fault, the detection & localization of three-phase ground fault, detection and location for multiple independent failure are still effective, there is not the check frequency of fault, secondly, the present invention normally, effectively can run work in the temporal variations in electric system non-faulting situation, does not change by all kinds of non-faulting state, as: the impact of the switching of distributed power source, the change of load, has good adaptivity, finally, the principle of the invention is simple, is applicable to focusing on of POWER SYSTEM STATE information, requires lower to communication bandwidth, and the process of concentrating is conducive to the cooperation of relay protection with control.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention will be further described.

Fig. 1 is electric system equivalent analysis figure;

Fig. 2 is the ultimate principle figure applying three-phase electrical power system of the present invention;

Fig. 3 is the structured flowchart of the specific embodiment of the present invention;

Fig. 4 is the process flow diagram realizing the inventive method.

Embodiment

Fig. 1 is electric system equivalent analysis figure.As shown in Figure 1, AC power 101 is positioned at the upstream of electric system, and the electric system of whole equivalence is divided arbitrarily by n+1 node, wherein containing n equivalent section 102, and the node at equivalent section 102 two ends is respectively i, j, wherein, n>0 and n is integer.The current phase angle of each Nodes is θ (x), wherein x=1,2 ..., n+1, if n →+∞, can think the current phase angle function that θ (x) is electric system, and be upwards continuous in this electric system central diameter.Therefore, the phase angle difference DELTA θ (i of the electric current of the electric system equivalence section 102 between arbitrary two not identical node i, j, j) may be defined as the difference of current phase angle at node i, j place, its expression formula is: Δ θ (i, j)=θ (i)-θ (j), in formula: i, j are two not identical nodes, i>0, j>i, and i, j are integer, θ (x) is the current phase angle at node x place, x=1,2 ..., n.

Fig. 2 is the ultimate principle figure applying three-phase electrical power system of the present invention.As shown in Figure 2, be positioned at the analyzed electric system of section 203 upstream and the electric system in downstream by equivalently represented be equivalent both upstream power system 201 and equivalent downstream power system 202, be the three-phase voltage source of equivalence.Analyzed section 203 is the electric system sections between node i, j, and the node i at analyzed section 203 two ends, j place are all configured with three-phase current information collecting device, the three-phase current information at acquisition node i place that can be synchronous and the three-phase current information at node j place, the Clarke transform of three-phase current information through node i place of two Nodes and the Clarke transform at node j place, obtain Clarke α, the β mould electric current at the Clarke α at node i place, β mould electric current and node j place.By the Clarke α of two Nodes, the Fourier transform (Fourier Transform) of β mould electric current through node i place and the Fourier transform at node j place, the Clarke α at node i place can be obtained, the Clarke α at β mould current phase angle information and node j place, β mould current phase angle information, and then can by the Clarke α to analyzed section 203 two ends Nodes, β mould current phase angle is poor, draw the phase angle difference of the Clarke α mould electric current of analyzed section 203, the phase angle difference of Clarke β mould electric current, then pass through Clarke α, the absolute value of phase angle difference of β mould electric current and the threshold k of setting _{Δ θ}relatively, failure determination result is drawn.

As shown in Figure 3, be configured with local measurement and data processing equipment 301 at each Nodes of electric system, in order to gather and to measure each phase current information.Local measurement and data processing equipment 301 utilize Clarke transform, the three-phase current information of collection can be become Clarke α, β mould current information.Local measurement and data processing equipment 301 utilize Fourier transform, and the Clarke α obtained by Clarke transform, β mould current information become Clarke α, β mould current phase angle information.Local measurement and data processing equipment 301 send Clarke α by communication link in real time to relay protection and control center 302, the data of β mould current phase angle, relay protection and control center 302 is provided with data storage device, preserve the information that each node is in the same time uploaded, form POWER SYSTEM STATE information matrix, relay protection and control center 302 calculates the phase angle difference of the Clarke α mould electric current of each section and the phase angle difference of Clarke β mould electric current, fault section is found out by the section fault detection and location method of the power distribution network containing DG, relay protection and control center 302 is immediately to the node i at the section two ends of fault, the protective relaying device at j place sends protection act signal, the section of excision fault, ensure the safety of electric system.

The performing step of the section fault detection and location method of the power distribution network containing DG of the present embodiment is as follows:

Step one, the local measurement configured by each Nodes and data processing equipment 301, gathered three-phase current information, utilize Clarke transform, three-phase current information is become Clarke α, β mould current information;

Step 2, the Clarke α obtained by Clarke transform, β mould current information, through Fourier transform, obtain Clarke α, β mould current phase angle;

Step 3, by the data of Clarke α, β mould current phase angle through communication links relay protection and control center 302;

Step 4, relay protection and control center 302 read the status information of each node of electric system of current time from data storage device, and generate the POWER SYSTEM STATE information matrix of current time, calculate the phase angle difference of the Clarke α mould electric current of each section and the phase angle difference of Clarke β mould electric current;

Step 5, according to following criterion, fault detection and location is carried out to all electric system sections: if the absolute value of the phase angle difference of the Clarke α mould electric current of certain unified power system section and the phase angle difference of Clarke β mould electric current is all less than or equal to threshold k _{Δ θ}time, then this section normally runs; If the absolute value of any one is greater than threshold k in the phase angle difference of the Clarke α mould electric current in certain unified power system section, the phase angle difference of Clarke β mould electric current _{Δ θ}time, then break down in this section, and trouble spot is positioned at this section;

Step 6, relay protection and control center 302 record the fault section label judged, meanwhile, relay protection and control center 302 sends actuating signal to the protective device at the node i at the section two ends of fault, j place, and the section of excision fault, completes protection.

Fig. 4 is the process flow diagram that relay protection and control center 302 realizes the inventive method.As shown in Figure 4; relay protection and control center 302 comprises Initialize installation module 401 and electric system real-time fault detection and locating module 402, comprises data and input and the phase angle difference calculating module 403 of each electric current modulus, section fault detection and location module 404 and comprehensive judgment module 405 in electric system real-time fault detection and locating module 402.Wherein, to the phase angle difference of the Clarke α mould electric current of certain unified power system section in section fault detection and location module 404, the algorithm that the phase angle difference of Clarke β mould electric current carries out detecting and judging adopts serial design, using the phase angle difference of Clarke α mould electric current as main detection limit, the phase angle difference of Clarke β mould electric current is as auxiliary detection limit, like this can while reduction algorithm complex and the requirement to hardware device, effectively ensure that the quick detection of singlephase earth fault, this is because fault most in electric system is all singlephase earth fault, and all singlephase earth faults all can utilize the phase angle difference of Clarke α mould electric current to detect, and adopt the phase angle difference of Clarke β mould electric current to there is the blind area detected when there is A phase earth fault.

The operational scheme of Initialize installation module 401 is:

Flow process one, carry out Initialize installation;

Flow process two, label is carried out to each node of electric system and section, the node being wherein numbered the section two ends of N in electric system is respectively i, j, wherein, N>0 and N is integer, i>0 and i is integer, j>i and j is integer, the data then entered in electric system real-time fault detection and locating module 402 input the phase angle difference calculating module 403 with each electric current modulus.

Data input with the operational scheme of the phase angle difference calculating module 403 of each electric current modulus is:

Clarke α, the β mould current phase angle information of flow process one, each Nodes of input current time;

Flow process two, set up POWER SYSTEM STATE information matrix;

The phase angle difference of flow process three, the Clarke α calculating each section, β mould electric current, then makes electric system segment number N=1, enters section fault detection and location module 404.

The operational scheme of section fault detection and location module 404 is:

Flow process one, judge whether the absolute value of the phase angle difference of the Clarke α mould electric current of section N is greater than threshold k _{Δ θ}, if so, then enter flow process three, if not, then enter flow process two;

Flow process two, judge whether the absolute value of the phase angle difference of the Clarke β mould electric current of section N is greater than threshold k _{Δ θ}, if so, then enter flow process three, if not, then enter comprehensive judgment module 405;

Flow process three, judgement section N inside break down;

Nodal scheme i, j that flow process four, record trouble sector label N and these section two ends are corresponding;

Flow process five, protective relaying device sending action signal to the node i at section N two ends, j place;

Flow process six, output: section N breaks down inside, then enters comprehensive judgment module 405.

The operational scheme of comprehensive judgment module 405 is:

Flow process one, judge whether electric system segment number N is less than section sum, if so, then enters flow process two, if not, then enter flow process three;

Flow process two, execution N=N+1, perform the program in section fault detection and location module 404 to next section;

Flow process three, judge each section of electric system whether all non-fault, if so, then enter flow process four, if not, then enter flow process five;

Flow process four, each section non-fault of judgement electric system, then enter the phase angle difference calculating module 403 of data input and each electric current modulus;

Flow process five, judgement electric system section N ₁, N ₂..., Nn fault export fault detection and location result, then enter the phase angle difference calculating module 403 of data input and each electric current modulus.

Claims (8)

1., containing a section fault detection and location method for the power distribution network of DG, it is characterized in that, the difference of the current phase angle of electric system section two ends Nodes is defined as the phase angle difference of electric current; Clarke transform is adopted three-phase current information to be become Clarke α, β mould current information; Be under the condition of non-purely resistive system in electric system, when the absolute value of the phase angle difference of the Clarke α mould electric current of electric system section and the phase angle difference of Clarke β mould electric current is 0 °, then judge there is no fault in this section; In the phase angle difference of the phase angle difference of the Clarke α mould electric current of electric system section, Clarke β mould electric current, the absolute value of any one is greater than 0 °, then judge to break down in this section, and trouble spot is positioned at this section;

Described section is defined as: electric system is at random divided into n+1 part, n>0 by for n node, and n is integer, makes any two parts not between same node point in electric system be called the section between these two nodes.

2. the section fault detection and location method of the power distribution network containing DG according to claim 1, is characterized in that, in actual applications, and can by arranging threshold k _{Δ θ}, to carry out the judgement of fault, wherein K _{Δ θ}> 0, that is: when the absolute value of the phase angle difference of the Clarke α mould electric current of electric system section and the phase angle difference of Clarke β mould electric current is all less than or equal to threshold k _{Δ θ}time, judge there is no fault in this section; In the phase angle difference of the phase angle difference of the Clarke α mould electric current of electric system section, Clarke β mould electric current, the absolute value of any one is greater than threshold k _{Δ θ}time, judge to break down in this section, and trouble spot is positioned at this section.

3. the section fault detection and location method of the power distribution network containing DG according to claim 1, is characterized in that, the performing step of the section fault detection and location method of the described power distribution network containing DG is as follows:

Step one, the local measurement configured by each Nodes and data processing equipment (301), gathered three-phase current information, utilize Clarke transform, three-phase current information is become Clarke α, β mould current information;

Step 2, the Clarke α obtained by Clarke transform, β mould current information, through Fourier transform, obtain Clarke α, β mould current phase angle;

Step 3, by the data of Clarke α, β mould current phase angle through communication links relay protection and control center (302);

Step 4, relay protection and control center (302) read the status information of each node of electric system of current time from data storage device, and generate the POWER SYSTEM STATE information matrix of current time, calculate the phase angle difference of the Clarke α mould electric current of each section and the phase angle difference of Clarke β mould electric current;

Step 5, according to following criterion, fault detection and location is carried out to all electric system sections: if the absolute value of the phase angle difference of the Clarke α mould electric current of certain unified power system section and the phase angle difference of Clarke β mould electric current is all less than or equal to threshold k _{Δ θ}time, then this section normally runs; If the absolute value of any one is greater than threshold k in the phase angle difference of the Clarke α mould electric current in certain unified power system section, the phase angle difference of Clarke β mould electric current _{Δ θ}time, then break down in this section, and trouble spot is positioned at this section;

Step 6, relay protection and control center (302) record the fault section label judged; meanwhile; relay protection and control center (302) sends actuating signal to the protective device at the node i at the section two ends of fault, j place, and the section of excision fault, completes protection.

4. the section fault detection and location method of the power distribution network containing DG according to claim 3, it is characterized in that, relay protection and control center (302) comprises Initialize installation module (401) and electric system real-time fault detection and locating module (402), comprises data and input and the phase angle difference calculating module (403) of each electric current modulus, section fault detection and location module (404) and comprehensive judgment module (405) in electric system real-time fault detection and locating module (402); Wherein, to the algorithm employing serial design that the phase angle difference of the Clarke α mould electric current of electric system section, the phase angle difference of Clarke β mould electric current detect and judge in section fault detection and location module (404), using the phase angle difference of Clarke α mould electric current as main detection limit, the phase angle difference of Clarke β mould electric current is as auxiliary detection limit.

5. the section fault detection and location method of the power distribution network containing DG according to claim 4, it is characterized in that, the operational scheme of Initialize installation module (401) is:

Flow process one, carry out Initialize installation;

Flow process two, label is carried out to each node of electric system and section, the node being wherein numbered the section two ends of N in electric system is respectively i, j, wherein, N>0 and N is integer, i>0 and i is integer, j>i and j is integer, the data then entered in electric system real-time fault detection and locating module (402) input the phase angle difference calculating module (403) with each electric current modulus.

6. the section fault detection and location method of the power distribution network containing DG according to claim 4, is characterized in that, data input with the operational scheme of the phase angle difference calculating module (403) of each electric current modulus is:

Clarke α, the β mould current phase angle information of flow process one, each Nodes of input current time;

Flow process two, set up POWER SYSTEM STATE information matrix;

The phase angle difference of flow process three, the Clarke α calculating each section, β mould electric current, then makes electric system segment number N=1, enters section fault detection and location module (404).

7. the section fault detection and location method of the power distribution network containing DG according to claim 4, it is characterized in that, the operational scheme of section fault detection and location module (404) is:

Flow process one, judge whether the absolute value of the phase angle difference of the Clarke α mould electric current of section N is greater than threshold k _{Δ θ}, if so, then enter flow process three, if not, then enter flow process two;

Flow process two, judge whether the absolute value of the phase angle difference of the Clarke β mould electric current of section N is greater than threshold k _{Δ θ}, if so, then enter flow process three, if not, then enter comprehensive judgment module (405);

Flow process three, judgement section N inside break down;

Nodal scheme i, j that flow process four, record trouble sector label N and these section two ends are corresponding;

Flow process five, protective relaying device sending action signal to the node i at section N two ends, j place;

Flow process six, output: section N breaks down inside, then enters comprehensive judgment module (405).

8. the section fault detection and location method of the power distribution network containing DG according to claim 4, it is characterized in that, the operational scheme of comprehensive judgment module (405) is:

Flow process one, judge whether electric system segment number N is less than section sum, if so, then enters flow process two, if not, then enter flow process three;

Flow process two, execution N=N+1, perform the flow process in section fault detection and location module (404) to next section;

Flow process three, judge each section of electric system whether all non-fault, if so, then enter flow process four, if not, then enter flow process five;

Flow process four, each section non-fault of judgement electric system, then enter the phase angle difference calculating module (403) of data input and each electric current modulus;

Flow process five, judgement electric system section N ₁, N ₂..., Nn fault export fault detection and location result, then enter the phase angle difference calculating module (403) of data input and each electric current modulus.