CN105158612B - A kind of thunderbolt interference identification method adaptive using line voltage traveling wave - Google Patents

Abstract

The invention relates to a method for identifying lightning strike interference by using pole-line voltage traveling wave self-adaptation, and belongs to the technical field of relay protection for DC transmission lines in electric power systems. The line is simulated and traversed every 10km, and the voltage waveform curves of lightning interference and lightning faults in the case of lightning strike wires and lightning protection lines are obtained and projected in the PCA space, and the lightning interference identification components of PCA are constructed according to their distribution. When the line is struck by lightning, the measured epipolar voltage curve is projected on the PCA space, and the Euclidean distance is used to measure the distance d _min between the PCA projection of the test data and the cluster center of the sample curve cluster obtained by simulation in the PCA space, Use the value of d _min to distinguish lightning strike interference and lightning strike fault. A large number of simulation verifications show that the invention has good effect and high reliability.

Description

A Lightning Disturbance Recognition Method Using Polar Voltage Traveling Wave Adaptive

technical field

The invention relates to a method for identifying lightning strike interference by using pole-line voltage traveling waves for principal component analysis, and belongs to the technical field of relay protection for DC transmission lines in power systems.

Background technique

Usually, lightning is harmful to high-voltage and ultra-high-voltage transmission lines when the lightning falls directly on the line, that is, direct lightning strikes. If the lightning directly strikes the HVDC line and causes the line insulator to flashover, it is said that the line has a lightning strike fault; if the lightning strikes the line and does not cause the line insulator to flashover, it means that the lightning strike line is not faulty. The lightning current surge injected at the lightning point of the line without lightning strike on the line is lightning interference to the line relay protection. Generally speaking, lightning interference has a great influence on the protection based on traveling wave or short-time window transient quantity, but has little influence on the protection based on long-time window fault transient quantity sampling value, especially for hardware filtering and then software The protection effect of the power frequency quantity extracted by DFT is very small. For the lightning surge that did not cause the flashover of the line insulator, for the line relay protection, there is a large transient energy disturbance on the line in the short time window after the lightning strike. For the case of no delay link and the fault data of the short time window No matter how high or low the sampling rate of the relay protection is, it will have an impact.

The current traveling wave protection sampling rate of DC transmission lines is 10kHz, and the judgment is extended by 5 sampling intervals. It is short-window transient protection, but lightning interference is not considered, and lightning interference identification components are not configured. In theory, lightning interference causes The risk of false activation and misjudgment of traveling wave protection, operation experience also shows that HVDC line lightning interference sometimes causes misjudgment and misresponse of existing traveling wave main protection. Therefore, we advocate that DC transmission lines should be equipped with lightning strike interference identification components, and the positive and negative lines should be separately configured, and their lightning strike interference identification components should be independently configured.

Contents of the invention

The technical problem to be solved by the present invention is to propose a method for identifying lightning strike interference using epipolar voltage traveling wave self-adaptation to solve the above problems.

The technical solution of the present invention is: a lightning strike interference identification method that utilizes polar line voltage traveling wave self-adaptation, builds an electromagnetic transient simulation model of a DC line, simulates and traverses the line every 10km, and obtains lightning strike wires from electromagnetic transient simulation In the case of lightning strike interference and lightning strike fault voltage waveform curve clusters in the case of lightning strike interference and lightning strike faults, principal component analysis is used to extract features, which are mapped to PCA space, and PCA lightning strike disturbance identification components are constructed according to their distribution. When the line is struck by lightning, the measured epipolar voltage curve is projected on the PCA space, and the Euclidean distance is used to measure the distance d _min between the PCA projection of the test data and the cluster center of the sample curve cluster obtained by simulation in the PCA space, Use the value of d _min to distinguish lightning strike interference and lightning strike fault.

Specific steps are as follows:

(1) Construct the historical sample data space, and obtain the projection distribution map of the sample in the PCA space. Carry out simulation traversal on the line every 10km, respectively set four situations of lightning strike wire interference, lightning strike wire fault, lightning strike lightning protection line interference and lightning strike lightning protection line failure, and the sampling rate is 1MHz to obtain the pole line voltage waveform curve cluster and perform PCA clustering to obtain The projection distribution diagram of the samples in the PCA space in the four cases, it can be seen from the results that the lightning strike fault and lightning strike interference are distributed on the left and right sides of the PCA space.

(2) Calculate the clustering center coordinates in PCA space under the four conditions of lightning conductor interference, lightning conductor fault, lightning lightning conductor interference and lightning conductor fault respectively

In formula (1), m _{and j} respectively represent the number of points where the measured end-to-line voltage is projected in the PCA space in the four cases.

(3) When the line is struck by lightning, project the pole-line voltage in the 1ms time window of the test data on the PCA space, and obtain the projection values (q′ ₁ , q′ ₂ ) of the test data on the PC ₁ axis and PC ₂ .

(4) Euclidean distance is used to measure the distance between the current test data projection and the center of each point cluster.

In formula (2), k represents the number of principal component projection values used, where k=2, namely (q' ₁ , q' ₂ ). N _j is the center of clustering point clusters in four cases.

(5) According to the minimum value of all the calculated distances d _j , the lightning strike interference discriminant formula based on PCA cluster analysis and Euclidean distance is obtained

d _min =min(d ₁ ,d ₂ ,d ₃ ,d ₄ ) (3)

In the above formula, d ₁ , d ₂ , d ₃ and d ₄ are defined as the distances between the PCA cluster centers of the test data in the PCA projection and the voltage curve clusters formed by the four lightning strike situations. d ₁ is defined as the distance between the test data projection and the lightning strike lightning conductor fault voltage curve cluster in the PCA space clustering center, d ₂ is defined as the distance between the test data projection and the lightning strike conductor fault voltage curve cluster in the PCA clustering center, d ₃ is defined as the distance between the test data projection and the lightning strike lightning conductor interference voltage curve cluster at the PCA cluster center, and d ₄ is defined as the distance between the test data projection and the lightning strike conductor interference voltage curve cluster at the PCA cluster center;

(6) According to the value of the distance d _min between the PCA projection of the test data and the sample curve cluster obtained by simulation in the PCA space clustering center, the lightning strike interference and lightning strike fault are judged. According to the distribution of lightning strike interference measurement data and lightning strike fault measurement data in PCA space are different, the criterion for identifying lightning strike interference is as follows:

If d _min ＝d ₁ or d _min ＝d ₂ , it is judged as a lightning fault (4)

If d _min ＝d ₃ or d _min ＝d ₄ , it is judged as lightning interference (5)

The beneficial effects of the present invention are:

(1) This method is based on the existing simulation data to realize the discrimination of lightning strike interference, no need to set the value, and the criterion has the characteristics of self-adaptation

(2) The distance measuring method utilizes the measured polar line voltage to realize the discrimination of lightning strike interference, which is easy to extract and the discrimination method is simple.

Description of drawings

Fig. 1 is a schematic diagram of the simulation system of the direct current transmission line of the present invention.

Fig. 2 is the clustering result of the voltage traveling wave curve cluster in PCA space under lightning disturbance and lightning fault according to the present invention, PC ₂ /kA is the ordinate projection value/kA, and PC ₁ /kA is the abscissa projection value/kA.

Figure 3 is the measurement terminal voltage curve cluster in the case of lightning flashover on the positive transmission line, where u/kV is voltage/kilovolt, and t/ms is time/millisecond.

Figure 4 is the measurement terminal voltage curve cluster when the positive transmission line is struck by lightning without flashover, u/kV is voltage/kilovolt, and t/ms is time/millisecond.

Detailed ways

The present invention will be further described below in combination with the accompanying drawings and specific embodiments.

A method for identifying lightning strike interference using pole line voltage traveling wave self-adaption, simulated traversal of the line every 10km, obtained the voltage waveform curves of lightning strike interference and lightning strike faults in the case of lightning strike conductors and lightning conductors, and projected them on the PCA space, according to the Distribution of lightning strike interference identification components with different PCA structures. When the line is struck by lightning, the measured epipolar voltage curve is projected on the PCA space, and the Euclidean distance is used to measure the distance d _min between the PCA projection of the test data and the cluster center of the sample curve cluster obtained by simulation in the PCA space, Use the value of d _min to distinguish lightning strike interference and lightning strike fault.

The specific steps of the discrimination method are as follows:

Build the electromagnetic transient simulation model of the DC line, the total length of the line is 1500km, the total length of the ground electrode line on the rectifier side is 109km, and the total length of the ground electrode line on the inverter side is 80km. The simulation traverses the line every 10km, and the voltage waveform curve clusters of lightning interference and lightning faults in the case of lightning strike wires and lightning protection wires are obtained from electromagnetic transient simulation, and principal component analysis is used to extract features, which are mapped to PCA space to obtain lightning strike wire interference , lightning conductor fault, lightning strike lightning conductor interference and lightning strike conductor fault, the clustering centers in PCA space are N ₁ (q ₁ ,q ₂ ), N ₂ (q ₁ ,q ₂ ), N ₃ (q ₁ ,q ₂ ) and N ₄ (q ₁ ,q ₂ ).

Embodiment 1: The simulation system of the ±800kV direct current transmission line is shown in FIG. 1 . A lightning strike occurred 550km away from the M terminal on the positive line, and the lightning protection line was not faulty.

According to the above step (3), the epipolar voltage within the 1ms time window of the test data is projected on the PCA space, and the projection values (q′ ₁ , q′ ₂ ) of the test data on the PC ₁ axis and PC ₂ are obtained.

According to step (4), the projection value (q′ ₁ ,q′ ₂ ) of the test data and each cluster center N ₁ (q ₁ ,q ₂ ), N ₂ (q ₁ ,q ₂ ), N ₃ (q ₁ ,q ₂ ) and N ₄ (q ₁ ,q ₂ ) are respectively d ₁ =4.9617×10 ⁴ , d ₂ =4.0782×10 ⁴ , d ₃ =3.2984×10 ⁴ , d ₄ =446.8166. According to step (5) and step (6), it is obtained that d _min =d ₄ , it can be judged that it is lightning strike interference.

Embodiment 2: The simulation system of the ±800kV direct current transmission line is shown in FIG. 1 . A lightning strike occurs at a distance of 980km from the M terminal to the positive pole line, and the lightning protection line is not faulty.

According to the above step (3), the epipolar voltage within the 1ms time window of the test data is projected on the PCA space, and the projection values (q′ ₁ , q′ ₂ ) of the test data on the PC ₁ axis and PC ₂ are obtained.

According to step (4), the projection value (q′ ₁ ,q′ ₂ ) of the test data and each cluster center N ₁ (q ₁ ,q ₂ ), N ₂ (q ₁ ,q ₂ ), N ₃ (q ₁ ,q ₂ ) and N ₄ (q ₁ ,q ₂ ) are respectively d ₁ =2.2249×10 ⁴ , d ₂ =1.1328×10 ⁴ , d ₃ =4.4948×10 ⁴ , d ₄ =2.9831×10 ⁴ . According to step (5) and step (6), it is obtained that d _min =d ₂ , and it can be judged that it is a lightning strike fault.

Embodiment 3: The simulation system of the ±800kV DC transmission line is shown in FIG. 1 . The positive line is 120km away from the M terminal, and the lightning protection line is not faulty.

According to the above step (3), the epipolar voltage within the 1ms time window of the test data is projected on the PCA space, and the projection values (q′ ₁ , q′ ₂ ) of the test data on the PC ₁ axis and PC ₂ are obtained.

According to step (4), the projection value (q′ ₁ ,q′ ₂ ) of the test data and each cluster center N ₁ (q ₁ ,q ₂ ), N ₂ (q ₁ ,q ₂ ), N ₃ (q ₁ ,q ₂ ) and N ₄ (q ₁ ,q ₂ ) are respectively d ₁ =4.7967×10 ⁴ , d ₂ =4.007×10 ⁴ , d ₃ =100.7772, d ₄ =3.5452×10 ³ . According to step (5) and step (6), it is obtained that d _min =d ₃ , it can be judged that it is lightning strike interference.

Claims (2)

1. A kind of 1. thunderbolt interference identification method adaptive using line voltage traveling wave, it is characterised in that：Build DC line Electromagnetic transient simulation model, emulation traversal is carried out every 10km to circuit, obtained thunderbolt wire by electromagnetic transient simulation and taken shelter from the thunder The voltage waveform cluster of thunderbolt interference and lightning fault in the case of line, and using principal component analysis extraction feature, it is mapped to PCA Space, different configuration PCA thunderbolt disturbance ecology element is distributed according to it, when circuit is struck by lightning, by the polar curve measured electricity Line projection buckle in PCA space, and is projected using euclidean distance metric test data in PCA with emulating the sample curve cluster obtained Distance d between PCA space cluster centre_min, pass through d_minValue come differentiate thunderbolt interference and lightning fault.
2. 2. the thunderbolt interference identification method adaptive using line voltage traveling wave according to claim 1, it is characterised in that Comprise the following steps that：

   (1) historical sample data space is built, obtains projective distribution figure of the sample in PCA space, circuit is carried out every 10km Emulation traversal, four kinds of the interference of thunderbolt wire, thunderbolt breakdown of conducting wires, the interference of thunderbolt lightning conducter and thunderbolt lightning conducter failure are set respectively Situation, sample rate 1MHz, obtain line voltage wavy curve cluster and carry out PCA clusters, sample is empty in PCA in the case of obtaining four kinds Between projective distribution figure, as can be seen from the results lightning fault and thunderbolt interference profile at left and right sides of PCA space；

   (2) interference of thunderbolt wire, thunderbolt breakdown of conducting wires, the interference of thunderbolt lightning conducter and thunderbolt lightning conducter four kinds of feelings of failure are calculated respectively Under condition it is all kinds of on PCA space in the case of cluster centre coordinate：

   <mrow> <msub> <mi>N</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <msub> <mi>q</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>q</mi> <mn>2</mn> </msub> <mo>)</mo> </mrow> <mo>=</mo> <mfrac> <mn>1</mn> <msub> <mi>m</mi> <mi>j</mi> </msub> </mfrac> <mo>{</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <msub> <mi>m</mi> <mi>j</mi> </msub> </munderover> <msub> <mi>q</mi> <mrow> <mn>1</mn> <mi>j</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>,</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <msub> <mi>m</mi> <mi>j</mi> </msub> </munderover> <msub> <mi>q</mi> <mrow> <mn>2</mn> <mi>j</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>)</mo> </mrow> <mo>}</mo> <mo>,</mo> <mi>j</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mn>3</mn> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow>

   In formula (1), m_jThe points that measuring end line voltage projects in PCA space in the case of four kinds, q are represented respectively₁、q₂Represent Historical sample data is in PC₁Axle and PC₂Projection value on axle；

   (3) when circuit is struck by lightning, the line voltage in window during test data 1ms is projected in PCA space, obtains testing number According in PC₁Axle and PC₂The projection value q of axle₁' and q₂′；

   (4) current test data projection and the distance at each point cluster center are measured using Euclidean distance；

   <mrow> <msub> <mi>d</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>,</mo> <msub> <mi>N</mi> <mi>j</mi> </msub> <mo>)</mo> </mrow> <mo>=</mo> <msqrt> <mrow> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msup> <mrow> <mo>(</mo> <msubsup> <mi>q</mi> <mi>k</mi> <mo>&amp;prime;</mo> </msubsup> <mo>-</mo> <msub> <mi>q</mi> <mi>k</mi> </msub> <mo>)</mo> </mrow> <mn>2</mn> </msup> </mrow> </msqrt> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow>

   K represents to use the number of principal component projection value in formula (2), here k=2, i.e. (q₁′,q₂'), N_jClustered for four kinds of situations The center of point cluster, f represent (q₁,q₂) this entirety；

   (5) according to all distance d for calculating gained_jIn minimum value, obtain the thunderbolt based on PCA cluster analyses and Euclidean distance Disturb discriminate：

   d_min=min (d₁,d₂,d₃,d₄) (3)

   In above formula, d₁、d₂、d₃And d₄Test data is defined as in the voltage curve cluster that PCA projections are formed with four kinds of thunderbolt situations to exist The distance between PCA cluster centres, d₁Test data projection is defined as with thunderbolt lightning conducter false voltage set of curves in PCA space The distance between cluster centre, d₂Test data projection is defined as with thunderbolt breakdown of conducting wires voltage curve cluster in PCA cluster centres The distance between, d₃Test data projection and thunderbolt lightning conducter interference voltage set of curves are defined as between PCA cluster centres Distance, d₄It is defined as the distance of test data projection and thunderbolt wire interference voltage set of curves between PCA cluster centres；

   (6) project and emulate distance of the sample curve cluster obtained between PCA space cluster centre in PCA according to test data d_minValue, come differentiate thunderbolt interference, lightning fault, according to thunderbolt interferometry data and lightning fault measurement data in PCA The distribution in space is the criterion such as following formula of different composition thunderbolt disturbance ecologies：

   If d_min=d₁Or d_min=d₂, then it is judged as lightning fault (4)

   If d_min=d₃Or d_min=d₄, then it is judged as thunderbolt interference (5).