CN110289605B - Intelligent direction protection method for hybrid compensation circuit based on instantaneous power curve cluster - Google Patents

Intelligent direction protection method for hybrid compensation circuit based on instantaneous power curve cluster Download PDF

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CN110289605B
CN110289605B CN201910564372.XA CN201910564372A CN110289605B CN 110289605 B CN110289605 B CN 110289605B CN 201910564372 A CN201910564372 A CN 201910564372A CN 110289605 B CN110289605 B CN 110289605B
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svm
instantaneous power
value
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CN110289605A (en
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束洪春
袁小兵
田鑫萃
花斌
龙立阿
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Kunming University of Science and Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H1/00—Details of emergency protective circuit arrangements
    • H02H1/0092—Details of emergency protective circuit arrangements concerning the data processing means, e.g. expert systems, neural networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured

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  • Engineering & Computer Science (AREA)
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  • Artificial Intelligence (AREA)
  • Evolutionary Computation (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The invention relates to an intelligent direction protection method for a hybrid compensation circuit based on an instantaneous power curve cluster, and belongs to the technical field of relay protection of power systems. Firstly, setting a single-phase earth fault along a line by electromagnetic transient simulation, extracting a fault phase voltage fault component delta u and a fault phase current fault component delta i from a measuring end, and calculating instantaneous power delta p; secondly, performing principal component analysis by using the calculated instantaneous power delta p curve cluster as historical sample data to obtain a first principal component PC1Value and second principal component PC2A value; thirdly, PC of historical sample data1And PC2Inputting the value as a sample attribute into a support vector machine, constructing a fault direction mechanism of the SVM, and setting that when the output result of the SVM is 1, the forward fault is represented, and when the output result of the SVM is 0, the reverse fault is represented; finally, the instantaneous power delta p of the data to be measured is obtained, and the PC is obtained1And PC2The value is input into a fault direction mechanism of the SVM, and the fault direction is judged according to a judgment mechanism.

Description

Intelligent direction protection method for hybrid compensation circuit based on instantaneous power curve cluster
Technical Field
The invention relates to an intelligent direction protection method for a hybrid compensation circuit based on an instantaneous power curve cluster, and belongs to the technical field of relay protection of power systems.
Background
Flexible Alternating Current Transmission (FACTS) is an important aspect of application of power electronic technology in a power alternating current transmission system, a Unified Power Flow Controller (UPFC) can respectively or simultaneously adjust voltage, impedance and phase angle of a transmission line, active power flow and reactive power flow of the line can be quickly and effectively controlled, and the FACTS are flexible FACTS controllers, so that popularization and application of the UPFC have important significance in building a strong power grid, reducing energy loss of the power grid, improving electric energy transmission efficiency and the like. However, the UPFC, which is a unified thyristor control device, inevitably brings new problems to the operation of the power system, and one of the important problems is the influence on the relay protection.
Disclosure of Invention
The invention aims to solve the technical problem of providing an intelligent direction protection method of a hybrid compensation circuit based on an instantaneous power curve cluster, effectively balancing the power flow of each power transmission channel, inhibiting low-frequency and subsynchronous oscillation and reducing the instability probability of a system by utilizing a UPFC and fixed series compensation hybrid scheme, thereby improving the power supply reliability of relay protection and the economical efficiency of power grid operation.
The technical scheme of the invention is as follows: a hybrid compensation line intelligent direction protection method based on an instantaneous power curve cluster comprises the steps of firstly, setting a single-phase earth fault along a line by electromagnetic transient simulation, extracting a fault phase voltage fault component delta u and a fault phase current fault component delta i from a measuring end, and calculating instantaneous power delta p; secondly, performing principal component analysis by using the calculated instantaneous power delta p curve cluster as historical sample data to obtain a first principal component PC1Value and second principal component PC2A value; thirdly, PC of historical sample data1And PC2Inputting the value as a sample attribute into a Support Vector Machine (SVM), constructing a SVM fault direction mechanism, and setting that when the output result of the SVM is 1, a forward fault is represented, and when the output result of the SVM is 0, a reverse fault is represented; finally, the instantaneous power delta p of the data to be measured is obtained, and the PC is obtained1And PC2The value is input into a fault direction mechanism of the SVM, and the fault direction is judged according to a judgment mechanism.
The method comprises the following specific steps:
step 1: in a hybrid compensation line containing UPFC and fixed series C, historical samples are formed according to simulation data, AG faults at a reverse position are arranged at intervals of 3km along the whole length of PM of the line, wherein the first end and the last end of the line are not provided with fault positions, AG faults at a forward position are arranged at intervals of 5km along the whole length of ME of the line, the first end and the last end of the line are not provided with fault positions, AG faults at a forward position are arranged at intervals of 5km along the whole length of FN of the line, AG faults at a reverse position are arranged at intervals of 4km along the whole length of NQ of the line, and the first end and the last end of the line are not provided with fault positions;
step 2: extracting fault phase voltage fault component delta u and fault phase current fault component delta i from simulation data, and calculating instantaneous power delta p according to the fault phase voltage fault component delta u and the fault phase current fault component delta i:
Δpi＝ΔUi×ΔIi (1)
in the formula (1), Δ piFor fault phase instantaneous power, Δ UiFor faulted phase voltage fault components, Δ IiIs a fault phase current fault component;
step 3: normalizing the sample data of the delta p curve cluster, and selecting the data of the front 2 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end and the data of the rear 18 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end in each sample data for normalization;
step 4: performing Principal Component Analysis (PCA) on the normalized data to obtain a first principal component PC1Value and second principal component PC2A value;
step 5: PC for sampling historical data1And PC2Inputting the value as a sample attribute into a Support Vector Machine (SVM), constructing a SVM fault direction mechanism, and setting that when the output result of the SVM is 1, a forward fault is represented, and when the output result of the SVM is 0, a reverse fault is represented;
step 6: the instantaneous power delta p of the data to be measured is solved, and the PC is solved1And PC2The value is input into a fault direction mechanism of the SVM, and the fault direction is judged according to a judgment mechanism.
The invention has the beneficial effects that:
(1) the direction protection of PCA cluster analysis by using the instantaneous power delta p curve can reliably judge the fault direction and is not influenced by the transition resistance and the fault initial phase angle;
(2) the instantaneous power delta p is used as a characteristic quantity, a UPFC + C hybrid compensation mode is adopted, and the forward fault identification and the reverse fault identification can be reliably realized no matter where a fault point is located on a line.
(3) By utilizing a mixed scheme of UPFC and fixed series compensation C, the power flow of each power transmission channel is effectively balanced, the instability probability of the system is reduced, and the power supply reliability of relay protection and the economical efficiency of power grid operation are improved.
Drawings
FIG. 1 is a UPFC and fixed series C hybrid compensation circuit simulation model diagram of the present invention;
FIG. 2 is a fault phase instantaneous power Δ p curve cluster diagram obtained at the M side when the fault initial phase angle is 90 °;
FIG. 3 is a fault phase instantaneous power Δ p curve cluster diagram obtained from the N side when the fault initial phase angle is 90 °;
FIG. 4 shows the waveform of the fault phase Δ p at PC for the M-side phase when the initial fault phase angle is 90 DEG according to the present invention1And PC2A projection on the shaft;
FIG. 5 shows the waveform of the fault phase Δ p at PC of N side when the initial phase angle of the fault is 90 DEG according to the present invention1And PC2A projection on the shaft;
FIG. 6 is a diagram showing the judgment result of the fault section of the PCA-SVM on the M side when the initial fault phase angle is 90 degrees;
FIG. 7 is a diagram showing the judgment result of the fault section of the PCA-SVM on the N side when the initial fault phase angle is 90 degrees;
FIG. 8 is a diagram of a fault phase instantaneous power Δ p curve cluster obtained at the M side when the fault initial phase angle is-90 ° in the present invention;
FIG. 9 is a diagram of a fault phase instantaneous power Δ p curve cluster obtained at the N side when the fault initial phase angle is-90 ° in the present invention;
FIG. 10 shows the waveform of the fault phase Δ p at PC side M when the initial phase angle of the fault is-90 deg. according to the present invention1And PC2A projection on the shaft;
FIG. 11 shows the waveform of the fault phase Δ p at PC of N side when the initial phase angle of the fault is-90 deg. according to the present invention1And PC2A projection on the shaft;
FIG. 12 is a diagram showing the judgment result of the fault section of the PCA-SVM on the M side when the initial fault angle is-90 deg. according to the present invention;
FIG. 13 is a diagram showing the discrimination result of the fault section of the PCA-SVM on the N side when the initial fault angle is-90 deg.
Detailed Description
The invention is further described with reference to the following drawings and detailed description.
Example 1: a 220kV mixed compensation circuit simulation model containing UPFC and fixed series compensation C is shown in FIG. 1; the circuit parameters are as follows: the total length of the PM section line is 100km, the total length of the ME section line is 75km, the total length of the FN section line is 75km, the total length of the NQ section line is 120km, wherein M and N are measuring ends, and P, E, F, Q are end points of the line. And the fixed series compensation C is 20.5 mu F, the sampling frequency is 20kHz, and when the initial fault phase angle is 90 degrees, the fault time t is 0.3455 s.
(1) According to the first step in the specification: in a mixed compensation circuit containing UPFC and fixed series compensation C, forming a history sample according to simulation data: and arranging an AG fault at a reverse position every 3km along the whole length of the line PM, and arranging 31 AG fault positions in total, wherein the fault positions are not arranged at the first end and the last end. And setting an AG fault at a forward position every 5km along the whole length of the line ME, and setting 14 AG fault positions in total, wherein the fault positions are not arranged at the first end and the last end. An AG fault at a forward position is arranged every 5km along the whole length of a line FN, and 14 AG fault positions are arranged in total, wherein no fault position is arranged at the front end and the rear end (14 forward AG faults on the left side of a UPFC, 14 forward AG faults on the right side of the UPFC). And arranging AG faults at a reverse position every 4km along the whole length of the line NQ, and arranging 29 AG fault positions in total, wherein the fault positions are not arranged at the first end and the last end.
(2) According to the second step in the specification: and extracting fault phase voltage fault components delta u and fault phase current fault components delta i from the simulation data, and calculating instantaneous power delta p according to the fault phase voltage fault components delta u and the fault phase current fault components delta i.
(3) According to the third step in the specification: and (3) carrying out normalization processing on the sample data of the delta p curve cluster, and selecting the data of the front 2 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end and the data of the rear 18 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end in each sample data to carry out normalization processing, wherein the results are shown in fig. 2 and fig. 3.
(4) According to the fourth step in the specification: carrying out principal component PCA clustering analysis on the normalized data to obtain a first principal component PC1Value and second principal component PC2The results are shown in fig. 4 and 5.
(5) According to the fifth step in the specification: PC for sampling historical data1And PC2And inputting the value as a sample attribute into a Support Vector Machine (SVM), constructing a SVM fault direction mechanism, and setting that when the output result of the SVM is 1, the forward fault is represented, and when the output result of the SVM is 0, the reverse fault is represented.
(6) According to the sixth step in the specification: will be testedThe instantaneous power Δ p is found from the data, and the PC is found1And PC2The value is input into a fault direction mechanism of the SVM, and the fault direction is judged according to a judgment mechanism. The discrimination results are shown in fig. 6 and 7.
Example 2: a 220kV mixed compensation circuit simulation model containing UPFC and fixed series compensation C is shown in FIG. 1; the circuit parameters are as follows: the total length of the PM section line is 100km, the total length of the ME section line is 75km, the total length of the FN section line is 75km, the total length of the NQ section line is 120km, wherein M and N are measuring ends, and P, E, F, Q are end points of the line. And the fixed series compensation C is 20.5 mu F, the sampling frequency is 20kHz, and when the initial fault phase angle is-90 degrees, the fault time t is 0.3555 s.
(1) According to the first step in the specification: in a mixed compensation circuit containing UPFC and fixed series compensation C, forming a history sample according to simulation data: and arranging an AG fault at a reverse position every 3km along the whole length of the line PM, and arranging 31 AG fault positions in total, wherein the fault positions are not arranged at the first end and the last end. And setting an AG fault at a forward position every 5km along the whole length of the line ME, and setting 14 AG fault positions in total, wherein the fault positions are not arranged at the first end and the last end. An AG fault at a forward position is arranged every 5km along the whole length of a line FN, and 14 AG fault positions are arranged in total, wherein no fault position is arranged at the front end and the rear end (14 forward AG faults on the left side of a UPFC, 14 forward AG faults on the right side of the UPFC). And arranging AG faults at a reverse position every 4km along the whole length of the line NQ, and arranging 29 AG fault positions in total, wherein the fault positions are not arranged at the first end and the last end.
(2) According to the second step in the specification: and extracting fault phase voltage fault components delta u and fault phase current fault components delta i from the simulation data, and calculating instantaneous power delta p according to the fault phase voltage fault components delta u and the fault phase current fault components delta i.
(3) According to the third step in the specification: and (3) normalizing the sample data of the delta p curve cluster, and selecting the data of the first 2 sampling points of the fault traveling wave reaching the M side and the N side and the data of the second 18 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end in each sample data to perform normalization processing, wherein the results are shown in fig. 8 and 9.
(4) According to the fourth step in the specification: performing principal component on the normalized dataPerforming PCA clustering analysis to obtain a first principal component PC1Value and second principal component PC2The results are shown in fig. 10 and 11.
(5 according to the fifth step in the description: PC of historical sample data1And PC2And inputting the value as a sample attribute into a Support Vector Machine (SVM), constructing a SVM fault direction mechanism, and setting that when the output result of the SVM is 1, the forward fault is represented, and when the output result of the SVM is 0, the reverse fault is represented.
(6) According to the sixth step in the specification: the instantaneous power delta p of the data to be measured is solved, and the PC is solved1And PC2The value is input into a fault direction mechanism of the SVM, and the fault direction is judged according to a judgment mechanism. The discrimination results are shown in fig. 12 and 13.
While the present invention has been described in detail with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, and various changes can be made without departing from the spirit and scope of the present invention.

Claims (1)

1. An intelligent direction protection method for a hybrid compensation circuit based on an instantaneous power curve cluster is characterized by comprising the following steps: firstly, setting a single-phase earth fault along a line by electromagnetic transient simulation, extracting a fault phase voltage fault component delta u and a fault phase current fault component delta i from a measuring end, and calculating instantaneous power delta p; secondly, performing principal component analysis by using the calculated instantaneous power delta p curve cluster as historical sample data to obtain a first principal component PC1Value and second principal component PC2A value; thirdly, PC of historical sample data1And PC2Inputting the value as a sample attribute into a support vector machine, constructing a fault direction mechanism of the SVM, and setting that when the output result of the SVM is 1, the forward fault is represented, and when the output result of the SVM is 0, the reverse fault is represented; finally, the instantaneous power delta p of the data to be measured is obtained, and the PC is obtained1And PC2Inputting the value into a SVM fault direction mechanism, and judging the fault direction according to a judgment mechanism, wherein the method specifically comprises the following steps:
step 1: in a hybrid compensation line containing UPFC and fixed series C, historical samples are formed according to simulation data, AG faults at a reverse position are arranged at intervals of 3km along the whole length of PM of the line, wherein the first end and the last end of the line are not provided with fault positions, AG faults at a forward position are arranged at intervals of 5km along the whole length of ME of the line, the first end and the last end of the line are not provided with fault positions, AG faults at a forward position are arranged at intervals of 5km along the whole length of FN of the line, AG faults at a reverse position are arranged at intervals of 4km along the whole length of NQ of the line, and the first end and the last end of the line are not provided with fault positions;
step 2: extracting fault phase voltage fault component delta u and fault phase current fault component delta i from simulation data, and calculating instantaneous power delta p according to the fault phase voltage fault component delta u and the fault phase current fault component delta i:
Δpi＝ΔUi×ΔIi (1)
in the formula (1), Δ piFor fault phase instantaneous power, Δ UiFor faulted phase voltage fault components, Δ IiIs a fault phase current fault component;
step 3: normalizing the sample data of the delta p curve cluster, and selecting the data of the front 2 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end and the data of the rear 18 sampling points of the fault traveling wave reaching the M side and the N side of the measurement end in each sample data for normalization;
step 4: performing principal component analysis on the normalized data to obtain a first principal component PC1Value and second principal component PC2A value;
step 5: PC for sampling historical data1And PC2Inputting the value as a sample attribute into a support vector machine, constructing a fault direction mechanism of the SVM, and setting that when the output result of the SVM is 1, the forward fault is represented, and when the output result of the SVM is 0, the reverse fault is represented;
step 6: the instantaneous power delta p of the data to be measured is solved, and the PC is solved1And PC2The value is input into a fault direction mechanism of the SVM, and the fault direction is judged according to a judgment mechanism.
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