CN107276081B - Power grid key section identification method and system - Google Patents

Power grid key section identification method and system Download PDF

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Publication number
CN107276081B
CN107276081B CN201710535045.2A CN201710535045A CN107276081B CN 107276081 B CN107276081 B CN 107276081B CN 201710535045 A CN201710535045 A CN 201710535045A CN 107276081 B CN107276081 B CN 107276081B
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simulation
power grid
section
power
transmission line
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CN107276081A (en
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陆佳政
简洲
郭俊
方针
李波
徐勋建
杨莉
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State Grid Corp of China SGCC
State Grid Hunan Electric Power Co Ltd
Disaster Prevention and Mitigation Center of State Grid Hunan Electric Power Co Ltd
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State Grid Corp of China SGCC
State Grid Hunan Electric Power Co Ltd
Disaster Prevention and Mitigation Center of State Grid Hunan Electric Power Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06QDATA PROCESSING SYSTEMS OR METHODS, SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL, SUPERVISORY OR FORECASTING PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL, SUPERVISORY OR FORECASTING PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q50/00Systems or methods specially adapted for specific business sectors, e.g. utilities or tourism
    • G06Q50/06Electricity, gas or water supply
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/20Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]

Abstract

The invention discloses a method and a system for distinguishing a key section of a power grid, which aim to solve the prior art problem that the traditional method does not fully consider the initial section. The method comprises the following steps: pre-simulating the running state of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss of the power grid during each simulation in the pre-simulation; recording the minimum load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the minimum load loss of the power grid and the tripping condition of each power transmission line; selecting a specific number of power transmission lines according to the sequence of the risk indexes from high to low, and selecting a power transmission line combination capable of constructing a section from the power transmission lines; and judging the consistency of the active power flow directions of the lines forming the section, and if the active power flow directions of all the lines forming the section are the same, identifying the section as a key section.

Description

Power grid key section identification method and system
Technical Field
The invention relates to the technical field of electrical engineering, in particular to a method and a system for distinguishing a key section of a power grid.
Background
The scale and complexity of modern power systems are increasing day by day, and the analysis and decision-making work of power grid operators under the condition of power grid faults is more and more difficult, and the current working state of the power grid and an emergency decision-making scheme are generally required to be obtained by means of the key section of the power grid.
At present, a manual setting method is generally adopted to determine a key section in actual operation of a power grid, the method depends on experience of operators too much, objectivity is not provided, and a grid structure is difficult to update in time when changed, so that the method is not suitable for rapid risk analysis under the mountain fire disaster of the power grid. However, the existing methods for identifying some critical sections do not fully consider the initial section set, and important critical sections may be omitted.
Disclosure of Invention
The invention aims to provide a method and a system for distinguishing a key section of a power grid, which are used for comprehensively and quickly distinguishing the key section of the power grid and solving the technical problem that the key section is not accurately distinguished in the traditional method.
In order to achieve the purpose, the invention provides a power grid key section identification method, which comprises the following steps:
pre-simulating the topological structure of the running state of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss amount of the power grid during each simulation in the pre-simulation;
performing total simulation on the running state of the power grid to be tested, recording the minimum load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the minimum load loss of the power grid and the tripping condition of each power transmission line;
selecting a specific number of power transmission lines according to the sequence of the risk indexes from high to low, and selecting a power transmission line combination capable of constructing a section from the selected specific number of power transmission lines;
and judging the consistency of the active power flow directions of the lines forming the section, and if the active power flow directions of all the lines forming the section are the same, identifying the section as a key section.
Based on the method, the invention also provides a power grid key section identification system, which comprises the following steps:
a pre-simulation module: the system is used for pre-simulating the operation state of the topological structure of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss amount of the power grid during each simulation in the pre-simulation;
a total simulation module: the system is used for performing total simulation on the running state of the power grid to be tested, recording the load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the load loss of the power grid and the tripping condition of each power transmission line;
a section identification module: the method is used for selecting a specific number of transmission lines according to the sequence of the risk indexes from high to low and selecting a transmission line combination capable of constructing a section from the selected specific number of transmission lines;
a discrimination module: the method is used for judging the consistency of the active power flow directions of the lines forming the section, and if the active power flow directions of all the lines forming the section are the same, the section is identified as a key section.
The method can comprehensively and quickly identify the key section of the power grid, and provides important basis for emergency analysis and decision of power grid operators under the condition of power grid faults. The invention has clear physical significance and high engineering value.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a flow chart of a method for identifying a critical section of a power grid according to a preferred embodiment of the invention;
FIG. 2 is a diagram of a power grid topology of a preferred embodiment of the present invention;
fig. 3 is a schematic key section of a power grid topology structure according to a preferred embodiment of the present invention.
Detailed Description
The embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways as defined and covered by the claims.
As shown in fig. 1, a flow of a method for identifying a critical section of a power grid includes:
and S1, pre-simulating the operation state of the topological structure of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss amount of the power grid during each simulation in the pre-simulation.
And setting the pre-simulation times, the simulation precision and the tripping probability of each power transmission line in the power grid by taking the topological structure of the power grid needing to be subjected to key section identification as an object. Because the required total simulation times cannot be determined, pre-simulation is required to be performed first, the required total simulation times are determined through the pre-simulation, the more the pre-simulation times are, the more accurate the required total simulation times are obtained, and the more accurate the required total simulation times are obtained when the pre-simulation times reach 200 times. The smaller the setting of the simulation precision is, the more accurate the obtained line risk index is, but the smaller the simulation precision is, the less significance is brought to the practical power grid operation analysis, the practical power grid operation precision can not reach the standard, and the simulation precision is generally taken as beta epsilon [0.01, 0.05 ]. The tripping probability of each transmission line is set to be the same value, so that the importance of each line can be compared according to the risk index of each line obtained through simulation, and the tripping probability is generally set to be 10% -50%, because the simulation efficiency is low when the tripping probability is too small, and the tripping probability is too large and does not accord with the actual situation.
Usually, the loss of the power grid is measured by the minimum load loss under the condition of the power grid fault, and the minimum load loss E of the power grid can be solved by adopting DC-OPF (direct current optimal power flow). The required total simulation times can be calculated by combining the set pre-simulation times, the simulation precision and the tripping probability of each power transmission line in the power grid with the acquired minimum load loss amount of the power grid during each simulation in the pre-simulation. The pre-simulation may be part of the total simulation, which may reduce the number of simulations required to perform the total simulation individually.
And S2, performing total simulation on the running state of the power grid to be tested, recording the minimum load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the minimum load loss of the power grid and the tripping condition of each power transmission line. The minimum load loss in this step can be calculated by the calculation method of the minimum load loss in step S1.
S3, selecting a specific number of transmission lines according to the sequence of the risk indexes from high to low, and selecting a transmission line combination capable of constructing a section from the selected specific number of transmission lines.
And sorting the risk indexes of all the power transmission lines according to the size of the risk indexes, and selecting the top T lines with the highest risk indexes according to the formulated selection rule. The minimum cut set of the power grid consisting of any of the T lines is listed. The method for determining the cut sets by the lines comprises a connected graph search algorithm and the like, and the constructed minimum cut set of the power grid is a section.
And S4, judging the consistency of the active power flow directions of the lines forming the section, and if the active power flow directions of all the lines forming the section are the same, identifying the section as a key section.
Since a section is usually composed of 2 or more than 2 lines, the active power flow direction of the lines constituting the section is uncertain, and therefore, it is necessary to perform the active power flow direction analysis on all the lines constituting a section. When the active power flow directions of the lines forming the same section are consistent, namely, one part of two parts, which divide the power grid topology into two parts by the section, flows into the other part, the section is identified as a key section. When the active power flow directions of the lines forming the same section are not consistent, the section is identified as a non-critical section.
The total times of simulation required can be accurately obtained by pre-simulating the power grid to be tested, and the risk indexes of all power transmission lines are obtained when the power grid to be tested is subjected to total simulation. And selecting the section formed by the line with higher risk index to determine the key section. The method can comprehensively and quickly identify the key section of the power grid, and provides important basis for emergency analysis and decision of power grid operators under the condition of power grid faults.
Further, the calculation method of the required total simulation times is as follows:
wherein beta is simulation precision, L is pre-simulation times,the minimum load loss of the power grid in the jth simulation is shown.
Further, the calculation mode of the transmission line risk index is as follows:
wherein M is the required simulation times,the minimum load loss of the grid in the kth simulation.
The number of transmission lines of a specific number is defined as:
wherein N is the total number of transmission lines.
Corresponding to the method, the invention also provides power grid key section identification, and the system comprises:
a pre-simulation module: the system is used for pre-simulating the operation state of the topological structure of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss amount of the power grid during each simulation in the pre-simulation;
a total simulation module: the system is used for performing total simulation on the running state of the power grid to be tested, recording the load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the load loss of the power grid and the tripping condition of each power transmission line;
a section identification module: the method is used for selecting a specific number of transmission lines according to the sequence of the risk indexes from high to low and selecting a transmission line combination capable of constructing a section from the selected specific number of transmission lines;
a discrimination module: and the method is used for judging the consistency of the active power flow direction of the line on the section, and identifying the section with the consistent direction as a key section.
Further, the calculation method of the total simulation times required by the total simulation module is as follows:
wherein beta is simulation precision, L is pre-simulation times,the load loss of the power grid in the jth simulation is shown.
Further, the risk indexes of the power transmission line in the total simulation module are as follows:
wherein M is the required simulation times,the loss of the grid in the kth simulation corresponds to the loss amount.
Further, the number of the specific number of transmission lines in the screening module is defined as:
wherein N is the total number of transmission lines.
Furthermore, the number of times of pre-simulation in the pre-simulation module is 200, the trip probability is 10% -50%, and the simulation precision is 0.01-0.05.
Referring to fig. 2, research is performed on IEEE10 machine 39 node standard calculation, and the power grid shown in fig. 2 has N-46 transmission lines in total, and the trip probability of each transmission line is 10%. And performing pre-simulation on the power grid for 250 times, wherein the simulation precision beta is 0.05, and the required total simulation number M is 3000 according to a calculation formula of the total simulation number. According to the tripping probability of each line, 3000 times of simulation are carried out on the power grid, and the risk index R of all power transmission lines is obtainedi. According to the definition selected by a specific number of transmission lines, the first 16 lines with higher risk indexes are selected, as shown in table 1:
table 1 top 16 lines with the highest risk indicators
And obtaining a minimum cut set of the power grid formed by the lines in the upper table through a connected graph search algorithm, judging the consistency of the active power flow direction of the lines by the minimum cut set, and screening out a key section of the power grid, wherein the key section is shown in fig. 3. The line composition of each critical section is shown in table 2:
TABLE 2 Key Cross section
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A power grid key section identification method is characterized by comprising the following steps:
pre-simulating the operation state of the topological structure of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss amount of the power grid during each simulation in the pre-simulation;
performing total simulation on the running state of the power grid to be tested, recording the minimum load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the minimum load loss of the power grid and the tripping condition of each power transmission line;
selecting a specific number of power transmission lines according to the sequence of the risk indexes from high to low, and selecting a power transmission line combination capable of constructing a section from the selected specific number of power transmission lines;
and judging the consistency of the active power flow directions of the lines which can construct the same section, and if the active power flow directions of all the lines which construct the same section are the same, distinguishing the section as a key section.
2. The method for distinguishing the critical section of the power grid according to claim 1, wherein the calculation formula of the required total simulation times is as follows:
wherein beta is simulation precision, L is pre-simulation times,the minimum load loss of the power grid in the jth simulation is shown.
3. The method for distinguishing the power grid key section according to claim 1, wherein the calculation mode of the power transmission line risk indicator is as follows:
wherein M is the required simulation times,the minimum load loss of the grid in the kth simulation.
4. A method according to claim 1, wherein the number of the specific number of transmission lines is defined as:
wherein N is the total number of transmission lines.
5. The method for distinguishing the key sections of the power grid according to claim 1, wherein the number of times of pre-simulation is 200, the trip probability is 10% -50%, and the simulation precision is 0.01-0.05.
6. A grid critical section identification system, comprising:
a pre-simulation module: the system is used for pre-simulating the running state of the power grid to be tested, and calculating the required total simulation times by combining the set pre-simulation times, the simulation precision and the trip probability of each power transmission line in the power grid with the minimum load loss amount of the power grid during each simulation in the pre-simulation;
a total simulation module: the system is used for performing total simulation on the running state of the power grid to be tested, recording the minimum load loss of the power grid and the tripping condition of each power transmission line in the power grid during each simulation in the total simulation, and calculating the risk index of each power transmission line according to the minimum load loss of the power grid and the tripping condition of each power transmission line;
a section identification module: the method is used for selecting a specific number of power transmission lines according to the sequence of risk indexes from high to low and selecting a power transmission line combination capable of constructing a section from the power transmission lines;
a discrimination module: and the method is used for judging the consistency of the active power flow directions of the lines forming the section, and if the active power flow directions of all the lines forming the section are the same, the section is identified as a key section.
7. A power grid key section identification system according to claim 6, characterized in that the required total number of simulations is calculated by:
wherein beta is simulation precision, L is pre-simulation times,the minimum load loss of the power grid in the jth simulation is shown.
8. The power grid key section identification system of claim 6, wherein the calculation mode of the transmission line risk indicator is as follows:
wherein M is the required simulation times,the minimum load loss of the grid in the kth simulation.
9. A power grid critical section discrimination system as claimed in claim 6, wherein the number of the specific number of transmission lines is defined as:
wherein N is the total number of transmission lines.
10. The system for distinguishing the critical sections of the power grid according to claim 6, wherein the number of times of pre-simulation is 200, the trip probability is 10% -50%, and the simulation precision is 0.01-0.05.
CN201710535045.2A 2017-07-03 2017-07-03 Power grid key section identification method and system Active CN107276081B (en)

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CN103500254B (en) * 2013-10-08 2016-02-03 华北电力大学(保定) A kind of electrical network key sections automatic search method considering to optimize on border, geographical zone
CN104133146B (en) * 2014-08-11 2017-10-24 国家电网公司 A kind of feeder automation fault handling logic on-the-spot test method
CN105893714B (en) * 2016-05-19 2019-02-26 国网四川省电力公司电力科学研究院 Based on the detection of automatic voltage control system closed loop and appraisal procedure under Bulk power system simulation system
CN106602548B (en) * 2016-11-25 2019-07-05 国电南瑞科技股份有限公司 A kind of identification method of transient state stable key transmission cross-section based on EEAC

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