Line overload risk control method and system

Abstract

The invention relates to the technical field of line overload regulation and control, and discloses a line overload risk control method and system, and the method comprises the steps: obtaining topological data in a power system and operation parameters during line overload; according to the topological data and the operation parameters, analyzing by using a power flow tracking algorithm, and finding out a line occupancy rate abnormal result when the line is overloaded; according to the topological data and the operation parameters, calculating the sensitivity of each node in the line to an overload branch through a sensitivity analysis method, and obtaining a sensitivity result; and according to the line occupancy rate abnormal result and the sensitivity result, performing overload risk elimination adjustment by using a preset line overload control strategy. According to the method, the advantages of power flow tracking and sensitivity analysis are combined, and compared with an existing power flow tracking method, when the overload risk happens to the line, the number of devices participating in adjustment of the overload line and the load removal amount are reduced, the overload line risk is effectively eliminated, and power grid safety accidents are prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of line overload regulation and control, and in particular to a line overload risk control method and system. Background Art

[0002] As the economy develops, the demand for electricity continues to rise, prompting the continuous expansion of the power system. The coverage of the power grid is getting wider and wider, and the length of transmission lines and the number of substations are increasing. The large-scale power grid makes it more difficult to monitor and manage the operation status of the lines, increasing the risk of line overload. Because more lines mean more nodes that may be overloaded, and once a key line is overloaded, it may trigger a chain reaction, affecting the power supply of a large area.

[0003] At present, the commonly used line overload control method is the traditional power flow tracking method. The power flow tracking method is based on power flow calculation. The power flow analysis can solve the generator to line occupancy rate, load to line occupancy rate and generator to load supply. It can quickly give a control plan and has the advantages of being fast and convenient, but there is a problem of a large number of regulating equipment. Summary of the invention

[0004] In view of the problem that the number of regulating devices is large in the process of line overload control using the power flow tracking method in the prior art, the present invention provides a line overload risk control method and system, which can combine the advantages of power flow tracking and sensitivity analysis, achieve optimal power adjustment and minimize load shedding operations when the line is overloaded, and reduce the number of equipment adjustments. The specific technical solution is as follows:

[0005] A line overload risk control method, comprising:

[0006] Obtain topological data in the power system and operating parameters when the line is overloaded;

[0007] According to the topological data and operating parameters, a power flow tracking algorithm is used to analyze and find abnormal line occupancy results when the line is overloaded;

[0008] According to the topological data and operating parameters, the sensitivity of each node in the line to the overloaded branch is calculated by a sensitivity analysis method to obtain a sensitivity result;

[0009] According to the abnormal line occupancy result and the sensitivity result, a preset line overload control strategy is used to eliminate the overload risk adjustment.

[0010] Preferably, the process of analyzing the topology data and the operation parameters using a power flow tracking algorithm to find abnormal line occupancy results includes:

[0011] Track the flow of the line network based on topological data;

[0012] According to the line network and the power injected into the generator node, the power distribution of each generator to each branch and the load supplied to each load are calculated;

[0013] According to the power distribution of each generator to each branch and the load supplied to each load, as well as the actual power of each branch and the actual load of each load, the occupancy rate of each generator to each branch and the supply rate to each load are calculated;

[0014] Reverse the flow direction of the power flow tracking in the line network and calculate the occupancy rate of each load on each branch;

[0015] According to the occupancy rate of each generator to each branch and the supply rate to each load, as well as the occupancy rate of each load to each branch, the generators and loads with abnormal line occupancy rates are obtained.

[0016] Preferably, the sensitivity of each node in the line to the overloaded branch is calculated by a sensitivity analysis method according to the topological data and the operating parameters to obtain the sensitivity result, which includes:

[0017] Obtain the voltage, susceptance matrix and correlation matrix of each node and each branch when the line network is used for power flow tracking, and calculate the correlation between the current of each branch and the node injection current;

[0018] The sensitivity of each node to the overloaded branch is calculated based on the correlation between the current of each branch and the node injection current and the voltage data of each branch and each node;

[0019] Arrange the sensitivity of the nodes to the overloaded branch from large to small to obtain the sensitivity result.

[0020] Preferably, the obtaining of the voltage, susceptance matrix and correlation matrix of each node and each branch when the line network performs power flow tracking, and calculating the correlation between each branch current and the node injection current comprises:

[0021] Obtain the voltage and susceptance matrix of each node and branch when the line network is used for power flow tracking;

[0022] Calculate the injected current of each node according to the voltage and susceptance matrix of each node;

[0023] Calculate the current of each branch according to the voltage of each node, the correlation matrix of each node and the susceptance matrix of each branch;

[0024] According to the injected current of each node and the current of each branch, the correlation between the current of each branch and the injected current of the node is calculated.

[0025] Preferably, the preset line overload control strategy includes:

[0026] Generator output reduction regulation control strategy, load shedding regulation control strategy and generator output increase regulation control strategy.

[0027] Preferably, the step of eliminating overload risk by using the generator output reduction control strategy according to the abnormal line occupancy result and the sensitivity result includes:

[0028] According to the sensitivity results, the sensitivity arrangement of the generator to the overload branch is obtained, and the reduced output set of the generator is formed;

[0029] Calculate the output reduction adjustment amount of each generator according to the preset transmission power threshold of the overload branch, the actual power and the output reduction set of the generator;

[0030] By comparing the reduced output adjustment amount of each generator with its corresponding power lower limit threshold, when the reduced output adjustment amount of a generator is less than its corresponding power lower limit threshold, there is no need to adjust the reduced output of the generator. On the contrary, the reduced output of each generator is adjusted according to the sensitivity arrangement, and the reduced output adjustment calculation of each motor is as follows:

[0031] The output reduction adjustment amount = the actual power of the overload branch - the preset transmission power threshold of the overload branch - the output reduction adjustment amount of the generator.

[0032] Preferably, the step of eliminating overload risk by using the load shedding regulation control strategy according to the abnormal line occupancy result and the sensitivity result includes:

[0033] According to the preset load occupancy rate threshold of the overloaded branch and the occupancy rate of each load to the overloaded branch, a set of abnormal loads with abnormal line occupancy rate is screened;

[0034] According to the supply rate of each generator to each load, the supplied load is selected and a load reduction force set is formed;

[0035] According to the abnormal load set, the reduced output set of the loads and the reduced output set of the generator, the load shedding amount of each load in the abnormal load set is calculated.

[0036] Preferably, the step of eliminating overload risk by using the generator output adjustment control strategy according to the abnormal line occupancy result and the sensitivity result includes:

[0037] The generator output adjustment set is screened according to a preset load supply rate threshold, a generator output reduction set and a load output reduction set;

[0038] According to the preset output power threshold and actual power of each generator in the generator output adjustment set, the output adjustment amount of each generator in the generator output adjustment set is obtained;

[0039] By comparing the output adjustment amount of each generator in the generator output adjustment set and the load shedding amount of each load in the abnormal load set, it is determined whether to shed the load.

[0040] Preferably, the determining whether to shed the load by comparing the output adjustment amount of each generator in the generator output adjustment set and the load shedding amount with abnormal line occupancy rate comprises:

[0041] When the output adjustment of a generator in the generator output adjustment set is greater than or equal to the load shedding amount of a load in the abnormal load set, the generator output adjustment is performed without load shedding. Otherwise, load shedding is performed, and the calculation of load shedding amount is as follows:

[0042] Load shedding amount = load shedding amount of the load in the abnormal load set - output adjustment amount of the generator in the generator output adjustment set.

[0043] A line overload risk control system, applied to the above-mentioned line overload risk control method, comprises:

[0044] A data acquisition unit, used to acquire topological data in the power system and operating parameters when the line is overloaded;

[0045] A power flow analysis unit, used to analyze the topology data and the operation parameters using a power flow tracking algorithm to find abnormal line occupancy results when the line is overloaded;

[0046] A sensitivity analysis unit, used to calculate the sensitivity of each node in the line to the overload branch by a sensitivity analysis method according to the topological data and the operating parameters, and obtain a sensitivity result;

[0047] The overload risk adjustment unit is used to eliminate the overload risk adjustment by using a preset line overload control strategy according to the abnormal line occupancy result and the sensitivity result.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] A line overload risk control method of the present invention obtains topological data in the power system and operating parameters when the line is overloaded; according to the topological data and operating parameters, a power flow tracking algorithm is used for analysis to find abnormal line occupancy results when the line is overloaded; according to the topological data and operating parameters, the sensitivity of each node in the line to the overloaded branch is calculated by a sensitivity analysis method to obtain a sensitivity result; according to the abnormal line occupancy result and the sensitivity result, a preset line overload control strategy is used to eliminate overload risk adjustment. The present invention combines the advantages of power flow tracking and sensitivity analysis. Compared with the existing power flow tracking method, when the line is at risk of overload, the number of devices involved in adjusting the overloaded line and the amount of load removal are reduced, effectively eliminating the risk of overloaded lines and preventing the occurrence of power grid safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0051] Figure 1 The present invention is a flow chart of a line overload risk control method.

[0052] Figure 2 The present invention is a flow chart of an embodiment of a line overload risk control method of the present invention.

[0053] Figure 3 The present invention is a flow chart of another embodiment of a line overload risk control method of the present invention.

[0054] Figure 4 The present invention is a schematic diagram of a line overload risk control system. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0057] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0058] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0059] See the following examples Figure 1 , Figure 2 , Figure 3 and Figure 4 .

[0060] The present application provides a line overload risk control method, including:

[0061] Step S1, obtaining topological data in the power system and operating parameters when the line is overloaded;

[0062] Collect the connection relationship information of the power grid from the database or monitoring system of the power system, including the connection mode of transmission lines, generators, loads and other equipment. For example, determine which generators are connected to which busbar, etc. Topological data is usually represented in the form of graphs or matrices, such as node-branch association matrix.

[0063] The operating parameters of the line when overloaded are obtained in real time through monitoring devices (such as current transformers, voltage transformers, etc.) installed at various nodes in the transmission line and generator. Mainly including data such as current, voltage, power (active power and reactive power) of each line. It is also necessary to obtain the rated parameters of the equipment, such as the rated current of the line, the rated capacity of the transformer, etc. By setting a suitable data collection frequency, such as collecting data every three minutes, it is ensured that the operating status when overload occurs can be accurately captured.

[0064] Step S2: Analyze the topological data and operating parameters using a power flow tracking algorithm to find abnormal line occupancy results when the line is overloaded;

[0065] The network model of the power system is constructed based on the acquired topological data, and the operating parameters are substituted into the power flow equation for calculation. The power flow tracking algorithm calculates the distribution of power transmission of each line by each generator and load node, that is, the line occupancy rate, by tracing the path of power flow from the generator to the load.

[0066] By comparing with the line occupancy reference value under normal operation, it is determined which lines have abnormal occupancy. If the occupancy of a line exceeds a certain preset threshold of its rated value, the occupancy of the line is considered abnormal.

[0067] Analyze the direction of abnormal line occupancy, that is, determine whether the line is overloaded due to excessive output of some generators or excessive load demand, so as to take targeted measures later.

[0068] Through the analysis and calculation of the power flow tracking algorithm, it is possible to explain the power source and flow direction of the overloaded line and determine which nodes have a greater impact on the overloaded line.

[0069] Step S3, calculating the sensitivity of each node in the line to the overloaded branch by a sensitivity analysis method according to the topological data and the operating parameters, and obtaining a sensitivity result;

[0070] Based on the topological data and operating parameters, a sensitivity analysis model of the power system is established. Sensitivity analysis indicates the degree of power change of the overload branch when the node injection power (generator output power or load consumption power) in the system changes slightly.

[0071] For each node, the power flow equation is linearized to calculate the relationship coefficient between the node injection power change and the overload branch power change, that is, the sensitivity.

[0072] The sensitivity results can accurately reflect the degree and direction of each node's influence on the overloaded branch power. Through this sensitivity analysis, it is possible to quickly locate which nodes' power adjustment is most effective in alleviating line overload, which helps to formulate a reasonable overload control strategy.

[0073] Step S4: according to the abnormal line occupancy result and the sensitivity result, a preset line overload control strategy is used to eliminate the overload risk.

[0074] Based on the abnormal line occupancy results and sensitivity results, multiple line overload control strategies are formulated. For example, if a generator has a high occupancy rate and high sensitivity to the overloaded line, the strategy includes reducing the output power of the generator. The strategy can also consider the power balance of the system. When reducing the power of the generator, the load needs to be adjusted accordingly, such as by shedding or transferring the load to maintain the power balance of the system.

[0075] By comprehensively utilizing the abnormal line occupancy rate results and sensitivity results, the preset line overload control strategy can adjust the power system in a targeted manner. This adjustment can effectively eliminate the risk of line overload and ensure the safe and stable operation of the power system, while also taking into account the economy of system operation and the reliability of power supply to users.

[0076] A line overload risk control method of the present invention combines the advantages of power flow tracking and sensitivity analysis. Compared with the existing power flow tracking method, when the line has an overload risk, it reduces the number of devices involved in regulating the overloaded line and the amount of load removal, effectively eliminating the overload line risk and preventing the occurrence of power grid safety accidents.

[0077] Specifically, in a preferred implementation of the present application, the analysis using a power flow tracking algorithm based on the topology data and the operating parameters to find abnormal line occupancy results includes:

[0078] Step S21, tracking the flow of the line network according to the topology data;

[0079] Before performing power flow tracking on generator nodes, the system needs to be converted into a lossless network.

[0080] Step S22: Calculate the power distribution of each generator to each branch and the load supplied to each load according to the line network and the power injected by the generator node;

[0081] The power of the line is distributed according to the proportional distribution principle. According to the line network and the power injected by the generator node, the power distribution of each generator to each branch and the load supplied to each load can be calculated.

[0082] Step S23, according to the power allocation of each generator to each branch and the load supplied to each load, as well as the actual power of each branch and the actual load of each load, calculate the occupancy rate of each generator to each branch and the supply rate to each load;

[0083] The occupancy rate of each generator on each branch can be expressed by the ratio of the power flow allocated by the generator to each branch to the actual power flow of the branch. The expression of the occupancy rate of the generator on the branch is:

[0084]

[0085] In the formula, X i,j is the occupancy rate of generator i on branch j; P i,j The power flow allocated to generator i on branch j; P j is the actual flow on branch j.

[0086] The supply rate of each generator to each load is expressed by the ratio of the power flow of each generator allocated to each load to the actual power flow of the load. The expression of the supply rate of the generator to the load is:

[0087]

[0088] Where Y i,kis the supply rate of generator i to load k; P i,k The power flow value assigned to generator i on load k; P k is the actual power flow value on load k.

[0089] Step S24, reverse the flow direction of the flow tracking in the line network, and calculate the occupancy rate of each load on each branch;

[0090] By converting each generator node in the line network into a load node with the same power, converting each load node into a generator node with the same power, and reversing the flow direction of each branch, the load occupancy rate of each branch can be obtained. The calculation formula is as follows:

[0091] The load occupancy rate of the branch is expressed by the ratio of the load flow distributed to each branch to the actual flow of the branch. The expression of the load occupancy rate of the branch is:

[0092]

[0093] Where: Z k,j is the occupancy rate of load k on branch j; P k,j P is the flow of load k allocated to branch j; j is the actual flow on branch j.

[0094] Step S25, according to the occupancy rate of each generator to each branch and the supply rate to each load, as well as the occupancy rate of each load to each branch, the generators and loads with abnormal line occupancy rates are obtained.

[0095] In order to determine whether the line occupancy rate is abnormal, a threshold is set based on the rated capacity of the line and the occupancy rate range under normal operation for comparison. For example, for a branch, if its rated current is 100A, the branch current generally does not exceed 80A during normal operation (i.e., the normal occupancy rate does not exceed 80%). When it is found through calculation that the occupancy rate of some generators or loads on the branch exceeds 80%, it is considered that these generators or loads have abnormal line occupancy rates on the branch.

[0096] When the generator's occupancy rate of a branch is too high, it means that the generator's power transmission burden on this branch is too heavy, which may easily lead to branch overload; if the load's occupancy rate of a branch is too high, it means that the load is too dependent on this branch. When a branch fails or is overloaded, the load will be greatly affected.

[0097] In this embodiment, i, j, and k are natural numbers. In practice, the number of generators i, the number of branches j, and the number of loads k can be determined according to the topological structure of the power system.

[0098] According to the occupancy rate of each generator to each branch and the supply rate to each load, as well as the occupancy rate of each load to each branch, the generators and loads with abnormal line occupancy rate are obtained. Through analysis based on the power flow tracking algorithm, the relationship between each generator, load and branch in the power grid can be understood, and the key factors that may cause line overload can be accurately found, thereby providing strong support for ensuring the safe and stable operation of the power system.

[0099] Specifically, in a preferred implementation of the present application, the sensitivity of each node in the line to the overloaded branch is calculated by a sensitivity analysis method according to the topological data and the operating parameters, and the sensitivity result obtained includes:

[0100] Step S31, obtaining the voltage, susceptance matrix and correlation matrix of each node and each branch when the line network performs power flow tracking, and calculating the correlation between the current of each branch and the node injection current; specifically including:

[0101] When conducting power system flow analysis, obtain the voltage and susceptance matrix of each node and branch when the line network is used for flow tracking;

[0102] According to the voltage and susceptance matrix of each node, the injection current of each node is calculated, and the expression is:

[0103] I p =Y p U p

[0104] In the formula, I p is the injected current of node p; Y p The susceptance matrix of node p; U p The voltage at node p;

[0105] According to the voltage of each node, the correlation matrix of each node and the susceptance matrix of each branch, the current of each branch is calculated; the expression is:

[0106] I l =Y l U p A T

[0107] In the formula, I l is the current in branch l; Y l is the susceptance matrix of branch l; A T is the node association matrix;

[0108] According to the injected current of each node and the current of each branch, the correlation between the current of each branch and the injected current of the node is calculated.

[0109] For example, for branch l, its current is a linear combination of the currents injected into each node, which is specifically expressed as follows:

[0110] I l =λ l-1 I 1 +λ l-2 I 2 +…+λ l-n I p

[0111] In the formula, the branch current I l The current I injected into node n p The correlation λ l-n ; and, |λ l-n The larger | is, the greater the impact of the injection current change of node i on the current in branch l.

[0112] Step S32, calculating the sensitivity of each node to the overloaded branch according to the correlation between the current of each branch and the node injection current and the voltage data of each branch and each node;

[0113] The power sensitivity matrix between the power variable of branch l and the injected power variable of node p is as follows:

[0114]

[0115] Where: U l is the voltage vector at the head end of branch l; U p is the voltage vector of node p; is the voltage phase angle at the first end of branch l; is the phase angle of node p. The larger β is, the greater the impact of the power change of node p in the system on the power change of branch l.

[0116] Step S33: Arrange the sensitivity of the nodes to the overloaded branch in descending order to obtain a sensitivity result.

[0117] In this embodiment, the correlation between each branch current and the node injection current is calculated to determine the influence of each node injection current on each branch current.

[0118] Arranging the sensitivity of the nodes to the overloaded branch in descending order to obtain the sensitivity results can quickly identify the nodes that have the greatest impact on the overloaded branch. When performing overload control and system regulation, priority can be given to taking measures on these highly sensitive nodes, such as adjusting the power injection of these nodes, to more effectively alleviate the overload of the overloaded branch and ensure the safe and stable operation of the power system.

[0119] Specifically, the preset line overload control strategy includes:

[0120] Generator output reduction regulation control strategy, load shedding regulation control strategy and generator output increase regulation control strategy.

[0121] Specifically, in a preferred implementation manner of the present application, the elimination of overload risk adjustment by using a generator output reduction adjustment control strategy according to the abnormal line occupancy result and the sensitivity result includes:

[0122] According to the sensitivity results, the sensitivity arrangement of the generator to the overload branch l is obtained, and the reduced output set G of the generator is formed. - ;

[0123] According to the preset transmission power threshold P of the overload branch l,max , actual power P l and the reduced output set of the generator G - , then the overload that needs to be eliminated on the load branch l is ΔP l =P l -P l,max , calculate the output adjustment of each generator, the expression is:

[0124]

[0125] In the formula, For the generator G i The amount of force reduction adjustment; S l For the generator G i Sensitivity to overload branch l.

[0126] By comparing the output adjustment of each generator The corresponding power lower limit threshold (assuming it is set to ) size, when the generator output reduction adjustment amount Less than the corresponding power lower limit threshold When the output reduction of the generator is not required, the output reduction of each generator is adjusted according to the sensitivity arrangement, and the output reduction adjustment of each motor is calculated as follows:

[0127] Output reduction adjustment amount = actual power of the overload branch - preset transmission power threshold of the overload branch - output reduction adjustment amount of the generator. Output reduction set G - Total adjustment for:

[0128]

[0129] Where n is equal to the reduced output set of the generator G - The sum of the elements of .

[0130] According to the sensitivity results, the sensitivity of the generators to the overloaded branch is arranged and a reduced output set is formed, which can quickly locate the generator that is most effective in alleviating the overloaded branch. The reduced output adjustment amount of each generator is calculated by combining the preset transmission power threshold of the overloaded branch, the actual power and the reduced output set of the generator, ensuring that the calculation of the reduced output adjustment amount is based on the actual overload situation of the current overloaded branch and the characteristics of the relevant generator.

[0131] In this embodiment, by comparing the output reduction adjustment amount of each generator with its corresponding power lower limit threshold, the abnormal operation of the generator due to over-adjustment is avoided. Adjustment is performed only when the output reduction adjustment amount is reasonable, ensuring that the generator participates in overload adjustment within the safe operation range. At the same time, adjustment according to the sensitivity arrangement can effectively reduce the power of the overload branch.

[0132] Specifically, in a preferred implementation manner of the present application, the use of a load shedding regulation control strategy to eliminate overload risk regulation according to the abnormal line occupancy result and the sensitivity result includes:

[0133] According to the preset load occupancy rate threshold of the overloaded branch and the occupancy rate of each load to the overloaded branch, a set of abnormal loads with abnormal line occupancy rate is screened;

[0134] According to the supply rate of each generator to each load, the supplied load is selected and a load reduction force set is formed;

[0135] According to the abnormal load set, the load reduction set and the generator reduction set, the load removal amount of each load in the abnormal load set is calculated. The specific calculation is as follows:

[0136]

[0137] In the formula, The load shedding amount of each load k in the abnormal load set; B k It is the proportion of load k's occupancy in the overload branch in the load's reduced output set.

[0138] The abnormal load set is selected based on the preset load occupancy threshold of the overload branch and the occupancy rate of each load to the overload branch, and the load that has a greater impact on the overload branch can be accurately found. The supplied loads are selected based on the supply rate of each generator to each load and a reduced output set is formed, taking into account the power supply relationship between the load and the generator.

[0139] In this embodiment, the load shedding amount of each load is calculated by comprehensively considering the abnormal load set, the load reduction set and the generator reduction set, and various factors of the generator and the load are fully considered. The load shedding amount calculated in this way can achieve a good balance between maintaining system power balance and relieving overload branch pressure.

[0140] Specifically, in a preferred implementation manner of the present application, the elimination of overload risk adjustment by using a generator output adjustment control strategy according to the abnormal line occupancy result and the sensitivity result includes:

[0141] The generator output adjustment set is screened according to a preset load supply rate threshold, a generator output reduction set and a load output reduction set;

[0142] According to the preset output power threshold and actual power of each generator in the generator output adjustment set, the output adjustment amount of each generator in the generator output adjustment set is obtained, and the specific calculation is as follows:

[0143] ΔP Gi =P G,max -P G

[0144] In the formula, Add output to adjust the generator G in the set i Output adjustment amount; P G,max The maximum power that the generator can output; P G is the actual power of the generator.

[0145] By comparing the output adjustment of each generator in the generator output adjustment set and the load shedding amount of each load in the abnormal load set The size relationship is used to determine whether to cut the load.

[0146] Specifically, the output adjustment amount of each generator in the generator output adjustment set is compared. and load shedding due to abnormal line occupancy The size relationship of the load is determined by:

[0147] When the output adjustment amount of a generator in the generator output adjustment set is The load shedding amount is greater than or equal to a load in the abnormal load set When the load is cut, the generator output is adjusted, and there is no need to cut the load. Otherwise, the load is cut, and the calculation of the load cut amount is as follows:

[0148] Load shedding amount = Load shedding amount of the load in the abnormal load set -Generator output adjustment in the generator output adjustment set

[0149] According to the preset load supply rate threshold, the generator output reduction set and the load output reduction set, the generator output adjustment set is screened to determine which generators are suitable for output adjustment. The output adjustment amount is calculated according to the preset output power threshold and actual power of each generator in the generator output adjustment set, ensuring that the generator output adjustment is based on its own capacity and current operating status.

[0150] In this embodiment, by comparing the output adjustment amount of each generator in the generator output adjustment set and the load shedding amount of each load in the abnormal load set, it is determined whether to shedding the load, thereby achieving an optimal choice between generator output adjustment and load shedding. When the generator has sufficient capacity to increase the output to compensate for the overload branch pressure, unnecessary load shedding can be avoided, thereby improving the reliability and economy of system operation.

[0151] The line overload risk control method of the present application was experimentally verified in the IEEE39 node system, and the developed scheme was verified by MATLAB simulation software. According to the experimental results, under the condition of the same overload line adjustment amount, the line overload risk control method of the present application combines the advantages of power flow tracking and sensitivity analysis, and reduces the number of devices involved in regulating the overload line and the amount of load removal compared to the traditional power flow tracking method. According to the experimental results, the line overload risk control method proposed in the present application is practical.

[0152] The present application also provides a line overload risk control system, which is applied to the above-mentioned line overload risk control method, comprising:

[0153] A data acquisition unit, used to acquire topological data in the power system and operating parameters when the line is overloaded;

[0154] A power flow analysis unit, used to analyze the topology data and the operation parameters using a power flow tracking algorithm to find abnormal line occupancy results when the line is overloaded;

[0155] A sensitivity analysis unit, used to calculate the sensitivity of each node in the line to the overload branch by a sensitivity analysis method according to the topological data and the operating parameters, and obtain a sensitivity result;

[0156] The overload risk adjustment unit is used to eliminate the overload risk adjustment by using a preset line overload control strategy according to the abnormal line occupancy result and the sensitivity result.

[0157] The functional explanation of each unit in a line overload risk control system in this embodiment is the same as that in an embodiment of a line overload risk control method, and the technical effects are also the same, so they will not be repeated here.

[0158] Those of ordinary skill in the art will appreciate that the units of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition of each example has been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0159] In the embodiments provided by the present invention, it should be understood that the division of units is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units can be combined into one unit, one unit can be split into multiple units, or some features can be ignored, etc.

[0160] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0161] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-0nlyMemory), random access memory (RAM, RandomAccessMemory), mobile hard disk, magnetic disk or optical disk, etc., which can store program code.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A line overload risk control method, characterized in that: include: Obtain topological data in the power system and operating parameters when the line is overloaded; According to the topological data and operating parameters, a power flow tracking algorithm is used to analyze and find abnormal line occupancy results when the line is overloaded; According to the topological data and operating parameters, the sensitivity of each node in the line to the overloaded branch is calculated by a sensitivity analysis method to obtain a sensitivity result; According to the abnormal line occupancy result and the sensitivity result, a preset line overload control strategy is used to eliminate the overload risk adjustment.

2. A line overload risk control method according to claim 1, characterized in that: The analysis based on the topological data and the operating parameters using the power flow tracking algorithm to find abnormal line occupancy results includes: Track the flow of the line network based on topological data; According to the line network and the power injected into the generator node, the power distribution of each generator to each branch and the load supplied to each load are calculated; According to the power distribution of each generator to each branch and the load supplied to each load, as well as the actual power of each branch and the actual load of each load, the occupancy rate of each generator to each branch and the supply rate to each load are calculated; Reverse the flow direction of the power flow tracking in the line network and calculate the occupancy rate of each load on each branch; According to the occupancy rate of each generator to each branch and the supply rate to each load, as well as the occupancy rate of each load to each branch, the generators and loads with abnormal line occupancy rates are obtained.

3. A line overload risk control method according to claim 2, characterized in that: The sensitivity of each node in the line to the overloaded branch is calculated by a sensitivity analysis method according to the topological data and the operating parameters to obtain the sensitivity result, including: Obtain the voltage, susceptance matrix and correlation matrix of each node and each branch when the line network is used for power flow tracking, and calculate the correlation between the current of each branch and the node injection current; The sensitivity of each node to the overloaded branch is calculated based on the correlation between the current of each branch and the node injection current and the voltage data of each branch and each node; Arrange the sensitivity of the nodes to the overloaded branch from large to small to obtain the sensitivity result.

4. A line overload risk control method according to claim 3, characterized in that: The method of obtaining the voltage, susceptance matrix and correlation matrix of each node and each branch when the line network is used for power flow tracking, and calculating the correlation between the current of each branch and the node injection current includes: Obtain the voltage and susceptance matrix of each node and branch when the line network is used for power flow tracking; Calculate the injected current of each node according to the voltage and susceptance matrix of each node; Calculate the current of each branch according to the voltage of each node, the correlation matrix of each node and the susceptance matrix of each branch; According to the injected current of each node and the current of each branch, the correlation between the current of each branch and the injected current of the node is calculated.

5. A line overload risk control method according to claim 3, characterized in that: The preset line overload control strategy includes: Generator output reduction regulation control strategy, load shedding regulation control strategy and generator output increase regulation control strategy.

6. A line overload risk control method according to claim 5, characterized in that: The step of eliminating overload risk by using the generator output reduction control strategy according to the abnormal line occupancy rate result and the sensitivity result includes: obtaining a generator sensitivity arrangement to the overload branch according to the sensitivity result, and forming a generator output reduction set; Calculate the output reduction adjustment amount of each generator according to the preset transmission power threshold of the overload branch, the actual power and the output reduction set of the generator; By comparing the reduced output adjustment amount of each generator with its corresponding power lower limit threshold, when the reduced output adjustment amount of a generator is less than its corresponding power lower limit threshold, there is no need to adjust the reduced output of the generator. On the contrary, the reduced output of each generator is adjusted according to the sensitivity arrangement, and the reduced output adjustment calculation of each motor is as follows: The output reduction adjustment amount = the actual power of the overload branch - the preset transmission power threshold of the overload branch - the output reduction adjustment amount of the generator.

7. A line overload risk control method according to claim 6, characterized in that: The step of eliminating overload risk by using the load shedding adjustment control strategy according to the abnormal line occupancy result and the sensitivity result includes: screening a set of abnormal loads with abnormal line occupancy according to a preset load occupancy threshold of the overload branch and the occupancy rate of each load to the overload branch; According to the supply rate of each generator to each load, the supplied load is selected and a load reduction force set is formed; According to the abnormal load set, the reduced output set of the loads and the reduced output set of the generator, the load shedding amount of each load in the abnormal load set is calculated.

8. A line overload risk control method according to claim 7, characterized in that: The step of eliminating overload risk by using the generator output adjustment control strategy according to the abnormal line occupancy rate result and the sensitivity result includes: selecting a generator output adjustment set according to a preset load supply rate threshold, a generator output reduction set and a load output reduction set; According to the preset output power threshold and actual power of each generator in the generator output adjustment set, the output adjustment amount of each generator in the generator output adjustment set is obtained; By comparing the output adjustment amount of each generator in the generator output adjustment set and the load shedding amount of each load in the abnormal load set, it is determined whether to shed the load.

9. A line overload risk control method according to claim 8, characterized in that: The step of comparing the output adjustment amount of each generator in the generator output adjustment set with the load shedding amount of the abnormal line occupancy rate to determine whether to shed the load includes: When the output adjustment of a generator in the generator output adjustment set is greater than or equal to the load shedding amount of a load in the abnormal load set, the generator output adjustment is performed without load shedding. Otherwise, load shedding is performed, and the calculation of load shedding amount is as follows: Load shedding amount = load shedding amount of the load in the abnormal load set - output adjustment amount of the generator in the generator output adjustment set.

10. A line overload risk control system, characterized in that: A line overload risk control method applied to any one of claims 1 to 9, comprising: A data acquisition unit, used to acquire topological data in the power system and operating parameters when the line is overloaded; A power flow analysis unit, used to analyze the topology data and the operation parameters using a power flow tracking algorithm to find abnormal line occupancy results when the line is overloaded; A sensitivity analysis unit, used to calculate the sensitivity of each node in the line to the overload branch by a sensitivity analysis method according to the topological data and the operating parameters, and obtain a sensitivity result; The overload risk adjustment unit is used to eliminate the overload risk adjustment by using a preset line overload control strategy according to the abnormal line occupancy result and the sensitivity result.

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