Power flow convergence adjustment method under power system maintenance mode

Abstract

The invention discloses a power flow convergence adjustment method under a power system maintenance mode, and is used for solving the problem that a reasonable convergence result cannot be given through adjustment when a required calculation scene actually has no solution. Obtaining network topology data of the power grid and determining a shutdown branch; constructing a first admittance matrix and a second admittance matrix before branch shutdown and a third admittance matrix after branch shutdown based on network topology data; solving a node with the minimum distance and a plurality of nodes with the maximum distances according to the first admittance matrix; performing power influence sorting by combining the second admittance matrix and the node with the minimum distance to obtain a plurality of positive / negative influence nodes; performing reactive power compensation node sorting by combining the third admittance matrix, the node with the minimum distance and each node with the maximum distance to obtain a plurality of reactive power compensation nodes; the reactive compensation capacity of each reactive compensation node is improved, load flow calculation is carried out again, and when the load flow is not converged, active output reduction / increase adjustment is carried out on the multiple positive / negative influence nodes based on a preset power target value, and an adjustment result is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of power system stability analysis, and in particular to a method for adjusting power flow convergence in a power system maintenance mode, a device for adjusting power flow convergence in a power system maintenance mode, an electronic device and a storage medium. Background Art

[0002] Power flow calculation is the basis of power grid planning and operation analysis. Its goal is to solve the steady-state operation status of the power system. If the power flow calculation does not converge, it is impossible to obtain accurate key parameters such as voltage, current and power distribution. As a result, potential overload or voltage instability problems cannot be detected, threatening the safe and stable operation of the power grid. Furthermore, making power grid planning or scheduling decisions based on non-convergent power flow calculation results may lead to wrong conclusions, causing equipment damage or other serious consequences. In addition, in real-time operation, the results obtained from power flow calculation can also be used as a reference for monitoring the status of the power grid. If convergence cannot be achieved, it is very likely to delay fault diagnosis or cause misoperation.

[0003] At present, most of the power system stability analysis uses converged power flow conditions as input. In view of the problem of non-convergence of power flow calculation that often occurs when arranging the operation mode of the power grid, there are currently two mainstream technologies to improve the convergence of power flow. One is the adjustment method based on expert experience. Specifically, by assuming that some nodes can provide unlimited reactive power compensation, the reactive power compensation required by the node is calculated and the required value is approached as close as possible from nearby nodes where reactive power compensation actually exists. The other is a data-driven configuration method. That is, from the massive data of historical convergence, a scenario close to the current calculation method is found, and the reactive power compensation value in the historical data is extracted to improve the convergence of the current calculation method.

[0004] However, when the above two methods are used, when the scenario to be calculated actually has no solution, only the conclusion of adjustment failure can be obtained, and a reasonable convergence result cannot be given through adjustment. This problem is particularly prominent in the calculation scenario of maintenance mode in power system analysis. Summary of the invention

[0005] The present invention provides a method for adjusting power flow convergence in a power system maintenance mode, a device for adjusting power flow convergence in a power system maintenance mode, an electronic device and a storage medium, which are used to solve or partially solve the technical problem that when the scenario to be calculated in the power system maintenance mode is actually unsolvable, the current technology cannot give a reasonable convergence result through adjustment.

[0006] The present invention provides a method for adjusting power flow convergence in a power system maintenance mode, comprising:

[0007] Obtain network topology data of the power grid and determine at least one outage branch line that needs to be shut down for maintenance;

[0008] For each of the outage branches, based on the network topology data, construct a first admittance matrix and a second admittance matrix of the complete network before the outage branch is shut down, and a third admittance matrix after the outage branch is shut down;

[0009] Solve the minimum distance node with the minimum electrical distance of the out-of-service branch according to the first admittance matrix, and simultaneously select a preset number of maximum electrical distance nodes;

[0010] Combining the second admittance matrix and the node with the minimum distance to sort the node power impact, to obtain a plurality of positive impact nodes and a plurality of negative impact nodes;

[0011] Combining the third admittance matrix, the node with the smallest distance and each node with the largest electrical distance, the nodes with reactive compensation capabilities are sorted to obtain a plurality of reactive compensation nodes;

[0012] Improve the reactive compensation capacity of each of the reactive compensation nodes, and recalculate the power flow. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, adjust the active output of the multiple positively impacted nodes to reduce the active output, and at the same time adjust the active output of the multiple negatively impacted nodes to increase the active output, so as to obtain the power flow convergence adjustment result.

[0013] Optionally, the network topology data includes N nodes and M branches of the power grid; and constructing a first admittance matrix and a second admittance matrix of the complete network before shutting down the shut-down branch, and a third admittance matrix after shutting down the shut-down branch based on the network topology data includes:

[0014] Based on the N nodes, construct an N-dimensional complex matrix with an initial value of 0 ;

[0015] Traverse the N nodes, when the node There is a branch to ground, and the equivalent impedance of the branch to ground is season The number of Increase ,get ;

[0016] Traverse the M branches and define nodes With Node The equivalent impedance between ;

[0017] Separate order The number of and Increase , number of Increase , number of Increase , obtain the first admittance matrix of the complete network before shutting down the shut-down branch ;

[0018] Respectively The number of , , Set the real part of ;

[0019] Separate order The number of and Increase , number of Increase , number of Increase , obtain the second admittance matrix of the complete network before shutting down the shut-down branch ;

[0020] Traverse the branches of the M branches except the out-of-service branch and define the node With Node The equivalent impedance between ,get ;

[0021] Respectively The number of , , Set the real part of ;

[0022] Separate order The number of and Increase , number of Increase , number of Increase , obtain the third admittance matrix of the complete network after shutting down the shut-down branch .

[0023] Optionally, the out-of-service branch is the mth branch among the M branches, and the nodes connected to the mth branch are node s and node t respectively; solving the minimum distance node with the minimum electrical distance of the out-of-service branch according to the first admittance matrix, and simultaneously screening out a preset number of maximum electrical distance nodes, includes:

[0024] Set N-dimensional vector , The sth element in is 1.0, and the rest are 0;

[0025] Set N-dimensional vector ;

[0026] Based on the first admittance matrix , by solving Get the The value of Select the node whose absolute value is greater than 0 and whose numerical value corresponds to the smallest serial number from all the numerical values ​​as the minimum distance node with the smallest electrical distance of the outage branch;

[0027] Regarding the All values ​​of are sorted from large to small according to their absolute values, and nodes corresponding to a preset number of serial numbers are selected from them in descending order as nodes with the largest electrical distance.

[0028] Optionally, the N nodes include S generator nodes; and the node power impact sorting is performed in combination with the second admittance matrix and the node with the minimum distance to obtain a plurality of positive impact nodes and a plurality of negative impact nodes, including:

[0029] Traverse the S generator nodes and set the N-dimensional vector , The cth element in is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0;

[0030] Set N-dimensional vector ;

[0031] Based on the second admittance matrix , by solving Get the The value of

[0032] Let the node power affect ,in, , They are The sth and tth elements of is the reactance of the outage branch;

[0033] Calculate the total number of generator nodes value, and set the The value is divided into multiple positive Values ​​and multiple negative value;

[0034] According to the stated The value is sorted from large to small for all The generator nodes with positive values ​​are sorted to obtain the positive impact nodes that are sorted from large to small in terms of the positive impact on node power when the outage branch is shut down;

[0035] According to the negative The absolute value of the value is in descending order for all The generator nodes with negative values ​​are sorted to obtain the negative impact nodes that are sorted from large to small when the outage branch is shut down and the negative impact on the node power is brought about.

[0036] Optionally, the step of sorting nodes with reactive compensation capabilities by combining the third admittance matrix, the node with the smallest distance, and each node with the largest electrical distance to obtain a plurality of reactive compensation nodes includes:

[0037] Traverse each of the nodes with the largest electrical distance and set an N-dimensional vector , The cth element in is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0;

[0038] Set N-dimensional vector ;

[0039] Based on the third admittance matrix , by solving Get the The value of

[0040] For each node c, compare the node c in the With the , and select the preset E nodes with the largest deviation values;

[0041] The E nodes in each group selected are combined, and all nodes with reactive power compensation capability obtained after the combination are sorted in descending order according to the deviation value, so as to obtain reactive power compensation nodes whose voltage changes before and after the shutdown are sorted in descending order.

[0042] Optionally, the increasing the reactive compensation capacity of each reactive compensation node includes:

[0043] For each reactive power compensation node, when one or more groups of reactors have been put into use at the reactive power compensation node, reducing one group of reactors;

[0044] When the reactive power compensation node has not previously been put into operation with a reactor, a group of capacitors is put into operation.

[0045] Optionally, the adjusting the active output of the plurality of positive impact nodes to decrease based on the preset power target value, and adjusting the active output of the plurality of negative impact nodes to increase, comprises:

[0046] For a first positive influence node ranked first among the multiple positive influence nodes, when it is determined that a first current output of the first positive influence node is greater than or equal to a preset power target value, the first current output is directly subtracted from the preset power target value to complete the active output reduction adjustment;

[0047] When it is determined that the first current output of the first positively influential node is less than the preset power target value, the output of the first positively influential node is set to 0, and the difference between the first current output and the preset power target value is adjusted by the positively influential nodes other than the first positively influential node in accordance with the active output reduction adjustment method of the first positively influential node.

[0048] For the first negatively impacting node ranked first among the multiple negatively impacting nodes, when it is determined that the difference between the maximum output of the first negatively impacting node and the second current output is greater than or equal to a preset power target value, the preset power target value is directly increased on the basis of the second current output to complete the active output increase adjustment;

[0049] When it is determined that the difference between the maximum output of the first negatively impacted node and the second current output is less than a preset power target value, the output of the first negatively impacted node is adjusted to the maximum output, and the difference between the preset power target value and the maximum output is adjusted according to the active output increase adjustment method of the first negatively impacted node, and the negatively impacted nodes other than the first negatively impacted node perform subsequent active output increase adjustments.

[0050] Optionally, the method further comprises:

[0051] After the active power output adjustment is completed, the power flow calculation is re-performed based on the power flow convergence adjustment result;

[0052] When the current power flow calculation result indicates that the power flow has converged, the adjustment is ended, and the power flow convergence adjustment result is used as the final operation mode.

[0053] Optionally, the method further comprises:

[0054] When the current power flow calculation result indicates that the power flow is not converged, and the current adjustment cycle number has not reached the preset upper limit number, the power flow convergence adjustment result is used as the current operation mode, and the process is re-jumped to the reactive compensation capacity execution step of the reactive compensation node;

[0055] When the current power flow calculation result indicates that the power flow does not converge, and the current adjustment cycle number reaches a preset upper limit number, the adjustment is stopped and an adjustment failure result is output.

[0056] The present invention also provides a power flow convergence adjustment device in a power system maintenance mode, comprising:

[0057] A data acquisition unit, used to acquire network topology data of the power grid and determine at least one outage branch that needs to be shut down for maintenance;

[0058] An admittance matrix construction unit, for constructing, for each of the outage branches, a first admittance matrix and a second admittance matrix of the complete network before the outage branch is shut down, and a third admittance matrix after the outage branch is shut down, based on the network topology data;

[0059] An electrical distance node solving unit, used for solving the minimum distance node with the minimum electrical distance of the out-of-service branch according to the first admittance matrix, and screening out a preset number of maximum electrical distance nodes;

[0060] A node power impact ranking unit, used to perform node power impact ranking in combination with the second admittance matrix and the node with the minimum distance, to obtain a plurality of positively impacted nodes and a plurality of negatively impacted nodes;

[0061] A reactive compensation capability node sorting unit, configured to sort reactive compensation capability nodes in combination with the third admittance matrix, the node with the smallest distance, and each node with the largest electrical distance, to obtain a plurality of reactive compensation nodes;

[0062] The active output adjustment unit is used to increase the reactive compensation capacity of each reactive compensation node and recalculate the power flow. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, the active output of the multiple positive impact nodes is reduced and the active output of the multiple negative impact nodes is increased to obtain the power flow convergence adjustment result.

[0063] The present invention also provides an electronic device, the device comprising a processor and a memory:

[0064] The memory is used to store program code and transmit the program code to the processor;

[0065] The processor is used to execute the power flow convergence adjustment method in the power system maintenance mode as described in any one of the above items according to the instructions in the program code.

[0066] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program codes, and the program codes are used to execute the power flow convergence adjustment method in the power system maintenance mode as described in any of the above items.

[0067] It can be seen from the above technical solutions that the present invention has the following advantages:

[0068] A method for adjusting power flow convergence in a power system maintenance mode is provided. The network topology data of the power grid is obtained to determine at least one outage branch that needs to be shut down during maintenance; for each outage branch, based on the network topology data, the first admittance matrix and the second admittance matrix of the complete network before the outage branch needs to be shut down, and the third admittance matrix after the outage branch needs to be shut down are constructed; according to the first admittance matrix, the minimum distance node with the minimum electrical distance of the outage branch is solved, and a preset number of maximum electrical distance nodes are screened out; the node power influence is sorted in combination with the second admittance matrix and the minimum distance node to obtain multiple positive influence nodes and multiple negative influence nodes; the reactive compensation capacity nodes are sorted in combination with the third admittance matrix, the minimum distance node and each maximum electrical distance node to obtain multiple reactive compensation nodes; the reactive compensation capacity of each reactive compensation node is increased, and the power flow calculation is re-performed. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, the active output reduction adjustment is performed on multiple positive influence nodes, and the active output increase adjustment is performed on multiple negative influence nodes to obtain the power flow convergence adjustment result. On the one hand, by finding the key units that affect the outage lines, the reactive voltage level on the transmission channel is increased in turn, and the transmission power transfer caused by the outage lines is reduced, so as to achieve the combination of reactive and active adjustments, and give a convergence method while keeping the active changes as small as possible and avoiding large-scale changes, so as to improve the convergence of the power flow calculation under the maintenance mode. On the other hand, under the premise that the original active distribution scenario is actually unsolvable, a reasonable convergence method is given through active output adjustment as much as possible, so as to improve the convergence of the power flow calculation under the maintenance mode, and provide a basis for the next step of other power grid analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0070] Figure 1 A flow chart of the steps of a power flow convergence adjustment method in a power system maintenance mode;

[0071] Figure 2 It is a schematic diagram of equivalent impedance of branches between nodes;

[0072] Figure 3 The present invention is a structural block diagram of a power flow convergence adjustment device in a power system maintenance mode. DETAILED DESCRIPTION

[0073] Embodiments of the present invention provide a method for adjusting power flow convergence in a power system maintenance mode, a device for adjusting power flow convergence in a power system maintenance mode, an electronic device and a storage medium, which are used to solve or partially solve the technical problem that when the scenario to be calculated in the power system maintenance mode is actually unsolvable, the current technology cannot give a reasonable convergence result through adjustment.

[0074] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only 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.

[0075] As an example, most of the current power system stability analysis uses converged power flow conditions as input. In response to the problem of non-convergence of power flow calculations that often occurs when arranging the operation mode of the power grid, there are currently two mainstream technologies to improve the convergence of power flow. One is the adjustment method based on expert experience. Specifically, by assuming that some nodes can provide unlimited reactive power compensation, the reactive power compensation required by the node is calculated and the required value is approached as close as possible from nearby nodes where reactive power compensation actually exists. The other is a data-driven configuration method. That is, from the massive data of historical convergence, a scenario close to the current calculation method is found, and the reactive power compensation values ​​in the historical data are extracted to improve the convergence of the current calculation method.

[0076] However, when the above two methods are used, when the scenario to be calculated actually has no solution, only the conclusion that the adjustment has failed can be obtained, and a reasonable convergence result cannot be given through adjustment.

[0077] After further analysis, the present invention found that the root cause of the problem is that the current methods for improving the convergence of power flow calculations all assume that the cause of non-convergence is unreasonable reactive compensation, while ignoring the potential cause of unreasonable active power distribution. Especially when the power grid is in an incomplete network state, such as when some key transmission channels are under maintenance (i.e., the maintenance mode calculation scenario in power system analysis), the processing method should be to significantly reduce the active power transmitted by the section, rather than just performing reactive compensation configuration.

[0078] Therefore, one of the core inventive points of the embodiment of the present invention is: for the special scenario of maintenance mode calculation in power system analysis, a method for adjusting the convergence of power flow in the maintenance mode of the power system is proposed. On the one hand, by finding the key units that affect the outage line, the reactive voltage level on the transmission channel and the transmission power transfer caused by the outage line are increased in turn, so as to realize the combination of reactive and active adjustment, and give a convergence method while keeping the active power change as small as possible and avoiding large-scale changes, thereby improving the convergence of power flow calculation in the maintenance mode. On the other hand, under the premise that the original active power distribution scenario is actually unsolvable, a reasonable convergence method is given by adjusting the active power output as much as possible, thereby improving the convergence of power flow calculation in the maintenance mode, and providing a basis for the next step of other power grid analysis.

[0079] Reference Figure 1 , shows a flow chart of a method for adjusting power flow convergence in a power system maintenance mode provided by an embodiment of the present invention, which may specifically include the following steps:

[0080] Step 101, obtaining network topology data of the power grid, and determining at least one outage branch that needs to be shut down for maintenance;

[0081] First, the network topology data of the power grid is obtained. The network topology data mainly includes a certain convergent power grid operation mode, N nodes and M branches of the power grid. Among them, the N nodes contain S generators (corresponding to S generator nodes) and K nodes with reactive compensation equipment. Taking the shutdown of a branch for maintenance as an example, assuming that the mth branch of the M branches needs to be repaired, the flow calculation will not converge after direct shutdown. At the same time, it is assumed that the nodes connected to the mth branch are node s and node t respectively.

[0082] Step 102, for each of the outage branches, based on the network topology data, constructing a first admittance matrix and a second admittance matrix of the complete network before shutting down the outage branch, and a third admittance matrix after shutting down the outage branch;

[0083] In some embodiments, based on the network topology data, a first admittance matrix and a second admittance matrix of the complete network before the branch is shut down, and a third admittance matrix after the branch is shut down may be constructed as follows:

[0084] First, based on N nodes, construct an N-dimensional complex matrix with an initial value of 0 .

[0085] Then traverse N nodes, when the node There is a branch to ground (such as load, parallel capacitive reactance, generator, etc., or DC equivalent branch to ground, etc.), and the equivalent impedance of the branch to ground is season The number of Increase ,get .

[0086] Traverse M branches and define nodes With Node The equivalent impedance between .node With Node The equivalent impedance of the branch between Figure 2 shown.

[0087] Separate order The number of and Increase , number of Increase , number of Increase , obtain the first admittance matrix of the complete network before the outage that requires the outage of the branch .

[0088] Respectively The number of , , Set the real part of .

[0089] Separate order The number of and Increase , number of Increase , number of Increase , obtain the second admittance matrix of the complete network before the outage that requires the outage of the branch .

[0090] Traverse the M branches except the out-of-service branches and define the nodes With Node The equivalent impedance between ,get .

[0091] Respectively The number of , , Set the real part of .

[0092] Separate order The number of and Increase , number of Increase , number of Increase , get the third admittance matrix of the complete network after the outage that requires the outage of the branch .

[0093] From the previous steps, we can see that the third admittance matrix The calculation process and the second admittance matrix Basically the same, the only difference is that when traversing the branch, the third admittance matrix Ignore the lines that need to be shut down. The third admittance matrix It can be understood as the second admittance matrix calculated after the line is shut down for maintenance. .

[0094] Step 103, solving the minimum distance node with the minimum electrical distance of the outage branch according to the first admittance matrix, and simultaneously screening out a preset number of maximum electrical distance nodes;

[0095] Combined with the above content, it can be known that the out-of-service branch is the mth branch among the M branches, and the nodes connected to the mth branch are node s and node t. In some embodiments, the minimum distance node with the minimum electrical distance of the out-of-service branch is solved according to the first admittance matrix, and a preset number of maximum electrical distance nodes are screened out, which can be:

[0096] First set the N-dimensional vector , The sth element in is 1.0, and the rest are 0.

[0097] Next, set the N-dimensional vector .

[0098] Based on the first admittance matrix , by solving get The value of All values ​​of , ... The node corresponding to the node with the absolute value greater than 0 and the smallest numerical sequence number (denoted as the rth) is selected as the node with the smallest distance for the outage branch with the smallest electrical distance.

[0099] right All values ​​of , ... Sort by absolute value from large to small, and select a preset number (which can be recorded as T, and the value is set according to the actual situation) of nodes corresponding to the serial numbers (i.e., the first T nodes) as the nodes with the largest electrical distance in descending order.

[0100] Step 104, sorting the node power influences by combining the second admittance matrix and the node with the minimum distance, and obtaining a plurality of positive influence nodes and a plurality of negative influence nodes;

[0101] Combined with the above content, N nodes include S generator nodes. In some embodiments, the node power impact is sorted in combination with the second admittance matrix and the node with the smallest distance to obtain multiple positive impact nodes and multiple negative impact nodes, which can be:

[0102] First, traverse the S generator nodes and set the N-dimensional vector , The cth element is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0.

[0103] Next, set the N-dimensional vector .

[0104] Then based on the second admittance matrix , by solving get The numerical value of .

[0105] Let the node power affect .in, , They are The sth and tth elements of is the reactance of the out-of-service branch.

[0106] Calculate the total number of generator nodes value, and set the The value is divided into multiple positive and negative values ​​according to the positive and negative values. Values ​​and multiple negative value.

[0107] According to the positive The value is sorted from large to small for all The generator nodes with positive values ​​are sorted to obtain the positive impact nodes that will have a positive impact on node power when the branch is shut down. The positive impact nodes can be recorded as nodes ,node …….

[0108] According to negative The absolute value of the value is in descending order for all The generator nodes with negative values ​​are sorted to obtain the nodes with negative impact on node power when the outage requires the shutdown of the branch. The negative impact nodes can be recorded as nodes ,node …….

[0109] In this step, by providing a generator selection method for generator output transfer, the unit adjustment for specific objects is realized during the subsequent active output adjustment, thereby reducing the current overload situation under the active power flow transfer and maintenance reduction mode and improving the current convergence.

[0110] Step 105, sorting nodes with reactive compensation capabilities by combining the third admittance matrix, the node with the smallest distance, and each node with the largest electrical distance, to obtain a plurality of reactive compensation nodes;

[0111] In some embodiments, the reactive compensation capability nodes are sorted by combining the third admittance matrix, the node with the smallest distance, and each node with the largest electrical distance to obtain multiple reactive compensation nodes, which may be:

[0112] First, traverse each node with the largest electrical distance and set the N-dimensional vector , The cth element is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0.

[0113] Next, set the N-dimensional vector .

[0114] Then based on the third admittance matrix , by solving get The value of

[0115] For each node c, compare the node c in and , and select the preset E nodes with the largest deviation values ​​(E can be set according to actual conditions).

[0116] Take the union of each group of E nodes selected, and sort all nodes with reactive compensation capability obtained after taking the union from large to small according to the deviation value, and obtain the reactive compensation nodes whose voltage changes before and after the outage are sorted from large to small. The reactive compensation nodes obtained after sorting can be recorded as nodes , …….

[0117] In this step, a node selection method for improving voltage support strength is given, so that in the subsequent process, the reactive compensation capacity of the selected nodes can be increased to increase the voltage level of the nodes that are more affected by the power flow transfer, thereby improving the power flow convergence.

[0118] Step 106, increase the reactive compensation capacity of each of the reactive compensation nodes, and recalculate the power flow. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, adjust the active output of the multiple positively impacted nodes to reduce the active output, and at the same time adjust the active output of the multiple negatively impacted nodes to increase the active output, so as to obtain the power flow convergence adjustment result.

[0119] Further, the reactive power compensation capacity of each reactive power compensation node can be improved by: for each reactive power compensation node (i.e., node , ...), so that its reactive power compensation increases by one level. That is, when the reactive power compensation node has previously put into use one or more groups of reactors, one group of reactors is reduced. When the reactive power compensation node has not previously put into use a reactor, a group of capacitors is put into use.

[0120] After increasing the reactive compensation capacity of each reactive compensation node, the power flow calculation is performed again. When the power flow calculation result indicates that the power flow has converged, the adjustment is completed, and the result is the final converged operation mode.

[0121] When the power flow calculation result indicates that the power flow is not converged, it is further possible to adjust the active output of multiple positively impacted nodes to reduce the active output, and adjust the active output of multiple negatively impacted nodes to increase the active output, based on the preset power target value.

[0122] Furthermore, the active output reduction adjustment measures are as follows:

[0123] For multiple positive impact nodes (node ,node ...) , when judging the first positive impact node The first current output Greater than or equal to the preset power target value (i.e. the power target value to be reduced is selected in advance), the first current output is directly used Subtract the preset power target value , complete the active output reduction adjustment.

[0124] When judging the first positive impact node The first current output Less than the preset power target value When the first positive impact node The output is set to 0, the first current output With the preset power target value The difference between , according to the first positive impact node The active output reduction adjustment method is to reduce the number of nodes except the first positive impact node. Positive impact nodes other than ,node …) to carry out subsequent active power output reduction adjustments.

[0125] The specific adjustment measures for increasing active output are as follows:

[0126] For multiple negatively impacted nodes (node ,node ...) , when judging the first negative impact node Maximum output With the second current output The difference is greater than or equal to the preset power target value When the current output is Add the preset power target value based on , complete the active output increase adjustment.

[0127] When determining the first negative impact node Maximum output With the second current output The difference is less than the preset power target value When the first negatively impacting node Adjust the output to the maximum output , the difference between the preset power target value and the maximum output , according to the first negative impact node The active output increase adjustment method is to remove the first negatively affecting node Negative impact nodes other than ,node …) to carry out subsequent active output increase adjustments.

[0128] After the active power output adjustment is completed, the power flow calculation is re-performed based on the power flow convergence adjustment results.

[0129] If the current power flow calculation result indicates power flow convergence, the adjustment is terminated and the power flow convergence adjustment result is used as the final operation mode.

[0130] If the current power flow calculation result indicates that the power flow is not converged, and the current adjustment cycle number has not reached the preset upper limit, the power flow convergence adjustment result is used as the current operation mode, and the process is redirected to the reactive compensation capacity execution step of the reactive compensation node. Thus, by adjusting the active power distribution transfer and reactive voltage level in turn, a convergence method can be given while keeping the active power change as small as possible.

[0131] If the current power flow calculation result indicates that the power flow is not converged, and the current adjustment cycle number reaches the preset upper limit, the adjustment is stopped and the adjustment failure result is output.

[0132] In another optional manner, when two or more branches are shut down at the same time, a sequential calculation method can also be used. That is, the calculation of multiple shut-down branches is decomposed into sequential shutdowns. For example, the first line is shut down to perform the power flow convergence adjustment described above, and then the second line is shut down to perform the power flow convergence adjustment, and so on, until the power flow convergence adjustment of the last branch to be shut down is completed.

[0133] In an embodiment of the present invention, a method for adjusting the convergence of power flow in the maintenance mode of a power system is proposed for the special scenario of maintenance mode calculation in power system analysis. On the one hand, by finding the key units that affect the outage lines, the reactive voltage level on the transmission channel is increased in turn, and the transmission power transfer caused by the outage lines is reduced, so as to realize the combination of reactive and active adjustment, and give a convergence method while keeping the active power changes as small as possible and avoiding large-scale changes, thereby improving the convergence of power flow calculation in the maintenance mode. On the other hand, under the premise that the original active power distribution scenario is actually unsolvable, a reasonable convergence method is given by adjusting the active power output as much as possible, thereby improving the convergence of power flow calculation in the maintenance mode, and providing a basis for other power grid analyses in the next step.

[0134] Reference Figure 3 , shows a structural block diagram of a power flow convergence adjustment device in a power system maintenance mode provided by an embodiment of the present invention, which may specifically include:

[0135] The data acquisition unit 301 is used to acquire network topology data of the power grid and determine at least one outage branch that needs to be shut down for maintenance;

[0136] The admittance matrix construction unit 302 is used to construct, for each of the outage branches, a first admittance matrix and a second admittance matrix of the complete network before the outage branch is shut down, and a third admittance matrix after the outage branch is shut down based on the network topology data;

[0137] An electrical distance node solving unit 303 is used to solve the minimum distance node with the minimum electrical distance of the outage branch according to the first admittance matrix, and simultaneously screen out a preset number of maximum electrical distance nodes;

[0138] A node power impact ranking unit 304 is used to perform node power impact ranking in combination with the second admittance matrix and the node with the minimum distance to obtain a plurality of positive impact nodes and a plurality of negative impact nodes;

[0139] A reactive compensation capability node sorting unit 305 is used to sort reactive compensation capability nodes in combination with the third admittance matrix, the minimum distance node and each of the maximum electrical distance nodes to obtain a plurality of reactive compensation nodes;

[0140] The active output adjustment unit 306 is used to increase the reactive compensation capacity of each reactive compensation node and recalculate the power flow. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, the active output of the multiple positive impact nodes is reduced and the active output of the multiple negative impact nodes is increased to obtain the power flow convergence adjustment result.

[0141] In an optional embodiment, the network topology data includes N nodes and M branches of the power grid; the admittance matrix construction unit 302 includes:

[0142] An initial N-dimensional complex matrix construction unit is used to construct an N-dimensional complex matrix with an initial value of 0 based on the N nodes. ;

[0143] The first adjustment unit of the N-dimensional complex matrix is ​​used to traverse the N nodes. There is a branch to ground, and the equivalent impedance of the branch to ground is season The number of Increase ,get ;

[0144] The equivalent impedance definition unit is used to traverse the M branches and define nodes With Node The equivalent impedance between ;

[0145] The first admittance matrix construction unit is used to respectively set The number of and Increase , number of Increase , number of Increase , obtain the first admittance matrix of the complete network before shutting down the shut-down branch ;

[0146] The second N-dimensional complex matrix adjustment unit is used to adjust The number of , , Set the real part of ;

[0147] The second admittance matrix construction unit is used to respectively set The number of and Increase , number of Increase , number of Increase , obtain the second admittance matrix of the complete network before shutting down the shut-down branch ;

[0148] The third N-dimensional complex matrix adjustment unit is used to traverse the branches of the M branches except the out-of-service branch and define nodes With Node The equivalent impedance between ,get ;

[0149] The fourth adjustment unit of the N-dimensional complex matrix is ​​used to adjust The number of , , Set the real part of ;

[0150] The third admittance matrix construction unit is used to respectively set The number of and Increase , number of Increase , number of Increase , obtain the third admittance matrix of the complete network after shutting down the shut-down branch .

[0151] In an optional embodiment, the out-of-service branch is the mth branch among the M branches, and the nodes connected to the mth branch are node s and node t respectively; the electrical distance node solving unit 303 includes:

[0152] The first N-dimensional vector setting unit is used to set the N-dimensional vector , The sth element in is 1.0, and the rest are 0;

[0153] The second N-dimensional vector setting unit is used to set the N-dimensional vector ;

[0154] A minimum distance node determination unit is used to determine the node based on the first admittance matrix , by solving Get the The value of Select the node whose absolute value is greater than 0 and whose numerical value corresponds to the smallest serial number from all the numerical values ​​as the minimum distance node with the smallest electrical distance of the outage branch;

[0155] The electrical distance maximum node determination unit is used to determine the All values ​​of are sorted from large to small according to their absolute values, and nodes corresponding to a preset number of serial numbers are selected from them in descending order as nodes with the largest electrical distance.

[0156] In an optional embodiment, the N nodes include S generator nodes; the node power impact sorting unit 304 includes:

[0157] The third N-dimensional vector setting unit is used to traverse the S generator nodes and set the N-dimensional vector , The cth element in is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0;

[0158] The fourth N-dimensional vector setting unit is used to set the N-dimensional vector ;

[0159] The N-dimensional vector first solving unit is used for solving the second admittance matrix based on , by solving Get the The value of

[0160] Node power impact definition unit, used to define node power impact ,in, , They are The sth and tth elements of is the reactance of the outage branch;

[0161] Node power impact calculation unit, used to calculate the power impact of all generator nodes. value, and set the The value is divided into multiple positive Values ​​and multiple negative value;

[0162] The positive impact node sorting unit is used to sort the nodes according to the positive The value is sorted from large to small for all The generator nodes with positive values ​​are sorted to obtain the positive impact nodes that are sorted from large to small in terms of the positive impact on node power when the outage branch is shut down;

[0163] The negative impact node sorting unit is used to sort the nodes according to the negative impact node. The absolute value of the value is in descending order for all The generator nodes with negative values ​​are sorted to obtain the negative impact nodes that are sorted from large to small when the outage branch is shut down and the negative impact on the node power is brought about.

[0164] In an optional embodiment, the reactive power compensation capability node sorting unit 305 includes:

[0165] The fifth N-dimensional vector setting unit is used to traverse each of the nodes with the largest electrical distance and set the N-dimensional vector , The cth element in is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0;

[0166] The sixth N-dimensional vector setting unit is used to set the N-dimensional vector ;

[0167] The N-dimensional vector second solving unit is used for solving the third admittance matrix based on the , by solving Get the The value of

[0168] The maximum deviation node screening unit is used for comparing the node c in the With the , and select the preset E nodes with the largest deviation values;

[0169] The reactive compensation node sorting unit is used to take the union of the E nodes in each group screened out, and sort all the nodes with reactive compensation capability obtained after taking the union in descending order according to the deviation value, so as to obtain the reactive compensation nodes whose voltage changes before and after the shutdown are sorted in descending order.

[0170] In an optional embodiment, the active output adjustment unit 306 includes:

[0171] A reactor reduction unit, for each reactive power compensation node, when one or more groups of reactors have been put into use in the reactive power compensation node, reducing one group of reactors;

[0172] The capacitor input unit is used to input a group of capacitors when the reactive power compensation node has not previously input a reactor.

[0173] In an optional embodiment, the active output adjustment unit 306 includes:

[0174] The first active output reduction adjustment execution unit is used for, for a first positive influence node ranked first among the multiple positive influence nodes, directly using the first current output minus the preset power target value to complete the active output reduction adjustment when it is determined that the first current output of the first positive influence node is greater than or equal to the preset power target value;

[0175] The second active output reduction adjustment execution unit is used for, when it is determined that the first current output of the first positive impact node is less than the preset power target value, setting the output of the first positive impact node to 0, and the difference between the first current output and the preset power target value is performed by the positive impact nodes other than the first positive impact node in accordance with the active output reduction adjustment method of the first positive impact node.

[0176] The first active output increase adjustment execution unit is used for, for a first negative impact node ranked first among the multiple negative impact nodes, when it is determined that the difference between the maximum output of the first negative impact node and the second current output is greater than or equal to a preset power target value, directly increasing the preset power target value on the basis of the second current output to complete the active output increase adjustment;

[0177] The second execution unit for active output increase adjustment is used to adjust the output of the first negative impact node to the maximum output when it is determined that the difference between the maximum output of the first negative impact node and the second current output is less than the preset power target value. The difference between the preset power target value and the maximum output is performed according to the active output increase adjustment method of the first negative impact node, and the subsequent active output increase adjustment is performed by the negative impact nodes other than the first negative impact node.

[0178] In an optional embodiment, the device further includes:

[0179] A power flow calculation re-execution unit, configured to re-calculate the power flow based on the power flow convergence adjustment result after the active power output adjustment is completed;

[0180] The first execution unit for ending adjustment is used to end the adjustment when the current power flow calculation result indicates that the power flow has converged, and use the power flow convergence adjustment result as the final operation mode.

[0181] In an optional embodiment, the device further includes:

[0182] An active output adjustment jump cycle execution unit is used to, when the current power flow calculation result indicates that the power flow is not converged and the current adjustment cycle number has not reached a preset upper limit number, use the power flow convergence adjustment result as the current operation mode and jump back to the reactive compensation capacity execution step of the reactive compensation node;

[0183] The second execution unit for ending adjustment is used to stop adjustment and output an adjustment failure result when the current power flow calculation result indicates that the power flow does not converge and the current adjustment cycle number reaches a preset upper limit number.

[0184] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the aforementioned method embodiment.

[0185] It should be noted that, in order to enable those skilled in the art to better distinguish data of the same type but with different actual meanings, the embodiments of the present invention use terms such as first and second to distinguish and explain some technical features. The terms such as first and second are only used to distinguish data and have no other special meanings. It can be understood that the present invention is not limited to this.

[0186] An embodiment of the present invention further provides an electronic device, the device comprising a processor and a memory:

[0187] The memory is used to store the program code and transmit the program code to the processor;

[0188] The processor is used to execute the power flow convergence adjustment method in the power system maintenance mode of any embodiment of the present invention according to the instructions in the program code.

[0189] An embodiment of the present invention further provides a computer-readable storage medium, which is used to store program codes, and the program codes are used to execute the power flow convergence adjustment method in the power system maintenance mode of any embodiment of the present invention.

[0190] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0191] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0192] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0193] 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.

[0194] 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. The computer software product is stored in a storage medium, including 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, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0195] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for adjusting power flow convergence in a power system maintenance mode, characterized in that: include: Obtain network topology data of the power grid and determine at least one outage branch line that needs to be shut down for maintenance; For each of the outage branches, based on the network topology data, construct a first admittance matrix and a second admittance matrix of the complete network before the outage branch is shut down, and a third admittance matrix after the outage branch is shut down; Solve the minimum distance node with the minimum electrical distance of the out-of-service branch according to the first admittance matrix, and simultaneously select a preset number of maximum electrical distance nodes; Combining the second admittance matrix and the node with the minimum distance to sort the node power impact, to obtain a plurality of positive impact nodes and a plurality of negative impact nodes; Combining the third admittance matrix, the node with the smallest distance and each node with the largest electrical distance, the nodes with reactive compensation capabilities are sorted to obtain a plurality of reactive compensation nodes; Improve the reactive compensation capacity of each of the reactive compensation nodes, and recalculate the power flow. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, adjust the active output of the multiple positively impacted nodes to reduce the active output, and at the same time adjust the active output of the multiple negatively impacted nodes to increase the active output, so as to obtain the power flow convergence adjustment result.

2. The power flow convergence adjustment method according to claim 1, characterized in that: The network topology data includes N nodes and M branches of the power grid; based on the network topology data, constructing a first admittance matrix and a second admittance matrix of the complete network before shutting down the shut-down branch, and a third admittance matrix after shutting down the shut-down branch, including: Based on the N nodes, construct an N-dimensional complex matrix with an initial value of 0 ; Traverse the N nodes, when the node There is a branch to ground, and the equivalent impedance of the branch to ground is season The number of Increase ,get ; Traverse the M branches and define nodes With Node The equivalent impedance between ; Separate order The number of and Increase , number of Increase , number of Increase , obtain the first admittance matrix of the complete network before shutting down the shut-down branch ; Respectively The number of , , Set the real part of ; Separate order The number of and Increase , number of Increase , number of Increase , obtain the second admittance matrix of the complete network before shutting down the shut-down branch ; Traverse the branches of the M branches except the out-of-service branch and define the node With Node The equivalent impedance between ,get ; Respectively The number of , , Set the real part of ; Separate order The number of and Increase , number of Increase , number of Increase , obtain the third admittance matrix of the complete network after shutting down the shut-down branch .

3. The power flow convergence adjustment method according to claim 2, characterized in that: The out-of-service branch is the mth branch among the M branches, and the nodes connected to the mth branch are node s and node t respectively; solving the minimum distance node with the minimum electrical distance of the out-of-service branch according to the first admittance matrix, and screening out a preset number of maximum electrical distance nodes, includes: Set N-dimensional vector , The sth element in is 1.0, and the rest are 0; Set N-dimensional vector ; Based on the first admittance matrix , by solving Get the The value of Select the node whose absolute value is greater than 0 and whose numerical value corresponds to the smallest serial number from all the numerical values ​​as the minimum distance node with the smallest electrical distance of the outage branch; Regarding the All values ​​of are sorted from large to small according to their absolute values, and nodes corresponding to a preset number of serial numbers are selected from them in descending order as nodes with the largest electrical distance.

4. The power flow convergence adjustment method according to claim 3, characterized in that: The N nodes include S generator nodes; the node power impact sorting is performed in combination with the second admittance matrix and the node with the minimum distance to obtain a plurality of positive impact nodes and a plurality of negative impact nodes, including: Traverse the S generator nodes and set the N-dimensional vector , The cth element in is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0; Set N-dimensional vector ; Based on the second admittance matrix , by solving Get the The value of Let the node power affect ,in, , They are The sth and tth elements of is the reactance of the outage branch; Calculate the total number of generator nodes value, and set the The value is divided into multiple positive Values ​​and multiple negative value; According to the stated The value is in descending order for all The generator nodes with positive values ​​are sorted to obtain the positive impact nodes that are sorted from large to small in terms of the positive impact on node power when the outage branch is shut down; According to the negative The absolute value of the value is in descending order for all The generator nodes with negative values ​​are sorted to obtain the negative impact nodes that are sorted from large to small when the outage branch is shut down and the negative impact on the node power is brought about.

5. The power flow convergence adjustment method according to claim 4, characterized in that: The step of combining the third admittance matrix, the node with the smallest distance, and each node with the largest electrical distance to sort nodes with reactive compensation capabilities to obtain a plurality of reactive compensation nodes includes: Traverse each of the nodes with the largest electrical distance and set an N-dimensional vector , The cth element in is 1.0, the rth element corresponding to the node with the smallest distance is -1.0, and the rest are 0; Set N-dimensional vector ; Based on the third admittance matrix , by solving Get the The value of For each node c, compare the node c in the With the , and select the preset E nodes with the largest deviation values; The E nodes in each group selected are combined, and all nodes with reactive power compensation capability obtained after the combination are sorted in descending order according to the deviation value, so as to obtain reactive power compensation nodes whose voltage changes before and after the shutdown are sorted in descending order.

6. The power flow convergence adjustment method according to claim 5, characterized in that: The step of increasing the reactive power compensation capacity of each reactive power compensation node comprises: For each reactive power compensation node, when one or more groups of reactors have been put into use at the reactive power compensation node, reducing one group of reactors; When the reactive power compensation node has not previously been put into operation with a reactor, a group of capacitors is put into operation.

7. The power flow convergence adjustment method according to claim 4, characterized in that: The adjusting the active output of the plurality of positively impacted nodes to decrease based on the preset power target value and adjusting the active output of the plurality of negatively impacted nodes to increase include: For a first positive influence node ranked first among the multiple positive influence nodes, when it is determined that a first current output of the first positive influence node is greater than or equal to a preset power target value, the first current output is directly subtracted from the preset power target value to complete the active output reduction adjustment; When it is determined that the first current output of the first positively influential node is less than the preset power target value, the output of the first positively influential node is set to 0, and the difference between the first current output and the preset power target value is adjusted by the positively influential nodes other than the first positively influential node in accordance with the active output reduction adjustment method of the first positively influential node. For the first negatively impacting node ranked first among the multiple negatively impacting nodes, when it is determined that the difference between the maximum output of the first negatively impacting node and the second current output is greater than or equal to a preset power target value, the preset power target value is directly increased on the basis of the second current output to complete the active output increase adjustment; When it is determined that the difference between the maximum output of the first negatively impacted node and the second current output is less than a preset power target value, the output of the first negatively impacted node is adjusted to the maximum output, and the difference between the preset power target value and the maximum output is adjusted according to the active output increase adjustment method of the first negatively impacted node, and the negatively impacted nodes other than the first negatively impacted node perform subsequent active output increase adjustments.

8. The power flow convergence adjustment method according to any one of claims 1 to 7, characterized in that: Also includes: After the active power output adjustment is completed, the power flow calculation is re-performed based on the power flow convergence adjustment result; When the current power flow calculation result indicates that the power flow has converged, the adjustment is ended, and the power flow convergence adjustment result is used as the final operation mode.

9. The power flow convergence adjustment method according to claim 8, characterized in that: Also includes: When the current power flow calculation result indicates that the power flow is not converged, and the current adjustment cycle number has not reached the preset upper limit number, the power flow convergence adjustment result is used as the current operation mode, and the process is re-jumped to the reactive compensation capacity execution step of the reactive compensation node; When the current power flow calculation result indicates that the power flow does not converge, and the current adjustment cycle number reaches a preset upper limit number, the adjustment is stopped and an adjustment failure result is output.

10. A power flow convergence adjustment device in a power system maintenance mode, characterized in that: include: A data acquisition unit, used to acquire network topology data of the power grid and determine at least one outage branch that needs to be shut down for maintenance; An admittance matrix construction unit, for constructing, for each of the outage branches, a first admittance matrix and a second admittance matrix of the complete network before the outage branch is shut down, and a third admittance matrix after the outage branch is shut down, based on the network topology data; An electrical distance node solving unit, used for solving the minimum distance node with the minimum electrical distance of the out-of-service branch according to the first admittance matrix, and screening out a preset number of maximum electrical distance nodes; A node power impact ranking unit, used to perform node power impact ranking in combination with the second admittance matrix and the node with the minimum distance, to obtain a plurality of positively impacted nodes and a plurality of negatively impacted nodes; A reactive compensation capability node sorting unit, configured to sort reactive compensation capability nodes in combination with the third admittance matrix, the node with the smallest distance, and each node with the largest electrical distance, to obtain a plurality of reactive compensation nodes; The active output adjustment unit is used to increase the reactive compensation capacity of each reactive compensation node and recalculate the power flow. When the power flow calculation result indicates that the power flow does not converge, based on the preset power target value, the active output of the multiple positive impact nodes is reduced and the active output of the multiple negative impact nodes is increased to obtain the power flow convergence adjustment result.

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