Fixed value setting optimization method for automatic voltage control of power grid

Abstract

The invention relates to a fixed value setting optimization method for automatic voltage control of a power grid, which comprises the following steps of: respectively clustering and grouping voltage curves and power factor curves of buses in main transformers in the power grid according to reactive voltage characteristic change of the power grid to set AVC fixed values; according to the reactive power balance evaluation result, the bus voltage and the main transformer power factor of the transformer substation are corrected in a rolling manner, so that the system runs within a qualified range in a reactive power and voltage manner; according to the method, a fixed value setting mode is more flexible and more targeted, reactive voltage characteristics of different transformer substations can be better adapted, and a regulation target is more accurate; rolling correction and closed-loop regulation of a reactive voltage control constant value are realized, the reactive voltage regulation speed and regulation effect are improved, and reactive layered and partitioned in-situ balance is realized; dependence of reactive voltage control fixed value setting work on manpower is reduced, manpower resources are saved, real-time optimization of reactive voltage is achieved under the conditions of different time periods and different load characteristics, and optimal reactive voltage regulation is guaranteed at any time.

Description

Technical Field

[0001] The invention relates to the technical field of power systems, and in particular to a method for optimizing the setting of fixed values ​​for automatic voltage control of a power grid. Background Art

[0002] Automatic voltage control refers to the centralized monitoring and analysis of the reactive voltage status of the entire network, and the coordinated optimization control of the widely dispersed reactive power devices of the power grid from a global perspective. The existing automatic voltage control (AVC) system refers to a system in the power system that can automatically adjust the reactive power and voltage by setting the control target (AVC constant); the system obtains the real-time telemetry and telesignal quantity of the power grid through the data acquisition module in the dispatching control system, and according to the set AVC constant, with the goal of achieving voltage control and reactive power control, automatically adjusts the gear of each main transformer, and automatically switches the reactive power compensation device of each station. The AVC system will control the main transformer tap adjustment and switch the reactive power compensation device according to the set AVC control constant, so that the bus voltage changes toward the set voltage control constant, and the power factor changes toward the set power factor control constant.

[0003] The setting process of AVC constants in the prior art is as follows: first, the priority of voltage and reactive power adjustment is determined as voltage>reactive power>network loss; second, the constant setting principle is determined: a unified voltage limit and power factor limit are set for the substations of the entire network, or a special voltage limit and power factor limit are set for a certain substation, which can only be set manually; finally, the control target is set under the condition that the voltages at all levels are qualified and the network loss of the entire network is minimized; however, this setting method has the following defects: the set values ​​lack specificity, are overly dependent on manual operation experience, the constants are not accurate, and the adjustment effect is limited; and dynamic classification, group setting and rolling correction are not possible. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the problems in the prior art that the set values ​​lack specificity, rely too much on manual operating experience, have inaccurate set values, and have limited adjustment effects; and lack dynamic classification, group setting, and rolling correction functions.

[0005] In order to solve the above technical problems, the present invention provides a method for optimizing the setting of a fixed value for automatic voltage control of a power grid, comprising:

[0006] Obtain telemetry data of the power factor of each main transformer in the power grid and the voltage value of the busbars on each side of the main transformer; draw the busbar voltage curve on the high-voltage side, the busbar voltage curve on the medium-voltage side, the busbar voltage curve on the low-voltage side, and the power factor curve of each main transformer; extract the characteristic values ​​of the busbar voltage curves and power factor curves on each side of all main transformers respectively; cluster the busbar voltage curves and power factor curves on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer respectively according to the extracted curve characteristic values, and divide the busbar voltage curves and power factor curves on each side into multiple groups;

[0007] According to the clustering results of the bus voltage curves on each side, the upper and lower limits of the AVC voltage control in each time period are set for each group of transformers respectively: the upper limit of the AVC voltage control in the current time period of the group is set according to the relationship between the average value of the curve voltage maximum value in the current time period of the group and the preset voltage safety operation upper limit value, as well as the voltage reduction rate; the lower limit of the AVC voltage control in the current time period of the group is set according to the relationship between the average value of the curve voltage minimum value in the current time period of the group and the preset voltage safety operation lower limit value, as well as the voltage increase rate;

[0008] According to the clustering results of the power factor curve, the upper and lower limits of the AVC power factor control in each time period are set for each group of transformers respectively: according to the relationship between the average value of the maximum power factor of the group in the current time period and the preset upper limit of the safe operation power factor, as well as the power factor down-regulation rate, the upper limit of the AVC power factor control in the current time period of the group is set; according to the relationship between the average value of the minimum power factor in the current time period of the group and the preset lower limit of the safe operation power factor, as well as the power factor up-regulation rate, the lower limit of the AVC power factor control in the current time period of the group is set;

[0009] According to the clustering results and the above process, the setting of AVC control constants of each main transformer in the power grid is completed.

[0010] In one embodiment of the present invention, reactive power balance in different dimensions is calculated based on the node dimension, the regional dimension, and the voltage level dimension respectively; after adjusting the voltage increase rate, the voltage decrease rate, the power factor increase rate, and the power factor decrease rate according to the reactive power balance amount, the AVC control setting of each transformer of the power grid is re-optimized, specifically including:

[0011] In the node dimension, the real-time value of reactive power on the high-voltage side of the current main transformer is collected, which is the net reactive value of the current main transformer node; according to the real-time value of active power on the high-voltage side of the current main transformer, combined with the reasonable power factor range, the reasonable maximum and minimum values ​​of reactive power are calculated; according to the relationship between the reasonable maximum and minimum values ​​of reactive power and the real-time value of reactive power on the high-voltage side of the current main transformer, the reactive balance amount in the node dimension is calculated; according to the evaluation result of reactive balance amount in the node dimension, after adjusting the voltage increase rate, voltage increase rate, power factor decrease rate, and power factor increase rate, the AVC control setting of the transformer in the current substation is re-optimized;

[0012] In the regional dimension, the real-time reactive power values ​​of all tie lines between multiple substations in the region and adjacent regions are collected, and the sum is the net reactive value of the region; the reasonable maximum and minimum reactive power values ​​of the region are calculated based on the sum of the real-time active power values ​​of all tie lines and the reasonable power factor range; the reactive balance of the regional dimension is calculated based on the relationship between the reasonable maximum and minimum reactive power values ​​of the region and the net reactive value of the region; according to the evaluation results of the reactive balance of the regional dimension, the voltage increase rate, voltage increase rate, power factor decrease rate, and power factor increase rate are adjusted, and the AVC control constants of the corresponding transformers of multiple substations in the region are re-optimized;

[0013] In the voltage level dimension, considering the current voltage level in the area, the real-time active power value and reactive power value of the current voltage level side line incoming switches corresponding to all main transformers in the area are collected, and their sum is calculated respectively; combined with the reasonable power factor range, the reasonable maximum and minimum reactive power values ​​at the voltage level are calculated; according to the relationship between the reasonable maximum and minimum reactive power values ​​at the voltage level and the sum of the reactive power of the current voltage level side line incoming switches corresponding to all main transformers in the area, the reactive balance amount in the voltage level dimension is calculated; according to the evaluation result of the reactive balance amount in the voltage level dimension, after adjusting the voltage increase rate, voltage increase rate, power factor decrease rate, and power factor increase rate, the AVC control constants of the current voltage level of the transformers corresponding to multiple substations in the area are re-optimized.

[0014] In one embodiment of the present invention, the power factor of each main transformer in the power grid and the voltage value telemetry data of the busbars on each side of the main transformer are obtained; the high-voltage side busbar voltage curve, the medium-voltage side busbar voltage curve, the low-voltage side busbar voltage curve and the power factor curve of each main transformer are drawn; and the characteristic values ​​of the busbar voltage curves and the power factor curves on each side of all main transformers are respectively extracted, including:

[0015] According to the reactive voltage analysis and control requirements, analyze the power factor of the main transformer and the voltage telemetry data of the busbars on each side of the main transformer over time; take the main transformer as the minimum analysis node, extract the daily 96-point curve of the power factor, the daily 96-point curve of the high-voltage side busbar voltage, the daily 96-point curve of the medium-voltage side busbar voltage, and the daily 96-point curve of the low-voltage side busbar voltage for each main transformer;

[0016] For the power factor curve of each main transformer, extract and calculate the characteristic values: minimum power factor, the time corresponding to the minimum power factor; maximum power factor, the time corresponding to the maximum power factor; maximum reactive power feed, the time corresponding to the maximum reactive power feed, and the duration of reactive power feed;

[0017] For the bus voltage curves on each side of each main transformer, the characteristic values ​​are extracted and calculated: the maximum value of the curve, the corresponding time of the maximum value of the curve; the minimum value of the curve, the corresponding time of the minimum value of the curve; the extreme value of the curve change rate, the corresponding time of the extreme value of the curve change rate.

[0018] In one embodiment of the present invention, according to the extracted curve characteristic values, the bus voltage curves and power factor curves on the high voltage side, low voltage side and medium voltage side of the main transformer are clustered respectively, and the bus voltage curves and power factor curves on each side are divided into multiple groups, including:

[0019] Set each bus voltage curve at T1, T2,... n-1 The voltage levels of adjacent time intervals are quite different, and the separation time values ​​of different voltage curves are T1, T2, etc. n-1 and the interval number n are different, T1, T2, T n-1 and bus voltage curves with similar n values ​​are grouped into the same group; compare the maximum and minimum values ​​of the bus voltage curves of the current voltage level of all main transformers, and group the bus voltage curves with similar maximum and minimum values ​​into the same group; the grouping of bus voltage curves is realized by using k-means clustering algorithm; after the clustering of this part is completed, the bus voltages on the high-voltage side, low-voltage side and medium-voltage side of the main transformer are divided into N1, N2, and N3 groups respectively, where the values ​​of N1, N2, and N3 can be specified by the number of main transformers; the clustering results of the bus voltage characteristics on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer are expressed in numerical form, which are recorded as u0, u1, and u2 respectively; where u0∈[0,1,2,...,N1], u1∈[0,1,2,...,N2], and u2∈[0,1,2,...,N3];

[0020] The power factor curves of all main transformers are adjusted at T'1, T'2,...T' m-1The power factor values ​​of adjacent time intervals are greatly different, and the separation time values ​​of different power factor curves are T'1, T'2, ······T' m-1 and the interval number m are different, T'1, T'2...T' m-1 The main transformer power factor curves with similar m values ​​are grouped into the same group; the maximum and minimum values ​​of all main transformer power factor curves are compared, and the main transformer power factor curves with similar maximum and minimum values ​​are grouped into the same group; the grouping of the main transformer power factor curves is achieved by using the k-means clustering algorithm; that is, after the clustering of this part is completed, the power curves are divided into N4 groups according to the characteristics, where the value of N4 can be specified by the number of main transformers; the clustering results of the main transformer power factor characteristics are expressed in numerical form, recorded as q; where q∈[0,1,2,...,N4].

[0021] In one embodiment of the present invention, after clustering the bus voltage curves and power factor curves on the high voltage side, low voltage side, and medium voltage side of the main transformer, the clustering results of the voltage and power factor of each main transformer include:

[0022] For main transformer i, the clustering results of the overall characteristics of its voltage and power factor are expressed as an array:

[0023] W i =[u0,u1,u2,q]

[0024] Among them, W i It means that after clustering and grouping, the high-voltage side voltage characteristics of the main transformer i are group u0, the low-voltage side voltage characteristics are group u1, the medium-voltage side voltage characteristics are group u2, and the power factor characteristics are group q; if the main transformer is a two-turn transformer, which only has a high-voltage side and a low-voltage side, the corresponding medium-voltage side voltage clustering result is set to 0, that is, u2=0.

[0025] In one embodiment of the present invention, according to the clustering results of the bus voltage curves on each side, the AVC voltage control upper and lower limits in each time period are set for each group of transformers respectively: according to the relationship between the average value of the curve voltage maximum value in the current time period of the group and the preset voltage safety operation upper limit value, and the voltage reduction rate, the AVC voltage control upper limit value in the current time period of the group is set; according to the relationship between the average value of the curve voltage minimum value in the current time period of the group and the preset voltage safety operation lower limit value, and the voltage increase rate, the AVC voltage control lower limit value in the current time period of the group is set, including:

[0026] According to the safety regulations, set the voltage safe operation upper limit value U sf,max , Voltage safe operation lower limit U sf,min ; Setting bus voltage control constants includes:

[0027] For the voltage curve of a certain voltage level after clustering, each group sets the upper and lower limit values ​​of voltage control in different time periods;

[0028] Voltage control upper limit setting: For time period k, the average value of the voltage maximum value of this group of curves in time period k is recorded as U k,vmax ;if U k,vmax >U sf,Umax , then the voltage upper limit of this group of curves in period k is set to U kmax =U sf,Umax -(U k,vmax -U sf,max )×E u,down , where E u,down is the voltage reduction rate, which is between 100% and 1%. If the voltage needs to be reduced to the maximum extent, then E u,down Take 100%; if U k,vmax ≤U sf,max , then the voltage upper limit of this group of curves in the k period is set to U kmax =U sf,max ; Among them, the time interval corresponding to the k period is T K-1 To T K Between K-1 , T K ∈[T1, T2······T n-1 ];

[0029] Voltage control lower limit setting: For time period k, the average value of the minimum voltage of this group of curves in time period k is recorded as U k,vmin ;if U k,vmin sf,min , then the voltage upper limit of this group of curves in the k period is set to U kmin =U sf,min +(U sf,min -U k,vmin )×E u,up , where E u,up is the voltage increase rate, which is between 1% and 100%. If the voltage needs to be increased to the maximum extent, then E u,up Take 100%; if U k,vmin ≥U sf,min , then the voltage upper limit of this group of curves in the k period is set to U kmin =U sf,min ; Among them, the time interval corresponding to the k period is T K-1 To T K Between K-1 , T K ∈[T1, T2······T n-1 ]; ​

[0030] In summary, for a group w after clustering the bus voltage curve of a certain voltage level, the AVC voltage control constant setting is expressed as a 3*N dimensional matrix:

[0031]

[0032] Among them, T N ∈[T1, T2······T n-1 ]; The first row of the matrix represents the time segment separation moment, the second row is the voltage upper limit value corresponding to each time segment, and the third row is the voltage lower limit value corresponding to each time segment.

[0033] In one embodiment of the present invention, according to the clustering result of the power factor curve, the AVC power factor control upper and lower limits in each time period are set for each group of transformers respectively: according to the relationship between the average value of the maximum power factor in the current time period of the group and the preset safe operation power factor upper limit, and the power factor down-regulation rate, the AVC power factor control upper limit in the current time period of the group is set; according to the relationship between the average value of the minimum power factor in the current time period of the group and the preset safe operation power factor lower limit, and the power factor up-regulation rate, the AVC power factor control lower limit in the current time period of the group is set, including:

[0034] According to the safety regulations, set the upper limit of the safe operation power factor Safe operation power factor lower limit The groups for setting AVC power factor control settings include:

[0035] Power factor control upper limit setting: For time period k, the average value of the maximum power factor of this group of curves in time period k is recorded as like Then the upper limit of the power factor of this group of curves in the k period is set to Among them, E c,down is the power factor reduction rate, which is between 100% and 1%. If the power factor needs to be reduced to the maximum extent, then E c,down Take 100%; if The power upper limit value of this group of curves in the time period is set to

[0036] Power factor control lower limit setting: For time period k, the average value of the minimum power factor of this group of curves in time period k is recorded as like The lower limit of the power factor of this group of curves in period k is set to Among them, E c,up is the power factor increase rate, Ec,up Its value is between 1% and 100%. If the power factor needs to be adjusted to the maximum extent, then E c,up Take 100%; if The lower limit of the power factor of this group of curves in the period is set to

[0037] In summary, the clustering of the main transformer power factor curves into groups v, where the AVC power factor control constant setting is expressed as a 3*M dimensional matrix:

[0038]

[0039] Among them, T M ∈[T'1, T'2······T' m-1 ]; The first row of the matrix represents the time of time segmentation, the second row represents the upper limit of the power factor corresponding to each time segment, and the third row represents the lower limit of the power factor corresponding to each time segment.

[0040] In one embodiment of the present invention, the reactive balance amount in the node dimension is calculated; after adjusting the voltage increase rate, the voltage decrease rate, the power factor increase rate, and the power factor decrease rate according to the reactive balance amount, the AVC control setting of the main transformer in the substation is re-optimized, including:

[0041] In the node dimension, the real-time value of reactive power Q on the high-voltage side of the main transformer in the current substation is collected. i , this value is the net reactive power value of the current main transformer node; when the reactive power flows from the high-voltage busbar to the main transformer itself, the reactive power and active power directions are the same, which means that the reactive power flow direction is reasonable; when the reactive power flows from the main transformer itself to the high-voltage busbar, it means that the reactive power of this node is abundant, and the abundant reactive power is reversed from the low voltage level to the high voltage level;

[0042] According to the real-time value of active power P on the high-voltage side i , Reasonable power factor Range, calculate the reasonable value range of reactive power [Q st.imin ,Q st.imax ]; its calculation formula is

[0043]

[0044] Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.imax =0.29P i , Q st.imin =0.25P i ;

[0045] Reactive balance Q of the node corresponding to the main transformer i bs,i The calculation method is:

[0046] (1) If Q st,imin ≤Q i ≤Q st,imax , Q bs,i =0; the power factor is reasonable, and the reactive power of the node is balanced locally;

[0047] (2) If Q i >Q st,imax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs,i =Q i -Q st,imax , the value is greater than 0, indicating that the node has a capacitive reactive power shortage; then the voltage increase rate E in the AVC setting of the group involved in the node is u,up , power factor increase rate E c,up If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding node will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation;

[0048] (3) If Q i st,imin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs,i =Q i -Q st,imin , the value is less than 0, and its absolute value represents the capacitive reactive surplus of the node; then the voltage reduction rate E in the AVC setting of the group involved in the node is u,down , Power factor reduction rate E c,down If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding node will be to invest more inductive reactive power compensation devices; wherein the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generators, and generator leading phase operation.

[0049] In one embodiment of the present invention, the reactive balance amount in the regional dimension is calculated; after adjusting the voltage increase rate, the voltage decrease rate, the power factor increase rate, and the power factor decrease rate according to the reactive balance amount, the AVC control setting values ​​of the main transformers corresponding to the multiple substations in the region are re-optimized, including:

[0050] In the regional dimension, the real-time values ​​of active power and reactive power of all tie lines between multiple substations in the region and adjacent regions are collected; the sum of the real-time values ​​of reactive power of all tie lines between the region and adjacent regions ∑Q li , which is the net reactive power value of the area; the sum of the real-time active power values ​​of all tie lines ∑P li , which is the net active value of the area;​

[0051] According to the sum of the real-time values ​​of active power of all tie lines ∑P li , Reasonable power factor Range, calculate the reasonable reactive power value range of the area [Q st,limin ,Q st,limax ], and its calculation formula is

[0052]

[0053] Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.limax =0.29∑P li , Q st.limin =0.25∑P li ;

[0054] The reactive balance Q in this area li bs,li The calculation method is:

[0055] (1) If Q st,limin ≤∑Q li ≤Q st,limax , Q bs,li =0; the power factor is reasonable and the reactive power in this area is balanced locally;

[0056] (2) If ∑Q li >Q st,limax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs,li =∑Q li -Q st,limax , the value is greater than 0, indicating the capacitive reactive power shortage in the area; the voltage increase rate E in the AVC setting of the group involved in the area u,up , power factor increase rate E c,up If the value of is set larger, i.e. close to 100%, the adjustment result of the area will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation;

[0057] (3) If ∑Q li st,limin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs,li =∑Q li -Q st,limin , the value is less than 0, and its absolute value represents the capacitive reactive power surplus of the area; the voltage reduction rate E in the AVC setting of the group involved in the area u,down , Power factor reduction rate E c,down ​If the value of is set larger, i.e. close to 100%, the adjustment result of this area will be to invest more inductive reactive power compensation devices; wherein, the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generation, and generator leading phase operation.

[0058] In one embodiment of the present invention, the reactive balance amount under the voltage level dimension is calculated; after adjusting the voltage increase rate, the voltage decrease rate, the power factor increase rate, and the power factor decrease rate according to the reactive balance amount, the AVC control setting of the current voltage level of the transformer corresponding to the multiple substations in the area is re-optimized, including:

[0059] In the voltage level dimension, considering the current voltage level in the area, the real-time active power and reactive power values ​​of the current voltage level side line incoming switches of all main transformers in the area are collected; the sum of the real-time active power values ​​of the voltage level side incoming switches of all main transformers in the area is recorded as ∑P vi The sum of the real-time values ​​of reactive power is recorded as ∑Q vi ;

[0060] According to the sum of the real-time values ​​of active power of all tie lines ∑P vi , Reasonable power factor Range, calculate the reasonable reactive value range at the voltage level [Q st,vimin ,Q st,vimax ], and its calculation formula is

[0061]

[0062] Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.vimax =0.29∑P vi , Q st.vimin =0.25∑P vi ;

[0063] Reactive power balance Q at voltage level vi bs,vi The calculation method is:

[0064] (1) If Q st,vimin ≤∑Q li ≤Q st,vimin , Q bs,vi =0; the power factor is reasonable, and the reactive power is balanced locally at this voltage level;

[0065] (2) If ∑Q vi >W st,vimax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs,vi =∑Q vi -Qst,vimax , the value is greater than 0, indicating the capacitive reactive power shortage at the voltage level; the voltage increase rate E in the AVC setting of the group involved in the current voltage level is u,up , power factor increase rate E c,up If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding area will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation;

[0066] (3) If ∑Q vi st,vimin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs,vi =∑Q vi -Q st,vimin , the value is less than 0, and the absolute value represents the capacitive reactive surplus at the voltage level; the voltage reduction rate E in the AVC setting of the group involved in the current voltage level is u,down , Power factor reduction rate E c,down If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding area will be to invest more inductive reactive power compensation devices; wherein the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generators, and generator leading phase operation.

[0067] The above technical solution of the present invention has the following advantages compared with the prior art:

[0068] (1) The method for optimizing the setting of fixed values ​​for automatic voltage control of a power grid described in the present invention can automatically group substation main transformers with similar reactive voltage characteristics, and set different control targets and limits for different groups; this makes the setting of fixed values ​​more flexible, more targeted, and more adaptable to the reactive voltage characteristics of different substations, thereby making the adjustment target more accurate;

[0069] (2) The method for optimizing the setting of the fixed value of automatic voltage control of a power grid described in the present invention can automatically analyze the balance of the total reactive power of the power grid in layers and zones, calculate the reactive power shortage or reactive power surplus of each node, each region, and each voltage level in real time, and optimize and correct the AVC strategy of the unbalanced node and the region where it is located; thereby realizing the rolling correction and closed-loop regulation of the reactive voltage control fixed value, improving the reactive voltage regulation speed and regulation effect, and realizing the reactive power layered and zoned local balance;

[0070] ​(3) The method for optimizing the constant value setting of automatic voltage control of a power grid described in the present invention performs rolling correction and automatic execution of the AVC voltage control strategy and the reactive control strategy according to the changes in the reactive characteristics of each power grid partition; thereby reducing the dependence on manual work for setting the reactive voltage control constant value, saving human resources, and achieving real-time optimization of reactive voltage under different time periods and different load characteristics, thereby ensuring optimal reactive voltage regulation at all times and improving the reactive voltage qualification rate of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0072] Figure 1 It is a schematic diagram of the basic operating principle of the automatic voltage control provided by the present invention;

[0073] Figure 2 It is a flow chart of a method for optimizing the setting of a fixed value for automatic voltage control of a power grid provided by the present invention;

[0074] Figure 3 It is a daily 96-point curve diagram of the high-voltage side voltage of the A main transformer provided by the present invention;

[0075] Figure 4 It is a daily 96-point curve diagram of the high-voltage side voltage of the B main transformer provided by the present invention;

[0076] Figure 5 It is a daily 96-point curve diagram of the power factor of the C main transformer provided by the present invention;

[0077] Figure 6 It is a daily 96-point curve diagram of the power factor of the D main transformer provided by the present invention;

[0078] Figure 7 It is a schematic diagram of a fixed value setting optimization system for automatic voltage control of a power grid provided by the present invention. DETAILED DESCRIPTION

[0079] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0080] The AVC system obtains the real-time telemetry and teleinformation of the power grid through the data acquisition module in the dispatching control system. According to the set AVC constant value, the gear of each main transformer is automatically adjusted, and the reactive compensation device (capacitor, reactor, SVG) of each substation is automatically switched on and off. The basic operating principle of automatic voltage control can be referred to Figure 1 shown.

[0081] Example 1

[0082] Reference Figure 2 As shown, a flowchart of a method for optimizing the constant value setting of automatic voltage control of a power grid provided by the present invention; the specific steps are as follows:

[0083] Step 1: According to the reactive voltage analysis and control requirements, analyze the power factor of the main transformer and the voltage telemetry data of the busbars on each side of the main transformer over time; take the main transformer as the minimum analysis node, and extract the daily 96-point curve of the power factor, the 96-point curve of the high-voltage side busbar voltage, the daily 96-point curve of the medium-voltage side busbar voltage, and the daily 96-point curve of the low-voltage side busbar voltage for each main transformer;

[0084] For the power factor curve of each main transformer, extract and calculate the characteristic values: minimum power factor, the time corresponding to the minimum power factor; maximum power factor, the time corresponding to the maximum power factor; maximum reactive power feed, the time corresponding to the maximum reactive power feed, and the duration of reactive power feed;

[0085] For the bus voltage curves on each side of each main transformer, extract and calculate the characteristic values: curve maximum, the time corresponding to the curve maximum; curve minimum, the time corresponding to the curve minimum; curve change rate extreme value, the time corresponding to the curve change rate extreme value;

[0086] Step 2: Cluster the bus voltage curves and power factor curves on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer according to the extracted curve characteristic values, and divide the bus voltage curves and power factor curves on each side into multiple groups;

[0087] Among them, the implementation principle of the k-means clustering algorithm is:

[0088] a. Each curve has an array of its multiple eigenvalues ​​as its "curve feature points";

[0089] b. Set the massive amount of "curve feature points" to be divided into several groups, assuming they are divided into N groups;

[0090] c. Randomly initialize the "center point" of each group among a large number of "curve feature points" to obtain N "initial center points";

[0091] d. Calculate the distance from each "curve feature point" to the "center point", and divide the "curve feature point" into the group to which the "center point" is closer;

[0092] e. Recalculate the "center point" of each group as the "latest center point" of the group;

[0093] f. Repeat the above steps until the difference in the change of the "latest center point" of each group in subsequent iterations is less than the set value;

[0094] The above clustering method is applied to group the curves, and the curves with similar characteristics are divided into the same group; the k-means clustering algorithm is used to cluster the bus voltages on the high-voltage side, low-voltage side and medium-voltage side of the main transformer, and they are divided into N1, N2, and N3 groups respectively, and the values ​​of N1, N2, and N3 are specified by the number of main transformers; among them, the time variation law of the voltage on each side of the main transformer in each group is similar, and the similarity is reflected in that each group of curves can be clustered at T1, T2······T n-1 The time intervals are separated at the same time and divided into n time intervals, and the voltage level difference between adjacent time intervals is large; the maximum value (highest voltage) of each curve in each group is close, and the minimum value (lowest voltage) of each curve in each group is close; the clustering results of the bus voltage characteristics on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer are expressed in numerical form, which are recorded as u0, u1, and u2 respectively; among them, u0∈[0,1,2,...,N1], u1∈[0,1,2,...,N2], u2∈[0,1,2,...,N3];

[0095] The k-means clustering algorithm is used to cluster the power factor curves of the main transformers. The power curves are divided into N4 groups according to their characteristics, and the value of N4 is specified by the number of main transformers. The characteristics of the curves of the power factor of the main transformers over time in each group are similar. The similarity is reflected in the following aspects: each group of curves can be clustered at T'1, T'2······T' m-1 The time intervals are separated into m time intervals, and the power factor values ​​between adjacent time intervals are relatively different; the maximum values ​​(highest power factor) of each group of curves are close, and the minimum values ​​(lowest power factor) of each group of curves are close; if reactive power is reversed, the power factor is directly taken as 1; the clustering results of the power factor characteristics of the main transformer are expressed in numerical form, respectively denoted as q; where q∈[0,1,2,...,N4];

[0096] For main transformer i, the clustering results of the overall characteristics of its voltage and power factor are expressed as an array:

[0097] W i =[u0,u1,u2,q]

[0098] Among them, W iIt means that after clustering and grouping, the high-voltage side voltage characteristics of the main transformer i are group u0, the low-voltage side voltage characteristics are group u1, the medium-voltage side voltage characteristics are group u2, and the power factor characteristics are group q; if the main transformer is a two-turn transformer, which only has a high-voltage side and a low-voltage side, the corresponding medium-voltage side voltage clustering result is set to 0, that is, u2 = 0;

[0099] Step 3: According to the clustering results of the bus voltage curves and power factors on each side, set the AVC voltage control upper and lower limits and AVC power factor control upper and lower limits in each time period for each group of transformers:

[0100] According to the safety regulations, set the voltage safe operation upper limit value U sf,max , Voltage safe operation lower limit U sf,min ; Setting the bus voltage control constants on each side of AVC includes:

[0101] For the voltage curve of a certain voltage level after clustering, each group sets the upper and lower limit values ​​of voltage control in different time periods;

[0102] Voltage control upper limit setting: For time period k, the average value of the voltage maximum value of this group of curves in time period k is recorded as U k,vmax ;if U k,vmax >U st,max , then the voltage upper limit of this group of curves in the k period is set to U kmax =U sf,max -(U k,vmax -U sf,max )×E u,down , where E u,down is the voltage reduction rate, which is between 100% and 1%. If the voltage needs to be reduced to the maximum extent, then E u,dowm Take 100%; if U k,vmax ≤U sf,max , then the voltage upper limit of this group of curves in the k period is set to U kmax =U sf,max ; Among them, the time interval corresponding to the k period is T K-1 To T K Between, T K-1 、T K ∈[T1, T2······T n-1 ];

[0103] Voltage control lower limit setting: For time period k, the average value of the minimum voltage of this group of curves in time period k is recorded as U k,vmin ;if U k,vmin sf,min , then the voltage upper limit of this group of curves in the k period is set to U kmin =U sf,min +(U​sf,min -U k,vmin )×E u,up , where E u,up is the voltage increase rate, which is between 1% and 100%. If the voltage needs to be increased to the maximum extent, then E u,up Take 100%; if U k,vmin ≥U sf,min , then the voltage upper limit of this group of curves in the k period is set to U kmin =U sf,min ; Among them, the time interval corresponding to the k period is T K-1 To T K Between, T K-1 、T K ∈[T1, T2······T n-1 ];

[0104] In summary, for a group w after clustering the bus voltage curve of a certain voltage level, the AVC voltage control constant setting is expressed as a 3*N dimensional matrix:

[0105]

[0106] Among them, T N ∈[T1, T2······T n-1 ]; The first row of the matrix represents the time interval, the second row is the voltage upper limit corresponding to each time period, and the third row is the voltage lower limit corresponding to each time period;

[0107] According to the safety regulations, set the upper limit of the safe operation power factor Safe operation power factor lower limit Setting the AVC power factor control settings includes:

[0108] Power factor control upper limit setting: For time period k, the average value of the maximum power factor of this group of curves in time period k is recorded as like Then the upper limit of the power factor of this group of curves in the k period is set to Among them, E c,down is the power factor reduction rate, which is between 100% and 1%. If the power factor needs to be reduced to the maximum extent, then E c,down Take 100%; if The power upper limit value of this group of curves in the time period is set to

[0109] Power factor control lower limit setting: For time period k, the average value of the minimum power factor of this group of curves in time period k is recorded as like The lower limit of the power factor of this group of curves in period k is set to Among them, E c,up is the power factor increase rate, E c,yp Its value is between 1% and 100%. If the power factor needs to be adjusted to the maximum extent, then E c,yp Take 100%; if The lower limit of the power factor of this group of curves in the period is set to

[0110] In summary, the clustering of the main transformer power factor curves into groups v, where the AVC power factor control constant setting is expressed as a 3*M dimensional matrix:

[0111]

[0112] Among them, T M ∈[T'1, T'2······T' m-1 ]; The first row of the matrix represents the time of time segmentation, the second row represents the upper limit of the power factor corresponding to each time segment, and the third row represents the lower limit of the power factor corresponding to each time segment;

[0113] According to the clustering grouping results W of the reactive power and voltage characteristics of the main transformer i i =[u0,u1,u2,q], according to the above setting steps, set the bus voltages on the high-voltage side, low-voltage side and medium-voltage side of the main transformer and set the power factor of the main transformer.

[0114] Step 4: The layered and zoned reactive power balance assessment is divided into three dimensions: node dimension, regional dimension, and voltage level dimension. The node dimension is the substation dimension, including:

[0115] (1) In the node dimension, collect the real-time value of reactive power Q on the high-voltage side of the main transformer in the current substation i , this value is the net reactive power value of the current main transformer node; when the reactive power flows from the high-voltage busbar to the main transformer itself, the reactive power and active power directions are the same, which means that the reactive power flow direction is reasonable; when the reactive power flows from the main transformer itself to the high-voltage busbar, it means that the reactive power of this node is abundant, and the abundant reactive power is reversed from the low voltage level to the high voltage level;

[0116] According to the real-time value of active power P on the high-voltage side i , Reasonable power factor Range, calculate the reasonable value range of reactive power [Q st.imin ,Q st.imax ]; its calculation formula is

[0117]

[0118] Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.imax =0.29P i , Q st.imin =0.25P i ;

[0119] Reactive balance Q of the node corresponding to the main transformer i bs,i The calculation method is:

[0120] If Q st,imin ≤Q i ≤Q st,imax , Q bs,i =0; the power factor is reasonable, and the reactive power of the node is balanced locally;

[0121] If Q i >Q st,imax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs,i =Q i -Q st,imax , the value is greater than 0, indicating the capacitive reactive power shortage of the node;

[0122] If Q i st,imin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs,i =Q i -Q st,imin , the value is less than 0, and its absolute value represents the capacitive reactive power surplus of the node;

[0123] (2) In the regional dimension, the real-time values ​​of active power and reactive power of all tie lines between multiple substations in the region and adjacent regions are collected; the sum of the real-time values ​​of reactive power of all tie lines between the region and adjacent regions ∑Q li , which is the net reactive power value of the area; the sum of the real-time active power values ​​of all tie lines ∑P li , which is the net active value of the area;

[0124] According to the sum of the real-time values ​​of active power of all tie lines ∑P li , Reasonable power factor Range, calculate the reasonable reactive power value range of the area [Q st,limin ,Q st,limax ], and its calculation formula is

[0125]

[0126] Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.limax ​=0.29∑P li , Q st.limin =0.25∑P li ;

[0127] The reactive balance Q in this area li bs,li The calculation method is:

[0128] If Q st,limin ≤∑Q li ≤Q st,limax , Q bs,li =0; the power factor is reasonable and the reactive power in this area is balanced locally;

[0129] If ∑Q li >Q st,limax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs,li =∑Q li -Q st,limax , the value is greater than 0, indicating that the capacitive reactive power shortage in the area;

[0130] If ∑Q li st,limin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs,li =∑Q li -Q st,limin , the value is less than 0, and its absolute value represents the capacitive reactive power surplus in the area;

[0131] (3) In the voltage level dimension, considering the current voltage level in the area, the real-time active power and reactive power values ​​of the current voltage level side line incoming switches of all main transformers in the area are collected; the sum of the real-time active power values ​​of the voltage level side incoming switches of all main transformers in the area is recorded as ∑P vi The sum of the real-time values ​​of reactive power is recorded as ∑Q vi ;

[0132] According to the sum of the real-time values ​​of active power of all tie lines ∑P vi , Reasonable power factor Range, calculate the reasonable reactive value range at the voltage level [Q st,vimin ,Q st,vimax ], and its calculation formula is

[0133]

[0134] Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.vimax =0.29∑P vi , Q st.vimin ​=0.25∑P vi ;

[0135] Reactive power balance Q at voltage level vi bs,vi The calculation method is:

[0136] If Q st,vimin ≤∑Q li ≤Q st,vimax , Q bs,vi =0; the power factor is reasonable, and the reactive power is balanced locally at this voltage level;

[0137] If ∑Q vi >Q at,vimax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs,vi =∑Q vi -Q st,vimax , the value is greater than 0, indicating the capacitive reactive power shortage at the voltage level;

[0138] If ∑Q vi st,vimin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs,vi =∑Q vi -Q st,vimin , the value is less than 0, and the absolute value represents the capacitive reactive surplus at the voltage level;

[0139] In the reactive balance assessment process, all data are collected by the dispatch control system;

[0140] According to the reactive power balance in different dimensions, the voltage increase rate, voltage decrease rate, power factor increase rate, and power factor decrease rate are adjusted, and the AVC control setting of each transformer in the power grid is re-optimized, including:

[0141] For nodes, regions, and voltage levels where capacitive reactive power is insufficient, that is, Q bs,i , Q bs,li , Q bs,vi When the calculated result is greater than 0, the voltage increase rate E in the AVC setting of the group involved in the above nodes, regions, and voltage levels is u,up , power factor increase rate E c,up If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding area and node will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation;

[0142] For nodes, regions, and voltage levels with abundant capacitive reactive power, that is, Q bs,i , Q bs,li ​, Q bs,vi When the calculated result is less than 0, the voltage reduction rate E in the AVC setting of the group involved in the above nodes, regions, and voltage levels is u,down , Power factor reduction rate E c,down If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding area and node will be to invest more inductive reactive power compensation devices; wherein the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generation, and generator leading phase operation.

[0143] Example 2

[0144] Based on the above embodiments, in this embodiment, refer to Figure 3-6 , the division of curves with similar characteristics into the same group in step 2 above is illustrated as follows:

[0145] Figure 3 , 4 The high-voltage side voltage curves are classified into the same group after clustering. It can be seen in the figure that the 96-point curves of the high-voltage side voltage of the main transformers A and B are divided into three time periods by T1=08:00 and T2=20:00. The maximum voltage values ​​are between 236.5 and 237.5 kV, and the minimum voltage values ​​are between 233 and 233.5 kV, which means that the bus voltages on the high-voltage sides of the main transformers A and B have similar time-varying patterns and are classified into the same group.

[0146] Figure 5 , 6 The power factor curves are classified into different groups after clustering. It can be seen from the figure that the 96-point curve of the power factor of the main transformer C can be divided into three time periods by T1 = 07:30 and T2 = 23:00, and the power factor fluctuates between 0.94 and 0.99 throughout the day; the 96-point curve of the power factor of the main transformer D can be divided into five time periods by T1 = 03:00, T2 = 04:50, T3 = 08:30, and T4 = 20:30, and the power factor fluctuates between 0.97 and 0.995 throughout the day. The power factors of the main transformers C and D change differently over time, and even have opposite trends, and are divided into two different groups.

[0147] Example 3

[0148] Refer to Figure 7 As shown, a schematic diagram of an optimization system for setting a fixed value of automatic voltage control AVC of a city power grid provided by the present invention; specifically comprising:

[0149] Data extraction module: extracts the main transformer active power, reactive power, voltage, power factor and other operating data curves from the dispatching control system, and extracts the curve characteristic values ​​for AVC constant value calculation and reactive power balance calculation;

[0150] Characteristic clustering module: cluster analysis is performed on the curves of bus voltage and power factor changes over time on the high-voltage side, medium-voltage side, and low-voltage side of each main transformer, and curves with similar reactive voltage characteristics are divided into the same group;

[0151] Fixed value setting module: according to the grouping situation after clustering, AVC fixed value setting is performed in groups, and different AVC control fixed values ​​are specified for different groups;

[0152] Reactive balance assessment and constant value correction module: Real-time calculation of reactive balance of each main transformer, each area, and each voltage level, and correction of AVC control constant value according to reactive power shortage or reactive power surplus to make reactive power voltage level operate within a reasonable range;

[0153] The optimization system of this embodiment is used to implement the aforementioned constant value setting optimization method for automatic voltage control of the power grid. Therefore, the specific implementation method of the constant value setting optimization system for automatic voltage control of the power grid can be seen in the implementation example part of the constant value setting optimization method for automatic voltage control of the power grid in the previous text. For example, the data extraction module, the characteristic clustering module, the constant value setting module, the reactive balance assessment and constant value correction module are respectively used to implement step 1, step 2, step 3, and step 4 in the above-mentioned constant value setting optimization method for automatic voltage control of the power grid. Therefore, its specific implementation method can refer to the description of the corresponding embodiments of each part, which will not be repeated here.

[0154] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid, characterized in that: include: Obtain telemetry data of the power factor of each main transformer in the power grid and the voltage value of the busbars on each side of the main transformer; draw the busbar voltage curve on the high-voltage side, the busbar voltage curve on the medium-voltage side, the busbar voltage curve on the low-voltage side, and the power factor curve of each main transformer; extract the characteristic values ​​of the busbar voltage curves and power factor curves on each side of all main transformers respectively; cluster the busbar voltage curves and power factor curves on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer respectively according to the extracted curve characteristic values, and divide the busbar voltage curves and power factor curves on each side into multiple groups; According to the clustering results of the bus voltage curves on each side, the upper and lower limits of the AVC voltage control in each time period are set for each group of transformers respectively: the upper limit of the AVC voltage control in the current time period of the group is set according to the relationship between the average value of the curve voltage maximum value in the current time period of the group and the preset voltage safety operation upper limit value, as well as the voltage reduction rate; the lower limit of the AVC voltage control in the current time period of the group is set according to the relationship between the average value of the curve voltage minimum value in the current time period of the group and the preset voltage safety operation lower limit value, as well as the voltage increase rate; According to the clustering results of the power factor curve, the upper and lower limits of the AVC power factor control in each time period are set for each group of transformers respectively: according to the relationship between the average value of the maximum power factor of the group in the current time period and the preset upper limit of the safe operation power factor, as well as the power factor down-regulation rate, the upper limit of the AVC power factor control in the current time period of the group is set; according to the relationship between the average value of the minimum power factor in the current time period of the group and the preset lower limit of the safe operation power factor, as well as the power factor up-regulation rate, the lower limit of the AVC power factor control in the current time period of the group is set; According to the clustering results and the above process, the setting of AVC control constants of each main transformer in the power grid is completed.

2. The method according to claim 1, characterized in that After completing the setting of the AVC control values ​​of each main transformer in the power grid, the reactive power balance in different dimensions is calculated based on the node dimension, regional dimension, and voltage level dimension. After adjusting the voltage increase rate, voltage decrease rate, power factor increase rate, and power factor decrease rate according to the reactive power balance, the AVC control values ​​of each transformer in the power grid are re-optimized, including: In the node dimension, the real-time value of reactive power on the high-voltage side of the current main transformer is collected, which is the net reactive value of the current main transformer node; according to the real-time value of active power on the high-voltage side of the current main transformer, combined with the reasonable power factor range, the reasonable maximum and minimum values ​​of reactive power are calculated; according to the relationship between the reasonable maximum and minimum values ​​of reactive power and the real-time value of reactive power on the high-voltage side of the current main transformer, the reactive balance amount in the node dimension is calculated; according to the evaluation result of reactive balance amount in the node dimension, after adjusting the voltage increase rate, voltage increase rate, power factor decrease rate, and power factor increase rate, the AVC control setting of the transformer in the current substation is re-optimized; In the regional dimension, the real-time reactive power values ​​of all tie lines between multiple substations in the region and adjacent regions are collected, and the sum is the net reactive value of the region; the reasonable maximum and minimum reactive power values ​​of the region are calculated based on the sum of the real-time active power values ​​of all tie lines and the reasonable power factor range; the reactive balance of the regional dimension is calculated based on the relationship between the reasonable maximum and minimum reactive power values ​​of the region and the net reactive value of the region; according to the evaluation results of the reactive balance of the regional dimension, the voltage increase rate, voltage increase rate, power factor decrease rate, and power factor increase rate are adjusted, and the AVC control constants of the corresponding transformers of multiple substations in the region are re-optimized; In the voltage level dimension, considering the current voltage level in the area, the real-time active power value and reactive power value of the current voltage level side line incoming switches corresponding to all main transformers in the area are collected, and their sum is calculated respectively; combined with the reasonable power factor range, the reasonable maximum and minimum reactive power values ​​at the voltage level are calculated; according to the relationship between the reasonable maximum and minimum reactive power values ​​at the voltage level and the sum of the reactive power of the current voltage level side line incoming switches corresponding to all main transformers in the area, the reactive balance amount in the voltage level dimension is calculated; according to the evaluation result of the reactive balance amount in the voltage level dimension, after adjusting the voltage increase rate, voltage increase rate, power factor decrease rate, and power factor increase rate, the AVC control constants of the current voltage level of the transformers corresponding to multiple substations in the area are re-optimized.

3. The method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 1, characterized in that: The method of obtaining the power factor of each main transformer in the power grid and the voltage value telemetry data of the busbars on each side of the main transformer; drawing the high-voltage side busbar voltage curve, the medium-voltage side busbar voltage curve, the low-voltage side busbar voltage curve and the power factor curve of each main transformer; and extracting the characteristic values ​​of the busbar voltage curves and power factor curves on each side of all main transformers respectively includes: According to the reactive voltage analysis and control requirements, analyze the power factor of the main transformer and the voltage telemetry data of the busbars on each side of the main transformer over time; take the main transformer as the minimum analysis node, extract the daily 96-point curve of the power factor, the daily 96-point curve of the high-voltage side busbar voltage, the daily 96-point curve of the medium-voltage side busbar voltage, and the daily 96-point curve of the low-voltage side busbar voltage for each main transformer; For the power factor curve of each main transformer, extract and calculate the characteristic values: minimum power factor, the time corresponding to the minimum power factor; maximum power factor, the time corresponding to the maximum power factor; maximum reactive power feed, the time corresponding to the maximum reactive power feed, and the duration of reactive power feed; For the bus voltage curves on each side of each main transformer, the characteristic values ​​are extracted and calculated: the maximum value of the curve, the corresponding time of the maximum value of the curve; the minimum value of the curve, the corresponding time of the minimum value of the curve; the extreme value of the curve change rate, the corresponding time of the extreme value of the curve change rate.

4. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 3, characterized in that: According to the extracted curve characteristic values, the bus voltage curves and power factor curves on the high voltage side, low voltage side and medium voltage side of the main transformer are clustered respectively, and the bus voltage curves and power factor curves on each side are divided into multiple groups, including: Each bus voltage curve is at T1, T2...T n-1 The voltage levels of adjacent time intervals are quite different, and the separation time values ​​of different voltage curves are T1, T2, ..., T n-1 and the interval number n are different, T1, T2...T n-1 and bus voltage curves with similar n values ​​are grouped into the same group; compare the maximum and minimum values ​​of the bus voltage curves of the current voltage level of all main transformers, and group the bus voltage curves with similar maximum and minimum values ​​into the same group; the grouping of bus voltage curves is realized by using k-means clustering algorithm; that is, after the clustering of this part is completed, the bus voltages on the high-voltage side, low-voltage side and medium-voltage side of the main transformer are divided into N1, N2, and N3 groups respectively, where the values ​​of N1, N2, and N3 can be specified by the number of main transformers; the clustering results of the bus voltage characteristics on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer are expressed in numerical form, which are recorded as u0, u1, and u2 respectively; where u0∈[0, 1, 2, ..., N1], u1∈[0, 1, 2, ..., N2], and u2∈[0, 1, 2, ..., N3]; The power factor curves of all main transformers are m-1 The power factor values ​​of adjacent time intervals are greatly different, and the separation time values ​​of different power factor curves are T′1, T′2, ... T′ m-1 and the interval number m is different, T′1, T′2, ... T′ m-1 The main transformer power factor curves with similar m values ​​are grouped into the same group; the maximum and minimum values ​​of all main transformer power factor curves are compared, and the main transformer power factor curves with similar maximum and minimum values ​​are grouped into the same group; the grouping of the main transformer power factor curves is achieved by using the k-means clustering algorithm; that is, after the clustering of this part is completed, the power curves are divided into N4 groups according to the characteristics, where the value of N4 can be specified by the number of main transformers; the clustering results of the main transformer power factor characteristics are expressed in numerical form, recorded as q; where q∈[0, 1, 2, ..., N4].

5. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 4, characterized in that: After clustering the bus voltage curves and power factor curves on the high-voltage side, low-voltage side, and medium-voltage side of the main transformer, the clustering results of the voltage and power factor of each main transformer include: For main transformer i, the clustering results of the overall characteristics of its voltage and power factor are expressed as an array: W i =[u0,u1,u2,q] Among them, W i It means that after clustering and grouping, the high-voltage side voltage characteristics of the main transformer i are group u0, the low-voltage side voltage characteristics are group u1, the medium-voltage side voltage characteristics are group u2, and the power factor characteristics are group q; if the main transformer is a two-turn transformer, which only has a high-voltage side and a low-voltage side, the corresponding medium-voltage side voltage clustering result is set to 0, that is, u2=0.

6. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 4, characterized in that: The above method is to set the AVC voltage control upper and lower limits in each time period for each group of transformers according to the clustering results of the bus voltage curves on each side: to set the AVC voltage control upper limit in the current time period of the group according to the relationship between the average value of the curve voltage maximum value in the current time period of the group and the preset voltage safety operation upper limit value, as well as the voltage reduction rate; to set the AVC voltage control lower limit in the current time period of the group according to the relationship between the average value of the curve voltage minimum value in the current time period of the group and the preset voltage safety operation lower limit value, as well as the voltage increase rate, including: According to the safety regulations, set the voltage safe operation upper limit value U sf，max , Voltage safe operation lower limit U sf，min ; Setting bus voltage control constants includes: For the voltage curve of a certain voltage level after clustering, each group sets the upper and lower limit values ​​of voltage control in different time periods; Voltage control upper limit setting: For time period k, the average value of the voltage maximum value of this group of curves in time period k is recorded as U k，vmax ;if U k，vmax >U sf，max , then the voltage upper limit of this group of curves in the k period is set to U kmax =U sf，max -(U k，vmax -U sf，max )×E u，down , where E u，down is the voltage reduction rate, which is between 100% and 1%. If the voltage needs to be reduced to the maximum extent, then E u，down Take 100%; if U k，vmax ≤U sf，max , then the voltage upper limit of this group of curves in the k period is set to U kmax =U sf，max ; Among them, the k period corresponds to the time interval T K-1 To T K Between K-1 , T K ∈[T1, T2, ... T n-1 ]; Voltage control lower limit setting: For time period k, the average value of the minimum voltage of this group of curves in time period k is recorded as U k，vmin ;if U k，vmin <U sf，min , then the voltage upper limit of this group of curves in the k period is set to U kmin =U sf，min +(U sf，min -U k，vmin )×E u，up , where E u，up is the voltage increase rate, which is between 1% and 100%. If the voltage needs to be increased to the maximum extent, then E u，up Take 100%; if U k，vmin ≥U sf，min , then the voltage upper limit of this group of curves in the k period is set to U kmin =U sf，min ; Among them, the k period corresponds to the time interval T K-1 To T K Between K-1 , T K ∈[T1, T2, ... T n-1 ]; In summary, for the group w after clustering the bus voltage curve of a certain voltage level, the AVC voltage control constant setting is expressed by a 3*N dimensional matrix as follows: Among them, T N ∈[T1, T2, ... T n-1 ]; The first row of the matrix represents the time segment separation moment, the second row is the voltage upper limit value corresponding to each time segment, and the third row is the voltage lower limit value corresponding to each time segment.

7. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 4, characterized in that: According to the clustering result of the power factor curve, the upper and lower limits of the AVC power factor control in each time period are set for each group of transformers respectively: the upper limit of the AVC power factor control in the current time period of the group is set according to the relationship between the average value of the maximum power factor in the current time period of the group and the preset upper limit of the safe operation power factor, and the power factor down-regulation rate; the lower limit of the AVC power factor control in the current time period of the group is set according to the relationship between the average value of the minimum power factor in the current time period of the group and the preset lower limit of the safe operation power factor, and the power factor up-regulation rate, including: According to the safety regulations, set the upper limit of the safe operation power factor Safe operation power factor lower limit The groups for setting AVC power factor control settings include: Power factor control upper limit setting: For time period k, the average value of the maximum power factor of this group of curves in time period k is recorded as like Then the upper limit of the power factor of this group of curves in the k period is set to Among them, E c,down is the power factor reduction rate, which is between 100% and 1%. If the power factor needs to be reduced to the maximum extent, then E c,down Take 100%; if The power upper limit value of this group of curves in the time period is set to Power factor control lower limit setting: For time period k, the average value of the minimum power factor of this group of curves in time period k is recorded as like The lower limit of the power factor of this group of curves in period k is set to Among them, E c，up is the power factor increase rate, E c,up Its value is between 1% and 100%. If the power factor needs to be adjusted to the maximum extent, then E c，up Take 100%; if The lower limit of the power factor of this group of curves in the period is set to In summary, the clustering of the main transformer power factor curves into groups v, where the AVC power factor control constant setting is expressed as a 3*M dimensional matrix: Among them, T M ∈[T′1, T′2, … T′ m-1 ]; The first row of the matrix represents the time of time segmentation, the second row represents the upper limit of the power factor corresponding to each time segment, and the third row represents the lower limit of the power factor corresponding to each time segment.

8. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 2, characterized in that: Calculate the reactive power balance in the node dimension; adjust the voltage increase rate, voltage decrease rate, power factor increase rate, and power factor decrease rate according to the reactive power balance, and re-optimize the AVC control setting of the main transformer in the substation, including: In the node dimension, the real-time value Q of the reactive power on the high-voltage side of the main transformer in the current substation is collected. i , this value is the net reactive power value of the current main transformer node; when the reactive power flows from the high-voltage busbar to the main transformer itself, the reactive power and active power directions are the same, which means that the reactive power flow direction is reasonable; when the reactive power flows from the main transformer itself to the high-voltage busbar, it means that the reactive power of this node is abundant, and the abundant reactive power is reversed from the low voltage level to the high voltage level; According to the real-time value of active power P on the high-voltage side i , Reasonable power factor Range, calculate the reasonable value range of reactive power [Q st.imin , Q st.imax ]; its calculation formula is Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.imax =0.29P i , Q st.imin =0.25P i ; Reactive balance Q of the node corresponding to the main transformer i bs,i The calculation method is: (1) If Q st，imin ≤Q i ≤Q st，imax , Q bs,i =0; the power factor is reasonable, and the reactive power of the node is balanced locally; (2) If Q i >Q st，imax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs，i =Q i -Q st,imax , the value is greater than 0, indicating that the node has a capacitive reactive power shortage; then the voltage increase rate E in the AVC setting of the group involved in the node is u，up , power factor increase rate E c,up If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding node will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation; (3) If Q i <Q st，imin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs，i =Q i -Q st，imin , the value is less than 0, and its absolute value represents the capacitive reactive surplus of the node; then the voltage reduction rate E in the AVC setting of the group involved in the node is u，down , Power factor reduction rate E c，down If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding node will be to invest more inductive reactive power compensation devices; wherein the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generators, and generator leading phase operation.

9. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 2, characterized in that: Calculate the reactive power balance in the regional dimension; adjust the voltage increase rate, voltage decrease rate, power factor increase rate, and power factor decrease rate according to the reactive power balance, and re-optimize the AVC control settings of the main transformers corresponding to multiple substations in the region, including: In the regional dimension, the real-time values ​​of active power and reactive power of all tie lines between multiple substations in the region and adjacent regions are collected; the sum of the real-time values ​​of reactive power of all tie lines between the region and adjacent regions ∑Q li , which is the net reactive power value of the area; the sum of the real-time active power values ​​of all tie lines ∑P li , which is the net active value of the area; According to the sum of the real-time values ​​of active power of all tie lines ∑P li , Reasonable power factor Range, calculate the reasonable reactive power value range of the area [Q st，limin , Q st，limax ], and its calculation formula is Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.limax =0.29∑P li , Q st.limin =0.25∑P li ; The reactive balance Q in this area li bs，li The calculation method is: (1) If Q st，limin ≤∑Q li ≤Q st，limax , Q bs，li =0; the power factor is reasonable and the reactive power in this area is balanced locally; (2) If ∑Q li >Q st，limax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs，li =∑Q li -Q st，limax , the value is greater than 0, indicating the capacitive reactive power shortage in the area; the voltage increase rate E in the AVC setting of the group involved in the area u，up , power factor increase rate E c，up If the value of is set larger, i.e. close to 100%, the adjustment result of the area will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation; (3) If ∑Q li <Q st，limin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs，li =∑Q li -Q st，limin , the value is less than 0, and its absolute value represents the capacitive reactive power surplus of the area; the voltage reduction rate E in the AVC setting of the group involved in the area u，down , Power factor reduction rate E c，down If the value of is set larger, i.e. close to 100%, the adjustment result of this area will be to invest more inductive reactive power compensation devices; wherein, the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generation, and generator leading phase operation.

10. A method for optimizing the setting of a fixed value for automatic voltage control of a power grid according to claim 2, characterized in that: Calculate the reactive power balance under the voltage level dimension; after adjusting the voltage increase rate, voltage decrease rate, power factor increase rate, and power factor decrease rate according to the reactive power balance, re-optimize the AVC control setting of the current voltage level of the transformers corresponding to multiple substations in the area, including: In the voltage level dimension, considering the current voltage level in the area, the real-time active power and reactive power values ​​of the current voltage level side line incoming switches of all main transformers in the area are collected; the sum of the real-time active power values ​​of the voltage level side incoming switches of all main transformers in the area is recorded as ∑P vi The sum of the real-time values ​​of reactive power is recorded as ∑Q vi ; According to the sum of the real-time values ​​of active power of all tie lines ∑P vi , Reasonable power factor Range, calculate the reasonable reactive value range at the voltage level [Q st，vimin , Q st，vimax ], and its calculation formula is Among them, the regulations stipulate that the reasonable power factor The range is 0.92~0.97, then Q st.vimax =0.29∑P vi , Q st.vimin =0.25∑P vi ; Reactive power balance Q at voltage level vi bs，vi The calculation method is: (1) If Q st，vimin ≤∑Q li ≤Q st，vimax , Q bs，vi =0; the power factor is reasonable, and the reactive power is balanced locally at this voltage level; (2) If ∑Q vi >Q st，vimax , reactive power is excessive, power factor is lower than the lower limit, capacitive reactive power is insufficient, reactive power balance is Q bs，vi =∑Q vi -Q st，vimax , the value is greater than 0, indicating the capacitive reactive power shortage at the voltage level; the voltage increase rate E in the AVC setting of the group involved in the current voltage level is u，up , power factor increase rate E c，up If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding area will be to invest more capacitive reactive power compensation devices; wherein the capacitive reactive power compensation devices include: withdrawing reactors, investing capacitors, SVG capacitive multiple generation, and generator delayed phase operation; (3) If ∑Q vi <Q st，vimin , reactive power is less positive or even reverse, the power factor is higher than the upper limit, capacitive reactive power is abundant, and the reactive power balance is Q bs，vi =∑Q vi -Q st，vimin , the value is less than 0, and the absolute value represents the capacitive reactive surplus at the voltage level; the voltage reduction rate E in the AVC setting of the group involved in the current voltage level is u，down , Power factor reduction rate E c，down If the value of is set larger, i.e. close to 100%, the adjustment result of the corresponding area will be to invest more inductive reactive power compensation devices; wherein the inductive reactive power compensation devices include: withdrawing capacitors, investing in reactors, SVG inductive multiple generators, and generator leading phase operation.

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