A reactive power regulation and control strategy with AVC co-control station

Abstract

This invention discloses a reactive power and voltage regulation control strategy with an AVC (Automatic Voltage Control) co-control station. A co-control station is set up at substation / switching station nodes where multiple power plants converge. AVC substations under the co-control station report their remaining adjustable reactive power capacity to the co-control station. Each regular substation or co-control station reports its own or the overall remaining adjustable reactive power capacity of the converged area to the AVC master station. The AVC master station performs secondary voltage control optimization calculations on the power grid in the control area and issues regulation commands to each regular substation and co-control station. Each regular substation and co-control station converts the commands into reactive power regulation quantities. Regular substations adjust their own reactive power capacity. The co-control station calculates the total reactive power regulation demand based on the topology and real-time reactive power output of its subordinate AVC substations. The co-control station calculates and issues reactive power regulation commands to each subordinate AVC substation for this round. Each subordinate substation receives the commands issued by the co-control station and completes the reactive power regulation. This invention bridges the communication gap between the master station and substations, improving the reactive power regulation capability of areas with multiple power plants converged.

Description

Technical Field

[0001] This invention relates to the field of reactive power and voltage control technology in power grids, and in particular to a reactive power and voltage regulation and control strategy with an AVC co-control station. Background Technology

[0002] With the continuous expansion of the power grid and the rapid growth of the proportion of renewable energy integration, the importance of reactive power regulation has become increasingly prominent. However, the current provincial automatic voltage control (AVC) system mainly relies on direct communication between the master station and a series of substations at power generation nodes. The master station is responsible for reactive power optimization calculations across the entire area and issues reactive power regulation commands to each substation, which then completes the regulation tasks according to the commands. This architecture has significant limitations in dealing with complex reactive power demands in local areas, especially in areas where power generation stations are concentrated. Due to the coupling correlation between the reactive power and voltage regulation of the substations in the vicinity, without a coordinated regulation mechanism, serious problems such as voltage overshoot and abnormal voltage fluctuations in local areas can easily occur due to unreasonable settings of reactive power and voltage sensitivity and response speed, threatening the safe and stable operation of the power system.

[0003] The aforementioned problems are particularly prominent in scenarios with high penetration rates of new energy sources and complex power grid structures. Therefore, there is an urgent need to introduce a coordination control unit that can compensate for the communication gap between the master station and the substation and improve the reactive power regulation capability of the multi-power station convergence area, so as to achieve more precise and effective reactive power and voltage regulation. Summary of the Invention

[0004] Purpose of the invention: To address the above problems, this invention provides a reactive power voltage regulation control strategy with an AVC coordinating control station. This coordinating control unit can compensate for communication gaps between the master station and the substations and improve the reactive power regulation capability of the multi-power plant aggregation area, thereby achieving more precise and effective reactive power voltage regulation.

[0005] Technical solution: This invention discloses a reactive power voltage regulation and control strategy with an AVC co-control station, comprising the following steps:

[0006] Step 1: Set up a co-control station at the substation / switching station node where multiple power plants converge in the power grid;

[0007] Step 2: The AVC substations under the control of the co-control station report the remaining adjustable reactive power capacity to the co-control station, and each regular substation or co-control station reports the total remaining adjustable reactive power capacity within the station or the aggregation area to the AVC master station.

[0008] Step 3: The AVC master station issues secondary control commands:

[0009] (3.1) The AVC master station receives the reactive power adjustable capacity reported by each regular substation and co-control station, and performs secondary voltage control optimization calculations for the power grid in the control area;

[0010] (3.2) The AVC master station issues reactive power, voltage or power factor adjustment commands to each conventional substation and co-control station;

[0011] (3.3) Each regular substation and co-control station converts the AVC master station commands into reactive power regulation quantities;

[0012] Step 4: The routine substation adjusts the reactive power capacity within the substation to complete the command adjustment;

[0013] Step 5: The co-control station calculates the total reactive power regulation demand to be issued based on the topology of its subordinate AVC substations and their real-time reactive power output.

[0014] Step 6: The coordinating control station calculates and issues reactive power adjustment instructions for each AVC substation in this round based on the principle of balancing the remaining adjustable reactive power capacity of each AVC substation under its jurisdiction.

[0015] Step 7: Each subordinate substation receives instructions from the control station and completes reactive power adjustment;

[0016] Step 8: The co-control station determines whether the target command issued by the AVC master station has been adjusted in place. If it has not been adjusted in place, it returns to step 5 and issues the next round of reactive power adjustment command to the subordinate AVC substations until the adjustment is in place or the cycle of this secondary reactive power voltage control command ends.

[0017] Furthermore, in step 1, in the AVC system, the co-control station, as a lower-level communication unit of the AVC master station, receives instructions from the AVC master station and has the same status as a conventional AVC substation set up in a power plant station with a single point of grid connection; at the same time, the co-control station, as the upper-level communication unit of the power plant station under its jurisdiction, issues reactive power regulation instructions to the AVC substations of each power plant station under its jurisdiction.

[0018] Furthermore, in step 3, the AVC master station acquires the central point voltage reference value information issued by the three-level voltage control every 15 minutes, and performs a round of secondary voltage control optimization calculation every 5 minutes based on the reactive power adjustable capacity reported by each regular substation and co-control station. The secondary control of the AVC master station performs reactive power optimization calculation with the goal of minimizing the central point voltage deviation and achieving reactive power balance among regular substations and co-control stations. Its objective function is:

[0019]

[0020] Where, ΔQ g To optimize the variables, namely the reactive power regulation of each conventional substation and coordinated control station within this round of regulation; W p The term represents the voltage offset component, ΔU p C represents the voltage deviation value of the central point within the jurisdiction of the AVC master station. g W is the reactive voltage sensitivity matrix at the central point;q The term represents the reactive power balancing component, Q. g Q g.max Q g.min These represent the current reactive power, upper reactive power limit, and lower reactive power limit of each regular substation and coordinated control station, respectively.

[0021] The equality constraints of the main station optimization model are the active and reactive power balance equations between the nodes in the system, specifically expressed as follows:

[0022]

[0023] Among them, P Gi Q Gi These represent the active and reactive power outputs of the generator at the i-th node, respectively; P Li Q Li These represent the active and reactive power demands of the i-th node, respectively; G ij B ij The elements Y of the nodal admittance matrix are respectively ij The real and imaginary parts;

[0024] The inequality constraints in the optimization model include single-step adjustment constraints, voltage constraints, and reactive power constraints for conventional substations and coordinated control stations. The specific expressions are as follows:

[0025]

[0026] Among them, C g U represents the reactive voltage sensitivity matrix for each coordinated control station and conventional substation. p U p.max U p.min U represents the current voltage, upper voltage limit, and lower voltage limit of the central point, respectively. H U H.max U H.min and ΔU H These represent the current voltage, upper voltage limit, lower voltage limit, and maximum allowable single-step adjustment for each regular substation and coordinated control station, respectively.

[0027] After the master station calculates the optimal reactive power regulation for each conventional substation and co-control station in this round, it directly distributes the data to each conventional substation and co-control station; or it distributes the data through matrix C. g After being converted into voltage commands, voltage commands or voltage deviation commands are sent to regular substations and co-control stations; or, after synchronously acquiring the active power output values ​​of each regular substation and co-control station, power factor adjustment commands are sent.

[0028] Furthermore, in step 3, after receiving the command from the AVC master station, the regular substation and the co-control station determine the command type and select an appropriate calculation formula according to each command type to obtain the reactive power regulation amount:

[0029] (4) When the AVC master station command is a reactive power deviation command, no conversion calculation is required;

[0030] (5) When the AVC master station command is a voltage bias command, the voltage deviation command is converted into a reactive power regulation quantity based on the reactive power voltage sensitivity. The specific calculation formula is as follows:

[0031] ΔQ g =λΔU target_g

[0032] Where, ΔU target_g The voltage deviation command is issued by the AVC master station. λ is the reactive voltage sensitivity setting value for the conventional substation and the co-control station, which is related to the line impedance from the conventional substation and the co-control station to the corresponding central node, and can be approximated as equal to... X0 is the line impedance from the conventional substation, the control station to the central point;

[0033] (6) When the AVC master station command is a voltage command, the voltage command is converted into a reactive power regulation quantity based on the reactive power voltage sensitivity. The specific calculation formula is as follows:

[0034] ΔQ g =λ(U target_g -U g )

[0035] Among them, U target_g The voltage command issued by the AVC master station, U g Real-time voltage for regular substations and coordinated control stations;

[0036] (4) When the AVC master station command is a power factor command, the power factor command is converted into reactive power regulation based on the active power aggregated from the current conventional substations and co-control stations. The specific calculation formula is as follows:

[0037] ΔQ g =[tan(arcζ target )-tan(arcζ0)]P g =tan(arcζ) target )P g -Q0

[0038] Where, ζ target This is a power factor command issued by the AVC master station. ζ0 represents the real-time power factor of the regular substation and the co-control station, Q0 represents the real-time reactive power of the regular substation and the co-control station, and P... g Let P be the real-time active power of the conventional substations and coordinated control stations. Ignoring the impact of active power fluctuations and reactive power regulation on active power losses, we can approximate P's active power as follows: g As a constant value, the reactive power regulation of the conventional substation and the coordinated control station can be obtained according to the above formula.

[0039] Furthermore, in step 4, the conventional substation adjusts the reactive power capacity within the station to complete the command adjustment. If the adjustment is incomplete in one attempt due to inaccurate sensitivity settings, the voltage deviation is remeasured after each reactive power adjustment to complete the command based on multiple reactive power adjustments.

[0040] Furthermore, in step 5, the co-control station calculates the total reactive power regulation demand of each subordinate substation based on the power grid topology and the real-time reactive power output of each substation. When the secondary term and active power fluctuations are not considered, the specific calculation formula is as follows:

[0041]

[0042] Where n is the number of substations under the jurisdiction of the co-control station in this cycle, Q1, Q2, ..., Q n and ΔQ1, ΔQ2, ..., ΔQ n These represent the real-time reactive power output and current-cycle reactive power output of each subordinate substation, denoted as X1, X2, ..., X. n U1, U2, ..., U are the line reactances of each substation from the collection point, X is the line reactance of the collection point from the control station, and U1, U2, ..., U2 are the line reactances of each substation from the collection point. n This refers to the voltage of each of the substations under its jurisdiction.

[0043] Furthermore, in step 6, the co-control station performs reactive power allocation based on the principle of balancing the remaining adjustable reactive power capacity of each subordinate AVC substation, specifically satisfying the formula:

[0044]

[0045] Where, ΔQ max _ i The remaining adjustable reactive power capacity of each subordinate substation;

[0046] Based on the above principles and the total reactive power regulation of the subordinate substations, the output of each subordinate substation meets the following requirements:

[0047]

[0048] According to the least squares method, the reactive power output of each subordinate substation can be obtained as follows:

[0049]

[0050] Where matrix A satisfies

[0051] Due to constraint redundancy, the reactive power output of each subordinate substation and the total reactive power regulation demand ΔQ of the co-control station are derived above. g There is a discrepancy between the two. To ensure that the reactive power collected by the co-control station matches the commands of the AVC master station, the discrepancy will be evenly distributed to each of the subordinate substations, and each subordinate substation needs to supplement its reactive power output.

[0052]

[0053] Therefore, the reactive power regulation instructions issued by the control station to each of its subordinate substations are as follows:

[0054] ΔQ i ′=ΔQ i +ΔQ di

[0055] Where, ΔQ i ′ represents the reactive power adjustment command value issued by the control station to each of its subordinate substations.

[0056] Beneficial effects:

[0057] This invention addresses the relationship between the provincial dispatch center and the power plant side in secondary voltage control. Furthermore, considering the potential for abnormal voltage fluctuations during AVC regulation due to the mutual coupling of reactive power and voltage regulation characteristics after multiple renewable energy power plants are aggregated, a co-control station is added between the provincial dispatch center and the power plant side. This invention specifically sets up a co-control station for the "multi-power plant aggregation of renewable energy" topology and provides a specific strategy for conventional AVC substations and the co-control station to jointly participate in the secondary voltage control of the AVC substation. The calculation methods for AVC substations and the co-control station receiving different commands from the AVC master station are derived; the calculation method for the reactive power regulation of multiple renewable energy power plants under the co-control station considering the coupling relationship is also derived, thus forming a complete reactive power and voltage regulation strategy including an AVC co-control station.

[0058] In its operation, this invention achieves efficient collaborative control between the AVC master station and the original AVC substations by setting up an AVC co-control station in the multi-power plant aggregation area. The co-control station, acting as a lower-level communication unit of the master station and a higher-level communication unit of the substations, undertakes the functions of data aggregation, optimized allocation, and command transmission, effectively compensating for the lack of coordination in reactive power and voltage control of traditional AVC systems in regional power grids. This invention accurately obtains the total remaining adjustable reactive power capacity of the aggregation area through the co-control station, and, combined with the power grid topology and the real-time reactive power output of the substations, accurately allocates reactive power regulation tasks to each substation under the principle of balance. This effectively improves the response speed and accuracy of reactive power regulation, maintains the stability of the voltage deviation regulation process, and enhances the stability and economy of power grid operation. Attached Figure Description

[0059] Figure 1 A flowchart of a reactive voltage regulation control strategy with an AVC co-control station;

[0060] Figure 2 This is a control block diagram of an AVC system including a co-control station;

[0061] Figure 3 This represents a typical local power grid topology that includes a control station. Detailed Implementation

[0062] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0063] This invention discloses a reactive voltage regulation control strategy with an AVC co-control station, comprising the following steps:

[0064] Step 1: Set up a co-control station at the substation / switching station node where multiple power plants converge in the power grid. In the AVC system, this co-control station acts as a subordinate communication unit of the AVC master station, receiving commands from the AVC master station, with the same status as a conventional AVC substation set up at a power plant with a single point of connection to the power grid. Simultaneously, this co-control station acts as the superior communication unit of the power plants under its jurisdiction, issuing reactive power regulation commands to the AVC substations of each subordinate power plant.

[0065] Step 2: The AVC substations under the control of the co-control station report the remaining adjustable reactive power capacity to the co-control station, and each regular substation or co-control station reports the total remaining adjustable reactive power capacity within the station or the aggregation area to the AVC master station.

[0066] The AVC substations under the control station are in online operation mode and report the remaining adjustable reactive power capacity of all reactive power equipment in the station to the control station. After the control station summarizes the data of each substation, it reports the total remaining adjustable reactive power capacity of the collection area to the AVC master station. At the same time, the regular substations report the remaining adjustable reactive power in their stations to the AVC master station, so that the AVC master station can make constraints when performing reactive power optimization calculations.

[0067] Step 3: The AVC master station issues secondary control commands:

[0068] (3.1) The AVC master station receives the reactive power adjustable capacity reported by each regular substation and co-control station, and performs secondary voltage control optimization calculations for the power grid in the control area.

[0069] (3.2) The AVC master station issues reactive power, voltage or power factor adjustment commands to each regular substation and co-control station.

[0070] (3.3) Each regular substation and co-control station converts the AVC master station commands into reactive power regulation quantities.

[0071] In step 3, the AVC master station acquires the central point voltage reference value information issued by the three-level voltage control every 15 minutes, and performs a round of secondary voltage control optimization calculations every 5 minutes based on the reactive power adjustable capacity reported by each regular substation and co-control station. The secondary control of the AVC master station performs reactive power optimization calculations with the objectives of minimizing the central point voltage deviation and achieving reactive power balance among regular substations and co-control stations. Its objective function is:

[0072]

[0073] Where, ΔQ g To optimize the variables, namely the reactive power regulation of each conventional substation and coordinated control station within this round of regulation; W p The term represents the voltage offset component, ΔU p C represents the voltage deviation value of the central point within the jurisdiction of the AVC master station. g W is the reactive voltage sensitivity matrix at the central point; q The term represents the reactive power balancing component, Q. g Q g.max Q g.min These represent the current reactive power, upper reactive power limit, and lower reactive power limit of each regular substation and coordinated control station, respectively.

[0074] The equality constraints of the main station optimization model are the active and reactive power balance equations between the nodes in the system, specifically expressed as follows:

[0075]

[0076] Among them, P Gi Q Gi These represent the active and reactive power outputs of the generator at the i-th node, respectively; P Li Q Li These represent the active and reactive power demands of the i-th node, respectively; G ij B ij The elements Y of the nodal admittance matrix are respectively ij The real and imaginary parts.

[0077] The inequality constraints in the optimization model include single-step adjustment constraints, voltage constraints, and reactive power constraints for conventional substations and coordinated control stations. The specific expressions are as follows:

[0078]

[0079] Among them, C g U represents the reactive voltage sensitivity matrix for each coordinated control station and conventional substation. p U p.max U p.min U represents the current voltage, upper voltage limit, and lower voltage limit of the central point, respectively. H U H.max U H.min and ΔU H These represent the current voltage, upper voltage limit, lower voltage limit, and maximum allowable single-step adjustment for each regular substation and coordinated control station.

[0080] After the master station calculates the optimal reactive power regulation for each conventional substation and co-control station in this round, it can directly distribute the data to each conventional substation and co-control station; alternatively, it can distribute the data through matrix C. gAfter being converted into voltage commands, voltage commands or voltage deviation commands are sent to regular substations and co-control stations; or, after synchronously acquiring the active power output values ​​of each regular substation and co-control station, power factor adjustment commands are sent.

[0081] After receiving commands from the AVC master station, the regular substations and co-control stations determine the command type and select the appropriate calculation formula based on each command type to obtain the reactive power regulation:

[0082] (1) When the AVC master station command is a reactive power deviation command, no conversion calculation is required.

[0083] (2) When the AVC master station command is a voltage bias command, the voltage deviation command can be converted into a reactive power regulation quantity based on the reactive power voltage sensitivity. The specific calculation formula is as follows:

[0084] ΔQ g =λΔU target_g

[0085] Where, ΔU target_g The voltage deviation command is issued by the AVC master station. λ is the reactive voltage sensitivity setting value for the conventional substation and the co-control station, which is related to the line impedance from the conventional substation and the co-control station to the corresponding central node, and can be approximated as equal to... Where X0 is the line impedance from the regular substation, the control station to the central point.

[0086] (3) When the AVC master station command is a voltage command, the voltage command can be converted into a reactive power regulation quantity based on the reactive power voltage sensitivity. The specific calculation formula is as follows:

[0087] ΔQ g =λ(U target_g -U g )

[0088] Among them, U target_g The voltage command issued by the AVC master station, U g This refers to the real-time voltage of the regular substations and the coordinated control station.

[0089] (4) When the AVC master station command is a power factor command, the power factor command can be converted into a reactive power regulation quantity based on the active power aggregated from the current conventional substations and co-control stations. The specific calculation formula is as follows:

[0090] ΔQ g =[tan(arcζ target )-tan(arcζ0)]P g =tan(arcζ) target )P g -Q0

[0091] Where, ζ targetThis is a power factor command issued by the AVC master station. ζ0 represents the real-time power factor of the regular substation and the co-control station, Q0 represents the real-time reactive power of the regular substation and the co-control station, and P... g For the real-time active power of conventional substations and coordinated control stations, and without considering the impact of active power fluctuations and reactive power regulation on active power losses, P can be approximated as... g As a constant value, the reactive power regulation of the conventional substation and the coordinated control station can be obtained according to the above formula.

[0092] Step 4: The routine substation adjusts the reactive power capacity within the station to complete the command adjustment.

[0093] The standard substation adjusts the reactive power capacity within its own substation to complete the command adjustment. If an inaccurate sensitivity setting results in an incomplete adjustment on the first attempt, the voltage deviation can be remeasured after each reactive power adjustment to complete the command adjustment after multiple adjustments.

[0094] Step 5: The co-control station calculates the total reactive power regulation demand to be issued based on the topology and real-time reactive power output of its subordinate AVC substations. The co-control station calculates the total reactive power regulation demand for each subordinate substation based on the grid topology and the real-time reactive power output of each substation. When secondary terms and active power fluctuations are not considered, the specific calculation formula is as follows:

[0095]

[0096] Where n is the number of substations under the jurisdiction of the co-control station in this cycle, Q1, Q2, ..., Q n and ΔQ1, ΔQ2, ..., ΔQ n These represent the real-time reactive power output and current-cycle reactive power output of each subordinate substation, denoted as X1, X2, ..., X. n U1, U2, ..., U are the line reactances of each substation from the collection point, X is the line reactance of the collection point from the control station, and U1, U2, ..., U2 are the line reactances of each substation from the collection point. n This refers to the voltage of each of the substations under its jurisdiction.

[0097] Step 6: The coordinating control station calculates and issues reactive power adjustment instructions for each AVC substation under its jurisdiction in this round, based on the principle of balancing the remaining adjustable reactive power capacity of each AVC substation.

[0098] The control station distributes reactive power according to the principle of balancing the remaining adjustable reactive power capacity of each AVC substation under its jurisdiction, specifically satisfying the formula.

[0099]

[0100] Where, ΔQ max _ i This refers to the remaining adjustable reactive power capacity of each of the substations under its jurisdiction.

[0101] Based on the above principles and the total reactive power regulation of the subordinate substations, the output of each subordinate substation meets the requirements.

[0102]

[0103] According to the least squares method, the reactive power output of each subordinate substation can be obtained as follows:

[0104]

[0105] Where matrix A satisfies

[0106] Due to constraint redundancy, the reactive power output of each subordinate substation and the total reactive power regulation demand ΔQ of the co-control station are derived above. g There is a discrepancy between the data points. To ensure that the reactive power collected by the control station matches the commands of the AVC master station, the discrepancy is evenly distributed to each of the subordinate substations, and each subordinate substation needs to supplement its reactive power output.

[0107]

[0108] Therefore, the reactive power regulation instructions issued by the control station to each of its subordinate substations are:

[0109] ΔQ i ′=ΔQ i +ΔQ di

[0110] Where, ΔQ i ′ represents the reactive power adjustment command value issued by the control station to each of its subordinate substations.

[0111] Step 7: Each subordinate substation receives the instructions issued by the coordinating control station and completes reactive power adjustment. Each subordinate substation can adjust the capacity of its reactive power compensation equipment as needed and complete the corresponding adjustment instructions.

[0112] Step 8: The co-control station determines whether the target command issued by the AVC master station has been adjusted in place. If it has not been adjusted in place, it returns to step 5 and issues the next round of reactive power adjustment command to the subordinate AVC substations until the adjustment is in place or the cycle of this secondary reactive power voltage control command ends.

[0113] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A reactive voltage regulation control strategy of an AVC containing co-control station, characterized in that, The method comprises the following steps: Step 1: setting a coordinated control station at a transformer substation / switching station node of a plurality of power plant stations in a power grid; Step 2: reporting, by an AVC substation under the coordinated control station, residual adjustable reactive power capacity to the coordinated control station, and reporting, by each conventional substation or the coordinated control station, residual adjustable reactive power capacity in the substation or a total residual adjustable reactive power capacity in a collection area to an AVC master station; Step 3: issuing, by the AVC master station, a secondary control instruction: (3.1) accepting, by the AVC master station, the reported reactive power adjustable capacity from each conventional substation and the coordinated control station, and performing secondary voltage control optimization calculation on the control area power grid; (3.2) issuing, by the AVC master station, a reactive power, voltage or power factor adjustment instruction to each conventional substation and the coordinated control station; (3.3) converting, by each conventional substation and the coordinated control station, the AVC master station instruction into a reactive power adjustment amount; Step 4: adjusting, by the conventional substation, the reactive power capacity in the substation to complete the instruction adjustment; Step 5: calculating, by the coordinated control station, a total reactive power adjustment amount demand to be issued according to a topology structure of an AVC substation under the coordinated control station and real-time reactive power output of the AVC substation; The coordinated control station calculates the total reactive power adjustment amount demand of each substation under the coordinated control station according to a power grid topology structure and real-time reactive power output of each substation under the coordinated control station, and when the quadratic term and active power fluctuation are not considered, the specific calculation formula is: ； Wherein, n is the number of sub-stations under the jurisdiction of the coordination station in the current cycle, Q1, Q2, …, Q n and ΔQ1, ΔQ2, …, ΔQ n are the real-time reactive power output and the reactive power output in the current cycle of each sub-station under jurisdiction, X1, X2, …, X n are the line reactance of each sub-station to the collection point, X is the line reactance of the collection point to the coordination station, U1, U2, …, U n are the voltages of each sub-station under jurisdiction. Step 6: calculating and issuing, by the coordinated control station, a reactive power adjustment amount instruction of each AVC substation under the coordinated control station in this round according to the principle of balancing the residual adjustable reactive power capacity of each AVC substation under the coordinated control station; The coordinated control station performs reactive power distribution according to the principle of balancing the residual adjustable reactive power capacity of each AVC substation under the coordinated control station, and the specific satisfaction formula is: ； where ΔQ max i is the remaining adjustable reactive power capacity of each substation.​ Based on the above principle and the total reactive power adjustment amount of the substation under the coordinated control station, the output of each substation under the coordinated control station satisfies: ； According to the least square method, the reactive power output of each substation under the coordinated control station is: ； where the matrix A satisfies ; Due to the constraint redundancy, the reactive power output of each substation under jurisdiction obtained according to the above derivation is deviated from the total reactive power regulation demand ΔQ of the coordinated control station g To ensure that the reactive power amount collected by the coordinated control station matches the instruction of the AVC master station, the deviation amount is evenly distributed to each substation under jurisdiction, and each substation under jurisdiction needs to supplement the reactive power output: ； Therefore, the reactive power adjustment amount instruction issued by the coordinated control station to each substation under the coordinated control station is: ； wherein, is the reactive power adjustment value issued by the coordination station to each subordinate substation; Step 7: receiving, by each substation under the coordinated control station, the instruction issued by the coordinated control station and completing reactive power adjustment; Step 8: judging, by the coordinated control station, whether the target instruction issued by the AVC master station is adjusted to place, and if not, returning to step 5 to issue a next round of reactive power adjustment instruction to the AVC substation under the coordinated control station until the adjustment is in place or the secondary reactive power and voltage control instruction period is over.

2. The reactive voltage regulation control strategy of claim 1, wherein, In step 1, in the AVC system, the coordinated control station is a lower-level communication unit of the AVC master station, receives the AVC master station instruction, and has the same status as the conventional AVC substation set in the power plant station adopting single-point collection into the power grid; meanwhile, the coordinated control station is a higher-level communication unit of the power plant station, and issues a reactive power adjustment instruction to the AVC substation of each power plant station under the coordinated control station.

3. The reactive voltage regulation control strategy of claim 1, wherein, In step 3, the AVC master station obtains the central point voltage reference value information issued by the three-level voltage control every 15 minutes, and performs one round of secondary voltage control optimization calculation every 5 minutes based on the reactive power adjustable capacity reported by each conventional substation and the coordinated control station, and the AVC master station performs reactive power optimization calculation with the minimum central point voltage offset and the reactive power balance of the conventional substation and the coordinated control station as the target, and the target function is: ； wherein, AQ g is an optimization variable, i.e., the total reactive power regulation demand of the coordination control station in this round of regulation; W p is a voltage offset component, AU p is a voltage deviation value of the hub point in the jurisdictional area of the AVC master station, C g is a reactive power voltage sensitivity matrix of the hub point; W q is a reactive power balance component, Q g , Q g.max , Q g.min respectively represent the current reactive power, the upper limit of reactive power and the lower limit of reactive power of each conventional substation and coordination control station. The equality constraint of the master station optimization model is the active and reactive power balance equation between each node in the system, and the specific expression is: ； wherein, Pgiand Qgiare, respectively, the active and reactive power generation of the i-th node; Pdiand Qdiare, respectively, the active and reactive power demand of the i-th node; Reand Imare, respectively, the real and imaginary parts of the nodal admittance matrix element Reand Im. The inequality constraint in the optimization model is the single-step adjustment amount constraint, the voltage constraint and the reactive power amount constraint of the conventional substation and the coordinated control station, and the specific expression is: ； wherein C g is the reactive power and voltage sensitivity matrix of each coordinated control station and conventional substation, U p , U p.max , U p.min respectively represent the current voltage, upper voltage limit and lower voltage limit of the hub point, U H , U H.max , U H.min and ΔU H respectively represent the current voltage, upper voltage limit, lower voltage limit and the allowed single-step maximum adjustment of each conventional substation and coordinated control station; The master station obtains the optimal reactive power adjustment amount of each regular substation and the coordinated control station in the current round through optimization calculation, and directly issues the optimal reactive power adjustment amount to each regular substation and the coordinated control station; or through matrix C g After being converted into voltage instructions, the voltage instructions or voltage deviation instructions are issued to the regular substation and the coordinated control station; or after synchronously obtaining the active power output values of each regular substation and the coordinated control station, the power factor adjustment instructions are issued.

4. The reactive voltage regulation control strategy of claim 1, wherein, In step 3, the conventional substation and the coordination substation judge the instruction type after accepting the instruction of the AVC master station, select the appropriate calculation formula according to the instruction type, and obtain the reactive power regulation amount: (1) When the instruction of the AVC master station is the reactive power deviation instruction, no transformation calculation is needed; (2) When the instruction of the AVC master station is the voltage deviation instruction, the voltage deviation instruction is transformed into the reactive power regulation amount according to the reactive power voltage sensitivity, and the specific calculation formula is: ； Wherein, ΔU target_g is the voltage deviation instruction issued by the AVC master station, λ is the reactive voltage sensitivity setting value of the conventional substation and the coordinated control station, which is related to the line impedance from the conventional substation and the coordinated control station to the corresponding hub node and is equal to , X0 is the line impedance from the conventional substation and the coordinated control station to the hub node; (3) When the instruction of the AVC master station is the voltage instruction, the voltage instruction is transformed into the reactive power regulation amount according to the reactive power voltage sensitivity, and the specific calculation formula is: ； Wherein, U target_g is the voltage instruction issued by the AVC master station, U g is the real-time voltage of the conventional substation and the coordinated control station. (4) When the instruction of the AVC master station is the power factor instruction, the power factor instruction is transformed into the reactive power regulation amount according to the current active power of the conventional substation and the coordination substation, and the specific calculation formula is: ； Wherein, ζ target is the power factor instruction issued by the AVC master station, ζ0 is the real-time power factor of the regular substation and the coordinated control station, Q0 is the real-time reactive power of the regular substation and the coordinated control station, P g is the real-time active power of the regular substation and the coordinated control station, when the influence of active fluctuation and reactive regulation on active loss is not considered, P g is approximately a constant value, and the reactive regulation amount of the regular substation and the coordinated control station is obtained according to the above formula.

5. The reactive voltage regulation control strategy of claim 1, wherein, In step 4, the conventional substation adjusts the reactive power capacity in the substation, completes the instruction regulation, and if the one-time regulation is not in place due to inaccurate sensitivity setting, the voltage deviation is measured again after each reactive power regulation to complete the instruction through multiple reactive power regulations.

Images