Reactive voltage regulation control strategy containing AVC (Automatic Voltage Control) coordinated control station

Abstract

The invention discloses a reactive voltage regulation control strategy containing an AVC (Automatic Voltage Control) coordination control station. A substation / switching station node where multiple power stations converge is provided with a coordination control station; aVC substations administered by the cooperative control stations report the residual adjustable reactive power capacity to the cooperative control stations, and each conventional substation or the cooperative control station reports the total residual adjustable reactive power capacity in the station or the convergence area to the AVC master station; the AVC master station carries out secondary voltage control optimization calculation on the power grid in the control area and issues regulation instructions to the conventional substations and the coordinated control station, and the conventional substations and the coordinated control station convert the instructions into reactive regulation variables; the conventional substation adjusts the reactive capacity in the substation; the coordinated control station calculates a total reactive power regulation quantity demand to be issued according to the topological structure of the AVC substation under the control and the real-time reactive power output of the AVC substation; the coordinated control station calculates and issues reactive regulation quantity instructions of the AVC substations administered in the round; and each sub-station under the jurisdiction receives the instruction issued by the coordinated control station and completes reactive power regulation. The communication gap between the master station and the substation is made up, and the reactive power regulation capacity of the multi-power-plant-station collection area is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of reactive power voltage control of power grids, and particularly to a reactive power voltage regulation and control strategy including an AVC coordinated control station. Background Art

[0002] With the continuous expansion of the scale of power grids and the rapid growth of the access ratio of new energy, the importance of reactive power voltage regulation has become increasingly prominent. However, the current provincial Automatic Voltage Control (AVC) system mainly communicates directly between the master station and a series of slave stations at power generation nodes. The master station is responsible for the reactive power optimization calculation of the entire region and issues reactive power voltage regulation instructions to each slave station, and the slave stations complete the regulation tasks according to the instructions. This architecture has obvious 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 of reactive power voltage regulation among the slave stations in the near-region aggregation, in the absence of a coordinated regulation mechanism, serious problems such as voltage overshoot and abnormal voltage fluctuations in local areas are likely to be caused by factors such as unreasonable setting of reactive power voltage sensitivity and response speed, threatening the safe and stable operation of the power system.

[0003] The above problems are particularly prominent in scenarios with a high penetration rate of new energy and a complex power grid structure. Therefore, there is an urgent need to introduce a coordinated control unit that can make up for the communication gap between the master station and the slave stations and improve the reactive power regulation ability in areas where multiple power generation stations are aggregated, so as to achieve more accurate and effective reactive power voltage regulation. Summary of the Invention

[0004] Object of the Invention: Aiming at the above problems, the present invention provides a reactive power voltage regulation and control strategy including an AVC coordinated control station, which can make up for the communication gap between the master station and the slave stations and improve the reactive power regulation ability in areas where multiple power generation stations are aggregated, so as to achieve more accurate and effective reactive power voltage regulation.

[0005] Technical Solution: The present invention discloses a reactive power voltage regulation and control strategy including an AVC coordinated control station, which comprises the following steps:

[0006] Step 1: Set up a coordinated control station at the substation / switching station node where multiple power generation stations in the power grid are aggregated;

[0007] Step 2: The AVC slave stations under the jurisdiction of the coordinated control station report the remaining adjustable reactive power capacity to the coordinated control station, and each conventional slave station or the coordinated control station reports the overall remaining adjustable reactive power capacity within the station or the aggregated area to the AVC master station;

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

[0009] (3.1) The AVC master station receives the reactive power adjustable capacities reported by each conventional slave station and the coordinated control station, and performs secondary voltage control optimization calculation on 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 sub-station and coordinated control station.

[0011] (3.3) Each conventional sub-station and coordinated control station converts the AVC master station commands into reactive power adjustment amounts.

[0012] Step 4: The conventional sub-station adjusts the reactive power capacity within the station to complete the command adjustment.

[0013] Step 5: The coordinated control station calculates the total reactive power adjustment amount demand to be issued based on the topological structure of the AVC sub-stations under its jurisdiction and their real-time reactive power output.

[0014] Step 6: The coordinated control station calculates and issues reactive power adjustment commands for each AVC sub-station under its jurisdiction in this round according to the principle of balancing the remaining adjustable reactive power capacity of each AVC sub-station under its jurisdiction.

[0015] Step 7: Each sub-station under jurisdiction receives the commands issued by the coordinated control station and completes reactive power adjustment.

[0016] Step 8: The coordinated control station determines whether the target commands issued by the AVC master station are adjusted in place. If not, it returns to Step 5 and issues the next round of reactive power adjustment commands to the AVC sub-stations under its jurisdiction until the adjustment is in place or the current secondary reactive power voltage control command cycle ends.

[0017] Further, in Step 1, in the AVC system, the coordinated control station, as a subordinate communication unit of the AVC master station, receives the AVC master station commands and has the same status as the conventional AVC sub-stations set in power plants that are connected to the power grid in a single-point manner. At the same time, the coordinated control station, as a superior communication unit of the power plants under its jurisdiction, issues reactive power adjustment commands to the AVC sub-stations of each power plant under its jurisdiction.

[0018] Further, in Step 3, the AVC master station obtains the central point voltage reference value information issued by the tertiary voltage control every 15 minutes, and based on the reactive power adjustable capacity reported by each conventional sub-station and coordinated control station, conducts an optimization calculation for the secondary voltage control every 5 minutes. The secondary control of the AVC master station conducts a reactive power optimization calculation with the goal of minimizing the central point voltage offset and balancing the reactive power of the conventional sub-stations and coordinated control stations. Its objective function is:

[0019]

[0020] where, ΔQ g is the optimization variable, that is, the reactive power adjustment amounts of each conventional sub-station and coordinated control station within this round of adjustment; the W p term is the voltage offset component, ΔU p is the central point voltage deviation value within the jurisdiction area of this AVC master station, and C g is the reactive power voltage sensitivity matrix of the central point; Wq The item is the reactive power balance component, Q g , Q g.max , Q g.min respectively represent the current reactive power, reactive power upper limit and reactive power lower limit of each conventional substation and coordinated control station;

[0021] The equality constraint of the master station optimization model is the active and reactive power balance equations between nodes in the system, and the specific expression is:

[0022]

[0023] Among them, P Gi , Q Gi are respectively the active and reactive power outputs of the generator at the i-th node; P Li , Q Li are respectively the active and reactive power demands of the load at the i-th node; G ij , B ij are respectively the real part and imaginary part of the element Y ij of the node admittance matrix;

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

[0025]

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

[0027] After the master station obtains the optimal reactive power adjustment amount of each conventional substation and coordinated control station in this round through optimization calculation, it directly issues it to each conventional substation and coordinated control station; or it is converted into a voltage command through the matrix C g and then issues a voltage command or a voltage deviation command to the conventional substation and coordinated control station; or after synchronously obtaining the active power output values of each conventional substation and coordinated control station, it issues a power factor adjustment command.

[0028] Furthermore, in step 3, after the conventional substation and the coordinated control station receive the AVC master station command, they judge the command type and select a suitable calculation formula according to each command type to obtain the reactive power adjustment amount:

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

[0030] (5) When the AVC master station instruction is a voltage bias instruction, the voltage deviation instruction is converted into a reactive power regulation amount according to the reactive power-voltage sensitivity. The specific calculation formula is:

[0031] ΔQ g =λΔU target_g

[0032] Where, ΔU target_g is the voltage deviation instruction issued by the AVC master station, and λ is the set value of the reactive power-voltage sensitivity of the conventional substation and the coordinated control station. It is related to the line impedance from the conventional substation and the coordinated control station to the corresponding central node and can be approximately equal to X 0 is the line impedance from the conventional substation and the coordinated control station to the central point;

[0033] (6) When the AVC master station instruction is a voltage instruction, the voltage instruction is converted into a reactive power regulation amount according to the reactive power-voltage sensitivity. The specific calculation formula is:

[0034] ΔQ g =λ(U target_g -U g )

[0035] Where, U target_g is the voltage instruction issued by the AVC master station, and U g is the real-time voltage of the conventional substation and the coordinated control station;

[0036] (4) When the AVC master station instruction is a power factor instruction, the power factor instruction is converted into a reactive power regulation amount according to the aggregated active power of the current conventional substation and the coordinated control station. The specific calculation formula is:

[0037] ΔQ g =[tan(arcζ target )-tan(arcζ 0 )]P g =tan(arcζ target )P g -Q 0

[0038] Where, ζ target is the power factor instruction issued by the AVC master station, ζ 0 is the real-time power factor of the conventional substation and the coordinated control station, Q 0 is the real-time reactive power of the conventional substation and the coordinated control station, P g is the real-time active power of the conventional substation and the coordinated control station. When the influence of active power fluctuation and reactive power regulation on active power loss is not considered, approximately let P gis a constant value, and the reactive power regulation amounts of the conventional substation and the coordinated control station are obtained according to the above formula.

[0039] Further, in the step 4, the conventional substation adjusts the reactive power capacity within the station. After completing the command adjustment, if the first adjustment is not in place due to inaccurate sensitivity setting, the voltage deviation is re-measured after each reactive power adjustment, and the command is completed based on multiple reactive power adjustments.

[0040] Further, in the step 5, the coordinated control station calculates the total reactive power regulation amount requirements of each subordinate substation according to the power grid topology structure and the real-time reactive power output of each subordinate substation. When the quadratic term and the active power fluctuation are not considered, the specific calculation formula is:

[0041]

[0042] where n is the number of subordinate substations under the jurisdiction of the coordinated control station in this cycle, Q 1 , Q 2 , …, Q n and ΔQ 1 , ΔQ 2 , …, ΔQ n are the real-time reactive power output and the reactive power output in this cycle of each subordinate substation respectively, X 1 , X 2 , …, X n are the line reactances of each subordinate substation from the collection point, X is the line reactance of the collection point from the coordinated control station, U 1 , U 2 , …, U n are the voltages of each subordinate substation.

[0043] Further, in the step 6, the coordinated control station performs reactive power distribution according to the principle of balancing the remaining adjustable reactive power capacity of each subordinate AVC substation, and specifically satisfies the formula:

[0044]

[0045] where ΔQ max _ i is the remaining adjustable reactive power capacity of each subordinate substation;

[0046] Based on the above principle and the total reactive power regulation amount of the subordinate substations, the output of each subordinate substation satisfies:

[0047]

[0048] According to the least square method, the reactive power output of each subordinate substation is:

[0049]

[0050] where the matrix A satisfies

[0051] Due to constraint redundancy, there is a deviation between the reactive power outputs of each subordinate substation obtained according to the above derivation and the total reactive power regulation demand ΔQ of the coordinated control station. To ensure the matching of the reactive power quantity collected by the coordinated control station and the AVC master station's command, the deviation quantity is evenly distributed to each subordinate substation, and each subordinate substation needs to supplement the reactive power output: g

[0052]

[0053] Therefore, the reactive power regulation quantity command issued by the coordinated control station to each subordinate substation is:

[0054] ΔQ i ′ = ΔQ i + ΔQ di

[0055] where ΔQ i ′ is the reactive power regulation quantity command value issued by the coordinated control station to each subordinate substation.

[0056] Beneficial effects:

[0057] The present invention focuses on the relationship between the provincial dispatching side and the substation side in secondary voltage control. At the same time, considering that after the multi-point aggregation of new energy substations, due to the mutual coupling effect of their reactive power-voltage regulation characteristics, there is a reason for easy voltage abnormal fluctuations in participating in AVC regulation. A coordinated control station is added between the provincial dispatching side and the substation side. The present invention specifically sets a coordinated control station for the topological structure of "multi-new energy substation aggregation", and gives the specific strategies for the conventional AVC substation and the coordinated control station to jointly participate in the secondary voltage control of the AVC substation. The calculation methods for the AVC substation and the coordinated control station to receive different commands from the AVC master station are deduced; the calculation method for the reactive power regulation quantity of each new energy substation under the coordinated control station considering the coupling relationship is also deduced, thus constituting a complete reactive power-voltage regulation strategy including an AVC coordinated control station.

[0058] In the operation of the present invention, by setting an AVC coordinated control station in the multi-power plant substation aggregation area, the efficient collaborative control between the AVC master station and the original AVC substation is realized. As the subordinate communication unit of the master station and the superior communication unit of the substation, the coordinated control station undertakes the functions of data aggregation, optimized distribution, and command transmission, effectively making up for the lack of coordination in the reactive power-voltage control of the traditional AVC system in the regional power grid. The present invention accurately obtains the total remaining adjustable reactive power capacity of the aggregation area through the coordinated control station, combines the power grid topology and the real-time reactive power output of the substation, and accurately distributes the reactive power regulation tasks of each substation under the principle of balance, which can effectively improve the response speed and accuracy of reactive power regulation, maintain the smoothness of the voltage deviation regulation process, and enhance the stability and economy of power grid operation. Description of the Drawings

[0059] Figure 1 ​It is the flowchart of a reactive power voltage regulation control strategy for the described AVC co-control station;

[0060] Figure 2 It is the control block diagram of the AVC system with a co-control station;

[0061] Figure 3 It is the typical local power grid topological structure with a co-control station. Specific implementation manners

[0062] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0063] The present invention discloses a reactive power voltage regulation control strategy for an AVC co-control station, including the following steps:

[0064] Step 1: Set up a co-control station at the substation / switching station node where multiple power plants in the power grid converge. Set up a co-control station at the substation / switching station node where multiple power plants in the power grid converge. In the AVC system, as a subordinate communication unit of the AVC master station, it receives the instructions of the AVC master station and has the same status as the conventional AVC substation set at the power plant that is connected to the power grid in a single-point manner; at the same time, this co-control station, as the superior communication unit of the power plants under its jurisdiction, issues reactive power regulation instructions to the AVC substations of each power plant under its jurisdiction.

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

[0066] The AVC substations under the jurisdiction of the co-control station are in the online operation mode and report the remaining adjustable reactive power capacity of all reactive power equipment in the station to the co-control station. After the co-control station summarizes the data of each substation under its jurisdiction, it reports the overall remaining adjustable reactive power capacity of the converging area to the AVC master station. At the same time, the conventional substation reports the remaining adjustable reactive power within the station to the AVC master station, which is convenient for the AVC master station to perform constraints during reactive power optimization calculation.

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

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

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

[0070] (3.3) Each conventional substation and co-control station convert the instructions of the AVC master station into reactive power regulation amounts.

[0071] In step 3, the AVC master station obtains the information of the reference voltage value of the central point sent by the tertiary voltage control every 15 minutes, and based on the reactive power adjustable capacity reported by each conventional substation and cooperative control station, conducts a round of secondary voltage control optimization calculation every 5 minutes. The secondary control of the AVC master station conducts reactive power optimization calculation with the goal of minimizing the voltage offset of the central point and balancing the reactive power of the conventional substation and cooperative control station. Its objective function is

[0072]

[0073] Among them, ΔQ g is the optimization variable, that is, the reactive power adjustment amount of each conventional substation and cooperative control station during this round of adjustment; the W p term is the voltage offset component, ΔU p is the voltage deviation value of the central point within the jurisdiction of this AVC master station, C g is the reactive power-voltage sensitivity matrix of the central point; the W q term is the reactive power balance component, Q g , Q g.max , Q g.min respectively represent the current reactive power, reactive power upper limit and reactive power lower limit of each conventional substation and cooperative control station.

[0074] The equality constraint of the master station optimization model is the active and reactive power balance equations between nodes in the system. The specific expression is:

[0075]

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

[0077] The inequality constraints in the optimization model are single-step adjustment amount constraints, voltage constraints and reactive power amount constraints of conventional substations and cooperative control stations. The specific expressions are:

[0078]

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

[0080] After the master station obtains the optimal reactive power regulation amount of each conventional substation and coordinated control station in this round through optimized calculation, it can be directly sent to each conventional substation and coordinated control station; or it can be g converted into a voltage command and sent to the conventional substation and coordinated control station as a voltage command or voltage deviation command through matrix C; or after synchronously obtaining the active power output values of each conventional substation and coordinated control station, send a power factor regulation command.

[0081] After the conventional substation and coordinated control station receive the AVC master station command, they judge the command type and select an appropriate calculation formula according to each command type to obtain the reactive power regulation amount:

[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 amount according to the reactive power-voltage sensitivity. The specific calculation formula is

[0084] ΔQ g =λΔU target_g

[0085] where ΔU target_g is the voltage deviation command issued by the AVC master station, and λ is the set value of the reactive power-voltage sensitivity of the conventional substation and coordinated control station. It is related to the line impedance from the conventional substation and coordinated control station to the corresponding central node and can be approximately equal to where X 0 is the line impedance from the conventional substation and coordinated 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 amount according to the reactive power-voltage sensitivity. The specific calculation formula is

[0087] ΔQ g =λ(U target_g -U g )

[0088] where U target_g is the voltage command issued by the AVC master station, and U g is the real-time voltage of the conventional substation and 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 amount according to the aggregated active power of the current conventional substation and coordinated control station. The specific calculation formula is

[0090] ΔQ g= [tan(arcζ target ) - tan(arcζ 0 )]P g = tan(arcζ target )P g - Q 0

[0091] where ζ target is the power factor command issued by the AVC master station, ζ 0 is the real-time power factor of the conventional substation and the coordinated control station, Q 0 is the real-time reactive power of the conventional substation and the coordinated control station, P g is the real-time active power of the conventional substation and the coordinated control station. When the influence of active power fluctuation and reactive power regulation on active power loss is not considered, P g can be approximately regarded as a constant value, and the reactive power regulation amount of the conventional substation and the coordinated control station can be obtained according to the above formula.

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

[0093] The conventional substation adjusts the reactive power capacity within the station to complete the command adjustment. If the first adjustment is not in place due to inaccurate sensitivity setting, the voltage deviation can be re-measured after each reactive power adjustment, and the command can be completed based on multiple reactive power adjustments.

[0094] Step 5: The coordinated control station calculates the total reactive power regulation amount demand to be issued according to the topological structure of the AVC substations under its jurisdiction and their real-time reactive power output. The coordinated control station calculates the total reactive power regulation amount demand of each substation under its jurisdiction according to the grid topological structure and the real-time reactive power output of each substation under its jurisdiction. When the quadratic term and active power fluctuation are not considered, the specific calculation formula is

[0095]

[0096] where n is the number of substations under the jurisdiction of the coordinated control station in this cycle, Q 1 , Q 2 , …, Q n and ΔQ 1 , ΔQ 2 , …, ΔQ n are the real-time reactive power output and the reactive power output in this cycle of each substation under its jurisdiction respectively, X 1 , X 2 , …, X n are the line reactances of each substation under its jurisdiction from the collection point, X is the line reactance of the collection point from the coordinated control station, U 1 , U 2 , …, U n are the voltages of each substation under its jurisdiction.

[0097] Step 6: The coordinated control station calculates and issues the reactive power regulation amount commands for each subordinate AVC sub-station in this round according to the principle of balancing the remaining adjustable reactive power capacity of each subordinate AVC sub-station.

[0098] The coordinated control station performs reactive power distribution according to the principle of balancing the remaining adjustable reactive power capacity of each subordinate AVC sub-station, specifically satisfying the formula

[0099]

[0100] where, ΔQ max _ i is the remaining adjustable reactive power capacity of each subordinate sub-station.

[0101] Based on the above principle and the total reactive power regulation amount of the subordinate sub-stations, the output of each subordinate sub-station satisfies

[0102]

[0103] According to the least squares method, the reactive power output of each subordinate sub-station can be obtained as

[0104]

[0105] where the matrix A satisfies

[0106] Due to constraint redundancy, there is a deviation between the reactive power output of each subordinate sub-station obtained according to the above derivation and the total reactive power regulation demand ΔQ g of the coordinated control station. To ensure that the aggregated reactive power of the coordinated control station matches the AVC master station command, the deviation amount is evenly distributed to each subordinate sub-station, and each subordinate sub-station needs to supplement the reactive power output

[0107]

[0108] Therefore, the reactive power regulation amount command issued by the coordinated control station to each subordinate sub-station is

[0109] ΔQ i ′ = ΔQ i + ΔQ di

[0110] where, ΔQ i ′ is the reactive power regulation amount command value issued by the coordinated control station to each subordinate sub-station.

[0111] Step 7: Each subordinate sub-station receives the command issued by the coordinated control station and completes reactive power regulation. Each subordinate sub-station can adjust the capacity of its own reactive power compensation equipment as needed to complete the corresponding regulation command.

[0112] Step 8: The coordinated control station determines whether the target instruction issued by the AVC master station has been adjusted in place. If it has not been adjusted in place, return to Step 5 to issue the next round of reactive power adjustment instructions to the subordinate AVC substations under its jurisdiction until the adjustment is in place or the current secondary reactive power voltage control instruction cycle ends.

[0113] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A reactive voltage regulation control strategy including an AVC cooperative control station, characterized in that: The following steps are involved: Step 1: Set up a cooperative control station at the substation / switch station node where multiple power plants gather in the power grid; Step 2: The AVC substations under the cooperative control station report the remaining adjustable reactive capacity to the cooperative control station, and each conventional substation or cooperative control station reports the overall remaining adjustable reactive capacity within the station or collection area to the AVC master station; Step 3: The AVC master station sends secondary control instructions: (3.1) The AVC master station receives the reactive adjustable capacity reported by each conventional substation and cooperative control station, and performs secondary voltage control optimization calculation on the control area power grid; (3.2) The AVC master station sends reactive power, voltage or power factor adjustment instructions to each conventional substation and cooperative control station; (3.3) Each conventional substation and cooperative control station converts the AVC master station command into reactive power regulation; Step 4: The conventional substation adjusts the reactive capacity within the station to complete the instruction adjustment; Step 5: The cooperative control station calculates the total reactive power regulation demand to be issued based on the topological structure of the AVC substation under its jurisdiction and its real-time reactive power output; Step 6: The cooperative control station calculates and issues reactive power regulation instructions for each AVC substation under its jurisdiction in this round according to the principle of balancing the remaining adjustable reactive power capacity of each AVC substation under its jurisdiction; Step 7: Each substation receives the instruction issued by the cooperative control station and completes reactive power regulation; Step 8: The auxiliary control station determines whether the target instruction issued by the AVC master station is adjusted in place. If not, it returns to step 5 and issues the next round of reactive power adjustment instructions to the AVC substations under its jurisdiction until the adjustment is in place or the secondary reactive voltage control instruction cycle ends.

2. A reactive voltage regulation control strategy including an AVC cooperative control station according to claim 1, characterized in that: In the step 1, in the AVC system, the auxiliary control station serves as a subordinate communication unit of the AVC master station and receives instructions from the AVC master station. Its status is the same as that of a conventional AVC substation set up in a power plant station that adopts a single point to feed into the power grid. At the same time, the auxiliary control station serves as an upper-level communication unit of the power plant station under its jurisdiction and issues reactive power regulation instructions to the AVC substations of each power plant station under its jurisdiction.

3. A reactive voltage regulation control strategy including an AVC cooperative control station according to claim 1, characterized in that: 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 a round of secondary voltage control optimization calculation every 5 minutes based on the reactive adjustable capacity reported by each conventional substation and cooperative control station. The secondary control of the AVC master station performs reactive optimization calculation with the goal of minimizing the central point voltage offset and reactive balance of conventional substations and cooperative control stations. Its objective function is: Among them, ΔQ g is the optimization variable, i.e., the reactive power regulation of each conventional substation and cooperative control station in this round of regulation; W p The term is the voltage offset component, ΔU p is the voltage deviation value of the central point in the area under the jurisdiction of the AVC master station, C g is the reactive voltage sensitivity matrix of the central point; W q The term is the reactive balance component, Q g , Q g.max , Q g.min Respectively represent the current reactive power, reactive upper limit and reactive lower limit of each conventional substation and cooperative control station; The equality constraint of the master station optimization model is the active and reactive balance equation between the nodes in the system. The specific expression is: Among them, P Gi ,Q Gi are respectively the active and reactive outputs of the generator at the i-th node; P Li ,Q Li are the active and reactive load demands of the i-th node respectively; G ij ,B ij are the node admittance matrix elements Y ij The real and imaginary parts of The inequality constraints in the optimization model are single-step regulation constraints, voltage constraints, and reactive power constraints for conventional substations and cooperative control stations. The specific expressions are: Among them, C g is the reactive voltage sensitivity matrix of each cooperative 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 central point, U H , U H.max , U H.min and ΔU H Respectively indicate the current voltage, voltage upper limit, voltage lower limit and maximum allowable single-step adjustment of each conventional substation and cooperative control station; After the master station obtains the optimal reactive power regulation of each conventional substation and cooperative control station in this round through optimization calculation, it directly sends it to each conventional substation and cooperative control station; or through matrix C g After being converted into a voltage command, a voltage command or a voltage deviation command is issued to the conventional substation and the cooperative control station; or after synchronously acquiring the active output value of each conventional substation and the cooperative control station, a power factor adjustment command is issued.

4. A reactive voltage regulation control strategy including an AVC cooperative control station according to claim 1, characterized in that: In step 3, after receiving the instruction from the AVC master station, the conventional substation and the cooperative control station determine the instruction type, and select a suitable calculation formula according to each instruction type to obtain the reactive power regulation amount: (1) When the AVC master station instruction is a reactive deviation instruction, no conversion calculation is required; (2) When the AVC master station instruction is a voltage bias instruction, the voltage deviation instruction is converted into a reactive adjustment amount according to the reactive voltage sensitivity. The specific calculation formula is: ΔQ g =λΔU target_g Among them, ΔU target_g is the voltage deviation command issued by the AVC master station, λ is the reactive voltage sensitivity setting value of the conventional substation and the cooperative control station, which is related to the line impedance from the conventional substation and the cooperative control station to the corresponding hub node and can be approximately equal to X0 is the line impedance from conventional substations and cooperative control stations to the central point; (3) When the AVC master station instruction is a voltage instruction, the voltage instruction is converted into a reactive adjustment amount according to the reactive voltage sensitivity. The specific calculation formula is: ΔQ g =λ(U target_g -U g ) Among them, U target_g It is the voltage command issued by the AVC master station, U g Real-time voltage of conventional substations and cooperative control stations; (4) When the AVC master station instruction is a power factor instruction, the power factor instruction is converted into reactive power regulation according to the active power aggregated by the current conventional substations and cooperative control stations. The specific calculation formula is: ΔQ g =[tan(arcζ target )-tan(arcζ0)]P g =tan(arcζ target )P g -Q0 Among them, target is the power factor command issued by the AVC master station, ζ0 is the real-time power factor of the conventional substation and the cooperative control station, Q0 is the real-time reactive power of the conventional substation and the cooperative control station, P g is the real-time active power of the conventional substation and the cooperative control station. When the influence of active power fluctuation and reactive power regulation on active power loss is not considered, P g is a constant value, and the reactive power regulation of the conventional substation and cooperative control station is obtained according to the above formula.

5. The reactive voltage regulation control strategy including the AVC cooperative control station according to claim 1 is characterized in that: In step 4, the conventional substation adjusts the reactive capacity within the station to complete the instruction adjustment. If the sensitivity setting is inaccurate and the adjustment is not in place at one time, the voltage deviation is re-measured after each reactive adjustment and the instruction is completed based on multiple reactive adjustments.

6. A reactive voltage regulation control strategy including an AVC cooperative control station according to claim 1, characterized in that: In step 5, the cooperative control station calculates the total reactive power regulation demand of each subordinate substation according to the grid topology and the real-time reactive power output of each subordinate substation. When the secondary term and active power fluctuation are not considered, the specific calculation formula is: Among them, n is the number of substations managed by the cooperative control station in this cycle, Q1, Q2, ..., Q n and ΔQ1, ΔQ2, …, ΔQ n are the real-time reactive power output of each substation and the reactive power output of this round, X1, X2, …, X n is the line reactance from each substation to the collection point, X is the line reactance from the collection point to the cooperative control station, U1, U2, ..., U n The voltage of each substation under its jurisdiction.

7. The reactive voltage regulation control strategy including the AVC cooperative control station according to claim 1, characterized in that: In step 6, the cooperative control station distributes reactive power according to the principle of balancing the remaining adjustable reactive capacity of each AVC substation under its jurisdiction, and specifically satisfies the formula: Among them, ΔQ max_i The remaining adjustable reactive capacity of each substation under its jurisdiction; Based on the above principles and the total reactive power regulation of the substations under its jurisdiction, the output of each substation under its jurisdiction meets the following requirements: According to the least squares method, the reactive power output of each substation can be obtained as: The matrix A satisfies Due to the redundancy of constraints, the reactive power output of each substation obtained from the above derivation and the total reactive power regulation demand ΔQ of the cooperative control station g There is a deviation between the two. To ensure that the reactive power collected by the cooperative control station matches the instructions of the AVC master station, the deviation is evenly distributed to each substation under its jurisdiction. Each substation under its jurisdiction needs to supplement reactive power: Therefore, the reactive power regulation instructions issued by the cooperative control station to each substation under its jurisdiction are: ΔQ′ i =ΔQ i +ΔQ di Among them, ΔQ′ i It is the reactive power regulation instruction value issued by the cooperative control station to each substation under its jurisdiction.

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