Reactive voltage coordination control method for transformer substation and new energy station

Abstract

The invention provides a transformer substation and new energy station reactive voltage coordination control method, which comprises the following steps: when an AVC system control strategy calculation cycle arrives, forming a control subarea by a 220kV transformer substation and all new energy stations connected with the 220kV transformer substation, and setting a 220kV bus of the transformer substation as a pilot bus; when the pilot bus voltage needs to be optimized, firstly, the operation state of reactive equipment of a transformer substation is adjusted; and then, according to the regulating variable of the pilot bus voltage, calculating the reactive power regulating variable of a new energy station generator set in the control subarea, and regulating the grid-connected bus voltage not to be out of limit so as to realize reactive power voltage coordination control of the control subarea. The reactive voltage regulation means of the new energy station and the transformer substation are coordinated, it is guaranteed that the voltages of the pilot bus and the grid-connected bus of the new energy station are qualified to the maximum extent, the problem of reactive voltage reverse regulation of the new energy station and the transformer substation is solved, and the safety and economical efficiency of power grid operation are improved.

Description

Technical Field

[0001] This invention belongs to the field of voltage control technology, and specifically relates to a method for coordinated control of reactive power and voltage in substations and new energy power plants. Background Technology

[0002] Automatic Voltage Control (AVC) systems are crucial for ensuring the safe (improved voltage stability margin), economical (reduced network losses), and high-quality (improved voltage qualification rate) operation of power transmission networks. Built upon the Power Grid Energy Management System (EMS), the AVC system utilizes real-time operational data from the power grid to scientifically determine the optimal reactive power and voltage adjustment scheme from a global network optimization perspective, automatically distributing the scheme to power plants, substations, and lower-level grid dispatching agencies for execution.

[0003] In their paper "Design of a Global Voltage Optimization Control System Based on Soft Partitioning" (Automation of Electric Power Systems, 2003, Vol. 27, No. 8, pp. 16-20), Sun Hongbin, Zhang Boming, and Guo Qinglai described the architecture of automatic voltage control (AVC) for large power grids. The master station of the AVC system is implemented in software at the power system control center. Its voltage control strategies for the transmission network mainly fall into two categories: reactive power control strategies for each generator in the power plant and reactive power equipment control strategies for substations. Currently, the main approach for reactive power control of each generator in the power plant is as follows: the AVC master station system at the dispatch center calculates the reactive power adjustment amount for each unit in the power plant through reactive power optimization and then sends it to the AVC substation system of the power plant via a data communication channel. Upon receiving the generator reactive power adjustment amount, the power plant's AVC substation adjusts the reactive power output of the generators in a step-by-step manner according to the current operating status of each generator in the power plant until the adjustment amount sent by the AVC master station is reached.

[0004] Currently, with a large number of new energy power plants (including photovoltaic power plants, wind farms, and energy storage stations) being connected to the grid through substations, the reactive power and voltage conflict between new energy power plants and substations is becoming increasingly serious. In traditional automatic voltage control, substations and new energy power plants are calculated and controlled independently, without considering the voltage constraints of the grid-connected bus. After the new energy power plants adjust according to the optimized voltage, the bus voltage of substations directly connected to the grid exceeds the limit. When the bus voltage of substations with new energy grid connection exceeds the limit, the equipment in the substation adjusts the voltage to eliminate the voltage limit, causing the problem of reverse reactive power regulation between new energy power plants and substations, reducing the reactive power and voltage safety margin of the system.

[0005] In summary, with the rapid expansion of the power grid and the widespread application of automatic voltage control systems, there is an urgent need to coordinate the reactive voltage regulation sequence of new energy power plants and substations, and to solve the problem of unreasonable reactive voltage control on the busbars of new energy power plants and directly connected substations. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a method for coordinated reactive power and voltage control between substations and renewable energy plants. This invention can fully utilize the reactive power and voltage regulation capabilities of substations and renewable energy plants to ensure, to the maximum extent possible, the qualified voltage of the busbar of the central busbar and the substation directly connected to the grid by the renewable energy plant, thus solving the problem of reverse reactive power and voltage regulation between renewable energy plants and substations, and improving the safety and economy of power grid operation.

[0007] This invention proposes a method for coordinated reactive power and voltage control between substations and renewable energy power plants, comprising:

[0008] When the AVC system control strategy calculation cycle arrives, the 220kV substation and all the new energy power stations connected to it are grouped into a control zone, and the 220kV bus of the substation is set as the central bus.

[0009] When the central bus voltage needs to be optimized, the operating status of the reactive power equipment of the substation is first adjusted; then, based on the adjustment amount of the central bus voltage, the reactive power adjustment amount of the generator units of the new energy power stations in the control zone is calculated, and the grid-connected bus voltage is adjusted to not exceed the limit, so as to achieve coordinated control of reactive power and voltage in the control zone.

[0010] In one specific embodiment of the present invention, it further includes:

[0011] Based on the results of power flow calculations, determine whether the central bus voltage needs optimization, wherein:

[0012] like - If M, that is, the absolute value of the central bus voltage regulation is greater than the dead zone, then the central bus voltage needs to be optimized;

[0013] like - If |≤M, then the central bus voltage is already within the optimization range and no adjustment is needed in the current cycle;

[0014] Where M is the dead zone for optimizing the central bus voltage. This is the current voltage of the central bus. Optimize the target value for the central bus voltage.

[0015] In one specific embodiment of the present invention, it further includes:

[0016] When the operating status of the reactive power equipment in the substation within the control zone is inconsistent with the optimization direction of the central bus voltage, the reactive power equipment in the substation shall be adjusted first, wherein:

[0017] When the voltage of the central bus falls below the lower limit, check whether there are any operating reactors in the substation within the control zone. If so, remove the reactors.

[0018] When the voltage of the central bus exceeds the upper limit, check whether there are any operating capacitors in the substation within the control zone. If so, remove the capacitors.

[0019] In a specific embodiment of the present invention, the step of calculating the reactive power adjustment of the generator units of the new energy power station within the control zone and adjusting the grid-connected bus voltage to prevent it from exceeding the limit includes:

[0020] 1) If the central bus voltage regulation amount >M, then the voltage of the central bus is increased by boosting the voltage of the new energy power stations within the control zone, where, The specific steps are as follows:

[0021] 1-1) Adjustment amount based on the central bus And the sensitivity of the generator units of new energy power stations to the central bus. Calculate the reactive power adjustment of the i-th generator unit in the new energy power station:

[0022]

[0023] 1-2) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of the generator sets in new energy power plants to the control bus Calculate the adjustment amount of the reactive power regulation of the i-th generator unit in the new energy power station on the control bus voltage:

[0024]

[0025] This leads to the voltage regulation of the control bus of the new energy power station:

[0026]

[0027] Where I represents the total number of generator units in the new energy power station;

[0028] 1-3) Current voltage of the control bus Voltage adjustment of the control bus of the new energy power station Summing these values ​​yields the adjusted target voltage value for the renewable energy power station:

[0029]

[0030] 1-4) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of generator units at new energy power plants to grid connection bus Calculate the adjustment amount of the reactive power adjustment of the i-th generator unit in the new energy power station on the grid-connected bus voltage:

[0031]

[0032] This leads to the total voltage adjustment of the grid-connected bus:

[0033]

[0034] 1-5) Current voltage of the grid-connected bus Total adjustment of grid bus voltage Summing these values ​​yields the estimated voltage of the grid-connected bus after adjustments for the renewable energy power station:

[0035]

[0036] 1-6) Estimated voltage of the grid-connected bus after adjustment of the new energy power station Make a judgment:

[0037] like , The minimum voltage limit for the grid-connected bus set in the AVC system. If the maximum voltage limit for the grid-connected bus is set in the AVC system, then the AVC system will issue an optimized voltage target value to the renewable energy power plant. ;

[0038] like Then the AVC system sends a leveling command to the new energy power station, i.e., the current voltage. Issue reactive power reduction requirements to substations To reduce the voltage of the grid-connected bus; when the substation receives a reactive power reduction control request At that time, the upper limit of the substation grid-connected bus voltage is set to the current voltage. The substation adjusts the reactive power equipment or the tap position of the main transformer to reduce the voltage of the grid-connected bus.

[0039] 2) If If <-M, then the voltage of the central bus is reduced by stepping down the voltage of the new energy power stations within the zone; the specific steps are as follows:

[0040] 2-1) Adjustment amount based on the central bus And the sensitivity of the generator units of new energy power stations to the central bus. Calculate the reactive power adjustment of the j-th generator unit in the new energy power station:

[0041]

[0042] 2-2) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of the generator sets in new energy power plants to the control bus Calculate the adjustment amount of reactive power regulation of the generator units in the new energy power station on the control bus voltage:

[0043]

[0044] This leads to the voltage regulation of the control bus of the new energy power station:

[0045]

[0046] 2-3) Current voltage of the control bus Voltage adjustment of the control bus of the new energy power station The difference is calculated to obtain the adjusted target voltage value for the renewable energy power station:

[0047]

[0048] 2-4) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of generator units at new energy power plants to grid connection bus Calculate the adjustment amount of the reactive power adjustment of the j-th generator unit in the new energy power station on the grid bus voltage:

[0049]

[0050] This leads to the total voltage adjustment of the grid-connected bus:

[0051]

[0052] 2-5) Current voltage of the grid-connected bus Total adjustment of grid bus voltage By subtracting the values, we obtain the estimated voltage of the grid-connected bus after the adjustment of the new energy power station:

[0053]

[0054] 2-6) Estimated voltage of the grid-connected bus after adjustment of the new energy power station Make a judgment:

[0055] like Then the AVC system sends the optimized voltage target value to the new energy power station. ;

[0056] like Then the AVC system sends a leveling command to the new energy power station, i.e., the current voltage. Issued a request for increased reactive power to the substation. To increase the voltage of the grid-connected bus; when the substation receives a request for increased reactive power control. At that time, the lower limit of the substation grid-connected bus voltage is set to the current voltage. The substation adjusts the reactive power equipment or the tap position of the main transformer to increase the voltage of the grid-connected bus.

[0057] Features and beneficial effects of the present invention:

[0058] This invention incorporates the bus voltage constraint of substations directly connected to the grid from renewable energy power plants into the automatic voltage calculation and control, coordinating the reactive voltage regulation capabilities of renewable energy power plants and substations, maximizing the guarantee of qualified voltage on the central bus and the grid-connected bus of renewable energy power plants, solving the problem of reverse reactive voltage regulation between renewable energy power plants and substations, and improving the safety and economy of power grid operation. Attached Figure Description

[0059] Figure 1 This is an overall flowchart of a reactive power and voltage coordination control method for substations and new energy power plants according to an embodiment of the present invention.

[0060] Figure 2 This is a schematic diagram of the topology for coordinated reactive power and voltage control of substations and new energy power plants in a specific embodiment of the present invention. Detailed Implementation

[0061] This invention proposes a method for coordinated control of reactive power and voltage in substations and new energy power plants. The invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments of this invention include, but are not limited to, the following.

[0062] This invention proposes a method for coordinated reactive power and voltage control between substations and renewable energy power plants, comprising:

[0063] When the AVC system control strategy calculation cycle arrives, the 220kV substation and all the new energy power stations connected to it are grouped into a control zone, and the 220kV bus of the substation is set as the central bus.

[0064] When the central bus voltage needs to be optimized, the operating status of the reactive power equipment of the substation is first adjusted; then, based on the adjustment amount of the central bus voltage, the reactive power adjustment amount of the generator units of the new energy power stations in the control zone is calculated, and the grid-connected bus voltage is adjusted to not exceed the limit, so as to achieve coordinated control of reactive power and voltage in the control zone.

[0065] In a specific embodiment of the present invention, the overall process of the reactive power and voltage coordinated control method for substations and renewable energy power plants is as follows: Figure 1 As shown, it includes the following steps:

[0066] 1) When the AVC system control strategy calculation cycle arrives, according to the topology, the new energy power stations that are electrically connected to the 220kV substation are retrieved, the 220kV substation and all the new energy power stations connected to it are combined into a control zone, and the 220kV bus of the substation is set as the central bus.

[0067] In this embodiment, the h-th control partition is denoted as ;

[0068] ;

[0069] in, For the j-th central busbar of the h-th partition, For the k-th substation in the h-th zone, This is the control bus for the l-th new energy power station in the h-th zone. For the m-th reactive power device in the h-th substation, This refers to the nth new energy power station generator unit in the hth partition.

[0070] 2) Based on the results of step 1), power flow calculations are performed on the power grid to obtain the sensitivity of the new energy power station generator units to the central bus, the sensitivity of the new energy power station generator units to the control bus, the sensitivity of the new energy power station generator units to the grid-connected bus, the sensitivity of the substation capacitors to the substation buses at each voltage level, and the optimized target value of the central bus voltage.

[0071] In this embodiment, by calculating the power flow, the sensitivity of the new energy power station generator units to the central bus is obtained for any control zone. Sensitivity of new energy power station generator units to control bus Sensitivity of new energy power station generator units to grid connection bus The sensitivity of the reactive power equipment in the substation to the high-voltage busbar of the substation The sensitivity of the reactive power equipment in the substation to the medium voltage side busbar of the substation The sensitivity of the reactive power equipment in the substation to the low-voltage busbar of the substation and the target value of the central bus voltage optimization .

[0072] 3) Based on the results of step 2), determine whether the central bus voltage needs to be optimized.

[0073] In this embodiment, the dead zone for optimizing the central bus voltage is set to M, and the current voltage of the central bus is... ,determination:

[0074] like - If M, meaning the absolute value of the central bus voltage regulation is greater than the dead zone, then the equipment within the zone needs to be adjusted to bring the central bus voltage within the optimized range, and then proceed to step 4).

[0075] like - If |≤M, then the central bus voltage is already within the optimization range, no adjustment is needed in the current cycle, the substation equipment is not adjusted, a level adjustment command is issued to the new energy power station, and then proceed to step 7).

[0076] 4) Determine whether the operating status of the substation's reactive power equipment is consistent with the optimization direction of the central bus voltage:

[0077] 4-1) If they match, proceed to step 5).

[0078] 4-2) If inconsistent, prioritize adjusting the reactive power equipment in the substation, then proceed to step 5), where:

[0079] When the voltage of the central bus falls below the lower limit, check whether there are any operating reactors in the substation within the zone. If so, disconnect the reactors.

[0080] When the voltage of the central bus exceeds the upper limit, check whether there are any operating capacitors in the substation within the zone. If so, remove the capacitors.

[0081] 5) Based on the central bus voltage regulation, calculate the reactive power regulation of the generator units in the control zone of the new energy power stations, and check whether the grid-connected bus voltage is qualified; the specific steps are as follows:

[0082] 5-1) Let the voltage regulation of the central bus be... ,like If M > M, then the voltage of the central bus is increased by boosting the voltage of the new energy power stations within the zone; the specific steps are as follows:

[0083] 5-1-1) Adjustment amount based on the central bus And the sensitivity of the generator units of new energy power stations to the central bus. Calculate the reactive power adjustment of the i-th generator unit in the new energy power station:

[0084]

[0085] 5-1-2) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of the generator sets in new energy power plants to the control bus Calculate the adjustment amount of the reactive power regulation of the i-th generator unit in the new energy power station on the control bus voltage:

[0086]

[0087] This leads to the voltage regulation of the control bus of the new energy power station:

[0088]

[0089] Where I represents the total number of generator units in the new energy power station.

[0090] 5-1-3) Current voltage of the control bus Voltage adjustment of the control bus of the new energy power station Summing these values ​​yields the adjusted target voltage value for the renewable energy power station:

[0091]

[0092] 5-1-4) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of generator units at new energy power plants to grid connection bus Calculate the adjustment amount of the reactive power adjustment of the i-th generator unit in the new energy power station on the grid-connected bus voltage:

[0093]

[0094] This leads to the total voltage adjustment of the grid-connected bus:

[0095]

[0096] 5-1-5) Current voltage of the grid-connected bus Total adjustment of grid bus voltage Summing these values ​​yields the estimated voltage of the grid-connected bus after adjustments for the renewable energy power station:

[0097]

[0098] 5-1-6) Estimated voltage of the grid-connected bus after adjustment of the new energy power station Make a judgment:

[0099] like , The minimum voltage limit for the grid-connected bus set in the AVC system. If the maximum voltage limit for the grid-connected bus is set in the AVC system, then the AVC system will issue an optimized voltage target value to the renewable energy power plant. Then proceed to step 7).

[0100] like Then the AVC system sends a leveling command to the new energy power station, i.e., the current voltage. Issue reactive power reduction requirements to grid-connected substations This is done to reduce the grid-connected bus voltage, and then proceed to step 6).

[0101] 5-2) If If <-M, then the voltage of the central bus is reduced by stepping down the voltage of the new energy power stations within the zone; the specific steps are as follows:

[0102] 5-2-1) Adjustment amount based on the central bus And the sensitivity of the generator units of new energy power stations to the central bus. Calculate the reactive power adjustment of the j-th generator unit in the new energy power station:

[0103]

[0104] 5-2-2) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of the generator sets in new energy power plants to the control bus Calculate the adjustment amount of reactive power regulation of the generator units in the new energy power station on the control bus voltage:

[0105]

[0106] This leads to the voltage regulation of the control bus of the new energy power station:

[0107]

[0108] 5-2-3) Current voltage of the control bus Voltage adjustment of the control bus of the new energy power station The difference is calculated to obtain the adjusted target voltage value for the renewable energy power station:

[0109]

[0110] 5-2-4) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of generator units at new energy power plants to grid connection bus Calculate the adjustment amount of the reactive power adjustment of the j-th generator unit in the new energy power station on the grid bus voltage:

[0111]

[0112] This leads to the total voltage adjustment of the grid-connected bus:

[0113]

[0114] 5-2-5) Current voltage of the grid-connected bus Total adjustment of grid bus voltage By subtracting the values, we obtain the estimated voltage of the grid-connected bus after the adjustment of the new energy power station:

[0115]

[0116] 5-2-6) Estimated voltage of the grid-connected bus after adjustment of the new energy power station Make a judgment:

[0117] like Then the AVC system sends the optimized voltage target value to the new energy power station. Then proceed to step 7).

[0118] like Then the AVC system sends a leveling command to the new energy power station, i.e., the current voltage. Issue additional reactive power demand to grid-connected substations To increase the grid-connected bus voltage, then proceed to step 6).

[0119] 6) Based on the results of step 5), adjust the substation equipment to eliminate the voltage over-limit of the grid bus.

[0120] In this embodiment, when the substation control module receives a reactive power reduction control request... At that time, the upper limit of the substation grid-connected bus voltage is set to the current voltage. The substation control module calculates control strategies to eliminate voltage exceeding the upper limit, and adjusts reactive power equipment or main transformer tap positions to reduce the grid bus voltage.

[0121] When the substation control module receives a reactive power control request At that time, the lower limit of the substation grid-connected bus voltage is set to the current voltage. The substation control module calculates control strategies to eliminate voltage exceeding the lower limit, and adjusts reactive power equipment or main transformer tap positions to increase the grid-connected bus voltage.

[0122] In this embodiment, the adjustment strategy ensures that the voltage of the central bus and the grid-connected bus is qualified, avoids reverse reactive power regulation between new energy power plants and substations, and maintains grid stability.

[0123] 7) When the next AVC system control strategy cycle arrives, return to step 1) and start a new round of automatic voltage control.

[0124] The method described in this embodiment will be further explained in detail below with reference to a specific example.

[0125] In one specific embodiment of the present invention, Figure 2 The topology of the control zone, consisting of new energy power plants and substations, is shown as an example. Figure 2 Among them, three 110kV renewable energy power stations, C1, C2, and C3, are connected to the grid via the medium-voltage side 110kV busbar of the main transformer T1 of the 220kV substation, forming a cluster C B1=|C1 C2 C3|, the 35kV busbar on the low-voltage side of the substation has two 10MVar capacitors R1 and R2 and two 10MVar reactors K1 and K2. Capacitor R1 is in operation, capacitor R2 is in hot standby, and reactors K1 and K2 are both in hot standby. The real-time voltage and upper and lower limits of the three busbars of the substation are shown in Table 1. The real-time active and reactive power of the generator sets of the new energy power station are shown in Table 2.

[0126] Table 1. Real-time voltage and upper / lower limits of the three busbars of a 220kV substation in a specific embodiment of the present invention.

[0127] voltage level Real-time voltage (unit: kV) Upper voltage limit (unit: kV) Lower voltage limit (unit: kV) 220 225.42 224 230 110 117.64 114 118 35 36.21 34 38

[0128] Table 2. Real-time Active and Reactive Power Meters of New Energy Power Station Generators in a Specific Embodiment of the Present Invention

[0129] Unit Name Real-time active power (unit: MW) Real-time reactive power (unit: MVar) G1 10.21 -2.45 G2 12.35 -3.24 G3 15.23 -3.25 G4 14.12 -4.23 G5 18.16 -4.56 G6 16.89 -5.12

[0130] In this embodiment, the AVC system performs reactive power optimization calculations and obtains that the optimized voltage of the 220kV bus of the 220kV substation is 227.5kV, and the optimization dead zone is 2kV. It is necessary to improve the optimization requirements of the 220kV bus voltage response.

[0131] The voltage of the central busbar did not exceed the limit, and the reactive power output of the generator units in the new energy power station was adjusted to achieve the optimization target of the central busbar.

[0132] Based on the reactive power sensitivity and reactive power balance principle of the central bus to the generator units of the new energy power station, the reactive power adjustment of the generator units of the new energy power station is calculated as shown in Table 3:

[0133] Table 3. Reactive power adjustment target table for generator sets in a specific embodiment of the present invention.

[0134] Unit Name Current reactive power (unit: MVar) Target reactive power (unit: MVar) G1 -2.45 2.55 G2 -3.24 1.67 G3 -3.25 2.05 G4 -4.23 2.12 G5 -4.56 1.56 G6 -5.12 1.78

[0135] Based on the sensitivity calculation of the generator sets of the new energy power station to the bus of the grid-connected substation, the voltage of the grid-connected bus is 118.4kV. The voltage exceeds the upper limit, so a reactive power reduction requirement is issued to the substation.

[0136] Capacitor R1 in the 220kV substation is taken out of operation according to reactive power regulation requirements;

[0137] When the AVC system's control cycle for new energy power plants arrives, it sends the target value of the control bus voltage to the new energy power plants and sends equipment adjustment instructions to the substations.

[0138] When the next AVC system control strategy cycle arrives, a new round of automatic voltage control will begin.

[0139] The above embodiments are merely one of the preferred embodiments of the present invention and should not be used to limit the scope of protection of the present invention. Any modifications or refinements made to the main design concept and spirit of the present invention that are not of substantial significance, but solve the same technical problem as the present invention, should be included within the scope of protection of the present invention.

Claims

1. A method for coordinated reactive power and voltage control in substations and renewable energy plants, characterized in that, include: When the AVC system control strategy calculation cycle arrives, the 220kV substation and all the new energy power stations connected to it are grouped into a control zone, and the 220kV bus of the substation is set as the central bus. When the central bus voltage needs to be optimized, the operating status of the reactive power equipment of the substation is first adjusted; then, based on the adjustment amount of the central bus voltage, the reactive power adjustment amount of the generator units of the new energy power stations in the control zone is calculated, and the grid-connected bus voltage is adjusted to not exceed the limit, so as to achieve coordinated control of reactive power and voltage in the control zone.

2. The method according to claim 1, characterized in that, Also includes: Based on the results of power flow calculations, determine whether the central bus voltage needs optimization, wherein: like - If M, that is, the absolute value of the central bus voltage regulation is greater than the dead zone, then the central bus voltage needs to be optimized; like - If |≤M, then the central bus voltage is already within the optimization range and no adjustment is needed in the current cycle; Where M is the dead zone for optimizing the central bus voltage. This is the current voltage of the central bus. Optimize the target value for the central bus voltage.

3. The method according to claim 2, characterized in that, Also includes: When the operating status of the reactive power equipment in the substation within the control zone is inconsistent with the optimization direction of the central bus voltage, the reactive power equipment in the substation shall be adjusted first, wherein: When the voltage of the central bus falls below the lower limit, check whether there are any operating reactors in the substation within the control zone. If so, remove the reactors. When the voltage of the central bus exceeds the upper limit, check whether there are any operating capacitors in the substation within the control zone. If so, remove the capacitors.

4. The method according to claim 3, characterized in that, The calculation of reactive power adjustment of the generator units of the new energy power stations within the control zone, and the adjustment of the grid-connected bus voltage to prevent it from exceeding the limit, includes: 1) If the central bus voltage regulation amount >M, then the voltage of the central bus is increased by boosting the voltage of the new energy power stations within the control zone, where, The specific steps are as follows: 1-1) Adjustment amount based on the central bus And the sensitivity of the generator units of new energy power stations to the central bus. Calculate the reactive power adjustment of the i-th generator unit in the new energy power station: 1-2) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of the generator sets in new energy power plants to the control bus Calculate the adjustment amount of the reactive power regulation of the i-th generator unit in the new energy power station on the control bus voltage: This leads to the voltage regulation of the control bus of the new energy power station: Where I represents the total number of generator units in the new energy power station; 1-3) Current voltage of the control bus Voltage adjustment of the control bus of the new energy power station Summing these values ​​yields the adjusted target voltage value for the renewable energy power station: 1-4) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of generator units at new energy power plants to grid connection bus Calculate the adjustment amount of the reactive power adjustment of the i-th generator unit in the new energy power station on the grid-connected bus voltage: This leads to the total voltage adjustment of the grid-connected bus: 1-5) Current voltage of the grid-connected bus Total adjustment of grid bus voltage Summing these values ​​yields the estimated voltage of the grid-connected bus after adjustments for the renewable energy power station: 1-6) Estimated voltage of the grid-connected bus after adjustment of the new energy power station Make a judgment: like , The minimum voltage limit for the grid-connected bus set in the AVC system. If the maximum voltage limit for the grid-connected bus is set in the AVC system, then the AVC system will issue an optimized voltage target value to the renewable energy power plant. ; like Then the AVC system sends a leveling command to the new energy power station, i.e., the current voltage. Issue reactive power reduction requirements to substations To reduce the voltage of the grid-connected bus; when the substation receives a reactive power reduction control request At that time, the upper limit of the substation grid-connected bus voltage is set to the current voltage. The substation adjusts the reactive power equipment or the tap position of the main transformer to reduce the voltage of the grid-connected bus. 2) If If <-M, then the voltage of the central bus is reduced by stepping down the voltage of the new energy power stations within the zone; the specific steps are as follows: 2-1) Adjustment amount based on the central bus And the sensitivity of the generator units of new energy power stations to the central bus. Calculate the reactive power adjustment of the j-th generator unit in the new energy power station: 2-2) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of the generator sets in new energy power plants to the control bus Calculate the adjustment amount of reactive power regulation of the generator units in the new energy power station on the control bus voltage: This leads to the voltage regulation of the control bus of the new energy power station: 2-3) Current voltage of the control bus Voltage adjustment of the control bus of the new energy power station The difference is calculated to obtain the adjusted target voltage value for the renewable energy power station: 2-4) Based on the reactive power adjustment of the generator sets in the new energy power station Sensitivity of generator units at new energy power plants to grid connection bus Calculate the adjustment amount of the reactive power adjustment of the j-th generator unit in the new energy power station on the grid bus voltage: This leads to the total voltage adjustment of the grid-connected bus: 2-5) Current voltage of the grid-connected bus Total adjustment of grid bus voltage By subtracting the values, we obtain the estimated voltage of the grid-connected bus after the adjustment of the new energy power station: 2-6) Estimated voltage of the grid-connected bus after adjustment of the new energy power station Make a judgment: like Then the AVC system sends the optimized voltage target value to the new energy power station. ; like Then the AVC system sends a leveling command to the new energy power station, i.e., the current voltage. Issued a request for increased reactive power to the substation. To increase the voltage of the grid-connected bus; when the substation receives a request for increased reactive power control. At that time, the lower limit of the substation grid-connected bus voltage is set to the current voltage. The substation adjusts the reactive power equipment or the tap position of the main transformer to increase the voltage of the grid-connected bus.

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