Short-circuit ratio adaptive new energy station reactive voltage cooperative control method and system

Abstract

The application discloses a short-circuit ratio adaptive new energy station reactive power and voltage cooperative control method and system, belongs to the new energy power generation control technical field, and is particularly suitable for wind power cluster control under a weak power grid environment. The voltage and current responses of a grid-connected point are collected to estimate the short-circuit ratio of the grid-connected point in real time; the droop gain and filter parameters of a voltage control loop are dynamically adjusted based on the short-circuit ratio; at the reactive power distribution level, the reactive power distribution coefficient is calculated by combining the current operating condition of the new energy equipment through a dynamic weighting strategy of real-time available capacity, and a distribution dead zone is eliminated through a deviation iterative redistribution algorithm; the optimized reactive power reference value is converted into a local voltage correction amount, and the deep integration of station-level centralized scheduling and unit-level rapid response is realized. The application effectively solves the problems of response delay, voltage out-of-limit and subsynchronous oscillation of the traditional PQ control under a weak power grid, and significantly improves the low voltage ride-through capability and grid-connected stability of the new energy station.

Description

Technical Field

[0001] This invention relates to the field of new energy grid connection control technology, specifically to a method and system for reactive power and voltage coordinated control of new energy power plants with short-circuit ratio adaptive control. Background Technology

[0002] In existing renewable energy power plant control technologies, to meet the grid's voltage or reactive power support requirements for the point of connection (PCC), renewable energy power plants typically employ a dual-loop control strategy for reactive power control. The specific implementation of this strategy is as follows: Outer loop control (wind farm level): The renewable energy power plant controller collects the actual values ​​of voltage, reactive power, or power factor at the PCC, compares them with target reference values, and calculates the total reactive power that needs to be adjusted across the entire plant. Subsequently, the controller allocates this total reactive power to each renewable energy device within the plant, forming a reactive power reference command for each device, which is then sent down via the communication network. Inner loop control (renewable energy device level): After receiving the reactive power reference command, the controller of a single renewable energy device performs closed-loop control by comparing it with the actual reactive power at the device's output terminal, outputting a reactive current reference value to the converter, thereby driving the renewable energy device to generate or absorb the specified reactive power. However, the above strategy has significant drawbacks in practical applications. Since changes in the reactive power of renewable energy devices directly alter their terminal voltage, under specific operating conditions such as weak grids or distributed grid access, forcibly executing the reactive power commands sent from the upper layer can easily lead to large fluctuations in the terminal voltage of the renewable energy devices. Once the terminal voltage exceeds the allowable range for normal operation (e.g., 0.9 pu-1.1 pu as specified by the standard), the renewable energy equipment will be forced to trigger High Voltage Ride-Through (HVRT) or Low Voltage Ride-Through (LVRT) logic, which may even lead to protective shutdown in severe cases. Such voltage overruns and grid disconnection accidents caused by reactive power dispatch occur frequently in actual engineering projects, seriously affecting the power generation efficiency of renewable energy power plants and the stable operation of the power grid.

[0003] In view of this, there is an urgent need to provide a reactive power and voltage coordinated control scheme for new energy power plants and new energy equipment to solve the above problems, and to effectively constrain the voltage at the generator terminals of new energy equipment within a safe range while responding to reactive power dispatch. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for reactive power and voltage coordinated control of new energy power plants with adaptive short-circuit ratio, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A reactive power and voltage coordinated control method for renewable energy power plants with adaptive short-circuit ratio, comprising the following steps:

[0007] Real-time data of voltage and current at the grid connection point of new energy power plants are collected. The short-circuit ratio of the grid connection point is calculated in real time using an online impedance estimation algorithm, and the grid connection point is divided into regions. When the grid connection point is in a weak grid area, it automatically switches to the enhanced voltage control mode.

[0008] Extract the measured voltage value and voltage reference value at the grid connection point, and calculate the voltage deviation; adjust the cutoff frequency of the low-pass filter based on the short-circuit ratio at the grid connection point to filter the voltage deviation; based on the filtered voltage deviation, calculate the total reactive power reference value of the new energy power station through a PI controller.

[0009] Real-time monitoring of the active power output and converter thermal status of each new energy device; calculation of the real-time available reactive power capacity of each new energy device based on the PQ operating limit circle diagram; calculation of the reactive power allocation coefficient based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire field; and calculation of the initial reactive power reference value of each new energy device based on the total reactive power reference value.

[0010] The initial reactive power reference value is optimized according to the limiting constraint. It is determined whether there is a reactive power deviation between the total reactive power reference value and the sum of the optimized initial reactive power reference values ​​of all new energy equipment. The final reactive power reference value of each new energy equipment is determined and sent to the new energy equipment at the grid connection point.

[0011] The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point to regulate the local voltage of the new energy equipment. Combined with the voltage safety boundary, a voltage reference value after limiting is obtained. The reactive power output of the new energy equipment is controlled based on the difference between the voltage reference value after limiting and the measured terminal voltage of the new energy equipment.

[0012] As a preferred embodiment of the adaptive short-circuit ratio reactive power and voltage coordinated control method for new energy power plants in this invention, the specific implementation process of collecting real-time data of voltage and current at the grid connection point of the new energy power plant, calculating the short-circuit ratio of the grid connection point in real time using an online impedance estimation algorithm, dividing the grid connection point into regions, and automatically switching to the enhanced voltage control mode when the grid connection point is in a weak grid area includes:

[0013] By injecting small disturbance signals or utilizing natural wind power fluctuations at the grid connection point of the renewable energy power plant, real-time data on the voltage and current at the grid connection point are collected, and the voltage change at the grid connection point is measured. With change in current ;

[0014] Calculation of equivalent impedance of power grid based on equivalent Thevenin model ;

[0015] According to the short-circuit ratio formula Calculate the short-circuit ratio:

[0016] Set the SCR threshold when When the voltage is below the SCR threshold, it is identified as a weak grid area and automatically switches to enhanced voltage control mode; otherwise, it is identified as a strong grid area.

[0017] As a preferred embodiment of the adaptive short-circuit ratio reactive power and voltage coordinated control method for new energy power plants in this invention, the specific implementation process of adjusting the cutoff frequency of the low-pass filter based on the short-circuit ratio at the grid connection point to filter the voltage deviation, and calculating the total reactive power reference value of the new energy power plant based on the filtered voltage deviation using a PI controller is as follows:

[0018] Based on the short-circuit ratio at the grid connection point, the cutoff frequency of the low-pass filter is calculated using the following formula:

[0019] ;

[0020] in, This represents the cutoff frequency of the adaptive low-pass filter in the k-th cycle. Indicates the weighting coefficient. This represents the short-circuit ratio at the grid connection point in the k-th cycle. This represents the minimum cutoff frequency of the adaptive low-pass filter.

[0021] The voltage deviation is filtered based on the cutoff frequency of the low-pass filter.

[0022] Based on the filtered voltage deviation, the reactive power correction at the grid connection point is calculated using a PI controller. The calculation formula is as follows:

[0023] ;

[0024] in, Let be the reactive power correction amount for the k-th cycle. The proportional gain of the PI controller. The voltage deviation after filtering in the k-th cycle. The integral coefficient of the PI controller. The sampling period of the PI controller. This represents the reactive power correction amount for the nth cycle.

[0025] The proportional gain of the PI controller and integral coefficient Gain scheduling is performed based on SCR; under weak grid conditions, the gain is reduced. To prevent system overshoot, and to adjust according to voltage recovery time requirements. ;

[0026] Based on equipment capacity limitations, the reactive power correction amount is constrained using the following formula:

[0027] ;

[0028] in, The reactive power after the constraint in the k-th cycle. The maximum permissible increase in reactive power. The maximum allowable reduction in reactive power. This represents the reactive power correction amount for the k-th cycle;

[0029] Based on the basic reactive power of the grid connection point By combining the constrained reactive power, we obtain the reference value of the total reactive power that the new energy equipment needs to generate, using the following formula:

[0030] ;

[0031] in, This is the reference value for the total reactive power in the k-th cycle.

[0032] As a preferred embodiment of the reactive power and voltage coordinated control method for new energy power plants with short-circuit ratio adaptive control in this invention, the specific implementation process of real-time monitoring of the active power output and converter thermal state of each new energy device, calculating the real-time available reactive power capacity of each new energy device in conjunction with the PQ operating limit circle diagram, calculating the reactive power allocation coefficient based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire power plant, and calculating the initial reactive power reference value of each new energy device in conjunction with the total reactive power reference value includes:

[0033] Real-time monitoring of the active power output and converter thermal status of each new energy device is performed. The current real-time active power of the new energy device, the maximum reactive power determined by the converter's heat dissipation limit, and the converter's apparent power limit are extracted. Combined with the PQ operating limit circle chart, the real-time available reactive power capacity of each new energy device is calculated using the following formula:

[0034]

[0035] in, The real-time available reactive power capacity of new energy equipment i. The maximum reactive power is determined by the heat dissipation limitations of the inverter in new energy equipment. For the apparent power limit of the converter, The current real-time active power of the new energy equipment i; Obtained by looking up a table;

[0036] The reactive power allocation coefficient is calculated based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire site. The calculation formula is as follows:

[0037] = ;

[0038] in, Let i be the reactive power distribution coefficient of the new energy equipment. Let N be the reactive power allocation coefficient of the new energy equipment j, and N be the number of new energy equipment.

[0039] The initial reactive power reference value for each new energy device is calculated based on the total reactive power reference value. The calculation formula is as follows:

[0040] ;

[0041] in, Let be the initial reactive power reference value of the i-th new energy device in the k-th cycle.

[0042] As a preferred embodiment of the adaptive short-circuit ratio reactive power and voltage coordinated control method for new energy power plants in this invention, the step of optimizing the initial reactive power reference value according to the limiting constraint, determining whether there is a reactive power deviation between the total reactive power reference value and the sum of the optimized initial reactive power reference values ​​of all new energy equipment, and determining the final reactive power reference value of each new energy equipment and sending it to the new energy equipment at the grid connection point specifically includes:

[0043] The initial reactive power reference value is limited by a reactive power limiter, using the following formula:

[0044] Qi_limit(k) = max(Qi_min, min(Qi_max, Qi(k))), where Qi_limit(k) is the initial reactive power reference value of the i-th new energy device after processing in the k-th cycle, Qi_min is the minimum reactive power value of the i-th new energy device, Qi_max is the maximum reactive power value of the i-th new energy device, and Qi(k) is the initial reactive power reference value of the i-th new energy device in the k-th cycle;

[0045] The final reactive power reference value of the new energy equipment is determined based on the processed initial reactive power reference value and total reactive power reference value, and then sent to the new energy equipment at the grid connection point.

[0046] Determine whether there is a reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing all new energy equipment;

[0047] When there is no reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing of all new energy equipment, the optimized initial reactive power reference value of each new energy equipment shall be used as the final reactive power reference value of each new energy equipment.

[0048] When there is a reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing by all new energy equipment, determine whether the reactive power deviation is greater than the preset deviation threshold.

[0049] When the reactive power deviation is greater than the preset deviation threshold, the reactive power deviation is allocated to all currently unloaded new energy devices according to the reactive power allocation ratio, and the initial reactive power reference value and the processed initial reactive power reference value of the corresponding new energy devices are updated.

[0050] When the reactive power deviation is not greater than the preset deviation threshold, the initial reactive power reference value after processing of each new energy device is used as the final reactive power reference value of each new energy device.

[0051] As a preferred embodiment of the adaptive short-circuit ratio reactive power and voltage coordinated control method for new energy power plants in this invention, the step of dynamically adjusting the droop gain based on the short-circuit ratio at the grid connection point to regulate the local voltage of the new energy equipment, and obtaining a voltage reference value after limiting by combining the voltage safety boundary; controlling the output reactive power of the new energy equipment based on the difference between the voltage reference value after limiting and the measured terminal voltage of the new energy equipment specifically includes:

[0052] The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point. The adjustment formula is as follows:

[0053] ;

[0054] in, For droop gain, Rated short-circuit ratio The base gain below, As a sensitivity adjustment factor, This is a real-time estimate;

[0055] This function ensures a larger output voltage correction when the mains impedance increases (SCR decreases). This allows the device terminal voltage to be within a wider voltage range;

[0056] Based on the final reactive power reference value, the final reactive power reference value is converted into voltage change ΔV, and the conversion formula is as follows:

[0057] ΔV= ×(Qref / Qbase);

[0058] Where Qref is the final reactive power reference value, and Qbase is the reactive power base value;

[0059] The base voltage setting value of the local voltage controller for new energy equipment is adjusted based on the voltage change during conversion to obtain the adjusted local voltage control reference value. The adjustment formula is as follows:

[0060] Vref_adj = Vturb_Ref + ΔV;

[0061] Wherein, Vref_adj is the adjusted local voltage control reference value, and Vturb_Ref is the base voltage setting value of the local voltage controller of the new energy equipment;

[0062] Based on the safety boundary of the allowable voltage for new energy equipment, the adjusted local voltage control reference value is limited by the following formula:

[0063] ;

[0064] in, This is the voltage reference value after limiting. This represents the maximum permissible voltage value for new energy equipment. This refers to the minimum permissible voltage value for new energy equipment.

[0065] The voltage reference value after limiting Measured terminal voltage value of new energy equipment Compare;

[0066] The difference between the voltage reference value after limiting and the actual measured voltage at the terminal of the new energy equipment is sent to the PI controller at the terminal of the new energy equipment.

[0067] The PI controller at the new energy equipment end outputs a reactive current reference value to the inner current loop of the new energy equipment converter;

[0068] The converter of the new energy equipment adjusts the reactive power output of the new energy equipment according to the reactive current reference value until the measured terminal voltage of the new energy equipment is equal to the voltage reference value after limiting.

[0069] A short-circuit ratio adaptive reactive power and voltage coordinated control system for new energy power plants, the system comprising a grid status sensing module, a central control decision module, an intelligent allocation module, and a local execution module;

[0070] The power grid status sensing module is used to collect real-time data of voltage and current at the grid connection point, estimate the short-circuit ratio of the grid connection point, and divide the grid connection point into regions. When the grid connection point is in a weak grid area, it automatically switches to the enhanced voltage control mode.

[0071] The overall control decision module includes an adaptive low-pass filter and a PI controller, used to calculate the total reactive power reference value of the new energy power station; the adaptive low-pass filter adjusts the cutoff frequency based on the short-circuit ratio of the grid connection point to filter the voltage deviation between the measured voltage value and the voltage reference value at the grid connection point; the PI controller is used to calculate the total reactive power reference value of the new energy power station based on the filtered voltage deviation.

[0072] The intelligent allocation module is used to assess the real-time available reactive power capacity of each new energy device and perform weighted allocation and iterative correction.

[0073] The local execution module, located at the new energy equipment end, is used to receive reactive power commands and convert them into voltage reference values ​​based on adaptive droop gain to drive the converter operation.

[0074] Compared with existing technologies, the beneficial effects achieved by this invention are as follows: The reactive power and voltage coordinated control method and system for renewable energy power plants with short-circuit ratio adaptive provided by this invention effectively integrates centralized control of renewable energy power plants with local control of renewable energy equipment by converting the reactive power reference value allocated at the renewable energy power plant level into voltage change and superimposing it on the local base voltage setting value of the renewable energy equipment. Its main advantages are: Firstly, this reactive power command-corrected voltage reference control strategy can fully utilize the fast response characteristics of the local voltage closed-loop controller of the renewable energy equipment, ensuring accurate response to the total reactive power demand of the grid while improving the dynamic response speed of a single unit to command tracking. Secondly, by directly limiting the adjusted voltage reference value, under specific operating conditions such as weak grids or distributed access, it can proactively and effectively prevent the risk of turbine terminal voltage exceeding limits when renewable energy equipment significantly adjusts reactive power, thereby significantly improving the safety and stability of wind turbine and all equipment operation.

[0075] Furthermore, by establishing a closed-loop PI control mechanism based on grid connection point voltage deviation, accurate calculation and dynamic adjustment of the total reactive power demand of renewable energy power plants are achieved. The use of a discretized PI algorithm effectively eliminates steady-state errors in voltage regulation, ensuring accurate tracking of the reference value at the grid connection point while guaranteeing rapid response to grid fluctuations. Strict amplitude limiting of the reactive power correction effectively prevents overly aggressive adjustment commands caused by integral saturation or abnormally large deviations, avoiding over-adjustment, oscillation, or exceeding equipment tolerance limits, thus significantly enhancing the robustness and operational safety of the reactive power control system for renewable energy power plants.

[0076] Furthermore, by adopting a proportional allocation strategy based on real-time available capacity, the current active power conditions are taken into full account, which fully considers the physical limitations of reactive power output of new energy equipment. This effectively avoids single-unit overload or capacity waste caused by blind allocation and achieves load balancing among units. By introducing an iterative redistribution mechanism with limit correction function, when some units reach their output limit, the unmet reactive power deficit can be automatically transferred to other units that still have margin. This mechanism maximizes the reactive power regulation potential of the entire site while strictly ensuring the safety of single-unit operation, and ensures high-precision execution and response of new energy power plants to the total reactive power command of the power grid.

[0077] Furthermore, a high-performance voltage closed-loop control loop was constructed locally for the new energy equipment. A PI regulator converts voltage deviations into current inner-loop commands for the converter. By employing a cascaded control structure, the millisecond-level fast response characteristics of the converter's current inner loop are fully utilized, ensuring that the new energy equipment can accurately track the voltage reference value without steady-state error. This control method, which directly acts on the underlying actuators, not only ensures the accurate implementation of the upper-level allocation strategy but also effectively smooths out instantaneous fluctuations in the generator terminal voltage, achieving rapid and stable support of the generator terminal voltage from the reactive power output of the new energy equipment. Attached Figure Description

[0078] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0079] Figure 1 This is a schematic diagram of the steps of the reactive power and voltage coordinated control method for new energy power plants with short-circuit ratio adaptive control according to the present invention; Figure 2 This is a schematic diagram of the reactive power and voltage coordinated control system for new energy power plants with short-circuit ratio adaptive design according to the present invention. Detailed Implementation

[0080] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0081] Please see Figures 1-2 In this first embodiment: a reactive power and voltage coordinated control method for new energy power plants with adaptive short-circuit ratio is provided, the method including:

[0082] Real-time data of voltage and current at the grid connection point of new energy power plants are collected. The short-circuit ratio of the grid connection point is calculated in real time using an online impedance estimation algorithm, and the grid connection point is divided into regions. When the grid connection point is in a weak grid area, it automatically switches to the enhanced voltage control mode.

[0083] Extract the measured voltage value and voltage reference value at the grid connection point, and calculate the voltage deviation; adjust the cutoff frequency of the low-pass filter based on the short-circuit ratio at the grid connection point to filter the voltage deviation; based on the filtered voltage deviation, calculate the total reactive power reference value of the new energy power station through a PI controller.

[0084] Real-time monitoring of the active power output and converter thermal status of each new energy device; calculation of the real-time available reactive power capacity of each new energy device based on the PQ operating limit circle diagram; calculation of the reactive power allocation coefficient based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire field; and calculation of the initial reactive power reference value of each new energy device based on the total reactive power reference value.

[0085] The initial reactive power reference value is optimized according to the limiting constraint. It is determined whether there is a reactive power deviation between the total reactive power reference value and the sum of the optimized initial reactive power reference values ​​of all new energy equipment. The final reactive power reference value of each new energy equipment is determined and sent to the new energy equipment at the grid connection point.

[0086] The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point to regulate the local voltage of the new energy equipment. Combined with the voltage safety boundary, a voltage reference value after limiting is obtained. The reactive power output of the new energy equipment is controlled based on the difference between the voltage reference value after limiting and the measured terminal voltage of the new energy equipment.

[0087] Specifically, the process involves collecting real-time voltage and current data at the grid connection point of new energy power plants, using an online impedance estimation algorithm to calculate the short-circuit ratio of the grid connection point in real time, and dividing the grid connection point into regions. When the grid connection point is located in a weak grid area, the automatic switching to enhanced voltage control mode includes the following steps:

[0088] By injecting small disturbance signals or utilizing natural wind power fluctuations at the grid connection point of the renewable energy power plant, real-time data on the voltage and current at the grid connection point are collected, and the voltage change at the grid connection point is measured. With change in current ;

[0089] Calculation of equivalent impedance of power grid based on equivalent Thevenin model ;

[0090] According to the short-circuit ratio formula Calculate the short-circuit ratio:

[0091] Set the SCR threshold when When the voltage is below the SCR threshold, it is identified as a weak grid area and automatically switches to enhanced voltage control mode.

[0092] Specifically, the implementation process involves adjusting the cutoff frequency of the low-pass filter based on the short-circuit ratio at the grid connection point to filter voltage deviations; and then calculating the total reactive power reference value of the renewable energy power station using a PI controller based on the filtered voltage deviations.

[0093] Based on the short-circuit ratio at the grid connection point, the cutoff frequency of the low-pass filter is calculated using the following formula:

[0094] ;

[0095] in, This represents the cutoff frequency of the adaptive low-pass filter in the k-th cycle. Indicates the weighting coefficient. This represents the short-circuit ratio at the grid connection point in the k-th cycle. This represents the minimum cutoff frequency of the adaptive low-pass filter.

[0096] The voltage deviation is filtered based on the cutoff frequency of the low-pass filter.

[0097] Based on the filtered voltage deviation, the reactive power correction at the grid connection point is calculated using a PI controller. The calculation formula is as follows:

[0098] ;

[0099] in, Let be the reactive power correction amount for the k-th cycle. The proportional gain of the PI controller. The voltage deviation in the k-th cycle is... The integral coefficient of the PI controller. The sampling period of the PI controller. Let n be the reactive power correction amount in the nth cycle. , This is the voltage reference value at the grid connection point. This is the measured voltage value at the grid connection point;

[0100] To prevent the infinite accumulation of the integral term, an anti-windup mechanism is considered to avoid integral saturation. When the calculated reactive power correction reaches the output limit, the accumulation of the integral term is immediately frozen to prevent integral saturation caused by prolonged voltage deviation. This is implemented for reactive power correction. (i.e., entering a saturation state) To maximize the allowable increase in reactive power, integral saturation is triggered immediately, directly resetting the integral term to 0;

[0101] The above calculation formula can be expanded into an incremental form to obtain: ,in, This represents the reactive power correction for the (k-1)th cycle. This represents the voltage deviation during the (k-1)th cycle;

[0102] exist When this occurs, it indicates that the measured voltage at the grid connection point is higher than the reference voltage value, and reactive power needs to be reduced (because reactive power is positively correlated with voltage, reducing reactive power can lower voltage), meaning the reactive power correction is less than 0. When this occurs, it indicates that the measured voltage at the grid connection point is lower than the reference voltage value, requiring an increase in reactive power (because reactive power is positively correlated with voltage, increasing reactive power can increase voltage), meaning the reactive power correction is greater than 0. When the measured voltage at the grid connection point is equal to the reference voltage at the grid connection point, the PI controller does not need to output reactive power correction.

[0103] Through the above process of obtaining reactive power correction, a PI control strategy combining positional and incremental characteristics was constructed. This strategy not only eliminates steady-state error in voltage regulation through integral action but also provides flexible algorithm implementation methods to adapt to the computational needs of different controllers. An anti-windup protection mechanism is integrated, which actively resets the integral term when reactive power output reaches its limit, fundamentally eliminating integral divergence and effectively avoiding response lag and voltage overshoot when the system exits saturation. Simultaneously, the clearly defined logical mapping relationship between voltage deviation and reactive power increase / decrease ensures the physical correctness of the adjustment direction, jointly guaranteeing the adjustment accuracy, dynamic stability, and rapid recovery capability of new energy power plants under complex voltage fluctuation conditions.

[0104] Based on equipment capacity limitations, the reactive power correction amount is constrained using the following formula:

[0105] ;

[0106] in, The reactive power after the constraint in the k-th cycle. The maximum permissible increase in reactive power. The maximum allowable reduction in reactive power. This represents the reactive power correction amount for the k-th cycle;

[0107] The reactive power correction output of the PI controller is constrained through limiting logic. Its main function is to ensure that control commands remain within the system's set safety threshold range, preventing excessive adjustment commands caused by sudden and severe fluctuations in the power grid or abnormal controller calculations. In specific operating conditions such as weak power grids or distributed grid integration, it effectively avoids equipment overload risks and secondary voltage oscillations or instability caused by excessive reactive power adjustment, providing a reliable safety boundary guarantee for the grid-connected operation of renewable energy power plants.

[0108] Based on the basic reactive power of the grid connection point By combining the constrained reactive power, we obtain the reference value of the total reactive power that the new energy equipment needs to generate, using the following formula:

[0109] ;

[0110] in, This is the reference value for the total reactive power in the k-th cycle.

[0111] Specifically, the process of real-time monitoring of the active power output and converter thermal status of each new energy device, calculating the real-time available reactive power capacity of each device using the PQ operating limit circle diagram, calculating the reactive power allocation coefficient based on the proportion of the real-time available reactive power capacity of each device to the total available capacity of the entire field, and calculating the initial reactive power reference value of each device using the total reactive power reference value includes:

[0112] Real-time monitoring of the active power output and converter thermal status of each new energy device is performed. The current real-time active power of the new energy device, the maximum reactive power determined by the converter's heat dissipation limit, and the converter's apparent power limit are extracted. Combined with the PQ operating limit circle chart, the real-time available reactive power capacity of each new energy device is calculated using the following formula:

[0113]

[0114] in, The real-time available reactive power capacity of new energy equipment i. The maximum reactive power is determined by the heat dissipation limitations of the inverter in new energy equipment. For the apparent power limit of the converter, The current real-time active power of the new energy equipment i;

[0115] By introducing a function that considers the impact of real-time active power on the reactive power capacity of renewable energy equipment, the current active power state of the renewable energy equipment is directly mapped to the reactive power output boundary. By accurately quantifying the actual adjustment capacity of each renewable energy unit at the current operating point, this overcomes the limitations of traditional methods that rely solely on rated nameplate parameters for scheduling. It can fully utilize the PQ characteristic curves of renewable energy equipment, tapping into greater reactive power potential at low wind speeds (low active power) and automatically tightening reactive power limits at high wind speeds (high active power). Thus, while ensuring that the units do not overload or exceed limits, it achieves the maximum utilization and refined management of the overall reactive power resources of renewable energy power plants.

[0116] The reactive power allocation coefficient is calculated based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire site. The calculation formula is as follows:

[0117] = ;

[0118] in, Let i be the reactive power distribution coefficient of the new energy equipment. Let N be the reactive power allocation coefficient of the new energy equipment j, and N be the number of new energy equipment.

[0119] The initial reactive power reference value for each new energy device is calculated based on the total reactive power reference value. The calculation formula is as follows:

[0120] ;

[0121] in, Let be the initial reactive power reference value of the i-th new energy device in the k-th cycle.

[0122] Specifically, the initial reactive power reference value is optimized based on the limiting constraint. It is then determined whether there is a reactive power deviation between the total reactive power reference value and the sum of the optimized initial reactive power reference values ​​of all new energy devices. The final reactive power reference value for each new energy device is determined and sent to the grid connection point. The new energy devices specifically include:

[0123] The initial reactive power reference value is limited by a reactive power limiter, using the following formula:

[0124] Qi_limit(k) = max(Qi_min, min(Qi_max, Qi(k))), where Qi_limit(k) is the initial reactive power reference value of the i-th new energy device after processing in the k-th cycle, Qi_min is the minimum reactive power value of the i-th new energy device, Qi_max is the maximum reactive power value of the i-th new energy device, and Qi(k) is the initial reactive power reference value of the i-th new energy device in the k-th cycle;

[0125] By constructing a proportional dynamic allocation strategy based on real-time capabilities and integrating a terminal safety limiting mechanism, the system allocates total reactive power demand according to the current actual adjustment capacity of each renewable energy device, avoiding single-unit overload or resource idleness caused by uneven allocation. This achieves balanced and optimized scheduling of reactive power output within the renewable energy power plant, ensuring that the renewable energy equipment group can efficiently and collaboratively respond to the overall control commands from the grid connection point. Furthermore, through strict upper and lower limit processing, it provides a final safety barrier for each power generation device, ensuring that the system operates efficiently without exceeding physical safety boundaries.

[0126] The final reactive power reference value of the new energy equipment is determined based on the processed initial reactive power reference value and total reactive power reference value, and then sent to the new energy equipment at the grid connection point.

[0127] Determine whether there is a reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing all new energy equipment;

[0128] When there is no reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing of all new energy equipment, the optimized initial reactive power reference value of each new energy equipment shall be used as the final reactive power reference value of each new energy equipment.

[0129] When there is a reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing by all new energy equipment, determine whether the reactive power deviation is greater than the preset deviation threshold.

[0130] When the reactive power deviation is greater than the preset deviation threshold, the reactive power deviation is allocated to all currently unloaded new energy devices according to the reactive power allocation ratio, and the initial reactive power reference value and the processed initial reactive power reference value of the corresponding new energy devices are updated.

[0131] When the reactive power deviation is not greater than the preset deviation threshold, the initial reactive power reference value after processing of each new energy device is used as the final reactive power reference value of each new energy device.

[0132] Based on the above, a secondary redistribution mechanism based on deviation feedback was constructed. This mechanism addresses the overall output shortfall caused by some renewable energy units reaching their output limits during the initial allocation. By precisely transferring the lost reactive power demand to renewable energy units with remaining capacity (not overloaded), it achieves in-depth utilization and complementarity of reactive power resources across the entire power plant. This significantly improves the accuracy and responsiveness of renewable energy power plants to overall commands, ensuring that grid connection requirements are met to the maximum extent even when some units are operating at saturation. Simultaneously, threshold-based judgment logic effectively filters out ineffective adjustments caused by minor errors, balancing the accuracy and stability of the control system.

[0133] Specifically, the droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point to regulate the local voltage of the new energy equipment. Combined with the voltage safety boundary, a voltage reference value after limiting is obtained. The reactive power output of the new energy equipment is controlled based on the difference between the limited voltage reference value and the measured terminal voltage of the new energy equipment. This specifically includes:

[0134] The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point. The adjustment formula is as follows:

[0135] ;

[0136] in, For droop gain, Rated short-circuit ratio The base gain below, As a sensitivity adjustment factor, This is a real-time estimate;

[0137] Based on the final reactive power reference value, the final reactive power reference value is converted into voltage change ΔV, and the conversion formula is as follows:

[0138] ΔV= ×(Qref / Qbase);

[0139] Where Qref is the final reactive power reference value, and Qbase is the reactive power base value;

[0140] The base voltage setting value of the local voltage controller for new energy equipment is adjusted based on the voltage change during conversion to obtain the adjusted local voltage control reference value. The adjustment formula is as follows:

[0141] Vref_adj = Vturb_Ref + ΔV;

[0142] Wherein, Vref_adj is the adjusted local voltage control reference value, and Vturb_Ref is the base voltage setting value of the local voltage controller of the new energy equipment;

[0143] The base voltage setting value of the local voltage controller for new energy equipment is 1.0 pu. Based on the above, a mapping and conversion mechanism from the reactive power domain to the voltage control domain is established. By introducing a droop gain coefficient, the reactive power commands issued by the central control are converted into corresponding voltage bias ΔV and superimposed on the local reference. This establishes an interface between the hierarchical scheduling of new energy power plants and the underlying control of individual units, ensuring that the reactive power strategy calculated at the upper level can be recognized and accurately executed by the converter's underlying logic, which is primarily controlled by voltage sources. Utilizing the QV droop control principle, it achieves automatic reactive power balancing and stable distribution during multi-unit parallel operation, while also providing individual units with flexible adjustment characteristics in response to grid reactive power demands, effectively improving the compatibility and robustness of the entire new energy power plant voltage control system.

[0144] Based on the safety boundary of the allowable voltage for new energy equipment, the adjusted local voltage control reference value is limited by the following formula:

[0145] ;

[0146] in, This is the voltage reference value after limiting. This represents the maximum permissible voltage value for new energy equipment. The limiter is the minimum voltage value allowed for new energy equipment. The upper and lower limits of the limiter are determined by the safe operating voltage range allowed for new energy equipment, thereby ensuring that the final voltage control target does not exceed the safety boundary.

[0147] The voltage reference value after limiting Measured terminal voltage value of new energy equipment Compare;

[0148] The difference between the voltage reference value after limiting and the actual measured voltage at the terminal of the new energy equipment is sent to the PI controller at the terminal of the new energy equipment.

[0149] The PI controller at the new energy equipment end outputs a reactive current reference value to the inner current loop of the new energy equipment converter;

[0150] The converter of the new energy equipment adjusts the reactive power output of the new energy equipment according to the reactive current reference value until the measured terminal voltage of the new energy equipment is equal to the voltage reference value after limiting.

[0151] Based on the above, a closed-loop voltage tracking control circuit at the bottom layer of the new energy equipment was constructed, forming a complete execution link from voltage deviation to current command and then to power output. It achieves real-time correction and precise locking of the set target voltage, ensuring that the new energy equipment can quickly and accurately translate the scheduling commands from the upper level into electrical responses at the physical level. Utilizing the zero steady-state error characteristic of the PI controller, it guarantees the control accuracy of the new energy equipment's terminal voltage under steady-state conditions. Simultaneously, through the rapid response capability of the inner current loop, it greatly improves the dynamic adjustment performance and anti-interference capability of the unit in the face of grid fluctuations.

[0152] In summary, through the reactive power and voltage coordinated control scheme for new energy power plants and equipment provided above, this embodiment of the application effectively integrates centralized control of new energy power plants and local control of new energy equipment by converting the reactive power reference value allocated at the new energy power plant level into voltage change and superimposing it on the local base voltage setting value of the new energy equipment. Its main advantages are: firstly, this reactive power command-corrected voltage reference control strategy can fully utilize the fast response characteristics of the local voltage closed-loop controller of the new energy equipment, ensuring accurate response to the total reactive power demand of the grid while improving the dynamic response speed of individual units to command tracking. Secondly, by directly limiting the adjusted voltage reference value, it can proactively and effectively prevent the risk of turbine terminal voltage exceeding limits when the new energy equipment significantly adjusts reactive power, thereby significantly improving the safety and stability of wind turbine and all equipment operation.

[0153] Furthermore, in some embodiments, a closed-loop PI control mechanism based on grid connection point voltage deviation is established to achieve accurate calculation and dynamic adjustment of the total reactive power demand of the renewable energy power plant. The use of a discretized PI algorithm effectively eliminates steady-state errors in voltage regulation, ensuring accurate tracking of the reference value at the grid connection point voltage while guaranteeing rapid response to grid fluctuations. By strictly limiting the amplitude of the reactive power correction, overly aggressive adjustment commands due to integral saturation or abnormally large deviations are effectively prevented, avoiding over-adjustment, oscillation, or exceeding the equipment's tolerance range. This significantly enhances the robustness and operational safety of the reactive power control system for renewable energy power plants.

[0154] Furthermore, in some embodiments, a proportional allocation strategy based on real-time available capacity is adopted, which fully considers the physical limitations of the current active power conditions on the reactive power output of new energy equipment. This effectively avoids single-unit overload or capacity waste caused by blind allocation and achieves load balancing among units. By introducing an iterative redistribution mechanism with limit correction function, when some units reach their output limit, the unmet reactive power deficit can be automatically transferred to other units that still have margin. This mechanism maximizes the reactive power regulation potential of the entire field while strictly ensuring the safety of single-unit operation, and ensures the high-precision execution and response of new energy power plants to the total reactive power command of the power grid.

[0155] Furthermore, in some embodiments, a high-performance voltage closed-loop control loop is constructed locally for the new energy equipment, converting voltage deviations into current inner-loop commands for the converter via a PI regulator. By employing a cascaded control structure, the millisecond-level fast response characteristics of the converter's current inner loop are fully utilized, ensuring that the new energy equipment can accurately track the voltage reference value without steady-state error. This control method, which directly acts on the underlying actuators, not only ensures the accurate implementation of the upper-level allocation strategy but also effectively smooths out instantaneous fluctuations in the generator terminal voltage, achieving rapid and stable support of the generator terminal voltage by the reactive power output of the new energy equipment.

[0156] A short-circuit ratio adaptive reactive power and voltage coordinated control system for new energy power plants, which includes a grid status perception module, a central control decision module, an intelligent allocation module, and a local execution module;

[0157] The power grid status sensing module is used to collect real-time data of voltage and current at the grid connection point, estimate the short-circuit ratio of the grid connection point, and divide the grid connection point into regions. When the grid connection point is in a weak grid area, it automatically switches to the enhanced voltage control mode.

[0158] The overall control decision module includes an adaptive low-pass filter and a PI controller, used to calculate the total reactive power reference value of the new energy power station; the adaptive low-pass filter adjusts the cutoff frequency based on the short-circuit ratio of the grid connection point to filter the voltage deviation between the measured voltage value and the voltage reference value at the grid connection point; the PI controller is used to calculate the total reactive power reference value of the new energy power station based on the filtered voltage deviation.

[0159] The intelligent allocation module is used to assess the real-time available reactive power capacity of each new energy device and perform weighted allocation and iterative correction.

[0160] The local execution module, located at the new energy equipment end, is used to receive reactive power commands and convert them into voltage reference values ​​based on adaptive droop gain to drive the converter operation.

[0161] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0162] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A reactive power and voltage coordinated control method for new energy power plants with adaptive short-circuit ratio, characterized in that, The method includes the following steps: Real-time data of voltage and current at the grid connection point of new energy power plants are collected. The short-circuit ratio of the grid connection point is calculated in real time using an online impedance estimation algorithm, and the grid connection point is divided into regions. When the grid connection point is in a weak grid area, it automatically switches to the enhanced voltage control mode. Extract the measured voltage value and voltage reference value at the grid connection point, and calculate the voltage deviation; adjust the cutoff frequency of the low-pass filter based on the short-circuit ratio at the grid connection point to filter the voltage deviation; based on the filtered voltage deviation, calculate the total reactive power reference value of the new energy power station through a PI controller. Real-time monitoring of the active power output and converter thermal status of each new energy device; calculation of the real-time available reactive power capacity of each new energy device based on the PQ operating limit circle diagram; calculation of the reactive power allocation coefficient based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire field; and calculation of the initial reactive power reference value of each new energy device based on the total reactive power reference value. The initial reactive power reference value is optimized according to the limiting constraint. It is determined whether there is a reactive power deviation between the total reactive power reference value and the sum of the optimized initial reactive power reference values ​​of all new energy equipment. The final reactive power reference value of each new energy equipment is determined and sent to the new energy equipment at the grid connection point. The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point to regulate the local voltage of the new energy equipment. Combined with the voltage safety boundary, a voltage reference value after limiting is obtained. The reactive power output of the new energy equipment is controlled based on the difference between the voltage reference value after limiting and the measured terminal voltage of the new energy equipment.

2. The reactive power and voltage coordinated control method for new energy power plants with adaptive short-circuit ratio as described in claim 1, characterized in that, The specific implementation process of collecting real-time voltage and current data at the grid connection point of the new energy power station, calculating the short-circuit ratio of the grid connection point in real time using an online impedance estimation algorithm, dividing the grid connection point into regions, and automatically switching to the enhanced voltage control mode when the grid connection point is in a weak grid area includes: By injecting small disturbance signals or utilizing natural wind power fluctuations at the grid connection point of the renewable energy power plant, real-time data on the voltage and current at the grid connection point are collected, and the voltage change at the grid connection point is measured. With change in current ; Calculation of equivalent impedance of power grid based on equivalent Thevenin model ; According to the short-circuit ratio formula Calculate the short-circuit ratio: Set the SCR threshold when When the voltage is below the SCR threshold, it is identified as a weak grid area and automatically switches to enhanced voltage control mode.

3. The reactive power and voltage coordinated control method for new energy power plants with adaptive short-circuit ratio as described in claim 2, characterized in that, The specific implementation process of adjusting the cutoff frequency of the low-pass filter based on the short-circuit ratio at the grid connection point to filter the voltage deviation; and calculating the total reactive power reference value of the renewable energy power station based on the filtered voltage deviation using a PI controller is as follows: Based on the short-circuit ratio at the grid connection point, the cutoff frequency of the low-pass filter is calculated using the following formula: ； in, This represents the cutoff frequency of the adaptive low-pass filter in the k-th cycle. Indicates the weighting coefficient. This represents the short-circuit ratio at the grid connection point in the k-th cycle. This represents the minimum cutoff frequency of the adaptive low-pass filter. The voltage deviation is filtered based on the cutoff frequency of the low-pass filter. Based on the filtered voltage deviation, the reactive power correction at the grid connection point is calculated using a PI controller. The calculation formula is as follows: ； in, Let be the reactive power correction amount for the k-th cycle. The proportional gain of the PI controller. The voltage deviation after filtering in the k-th cycle. The integral coefficient of the PI controller. The sampling period of the PI controller. This represents the reactive power correction amount for the nth cycle. Based on equipment capacity limitations, the reactive power correction amount is constrained using the following formula: ； in, The reactive power after the constraint in the k-th cycle. The maximum permissible increase in reactive power. The maximum allowable reduction in reactive power. This represents the reactive power correction amount for the k-th cycle; Based on the basic reactive power of the grid connection point By combining the constrained reactive power, we obtain the reference value of the total reactive power that the new energy equipment needs to generate, using the following formula: ； in, This is the reference value for the total reactive power in the k-th cycle.

4. The reactive power and voltage coordinated control method for new energy power plants with adaptive short-circuit ratio as described in claim 3, characterized in that, The system monitors the active power output and converter thermal status of each new energy device in real time, and calculates the real-time available reactive power capacity of each new energy device in conjunction with the PQ operating limit circle diagram. The specific implementation process of calculating the reactive power allocation coefficient based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire site, and combining the total reactive power reference value to calculate the initial reactive power reference value of each new energy device, includes: Real-time monitoring of the active power output and converter thermal status of each new energy device is performed. The current real-time active power of the new energy device, the maximum reactive power determined by the converter's heat dissipation limit, and the converter's apparent power limit are extracted. Combined with the PQ operating limit circle chart, the real-time available reactive power capacity of each new energy device is calculated using the following formula: ； in, The real-time available reactive power capacity of new energy equipment i. The maximum reactive power is determined by the heat dissipation limitations of the inverter in new energy equipment. For the apparent power limit of the converter, The current real-time active power of the new energy equipment i; The reactive power allocation coefficient is calculated based on the proportion of the real-time available reactive power capacity of each new energy device to the total available capacity of the entire site. The calculation formula is as follows: = ； in, Let i be the reactive power distribution coefficient of the new energy equipment. Let N be the reactive power distribution coefficient of new energy equipment j, and N be the number of new energy equipment in operation. The initial reactive power reference value for each new energy device is calculated based on the total reactive power reference value. The calculation formula is as follows: ； in, Let be the initial reactive power reference value of the i-th new energy device in the k-th cycle.

5. The reactive power and voltage coordinated control method for new energy power plants with short-circuit ratio adaptive control according to claim 4, characterized in that, The step of optimizing the initial reactive power reference value according to the limiting constraint, determining whether there is a reactive power deviation between the total reactive power reference value and the sum of the optimized initial reactive power reference values ​​of all new energy equipment, and determining the final reactive power reference value of each new energy equipment and sending it to the grid connection point specifically includes: The initial reactive power reference value is limited by a reactive power limiter, using the following formula: Qi_limit(k) = max(Qi_min, min(Qi_max, Qi(k))), where Qi_limit(k) is the initial reactive power reference value of the i-th new energy device after processing in the k-th cycle, Qi_min is the minimum reactive power value of the i-th new energy device, Qi_max is the maximum reactive power value of the i-th new energy device, and Qi(k) is the initial reactive power reference value of the i-th new energy device in the k-th cycle; The final reactive power reference value of the new energy equipment is determined based on the processed initial reactive power reference value and total reactive power reference value, and then sent to the new energy equipment at the grid connection point. Determine whether there is a reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing all new energy equipment; When there is no reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing of all new energy equipment, the optimized initial reactive power reference value of each new energy equipment shall be used as the final reactive power reference value of each new energy equipment. When there is a reactive power deviation between the total reactive power reference value and the sum of the initial reactive power reference values ​​after processing by all new energy equipment, determine whether the reactive power deviation is greater than the preset deviation threshold. When the reactive power deviation is greater than the preset deviation threshold, the reactive power deviation is allocated to all currently unloaded new energy devices according to the reactive power allocation ratio, and the initial reactive power reference value and the processed initial reactive power reference value of the corresponding new energy devices are updated. When the reactive power deviation is not greater than the preset deviation threshold, the initial reactive power reference value after processing of each new energy device is used as the final reactive power reference value of each new energy device.

6. The reactive power and voltage coordinated control method for new energy power plants with adaptive short-circuit ratio according to claim 4, characterized in that, The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point to regulate the local voltage of the new energy equipment. Combined with the voltage safety boundary, a voltage reference value after limiting is obtained. Controlling the reactive power output of new energy equipment based on the difference between the voltage reference value after limiting and the measured terminal voltage of the new energy equipment specifically includes: The droop gain is dynamically adjusted based on the short-circuit ratio at the grid connection point. The adjustment formula is as follows: ； in, For droop gain, Rated short-circuit ratio The base gain below, As a sensitivity adjustment factor, This is a real-time estimate; Based on the final reactive power reference value, the final reactive power reference value is converted into voltage change ΔV, and the conversion formula is as follows: ΔV= ×(Qref / Qbase); Where Qref is the final reactive power reference value, and Qbase is the reactive power base value; The base voltage setting value of the local voltage controller for new energy equipment is adjusted based on the voltage change during conversion to obtain the adjusted local voltage control reference value. The adjustment formula is as follows: Vref_adj = Vturb_Ref + ΔV; Wherein, Vref_adj is the adjusted local voltage control reference value, and Vturb_Ref is the base voltage setting value of the local voltage controller of the new energy equipment; Based on the safety boundary of the allowable voltage for new energy equipment, the adjusted local voltage control reference value is limited by the following formula: ； in, This is the voltage reference value after limiting. This represents the maximum permissible voltage value for new energy equipment. This refers to the minimum permissible voltage value for new energy equipment. The voltage reference value after limiting Measured terminal voltage value of new energy equipment Compare; The difference between the voltage reference value after limiting and the actual measured voltage at the terminal of the new energy equipment is sent to the PI controller at the terminal of the new energy equipment. The PI controller at the new energy equipment end outputs a reactive current reference value to the inner current loop of the new energy equipment converter; The converter of the new energy equipment adjusts the reactive power output of the new energy equipment according to the reactive current reference value until the measured terminal voltage of the new energy equipment is equal to the voltage reference value after limiting.

7. A short-circuit ratio adaptive reactive power and voltage coordinated control system for new energy power plants, using the short-circuit ratio adaptive reactive power and voltage coordinated control method for new energy power plants as described in any one of claims 1-6, characterized in that, The system includes a power grid status perception module, a central control decision module, an intelligent allocation module, and a local execution module; The power grid status sensing module is used to collect real-time data of voltage and current at the grid connection point, estimate the short-circuit ratio of the grid connection point, and divide the grid connection point into regions. When the grid connection point is in a weak grid area, it automatically switches to the enhanced voltage control mode. The overall control decision module includes an adaptive low-pass filter and a PI controller, used to calculate the total reactive power reference value of the new energy power station; the adaptive low-pass filter adjusts the cutoff frequency based on the short-circuit ratio of the grid connection point to filter the voltage deviation between the measured voltage value and the voltage reference value at the grid connection point; the PI controller is used to calculate the total reactive power reference value of the new energy power station based on the filtered voltage deviation. The intelligent allocation module is used to assess the real-time available reactive power capacity of each new energy device and perform weighted allocation and iterative correction. The local execution module, located at the new energy equipment end, is used to receive reactive power commands and convert them into voltage reference values ​​based on adaptive droop gain to drive the converter operation.

Images