Power grid voltage reactive power composite coordination control system and method for new energy power generation

Abstract

The invention discloses a power grid voltage reactive power composite coordination control system and method for new energy power generation. The method comprises the following steps: monitoring the output power and reactive power demand of new energy power generation in real time by using big data and an artificial intelligence technology; predicting the change trend of new energy power generation in unit time in the future according to the real-time monitoring data; according to the prediction result and the real-time reactive power demand, compensation is carried out through a dynamic reactive power compensation module; reactive power compensation devices are arranged in the new energy power generation station and at key nodes of a power grid to respond to local reactive power requirements and overall regulate reactive power balance of the power grid; the output of the reactive power compensation device is automatically adjusted through the intelligent control unit, and reactive power distribution and adjustment are achieved; through the dynamic reactive power compensation module, compensation is carried out in real time according to the power factor of the new energy power station and the reactive power demand of the power grid, voltage fluctuation and flicker are effectively prevented, the stability of the power grid is improved, meanwhile, a reactive power compensation strategy can be dynamically adjusted, and stable operation of the power grid under various working conditions is ensured.

Description

Technical Field

[0001] The present invention relates to a new energy energy-saving technology, and in particular to a voltage-reactive composite coordinated control system and method for a power grid for power generation of new energy. Background Art

[0002] With the depletion of fossil energy, the development and utilization of new energy such as solar energy, geothermal energy, wind energy and nuclear fusion energy will realize the reconstruction of the national power supply structure, get rid of the dependence on fossil energy and reduce the pollution to the environment. The large-scale development of new energy power generation is an inevitable trend. New energy refers to renewable energy such as solar energy, wind energy, wave energy and thermal cycle between the surface and deep layers of the ocean that can be used through innovative power generation technology. New energy has excellent development prospects and unlimited development possibilities. However, the access of new energy power generation to the power grid will change the structure of the original power grid, making the operation and control of the power grid complicated, which will bring economic and safety risks to the original distribution network that cannot be ignored. For example, the access of new energy will bring the risk of poor quality of the transmitted power to the power grid, the risk of increased network loss to the power grid, and the risk of voltage instability during the operation of the power grid. The goal of reactive power optimization is to adjust the reactive output of reactive sources to make the voltage quality of the power grid qualified while reducing the active network loss. The traditional reactive power compensation model and its solution method all use deterministic mathematical methods, and the conclusion has excellent theoretical support.

[0003] However, for a dynamically operating power system, the task of reactive power optimization of the distribution network is to reduce voltage fluctuations at system nodes and limit voltage over-limit behavior, thereby reducing losses in the entire network. How to maintain the voltage deviation of each node in the distribution system at an acceptable level is a reactive power optimization problem that the power system urgently needs to solve.

[0004] Therefore, there is an urgent need for a grid voltage-reactive composite coordinated control system and method for renewable energy power generation to solve the technical problems existing in the above-mentioned prior art. Summary of the invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a voltage-reactive composite coordinated control system and method for a power grid for power generation using renewable energy.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a voltage-reactive composite coordinated control system for a new energy power generation grid, comprising: a real-time monitoring module, a prediction module, a dynamic reactive power compensation module, a reactive power compensation unit and an intelligent control unit;

[0007] The real-time monitoring module uses big data and artificial intelligence technology to monitor the output power and reactive power demand of the new energy power station in real time, and obtains the predicted values ​​of node voltage and branch power flow at the target benchmark operating point;

[0008] The prediction module predicts the change trend of the new energy power station within a unit time in the future according to the probability distribution of the predicted value;

[0009] The dynamic reactive power compensation module includes a static reactive power compensator and a static reactive power generator, and performs compensation according to the prediction result of the prediction module and the real-time reactive power demand;

[0010] The reactive power compensation unit adopts a reactive power compensation device layout combining decentralized and centralized types, and is set inside the new energy power station and at key nodes of the power grid to respond to local reactive power demand and coordinately adjust the reactive power balance of the power grid;

[0011] The intelligent control unit automatically adjusts the output of the reactive power compensation device according to the characteristics of the renewable energy power station and the operating status of the power grid, generates a dispatching strategy, and optimizes the distribution of reactive power.

[0012] In a preferred embodiment of the present invention, it also includes an energy storage integrated module, which integrates a battery energy storage system, a supercapacitor and a hybrid energy storage system; the energy storage integrated module optimizes the discharge strategy and power distribution through an intelligent control algorithm to optimize the scheduling strategy of the intelligent control unit.

[0013] In a preferred embodiment of the present invention, the target reference operating point is obtained by weighted calculation of the minimum value of the deviation value of each node voltage and the deviation value of the total voltage. The function expression of the target reference operating point is:

[0014]

[0015] In the formula, F t (x) represents the objective function within the dispatch period t; x represents the control variable of the grid-connected power of the renewable energy power station and the grid-connected power of the wind turbine; i represents the i-th node of the renewable energy power station; N represents the total number of nodes of the renewable energy power station; λ1+λ2=1 represents the weighting coefficient of the renewable energy power station, which takes values ​​of 0.6V and 0.4V respectively; V i Represents the voltage amplitude of node i; V n Indicates the optimal reference voltage amplitude.

[0016] In a preferred embodiment of the present invention, the predicted value is the average value of the voltage deviation value per unit time, and its function calculation expression is:

[0017]

[0018] Where V i,t is the voltage amplitude of node i in the scheduling period t; V i,0 is the ideal voltage amplitude of node i in the scheduling period t; ΔV i,max is the maximum allowable voltage deviation of node i.

[0019] In a preferred embodiment of the present invention, the compensation decision of the dynamic reactive power compensation module includes: when the power factor of the new energy power station is lower than the target benchmark operating point, reactive power compensation is performed on the new energy power station. During compensation, the reactive power compensation unit compares and matches the compensation capacity of each group of capacitors with the reactive power shortage of the new energy power station. If the reactive power shortage is less than the capacitor with the minimum capacity, the static reactive power compensator and the static reactive power generator are used to perform combined reactive power compensation.

[0020] In a preferred embodiment of the present invention, the operating constraints of the reactive power compensation include the following:

[0021]

[0022] Where V i CB is the compensation amount of the static VAR compensator and static VAR generator in node i; It is the single group compensation amount in the static VAR compensator and static VAR generator; is the number of combinations of static VAR compensators and static VAR generators in node i; is the total number of combinations of static VAR compensators and static VAR generators installed in node i.

[0023] In a preferred embodiment of the present invention, when the When the supercapacitor responds to the demand for reactive power, the hybrid energy storage system realizes coordinated scheduling with the reactive compensation unit and the renewable energy power station according to the operating status of the power grid and the characteristics of the renewable energy power station through an intelligent control algorithm, and optimizes the scheduling strategy according to the real-time demand and operating status of the power grid nodes.

[0024] In a preferred embodiment of the present invention, the dispatching strategy reduces the loss of the grid voltage in the new energy power station by combining the compensation amount issued by the static VAR compensator and the static VAR generator with the optimization strategy of the hybrid energy storage system, and its function expression is:

[0025]

[0026] Where V i 、V j are the voltage amplitudes of nodes i and j respectively; N z is the total number of power grid branches of renewable energy power stations; G k(i,j) is the conductance of branch k connecting nodes i and j; θ i ,θ j are the voltage phases of node i and node j respectively.

[0027] In a preferred embodiment of the present invention, the intelligent control unit can dynamically adjust the reactive power compensation and the operation strategy of the energy storage integrated module according to the changes in the grid load and the voltage fluctuations of the new energy power station.

[0028] In a preferred embodiment of the present invention, a method for voltage-reactive composite coordinated control of a power grid for renewable energy power generation is provided, which is applied to the above-mentioned coordinated control system and includes the following steps:

[0029] S1. Use big data and artificial intelligence technology to monitor the output power and reactive power demand of renewable energy power generation in real time;

[0030] S2. Predict the changing trend of new energy power generation in the future unit time based on real-time monitoring data;

[0031] S3, according to the prediction results and real-time reactive power demand, compensation is performed through the dynamic reactive power compensation module;

[0032] S4. Distributed and centralized reactive power compensation devices are installed inside renewable energy power generation sites and at key nodes of the power grid to respond to local reactive power demands and coordinately adjust the reactive power balance of the power grid;

[0033] S5, automatically adjust the output of the reactive power compensation device through the intelligent control unit to achieve reactive power distribution and regulation;

[0034] S6. Integrate battery energy storage system, supercapacitor and hybrid energy storage system, and realize coordinated scheduling between energy storage system, reactive power compensation device and new energy power generation system through intelligent scheduling system.

[0035] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0036] (1) The present invention uses a dynamic reactive power compensation module to compensate in real time according to the power factor of the renewable energy power station and the reactive power demand of the power grid, effectively preventing voltage fluctuations and flicker and improving the stability of the power grid. At the same time, the intelligent control unit can dynamically adjust the reactive power compensation strategy according to the changes in the power grid load and the voltage fluctuations of the renewable energy power station to ensure the stable operation of the power grid under various working conditions.

[0037] (2) The reactive power compensation unit adopts a layout that combines decentralized and centralized layouts, which not only responds to local reactive power demand, but also coordinates and adjusts the reactive power balance of the power grid and optimizes the distribution of reactive power. In addition, the coordinated dispatch between the energy storage integrated module and the reactive power compensation device and the new energy power generation system is achieved, thereby further improving the utilization efficiency and rationality of reactive power distribution.

[0038] (3) By real-time monitoring of the output power and reactive power demand of renewable energy power stations and combining the prediction module with accurate prediction of future trends, data support is provided for optimizing renewable energy power generation strategies, thereby improving power generation efficiency. Through precise reactive power compensation and intelligent scheduling, reactive power losses in the power grid are reduced, and the effective output power of renewable energy power generation is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 is a system flow chart of a preferred embodiment of the present invention;

[0041] Figure 2 It is a system method flow chart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0044] It should be noted in advance that the principle of reactive power compensation is to connect a device with a capacitive power load and an inductive power load in the same circuit. When the capacitive load releases energy, the inductive load absorbs energy, and when the inductive load releases energy, the capacitive load absorbs energy, and energy is exchanged between the two loads. In this way, the reactive power absorbed by the inductive load can be compensated by the reactive power output by the capacitive load.

[0045] Reactive power is the electrical power used to exchange electric and magnetic fields within a circuit and to establish and maintain a magnetic field in electrical equipment. It does not do work externally, but is converted into other forms of energy. Any electrical equipment with an electromagnetic coil consumes reactive power to establish a magnetic field. Reactive power is by no means useless power, and it is very useful. The motor needs to establish and maintain a rotating magnetic field to rotate the rotor, thereby driving mechanical movement. The rotor magnetic field of the motor is established by obtaining reactive power from the power supply. The transformer also needs reactive power to generate a magnetic field in the primary coil of the transformer and induce voltage in the secondary coil. Therefore, without reactive power, the motor will not rotate, the transformer will not be able to transform voltage, and the AC contactor will not be attracted.

[0046] Function of reactive power: Under normal circumstances, electrical equipment not only needs to obtain active power from the power supply, but also reactive power from the power supply. If the reactive power in the power grid is in short supply, the electrical equipment will not have enough reactive power to establish a normal electromagnetic field. Then, these electrical equipment cannot maintain rated operation, and the terminal voltage of the electrical equipment will drop, thus affecting the normal operation of the electrical equipment. The reactive power supplied by the generator and high-voltage transmission line is far from meeting the needs of the load, so some reactive compensation devices should be set up in the power grid to supplement the reactive power to ensure the user's needs for reactive power, so that the electrical equipment can work under the rated voltage.

[0047] like Figure 1 As shown, a voltage-reactive composite coordinated control system and method for a new energy power generation grid includes: a real-time monitoring module, a prediction module, a dynamic reactive power compensation module, a reactive power compensation unit, and an intelligent control unit;

[0048] The real-time monitoring module uses big data and artificial intelligence technology to monitor the output power and reactive power demand of renewable energy power stations in real time, and obtains the predicted values ​​of node voltage and branch power flow at the target benchmark operating point;

[0049] Furthermore, the target reference operating point is calculated by weighted value addition of the deviation value of each node voltage and the minimum value of the deviation value of the total voltage. The function expression of the target reference operating point is:

[0050]

[0051] In the formula, F t (x) represents the objective function within the dispatch period t; x represents the control variable of the grid-connected power of the renewable energy power station and the grid-connected power of the wind turbine; i represents the i-th node of the renewable energy power station; N represents the total number of nodes of the renewable energy power station; λ1+λ2=1 represents the weighting coefficient of the renewable energy power station, which takes values ​​of 0.6V and 0.4V respectively; V i Represents the voltage amplitude of node i; V nIndicates the optimal reference voltage amplitude.

[0052] Furthermore, the predicted value is the average value of the voltage deviation value per unit time, and its function calculation expression is:

[0053]

[0054] Where V i,t is the voltage amplitude of node i in the scheduling period t; V i,0 is the ideal voltage amplitude of node i in the scheduling period t; ΔV i,max is the maximum allowable voltage deviation of node i.

[0055] It is necessary to further explain here that the output power and reactive power demand of renewable energy power stations are often affected by many factors, such as wind speed, light intensity, grid load changes, etc. These factors are uncertain and volatile, resulting in a certain degree of randomness and variability in the output power and reactive power demand of renewable energy power stations. By calculating the average value of the voltage deviation value per unit time, these random fluctuations can be smoothed to a certain extent, improving the stability and reliability of the data.

[0056] The prediction module needs to predict the future change trend of the renewable energy power station within a unit time based on the real-time monitoring data. If the instantaneous value of real-time monitoring is directly used as the prediction value, it may be interfered by factors such as noise and abnormal values, resulting in inaccurate prediction results. Using the average value as the prediction value can effectively reduce the impact of these interference factors and improve the accuracy and reliability of the prediction.

[0057] The prediction module predicts the change trend of the new energy power station within a unit time in the future according to the probability distribution of the predicted value;

[0058] The dynamic reactive power compensation module includes a static reactive power compensator and a static reactive power generator, which performs compensation according to the prediction results of the prediction module and the real-time reactive power demand;

[0059] Furthermore, the compensation decision of the dynamic reactive power compensation module includes: when the power factor of the renewable energy power station is lower than the target benchmark operating point, reactive power compensation is performed on the renewable energy power station. During compensation, the reactive power compensation unit compares and matches the compensation capacity of each group of capacitors with the reactive power shortage of the renewable energy power station. If the reactive power shortage is less than the capacitor with the minimum capacity, a combined reactive power compensation is performed using a static reactive compensator and a static reactive generator.

[0060] The reactive power compensation unit adopts a reactive power compensation device layout combining decentralized and centralized types, and is installed inside the renewable energy power station and at key nodes of the power grid to respond to local reactive power demand and coordinately adjust the reactive power balance of the power grid;

[0061] Furthermore, the operating constraints of reactive power compensation include the following:

[0062]

[0063] Where V i CB is the compensation amount of the static VAR compensator and static VAR generator in node i; It is the single group compensation amount in the static VAR compensator and static VAR generator; is the number of combinations of static VAR compensators and static VAR generators in node i; is the total number of combinations of static VAR compensators and static VAR generators installed in node i.

[0064] when When the supercapacitor responds to the demand for reactive power, the hybrid energy storage system uses an intelligent control algorithm to achieve coordinated scheduling with the reactive compensation unit and the renewable energy power station according to the operating status of the power grid and the characteristics of the renewable energy power station, and optimizes the scheduling strategy according to the real-time demand and operating status of the power grid nodes.

[0065] Furthermore, when it is monitored in real time that the reactive power demand of the renewable energy power station exceeds a preset threshold or it is predicted that the reactive power demand will increase significantly in the future, the response mechanism of the supercapacitor and hybrid energy storage system is triggered.

[0066] Due to their high power density and fast charging and discharging capabilities, supercapacitors first respond to the instantaneous demand for reactive power and provide immediate reactive support to smooth out grid voltage fluctuations.

[0067] Hybrid energy storage systems (including battery energy storage systems and other energy storage technologies) use intelligent control algorithms to formulate long-term and short-term reactive power compensation and power quality regulation strategies based on the operating status of the power grid (such as load changes, voltage stability, etc.) and the characteristics of renewable energy power stations (such as output power fluctuations, prediction accuracy, etc.).

[0068] The intelligent control unit comprehensively evaluates the current status, remaining capacity and charging and discharging efficiency of the supercapacitor and hybrid energy storage system, and coordinates the reactive power output between the two to ensure that both the immediate reactive power demand can be met and the service life and economic benefits of the energy storage system can be optimized.

[0069] According to the real-time demand and operating status of the grid nodes, the intelligent control unit dynamically adjusts the output of the reactive compensation device (including supercapacitors, hybrid energy storage systems and SVC / SVG) to ensure the accurate distribution of reactive power and the stability of the grid voltage.

[0070] The intelligent control unit automatically adjusts the output of the reactive power compensation device according to the characteristics of the renewable energy power station and the operating status of the power grid, generates a dispatching strategy, and optimizes the distribution of reactive power. The intelligent control unit can dynamically adjust the operating strategy of the reactive power compensation and energy storage integrated modules according to the changes in the power grid load and the voltage fluctuations of the renewable energy power station.

[0071] It also includes an energy storage integration module, which integrates a battery energy storage system, a supercapacitor and a hybrid energy storage system; the energy storage integration module optimizes the discharge strategy and power distribution through an intelligent control algorithm, and is used to optimize the scheduling strategy of the intelligent control unit.

[0072] The dispatching strategy reduces the loss of grid voltage in the renewable energy power station by combining the compensation amount issued by the static VAR compensator and the static VAR generator with the optimization strategy of the hybrid energy storage system. Its function expression is:

[0073]

[0074] Where V i 、V j are the voltage amplitudes of nodes i and j respectively; N z is the total number of power grid branches of renewable energy power stations; G k(i,j) is the conductance of branch k connecting nodes i and j; θ i ,θ j are the voltage phases of node i and node j respectively.

[0075] like Figure 2 As shown, a voltage-reactive composite coordinated control method for a renewable energy power grid is applied to the above-mentioned coordinated control system, and includes the following steps:

[0076] S1. Use big data and artificial intelligence technology to monitor the output power and reactive power demand of renewable energy power generation in real time;

[0077] S2. Predict the changing trend of new energy power generation in the future unit time based on real-time monitoring data;

[0078] S3, according to the prediction results and real-time reactive power demand, compensation is performed through the dynamic reactive power compensation module;

[0079] S4. Distributed and centralized reactive power compensation devices are installed inside renewable energy power generation sites and at key nodes of the power grid to respond to local reactive power demands and coordinately adjust the reactive power balance of the power grid;

[0080] S5, automatically adjust the output of the reactive power compensation device through the intelligent control unit to achieve reactive power distribution and regulation;

[0081] S6. Integrate battery energy storage system, supercapacitor and hybrid energy storage system, and realize coordinated scheduling between energy storage system, reactive power compensation device and new energy power generation system through intelligent scheduling system.

[0082] Example

[0083] Experiment 1: The purpose is to verify the real-time monitoring, prediction and dynamic reactive power compensation functions of the system.

[0084] The main part of this simulation is a 14-node 10kV active distribution network, which selects 2 synchronous generators, a wind turbine generator set, and a photovoltaic power station as power sources. The synchronous generator is a diesel generator with a rated voltage of 10.5kV and a rated power of 200MW; the wind turbine generator set consists of 12 asynchronous double-feedback wind turbines with a rated power of 1.5MW; the DC side voltage of the photovoltaic array is 66V, the AC side voltage is 10.5kV, and the total rated output power is 6MW; the maximum reactive power that the hybrid reactive compensation device (i.e., static VAR compensator and static VAR generator) can provide is 100MVar, and the hybrid reactive compensation device is connected in parallel near the outgoing end of the line, close to the load.

[0085] Experimental data:

[0086] Table 1

[0087]

[0088] The prediction error indicates the prediction accuracy of the prediction module on the output power change trend in the future unit time.

[0089] The reactive power compensation amount is the compensation amount performed by the dynamic reactive power compensation module according to the prediction results and the real-time reactive power demand.

[0090] Experiment 2: The purpose is to verify the effect of reactive power compensation unit on improving grid voltage stability.

[0091] The equipment parameters are consistent with those in Experiment 1.

[0092] Experimental data:

[0093] Table 2

[0094]

[0095] The voltage deviation before reactive power compensation refers to the voltage deviation of the grid node when reactive power compensation is not performed.

[0096] The voltage deviation after reactive power compensation indicates the voltage deviation after compensation by the reactive power compensation unit, which shows the significant improvement effect of reactive power compensation on voltage stability.

[0097] Experiment 3: The purpose is to verify the optimization effect of the energy storage integration module on the overall scheduling strategy of the system.

[0098] The equipment parameters are consistent with those in Experiment 1.

[0099] Experimental data:

[0100] Table 3

[0101]

[0102] The grid loss before the energy storage system discharges refers to the grid loss when the energy storage system is not optimized and dispatched.

[0103] The grid loss after the energy storage system is discharged refers to the grid loss after optimized scheduling through the energy storage system integrated module.

[0104] The optimization ratio indicates the degree to which the integration of the energy storage system reduces grid losses, showing the effective optimization of the energy storage system on the overall system scheduling strategy.

[0105] When the present invention is used, it uses big data and artificial intelligence technology to monitor the output power and reactive power demand of the new energy power station in real time, and calculates and obtains the predicted values ​​of node voltage and branch power flow at the target benchmark operating point. These predicted values ​​provide a basis for subsequent reactive power compensation and scheduling strategies.

[0106] According to the prediction value provided by the real-time monitoring module and combined with the probability distribution model, the change trend of the new energy power station in the future unit time is predicted. The prediction results are used to guide the reactive compensation strategy of the dynamic reactive compensation module and the reactive power distribution and regulation of the intelligent control unit.

[0107] The dynamic reactive power compensation module includes a static VAR compensator (SVC) and a static VAR generator (SVG), which performs compensation based on the prediction results of the prediction module and the real-time reactive power demand. When the power factor of the renewable energy power station is lower than the target benchmark operating point, reactive power compensation is started. The reactive power compensation unit compares and matches the compensation capacity of each group of capacitors with the reactive power shortage of the renewable energy power station. If the reactive power shortage is less than the capacitor with the smallest capacity, the SVC and SVG are used for combined reactive power compensation.

[0108] The reactive power compensation unit adopts a reactive power compensation device layout that combines decentralized and centralized types. It is installed inside new energy power stations and key nodes of the power grid. While responding to local reactive power demands, it coordinates and adjusts the reactive power balance of the power grid and optimizes the distribution of reactive power.

[0109] The intelligent control unit automatically adjusts the output of the reactive power compensation device according to the characteristics of the renewable energy power station and the operating status of the power grid, generates a dispatching strategy, and optimizes the distribution of reactive power to ensure the stability of the grid voltage and the effective output power of the renewable energy power station.

[0110] The energy storage integrated module integrates battery energy storage system, supercapacitor and hybrid energy storage system, optimizes discharge strategy and power distribution through intelligent control algorithm, and is used to optimize the scheduling strategy of the intelligent control unit.

[0111] When the grid demand or the status of the renewable energy power station changes, the energy storage system can respond to the demand for reactive power and achieve coordinated scheduling with the reactive power compensation unit and the renewable energy power station.

[0112] The dispatch strategy optimizes the intelligent control unit based on the compensation issued by SVC and SVG, combined with the optimization strategy of the hybrid energy storage system, to reduce the loss of grid voltage in the renewable energy power station. The dispatch strategy also considers the changes in grid load and voltage fluctuations in renewable energy power stations to ensure the stable operation of the grid under various working conditions.

[0113] In summary, the grid voltage-reactive composite coordinated control system and method of renewable energy power generation of the present invention realizes reactive power optimization and voltage stability control after the renewable energy power station is connected to the grid through real-time monitoring, prediction, dynamic reactive compensation, reactive compensation unit optimization, automatic adjustment of intelligent control units, and coordinated scheduling of energy storage systems.

[0114] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A grid voltage and reactive power composite coordinated control system for renewable energy power generation, characterized in that: include: Real-time monitoring module, prediction module, dynamic reactive power compensation module, reactive power compensation unit and intelligent control unit; The real-time monitoring module uses big data and artificial intelligence technology to monitor the output power and reactive power demand of the new energy power station in real time, and obtains the predicted values ​​of node voltage and branch power flow at the target benchmark operating point; The prediction module predicts the change trend of the new energy power station within a unit time in the future according to the probability distribution of the predicted value; The dynamic reactive power compensation module includes a static reactive power compensator and a static reactive power generator, and performs compensation according to the prediction result of the prediction module and the real-time reactive power demand; The reactive power compensation unit adopts a reactive power compensation device layout combining decentralized and centralized types, and is set inside the new energy power station and at key nodes of the power grid to respond to local reactive power demand and coordinately adjust the reactive power balance of the power grid; The intelligent control unit automatically adjusts the output of the reactive power compensation device according to the characteristics of the renewable energy power station and the operating status of the power grid, generates a dispatching strategy, and optimizes the distribution of reactive power.

2. The voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 1, characterized in that: It also includes an energy storage integration module, which integrates a battery energy storage system, a supercapacitor and a hybrid energy storage system; the energy storage integration module optimizes the discharge strategy and power distribution through an intelligent control algorithm to optimize the scheduling strategy of the intelligent control unit.

3. The voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 1, characterized in that: The target reference operating point is obtained by weighted calculation of the minimum value of the deviation value of each node voltage and the deviation value of the total voltage. The function expression of the target reference operating point is: In the formula, F t (x) represents the objective function within the dispatch period t; x represents the control variable of the grid-connected power of the renewable energy power station and the grid-connected power of the wind turbine; i represents the i-th node of the renewable energy power station; N represents the total number of nodes of the renewable energy power station; λ1+λ2=1 represents the weighting coefficient of the renewable energy power station, which takes values ​​of 0.6V and 0.4V respectively; V i Represents the voltage amplitude of node i; V n Indicates the optimal reference voltage amplitude.

4. The voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 1, characterized in that: The predicted value is the average value of the voltage deviation value per unit time, and its function calculation expression is: Where V i,t is the voltage amplitude of node i in the scheduling period t; V i,0 is the ideal voltage amplitude of node i in the scheduling period t; ΔV i,max is the maximum allowable voltage deviation of node i.

5. The voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 1, characterized in that: The compensation decision of the dynamic reactive power compensation module includes: when the power factor of the renewable energy power station is lower than the target benchmark operating point, reactive power compensation is performed on the renewable energy power station. During compensation, the reactive power compensation unit compares and matches the compensation capacity of each group of capacitors with the reactive power shortage of the renewable energy power station. If the reactive power shortage is less than the capacitor with the minimum capacity, the static reactive power compensator and the static reactive power generator are used to perform combined reactive power compensation.

6. A voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 5, characterized in that: The operating constraints of the reactive power compensation include the following: Where V i CB is the compensation amount of the static VAR compensator and static VAR generator in node i; It is the single group compensation amount in the static VAR compensator and static VAR generator; is the number of combinations of static VAR compensators and static VAR generators in node i; is the total number of combinations of static VAR compensators and static VAR generators installed in node i.

7. A voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 2 or 5, characterized in that: When the When the supercapacitor responds to the demand for reactive power, the hybrid energy storage system realizes coordinated scheduling with the reactive compensation unit and the renewable energy power station according to the operating status of the power grid and the characteristics of the renewable energy power station through an intelligent control algorithm, and optimizes the scheduling strategy according to the real-time demand and operating status of the power grid nodes.

8. A voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 1 or 7, characterized in that: The dispatching strategy reduces the loss of the grid voltage in the new energy power station by combining the compensation amount issued by the static VAR compensator and the static VAR generator with the optimization strategy of the hybrid energy storage system. The function expression is: Where V i 、V j are the voltage amplitudes of nodes i and j respectively; N z is the total number of power grid branches of renewable energy power stations; G k(i,j) is the conductance of branch k connecting nodes i and j; θ i ,θ j are the voltage phases of node i and node j respectively.

9. The voltage-reactive composite coordinated control system for a renewable energy power generation grid according to claim 1, characterized in that: The intelligent control unit can dynamically adjust the reactive power compensation and the operation strategy of the energy storage integrated module according to the changes in the grid load and the voltage fluctuations of the new energy power station.

10. A voltage-reactive composite coordinated control method for a renewable energy power grid, applied to the coordinated control system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Use big data and artificial intelligence technology to monitor the output power and reactive power demand of renewable energy power generation in real time; S2. Predict the changing trend of new energy power generation in the future unit time based on real-time monitoring data; S3, according to the prediction results and real-time reactive power demand, compensation is performed through the dynamic reactive power compensation module; S4. Distributed and centralized reactive power compensation devices are installed inside renewable energy power generation sites and at key nodes of the power grid to respond to local reactive power demands and coordinately adjust the reactive power balance of the power grid; S5, automatically adjust the output of the reactive power compensation device through the intelligent control unit to achieve reactive power distribution and regulation; S6. Integrate battery energy storage system, supercapacitor and hybrid energy storage system, and realize coordinated scheduling between energy storage system, reactive power compensation device and new energy power generation system through intelligent scheduling system.

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