Photovoltaic system control method and device for plateau isolated network energy station

Abstract

The invention discloses a photovoltaic system control method and device for a plateau isolated network energy station, the plateau isolated network energy station comprises a scheduling master station and a photovoltaic system, the photovoltaic system is equipped with a photovoltaic fast power device, and the photovoltaic fast power device is used for acquiring target data of the photovoltaic system in real time. Performing power control and adjustment according to the target data and a control instruction sent by the scheduling master station; the dispatching master station is used for configuring a control strategy of the photovoltaic system, receiving and processing data uploaded by the photovoltaic fast power device and sending a control instruction to the photovoltaic fast power device; the control method comprises the following steps: initializing and configuring a system; a photovoltaic fast power device is started to execute photovoltaic station active power control and photovoltaic station voltage control; and operating the control strategy of the dispatching master station according to a preset control mode under the photovoltaic grid-following operation condition. Through close cooperation between the dispatching master station and the photovoltaic fast power device, real-time monitoring and accurate control of a photovoltaic system are realized, and thus the stability and reliability of a power grid are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of plateau power supply, and in particular relates to a photovoltaic system control method and device for a plateau isolated grid energy station. Background Art

[0002] my country has a vast territory and a large east-west longitude span. In the northwest of my country, solar energy resources are excellent and suitable for the construction of large-scale solar energy utilization projects. However, it cannot be ignored that the northwest is a plateau area with a sparse population, and the current power grid system is at the end of the power system in the northwest and is unstable. Under certain special conditions, the end of the power system is prone to instability, and the voltage or frequency is prone to large fluctuations. In extreme cases, if it is disconnected from the national grid and photovoltaic or solar thermal power generation is unstable, the plateau energy power station will not be able to meet the power demand of the load, resulting in the collapse of the energy power station.

[0003] The Zabuye Salt Lake lithium extraction project is located in a plateau, remote location, high fossil energy costs, and weak power grid support. The load of the lithium carbonate processing plant is relatively stable, the safety risk is small, and the power outage losses are controllable. Therefore, it is an economically reasonable choice to use the abundant local solar energy resources to build an independent power grid based on new energy to power the lithium carbonate processing plant. The location of the Zabuye Salt Lake has sufficient sunlight and rich land resources, which is suitable for the establishment of a "solar thermal + photovoltaic + energy storage" energy supply system. Traditional power generation methods are difficult to quickly adapt to this cold and dry plateau climate change, but previously lacked a control solution for plateau energy power stations including photovoltaic power generation systems to accurately control active and reactive power. It is greatly affected by weather conditions and has obvious volatility and intermittency, which easily leads to unstable power grid operation.

[0004] Therefore, it is necessary to propose a photovoltaic system control method and device for plateau isolated grid energy stations to solve how to achieve efficient, stable and controllable operation of the photovoltaic system when connected to the grid, especially automatic generation control (AGC) and automatic voltage control (AVC) in constant power mode. Summary of the invention

[0005] To solve the above problems, the purpose of the present invention is to provide a photovoltaic system control method and device for a plateau isolated grid energy station. Through the close cooperation between the dispatching master station and the photovoltaic fast power device, real-time monitoring and precise control of the photovoltaic system are realized, thereby improving the stability and reliability of the power grid.

[0006] The present invention provides a photovoltaic system control method for a plateau isolated grid energy station, which is applied to a plateau isolated grid energy station. The plateau isolated grid energy station includes a dispatching master station and a photovoltaic system. The photovoltaic fast power device is equipped with a photovoltaic fast power device, which is used to collect target data of the photovoltaic system in real time and perform power control and regulation according to the target data and the control instructions issued by the dispatching master station; The dispatching master station is used to configure the control strategy of the photovoltaic system, receive and process the data uploaded by the photovoltaic fast power device, and send control instructions to the photovoltaic fast power device; The control method comprises the following steps: Initialize and configure the system; Start the photovoltaic fast power device to perform photovoltaic station active power control and photovoltaic station voltage control; Under the photovoltaic grid-following operation condition, the control strategy of the dispatching master station is operated according to the preset control mode.

[0007] Preferably, the system initialization and configuration includes: Configuring target parameters of the photovoltaic fast power device, the target parameters including communication port, collection cycle and adjustment margin; The control strategy of the photovoltaic system is configured in the dispatching master station, wherein the control strategy includes MPPT mode, constant power mode, RAGC real-time secondary frequency regulation and RAVC real-time secondary voltage regulation; The PV benchmark unit is configured at the dispatching master station, and the corresponding box transformer is selected as the benchmark unit. Through the functions of the PV benchmark unit itself, the maximum power that can be generated by the PV in real time is calculated, and dispatched according to the grid demand.

[0008] Preferably, the photovoltaic station active power control includes: The photovoltaic station active power control comprises the following steps: After startup, monitor the communication port to see if there is a new total active power command for the PV station; The total active power of the current photovoltaic station is collected and calculated synchronously according to the preset cycle, and the deviation △P between the total active power instruction and the total current power of the photovoltaic station is calculated; Obtain the current frequency and calculate the deviation between the current frequency and the preset frequency threshold, and obtain the primary frequency modulation power k△f to be compensated according to the deviation, where the power control deviation △Pc=△P+k△f, k is the primary frequency modulation power compensation coefficient, and △f is the frequency deviation; The power control deviation △Pc is distributed to each photovoltaic PCS according to the adjustment margin of each photovoltaic PCS, and the power amount that each PCS needs to adjust, that is, the correction power, is obtained; According to the current power of each photovoltaic inverter and the calculated corrected power, a new power instruction of the inverter is obtained to form a multicast control instruction; The control instructions are sent to the photovoltaic inverter using multicast or broadcast mode.

[0009] Preferably, the photovoltaic station voltage control includes: Taking the grid-connected bus voltage as the control target, the required reactive power regulation is calculated based on the voltage deviation and system impedance; Allocate reactive power regulation according to the regulation capacity margin of the inverter and the local reactive power compensation device; Calculate the target reactive power of each photovoltaic inverter and reactive power compensation device, and form reactive power multicast control instructions; The control instructions are sent to the photovoltaic inverter or reactive power compensation equipment in a multicast or broadcast mode.

[0010] Preferably, the control strategy for operating the dispatching master station according to the preset control mode under the photovoltaic grid-following operation condition includes: When the PV active power control is put into MPPT mode, the PV fast power device no longer limits the active power of the PV inverter, and sets the active power target value of the PV inverter to the rated power, so that the PV active power is output at the maximum. When the photovoltaic active power control is put into MTTP mode, the corresponding reactive power control is put into constant power factor mode. The current reactive power still runs according to the instruction of photovoltaic fast power. It is put into constant power factor operation through the dispatching master station and the power factor target value is set. Among them, photovoltaic fast power adjusts the reactive power instruction according to the power factor target value. When the photovoltaic active power control is put into constant power mode, the photovoltaic fast power device receives the active power control command and reactive power control command from the dispatching master station. At the same time, the fast power device puts into frequency and voltage droop function, generates active and reactive power deviation commands according to the real-time frequency and voltage changes, and distributes and sends them to the photovoltaic inverter after superimposing with the master station power command, so that the active power output and reactive power output of the photovoltaic system meet the real-time regulation of the power grid; The preset control mode includes an MPPT mode and a constant power control mode.

[0011] As a preferred embodiment, when the photovoltaic active power control is put into constant power mode, the system frequency and voltage are detected in real time, and the active power-frequency droop control is used to assist in adjusting the active power of power generation; when the system frequency decreases, the photovoltaic system increases the active power output; when the system frequency increases, the photovoltaic system reduces the active power output, thereby realizing the primary frequency regulation function; The reactive power of power generation is assisted by reactive-voltage droop control; when the system voltage drops, the photovoltaic system generates reactive power; when the system voltage rises, the photovoltaic system reduces the reactive power generated or absorbs reactive power, thereby realizing the primary voltage regulation function; After superimposing the power command of the dispatching master station and the command of the droop control, the target value is evenly distributed to the operating inverters of the photovoltaic system except the benchmark unit.

[0012] Preferably, when the photovoltaic active power control is put into constant power mode, the RAGC real-time secondary frequency modulation and RAVC real-time secondary voltage regulation strategies of the dispatching master station dispatching layer are put into operation, and the active power instructions and reactive power instructions of the photovoltaic system are generated according to the power distribution in combination with the optical power prediction data, and sent to the photovoltaic fast power device for execution, so as to achieve the maximum photovoltaic power consumption, while taking into account the RAGC real-time secondary frequency modulation and RAVC real-time secondary voltage regulation functions.

[0013] The present invention also provides a photovoltaic system control device for a plateau isolated grid energy station, which implements the photovoltaic system control method for a plateau isolated grid energy station as described in an embodiment of the present invention and is applied to a plateau isolated grid energy station, wherein the plateau isolated grid energy station includes a dispatching master station and a photovoltaic system. The photovoltaic system is equipped with a photovoltaic fast power device, which is used to collect target data of the photovoltaic system in real time and perform power control and adjustment according to the target data and the control instructions issued by the dispatching master station; The dispatching master station is used to configure the control strategy of the photovoltaic system, receive and process the data uploaded by the photovoltaic fast power device, and send control instructions to the photovoltaic fast power device; The control device includes: Initialization module, used to initialize and configure the system; Configure the startup module to start the photovoltaic fast power device to perform photovoltaic station active power control and photovoltaic station voltage control; The strategy control module is used to run the control strategy of the dispatching master station according to the preset control mode under the photovoltaic grid-following operation condition.

[0014] The present invention also provides an electronic device, comprising: A memory, the memory being used to store a processing program; A processor, when executing the processing program, implements the photovoltaic system control method of the plateau isolated grid energy station as described in the embodiment of the present invention.

[0015] The present invention also provides a readable storage medium, on which a processing program is stored. When the processing program is executed by a processor, the photovoltaic system control method of a plateau isolated grid energy station as described in an embodiment of the present invention is implemented.

[0016] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: 1. Improve the stability and reliability of the photovoltaic system: By collecting the target data of the photovoltaic system in real time and performing power control and adjustment based on these data and the control instructions issued by the dispatching master station, the stability and reliability of the photovoltaic system can be effectively improved. Especially in the plateau isolated grid environment, this control method can better cope with grid fluctuations and load changes.

[0017] 2. Optimize energy utilization efficiency: The MPPT mode and constant power control mode can be used to adjust the output power of the photovoltaic system according to the actual needs of the power grid, thereby maximizing the utilization of energy. In addition, the combination of optical power prediction data and real-time secondary frequency and voltage regulation strategies can further improve the absorption capacity of the photovoltaic system.

[0018] 3. Enhance the grid regulation capability: Through active-frequency droop control and reactive-voltage droop control, the photovoltaic system can automatically adjust the active and reactive output when the frequency and voltage fluctuate, and assist the grid in primary frequency and voltage regulation. This enhances the grid regulation capability and helps maintain the stable operation of the grid.

[0019] 4. Improve economic benefits: Optimizing the operation mode of the photovoltaic system can not only improve power generation efficiency, but also reduce operating costs, thereby improving economic benefits. This is especially important for plateau isolated grid energy stations, because such stations are often located in remote areas and have high maintenance costs.

[0020] 5. Improve communication reliability: By configuring the target parameters of the photovoltaic fast power device such as communication port, acquisition cycle and adjustment margin, the reliability and stability of data transmission can be improved. This is crucial for remote monitoring and control of photovoltaic systems.

[0021] 6. Flexible control strategies: The dispatching master station can select different control strategies according to different operating conditions, such as MPPT mode, constant power mode, RAGC real-time secondary frequency regulation and RAVC real-time secondary voltage regulation, which makes the control system more flexible and able to adapt to various complex working conditions.

[0022] 7. Simplify operation and maintenance: Through automated control methods and remote monitoring functions, the need for manual intervention can be reduced, the operating process can be simplified, and the difficulty and cost of maintenance can be reduced.

[0023] 8. Support large-scale applications: This solution is suitable for photovoltaic systems of various sizes. Whether it is a small distributed photovoltaic or a large centralized photovoltaic power station, effective control and management can be achieved in this way. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein: Figure 1 It is a schematic flow chart of a photovoltaic system control method for a plateau isolated grid energy station described in an embodiment of the present invention; Figure 2 It is a strategy diagram for connecting the machine-grid coordinated dispatching master station and the photovoltaic system control in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0026] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] like Figure 1-2 As shown, the present invention provides a photovoltaic system control method for a plateau isolated grid energy station, wherein the plateau isolated grid energy station includes a dispatching master station and a photovoltaic system, wherein the plateau isolated grid energy station is equipped with the photovoltaic fast power device, which is used to collect target data of the photovoltaic system in real time, and perform power control and adjustment according to the target data and the control instructions issued by the dispatching master station; the dispatching master station is used to configure the control strategy of the photovoltaic system, receive and process the data uploaded by the photovoltaic fast power device, and send control instructions to the photovoltaic fast power device; The control method comprises the following steps: Initialize and configure the system, including the following steps: Configure the target parameters of the photovoltaic fast power device, which include the communication port, collection cycle and adjustment margin; configure the control strategy of the photovoltaic system in the dispatching master station, which includes MPPT mode, constant power mode, RAGC real-time secondary frequency regulation and RAVC real-time secondary voltage regulation; configure the photovoltaic benchmark unit to the dispatching master station, and select the corresponding box transformer as the benchmark unit. Through the functions of the photovoltaic benchmark unit itself, calculate the maximum real-time power that can be generated by the photovoltaic, and dispatch it according to the grid demand.

[0028] Start the photovoltaic fast power device to perform photovoltaic station active power control and photovoltaic station voltage control; The photovoltaic fast power device used in this embodiment is the Beijing Sifang CSC-398 regional coordinated stability control device. According to the technical description of the device, it includes the following functions: The photovoltaic station active power control comprises the following steps: After startup, monitor the communication port to see if there is a new total active power command for the PV station; According to the preset period such as 20ms, the total active power of the current photovoltaic station is collected and calculated synchronously, and the deviation △P between the total active power command and the total current power of the photovoltaic station is calculated; Get the current frequency and calculate the deviation between the current frequency and the preset frequency threshold, such as 50Hz, and calculate the primary frequency modulation power k△f to be compensated according to the deviation, where the power control deviation △Pc=△P+k△f, k is the primary frequency modulation power compensation coefficient, and △f is the frequency deviation; The power control deviation △Pc is distributed to each photovoltaic PCS according to the adjustment margin of each photovoltaic PCS, and the power amount that each PCS needs to adjust, that is, the correction power, is obtained; According to the current power of each photovoltaic inverter and the calculated corrected power, a new power instruction of the inverter is obtained to form a multicast control instruction; The control instructions are sent to the photovoltaic inverter using multicast or broadcast mode.

[0029] In this embodiment, the photovoltaic station voltage control includes: Taking the grid-connected bus voltage as the control target, the required reactive power regulation is calculated based on the voltage deviation and system impedance; Allocate reactive power regulation according to the regulation capacity margin of the inverter and the local reactive power compensation device; Calculate the target reactive power of each photovoltaic inverter and reactive power compensation device, and form reactive power multicast control instructions; The control instructions are sent to the photovoltaic inverter or reactive power compensation equipment in a multicast or broadcast mode.

[0030] In this embodiment, the photovoltaic power generation is a grid-following photovoltaic power generation system, which is directly connected to the microgrid and connected in parallel with the energy storage system or the solar thermal unit, without the need to switch the operating mode.

[0031] The control mode relationship under the corresponding operation mode of the photovoltaic system is shown in Table 1 below.

[0032] Table 1 Photovoltaic operation mode table In this embodiment, photovoltaic grid-following operation is designed in two modes: MPPT mode and constant power control mode. This project mainly uses the constant power control mode. The control strategy design of the dispatching master station in the two modes is described in detail below.

[0033] Under the photovoltaic grid-following operation condition, the control strategy of the dispatching master station is operated according to the preset control mode.

[0034] 1. MPPT mode & constant power factor mode When the photovoltaic active power control is put into MPPT mode, the photovoltaic fast power device no longer limits the active power of the photovoltaic inverter, and sets the active power target value of the photovoltaic inverter to the rated power to maximize the photovoltaic active power output.

[0035] When the photovoltaic active power control is put into MTTP mode, the corresponding reactive power control is put into constant power factor mode. At this time, the reactive power still runs according to the instructions of the photovoltaic fast power, and is put into constant power factor operation through the dispatching master station, and the power factor target value is set. The photovoltaic fast power adjusts the reactive command according to the power factor target value.

[0036] (1) Control strategy of photovoltaic fast power device The active power control of the photovoltaic fast power device is put into "MPPT mode" by dispatching the main station, and the active power target value of the running inverter is set to the rated power; The reactive power control of the photovoltaic fast power device is put into "constant power factor mode" through the dispatching master station, accepts the power factor target value of the dispatching master station, calculates the reactive power instruction according to the power factor instruction and real-time active power, and sends it to the photovoltaic inverter to make the power factor of the photovoltaic final output reach the target value.

[0037] (2) Dispatching master station control strategy When the photovoltaic system operates in MPPT mode, the dispatching master station no longer adjusts the real-time active power and reactive power of the photovoltaic system, and the AGC instruction switches to tracking mode; the reactive power control switches to constant power factor mode, and the power factor target value is manually set by the operator.

[0038] 2. Constant power control mode When the photovoltaic active power control is put into constant power mode, the photovoltaic fast power device receives the active power control instructions and reactive power control instructions from the dispatching master station. At the same time, the fast power device puts into frequency and voltage droop function, generates active and reactive power deviation instructions according to the real-time frequency and voltage changes, and distributes them to the photovoltaic inverter after superimposing with the master station power instruction, so that the active power output and reactive power output of the photovoltaic system meet the real-time regulation of the power grid.

[0039] (1) Control strategy of photovoltaic fast power device The photovoltaic fast power device is put into constant power mode through the dispatching master station and receives the active power target value and reactive power target value sent by the dispatching master station.

[0040] The photovoltaic fast power device detects the system frequency and voltage in real time, and assists in regulating the active power of power generation through active-frequency (PF) droop control to help stabilize the system frequency. When the system frequency decreases, the photovoltaic system increases the active output; when the system frequency increases, the photovoltaic system reduces the active output, thereby realizing the primary frequency regulation function.

[0041] The photovoltaic fast power device assists in regulating the reactive power of power generation and stabilizing the system voltage through reactive-voltage (QV) droop control. When the system voltage drops, the photovoltaic system generates reactive power; when the system voltage rises, the photovoltaic system reduces the reactive power generated or absorbs reactive power, thereby achieving a primary voltage regulation function.

[0042] The photovoltaic fast power device superimposes the power command of the dispatching master station with the command of the droop control, and then evenly distributes the target value to the operating inverters of the photovoltaic system except the benchmark unit.

[0043] (2) Dispatching master station control strategy When the photovoltaic system is running in constant power mode, the dispatching master station sends active power instructions and reactive power instructions to the photovoltaic fast power device according to the regulation of the power grid to realize the regulation and control of the photovoltaic system. At the same time, the target frequency and voltage of the power grid are set.

[0044] The dispatching master station puts into operation the "real-time secondary frequency regulation (RAGC)" and "real-time secondary voltage regulation (RAVC)" functions of the dispatching layer, combines the optical power prediction data, and generates active power instructions and reactive power instructions for the photovoltaic system according to power allocation, which are sent to the photovoltaic fast power device for execution, thereby achieving maximum photovoltaic power consumption while taking into account the real-time secondary frequency regulation (RAGC) and real-time secondary voltage regulation (RAVC) functions.

[0045] The frequency target value is 50Hz by default and can be fine-tuned according to the actual needs of the operator.

[0046] The voltage target value is set to 35 kV by default and can be fine-tuned based on the actual needs of the operator.

[0047] The photovoltaic control function design of the dispatching master station in this embodiment is specifically described as follows: 1. Photovoltaic remote / local control switching When the photovoltaic fast power device is operating normally, a remote control signal is issued, and the photovoltaic can be put into remote control in the dispatching master station; similarly, when the photovoltaic is remotely controlled, the photovoltaic fast power can be switched to local control in the dispatching master station. In this project, the fast power device is not equipped with a local control operation interface, so it is put into the master station remote control mode during normal operation.

[0048] (1) Conditions for remote control: Fast power station control / remote control status: The soft pressure plate set by the fast power, the fast power actively selects whether to be controlled by the upper controller. The signal is 0, indicating the local station control state, which is controlled locally by the fast power; 1 indicates the remote state, and the fast power receives remote control instructions.

[0049] (2) Start remote control command from the dispatching master station: The upper controller enables control input: the dispatching master station issues a switch, and the dispatching master station actively decides whether to control the system. 1 indicates remote control, and 0 indicates local energy storage control.

[0050] 2. Photovoltaic remote start and stop control When the photovoltaic system is switched to remote control by the master station, the overall start and stop operations of the photovoltaic system can be performed by remotely controlling the master station.

[0051] (1) Remote start permission conditions: Fast power has been put into remote control: Fast power has been put into remote control of the dispatching master station; Fast power communication is normal: the communication between the dispatching master station and the fast power device GOOSE is normal; PV ready state: start-up conditions are met; Stop state: In the stop state, all inverters are shut down.

[0052] (2) Remote stop permission conditions: Fast power has been put into remote control: Fast power has been put into remote control of the dispatching master station; Fast power communication is normal: the communication between the dispatching master station and the fast power system GOOSE is normal; Running status: PV running status, inverter startup is completed and at least one inverter is running.

[0053] 3. Photovoltaic online control mode When the photovoltaic fast power device is switched to the remote control of the master station, the control mode of the fast power device can be adjusted by scheduling the remote operation of the master station to switch the photovoltaic MPPT mode and constant power mode. This project is an isolated grid operation. In order to ensure the stability of the power grid, the photovoltaic control is put into constant power mode by default.

[0054] (1) Conditions for allowing switching to constant power mode: PV has been put into remote control: PV has been put into remote control of the dispatching master station; fast power communication is normal: the dispatching master station and the fast power device GOOSE communication are normal; MPPT mode: PV fast power operates in MPPT mode; PV power signal is normal: PV power signal is normal and not over the limit.

[0055] (2) Conditions for allowing switching to MPPT mode: PV has been put into remote control: PV has been put into remote control of the dispatching master station; fast power communication is normal: the dispatching master station and the fast power device GOOSE communication are normal; constant power mode: PV operates in constant power mode.

[0056] 4. Photovoltaic AGC control When the PV system is running in constant power mode and has been put into remote control of the master station, the PV fast power device receives the AGC power command sent by the dispatching master station through PQ control, quickly responds to active load distribution, and completes frequency droop support to assist in stable regulation of the power grid.

[0057] On the one hand, the real-time secondary frequency regulation function of the dispatching master station is put into the power grid to generate the real-time secondary frequency regulation power allocation instruction P2S for the photovoltaic system according to the frequency fluctuation; on the other hand, according to the economic dispatching control of the dispatching master station, the photovoltaic power generation plan instruction value P3S is generated in combination with the energy storage charging plan and the solar thermal unit power generation plan; in addition, the photovoltaic power instruction PSOC is generated in conjunction with the SOC value protection of the energy storage; the three instructions P2S, P3S and PSOC are superimposed to generate the AGC power instruction of the photovoltaic system, which is sent to the photovoltaic fast power device for execution through GOOSE communication.

[0058] 5. Photovoltaic AVC control When the PV system is running in constant power mode and has been put into remote control by the master station, the PV fast power device receives the AVC power command sent by the dispatching master station through PQ control, quickly responds to reactive load distribution, and completes voltage droop support to assist in stable regulation of the power grid.

[0059] On the one hand, the real-time secondary voltage regulation function of the dispatching master station is put into use in the power grid, and the real-time secondary voltage regulation reactive power distribution instruction Q2S of the real-time photovoltaic system is generated according to the voltage fluctuation; in addition, the reactive power adjustment instruction Q3S of the photovoltaic system is generated in combination with the distribution of reactive power of the whole network; the AVC reactive power instruction of the photovoltaic system is generated by superimposing the two instructions Q2S and Q3S, and is sent to the photovoltaic system for execution through GOOSE communication.

[0060] 6. Photovoltaic benchmark unit control In order to accurately calculate the maximum power that can be generated by photovoltaics in real time, the photovoltaic system is equipped with a photovoltaic benchmark unit function. The benchmark unit is in the MPPT maximum power generation mode, and the maximum power that can be generated by the photovoltaic system is calculated through the photovoltaic benchmark unit.

[0061] The dispatching master station is equipped with the photovoltaic benchmark unit control function. Through manual operation, the corresponding box transformer can be set as the benchmark unit, and the operation result is sent to the photovoltaic fast power device. After receiving the benchmark unit command, the photovoltaic fast power device switches the corresponding box transformer to MPPT mode, and the remaining units execute AGC and AVC control commands.

[0062] join Figure 2As shown in the figure, the strategy of the machine-grid coordination dispatching master station and the photovoltaic system control docking is as follows: the master station sends "active power command" or "MPPT mode command = rated power" to the photovoltaic control system as needed. The photovoltaic control system first determines whether it is in remote mode (MPPY mode). If it is remote mode, the MPPT mode is executed; if it is not remote mode, the next step is made. Determine whether it is a light-optimal mode switch. If it is a light-optimal mode switch, the light-optimal mode switch process is entered; if it is not a light-optimal mode switch, the next step is made. According to different conditions (such as frequency / voltage deviation, etc.), the photovoltaic control system will adjust the output power and feed back the adjusted power to the master station. At the same time, the photovoltaic control system will also calculate the PQ total power command and send it together with the power command of a single box transformer to the power command of the commissioning standard unit and the non-standard box transformer for processing. Finally, all this information will be summarized into the local power command for unified management and scheduling. In addition, when down-heavy switching is required, the photovoltaic control system will send a signal for down-heavy switching function switching and perform corresponding operations. During the whole process, the photovoltaic control system will also monitor and adjust various parameters to ensure the stable operation of the system.

[0063] The principle adopted in this implementation is: AGC power command: PAGC=P2S+P3S+PSOC, AVC reactive power command: QAVC=Q2S+Q3S. Algorithm improvement: Model predictive control (MPC): can be used to predict short-term changes in photovoltaic power generation and improve the accuracy of AGC and AVC commands. Machine learning algorithm: used to optimize the MPPT control of benchmark units and improve the power generation efficiency of photovoltaic systems.

[0064] For example, assume that the parameters of the photovoltaic system of a plateau isolated grid energy station at a certain moment are as follows: the P2S command caused by frequency deviation is +10MW. The P3S command under economic dispatch control is -5MW. The PSOC command under energy storage SOC protection is +3MW. Then the AGC power command is: PAGC=+10MW-5MW+3MW=+8MW. The dispatching master station sends the +8MW AGC power command to the photovoltaic fast power device through GOOSE communication, and the photovoltaic system will increase the active power output to respond to the frequency demand of the power grid. Similarly, for AVC control, if the Q2S command is +20MVar and the Q3S command is -10MVar, the AVC reactive power command is QAVC=+20MVar-10MVar=+10MVar, and the photovoltaic system will adjust the reactive power output to maintain the grid voltage stability. Through these control strategies, the photovoltaic system of the plateau isolated grid energy station can effectively participate in the frequency and voltage regulation of the power grid and improve the stability and reliability of the power grid.

[0065] Based on the same inventive concept, the present invention also provides a photovoltaic system control device for a plateau isolated grid energy station, which implements the photovoltaic system control method for the plateau isolated grid energy station as described above. The plateau isolated grid energy station includes a dispatching master station and a photovoltaic system, wherein: The photovoltaic system is equipped with a photovoltaic fast power device, which is used to collect target data of the photovoltaic system in real time and perform power control and adjustment according to the target data and the control instructions issued by the dispatching master station; The dispatching master station is used to configure the control strategy of the photovoltaic system, receive and process the data uploaded by the photovoltaic fast power device, and send control instructions to the photovoltaic fast power device; The control device includes: Initialization module, used to initialize and configure the system; Configure the startup module to start the photovoltaic fast power device to perform photovoltaic station active power control and photovoltaic station voltage control; The strategy control module is used to run the control strategy of the dispatching master station according to the preset control mode under the photovoltaic grid-following operation condition.

[0066] It should be noted that the division of the modules in the embodiment of the device / system is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or physically separated. Moreover, these modules can be implemented in the form of software calling through processing elements; or in the form of hardware; or some units can be implemented in the form of software calling through processing elements, and some units can be implemented in the form of hardware.

[0067] The implementation principle of the above modules has been described in the above embodiments, so it will not be repeated here.

[0068] Based on the same concept, in some embodiments of the present application, an electronic device is also provided. The electronic device includes a memory and a processor, wherein the memory is used to store a processing program, and the processor executes the processing program according to instructions. When the processor executes the processing program, the photovoltaic system control method of the plateau isolated grid energy station in the above-mentioned embodiment is realized.

[0069] In some embodiments of the present application, a readable storage medium is also provided, which may be a non-volatile readable storage medium or a volatile readable storage medium. The readable storage medium stores instructions, and when the instructions are executed on a computer, an electronic device including the readable storage medium executes the aforementioned photovoltaic system control method for a plateau isolated grid energy station.

[0070] It is understandable that for the photovoltaic system control method of the plateau isolated grid energy station mentioned above, if it is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or part of the contribution to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-only memory, ROM), random access memory (Random access memory, RAM), disk or optical disk and other media that can store program codes.

[0071] Computer readable storage media may include data signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program codes contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0072] The program code involved in executing the technical solution disclosed in this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Python, C++, etc., and also conventional procedural programming languages ​​such as C language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, as an independent software package, partially on the user computing device and partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect through the Internet).

[0073] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the protection scope of the present invention.

Claims

1. A photovoltaic system control method for a plateau isolated grid energy station, characterized in that: Applied to plateau isolated grid energy station, which includes dispatching master station and photovoltaic system. The photovoltaic system is equipped with a photovoltaic fast power device, which is used to collect target data of the photovoltaic system in real time and perform power control and adjustment according to the target data and the control instructions issued by the dispatching master station; The dispatching master station is used to configure the control strategy of the photovoltaic system, receive and process the data uploaded by the photovoltaic fast power device, and send control instructions to the photovoltaic fast power device; The control method comprises the following steps: Initialize and configure the system; Start the photovoltaic fast power device to perform photovoltaic station active power control and photovoltaic station voltage control; Under the photovoltaic grid-following operation condition, the control strategy of the dispatching master station is operated according to the preset control mode.

2. The photovoltaic system control method of the plateau isolated grid energy station according to claim 1 is characterized in that: The system initialization and configuration includes: Configuring target parameters of the photovoltaic fast power device, the target parameters including communication port, collection cycle and adjustment margin; The control strategy of the photovoltaic system is configured in the dispatching master station, wherein the control strategy includes MPPT mode, constant power mode, RAGC real-time secondary frequency regulation and RAVC real-time secondary voltage regulation; The PV benchmark unit is configured at the dispatching master station, and the corresponding box transformer is selected as the benchmark unit. Through the functions of the PV benchmark unit itself, the maximum power that can be generated by the PV in real time is calculated, and dispatched according to the grid demand.

3. The photovoltaic system control method of the plateau isolated grid energy station according to claim 1 is characterized in that: The photovoltaic station active power control includes: The photovoltaic station active power control comprises the following steps: After startup, monitor the communication port to see if there is a new total active power command for the PV station; The total active power of the current photovoltaic station is collected and calculated synchronously according to the preset cycle, and the deviation △P between the total active power instruction and the total current power of the photovoltaic station is calculated; Obtain the current frequency and calculate the deviation between the current frequency and the preset frequency threshold, and obtain the primary frequency modulation power k△f to be compensated according to the deviation, where the power control deviation △Pc=△P+k△f, k is the primary frequency modulation power compensation coefficient, and △f is the frequency deviation; The power control deviation △Pc is distributed to each photovoltaic PCS according to the adjustment margin of each photovoltaic PCS, and the power amount that each PCS needs to adjust, that is, the correction power, is obtained; According to the current power of each photovoltaic inverter and the calculated corrected power, a new power instruction of the inverter is obtained to form a multicast control instruction; The control instructions are sent to the photovoltaic inverter using multicast or broadcast mode.

4. The photovoltaic system control method of the plateau isolated grid energy station according to claim 1 is characterized in that: The photovoltaic station voltage control includes: Taking the grid-connected bus voltage as the control target, the required reactive power regulation is calculated based on the voltage deviation and system impedance; Allocate reactive power regulation according to the regulation capacity margin of the inverter and the local reactive power compensation device; Calculate the target reactive power of each photovoltaic inverter and reactive power compensation device, and form reactive power multicast control instructions; The control instructions are sent to the photovoltaic inverter or reactive power compensation equipment in a multicast or broadcast mode.

5. The photovoltaic system control method of the plateau isolated grid energy station according to claim 1 is characterized in that: The control strategy for operating the dispatching master station according to the preset control mode under the photovoltaic grid-following operation condition includes: When the PV active power control is put into MPPT mode, the PV fast power device no longer limits the active power of the PV inverter, and sets the active power target value of the PV inverter to the rated power, so that the PV active power is output at the maximum. When the photovoltaic active power control is put into MTTP mode, the corresponding reactive power control is put into constant power factor mode. The current reactive power still runs according to the instruction of photovoltaic fast power. It is put into constant power factor operation through the dispatching master station and the power factor target value is set. Among them, photovoltaic fast power adjusts the reactive power instruction according to the power factor target value. When the photovoltaic active power control is put into constant power mode, the photovoltaic fast power device receives the active power control command and reactive power control command from the dispatching master station. At the same time, the fast power device puts into frequency and voltage droop function, generates active and reactive power deviation commands according to the real-time frequency and voltage changes, and distributes and sends them to the photovoltaic inverter after superimposing with the master station power command, so that the active power output and reactive power output of the photovoltaic system meet the real-time regulation of the power grid; The preset control mode includes an MPPT mode and a constant power control mode.

6. The photovoltaic system control method of the plateau isolated grid energy station according to claim 5 is characterized in that: When the photovoltaic active power control is put into constant power mode, the system frequency and voltage are detected in real time, and the active power-frequency droop control is used to assist in adjusting the active power of power generation; when the system frequency decreases, the photovoltaic system increases the active power output; when the system frequency increases, the photovoltaic system reduces the active power output, thereby realizing the primary frequency regulation function; The reactive power of power generation is assisted by reactive-voltage droop control; when the system voltage drops, the photovoltaic system generates reactive power; when the system voltage rises, the photovoltaic system reduces the reactive power generated or absorbs reactive power, thereby realizing the primary voltage regulation function; After superimposing the power command of the dispatching master station and the command of the droop control, the target value is evenly distributed to the operating inverters of the photovoltaic system except the benchmark unit.

7. The photovoltaic system control method of the plateau isolated grid energy station according to claim 5 is characterized in that: When the photovoltaic active power control is put into constant power mode, the RAGC real-time secondary frequency regulation and RAVC real-time secondary voltage regulation strategies of the dispatching master station dispatching layer are put into operation. Combined with the optical power prediction data and based on the power distribution, the active power command and reactive power command of the photovoltaic system are generated and sent to the photovoltaic fast power device for execution, thereby achieving the maximum photovoltaic power consumption and taking into account the RAGC real-time secondary frequency regulation and RAVC real-time secondary voltage regulation functions.

8. A photovoltaic system control device for a plateau isolated grid energy station, characterized in that: A photovoltaic system control method for a plateau isolated grid energy station as claimed in any one of claims 1 to 7 is implemented, and is applied to a plateau isolated grid energy station, wherein the plateau isolated grid energy station comprises a dispatching master station and a photovoltaic system, wherein: The photovoltaic system is equipped with a photovoltaic fast power device, which is used to collect target data of the photovoltaic system in real time and perform power control and adjustment according to the target data and the control instructions issued by the dispatching master station; The dispatching master station is used to configure the control strategy of the photovoltaic system, receive and process the data uploaded by the photovoltaic fast power device, and send control instructions to the photovoltaic fast power device; The control device includes: Initialization module, used to initialize and configure the system; Configure the startup module to start the photovoltaic fast power device to perform photovoltaic station active power control and photovoltaic station voltage control; The strategy control module is used to run the control strategy of the dispatching master station according to the preset control mode under the photovoltaic grid-following operation condition.

9. An electronic device, characterized in that: include: A memory, the memory being used to store a processing program; A processor, wherein when executing the processing program, the processor implements the photovoltaic system control method of a plateau isolated grid energy station as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: The readable storage medium stores a processing program, and when the processing program is executed by the processor, the photovoltaic system control method of the plateau isolated grid energy station as described in any one of claims 1 to 7 is implemented.

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