Low-voltage power distribution network optical storage converter and electric energy quality special-purpose treatment equipment cooperation method

Abstract

The invention provides a low-voltage power distribution network optical storage converter and electric energy quality special management equipment cooperation method and device, and relates to the technical field of low-voltage power distribution network electric energy quality control. Reactive power and active power output of the energy storage system, the electric energy quality special treatment equipment and the photovoltaic inverter are coordinated in sequence, and voltage support and fluctuation treatment are dynamically achieved; when the voltage exceeds the upper limit, the energy storage system outputs reactive power to support the voltage, and if the voltage still exceeds the upper limit, electric energy quality treatment equipment is called to participate in treatment; furthermore, the energy storage system can be switched to output active power, reactive power support is assisted by a photovoltaic inverter, and finally, a flexible power point tracking mode is entered after the voltage is recovered. Through the method, the coordinated operation between the optical storage system and the treatment equipment is realized, the problem of overweight load of single equipment is avoided, the voltage stability of the power distribution network and the photovoltaic power generation utilization rate are improved, and the service life of the energy storage equipment is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of power quality of low-voltage distribution networks, and in particular to a method for coordinating a photovoltaic storage converter and a dedicated power quality management device in a low-voltage distribution network. Background Art

[0002] With the continued development of low-voltage distribution networks, the penetration rate of photovoltaic power generation has increased significantly in some nodes and regions. Under the guidance of maximum power point tracking (MPPT), photovoltaic power generation devices track and capture the maximum output power of solar energy in real time. However, this operating mode causes the output power of photovoltaic power generation to fluctuate in real time with dynamic changes in external conditions such as light intensity and ambient temperature. On the one hand, the time-varying active power of photovoltaic (PV) generators can cause large fluctuations in power flow within the distribution network. Such fluctuations can cause node voltages to exceed the allowable range, and in severe cases, trigger voltage over-limit alarms, threatening the safe operation of the distribution network. On the other hand, the rapid changes in PV power generation can also cause significant voltage fluctuations at the grid connection point. This not only affects the normal operation of load equipment connected to that point, reducing its service life, but can also cause malfunction of sensitive equipment, adversely affecting industrial production and residential life.

[0003] To address these issues, specialized power quality management devices, such as energy storage systems (ESS), static var generators (SVG), and active power filters (APF), are widely used in distribution networks. Energy storage systems store excess energy and release it when photovoltaic power generation is insufficient or when load demand surges, thereby balancing active power. SVGs and APFs rapidly adjust active and reactive power output to stabilize grid voltage and improve power factor. In the past, due to the relatively low installed capacity of photovoltaic power generation, a combination of photovoltaics, energy storage systems, and specialized power quality management devices achieved good results in maintaining voltage stability and power balance in distribution networks.

[0004] In recent years, with the advancement of photovoltaic power generation technology and the reduction of costs, the penetration rate of photovoltaic power generation has continued to increase. The capacity requirements of energy storage systems and power quality management equipment have correspondingly increased to meet the needs of effectively controlling and regulating photovoltaic power generation. However, the high purchase and operation and maintenance costs of energy storage systems and power quality management equipment have limited their large-scale application. Furthermore, under existing collaborative approaches, the entire capacity of power quality management equipment is typically used only to balance the power of photovoltaic power generation, leaving no capacity to address other complex voltage quality issues such as voltage swells and sags.

[0005] Against this backdrop, the flexible power point tracking (FPPT) algorithm has emerged. This algorithm dynamically adjusts the operating point of photovoltaic (PV) generators, reducing PV power generation and thereby alleviating voltage issues caused by power fluctuations. A PV-energy storage system-power quality control device solution based on the FPT algorithm has improved distribution network voltage stability to a certain extent. However, this reduction in PV power inevitably results in power loss and energy waste. Furthermore, these control strategies often overlook the coordinated optimization of reactive power between PV generation, energy storage systems, and static VAR generators. In reality, both PV generation and energy storage systems possess a certain degree of reactive power regulation capability. By rationally regulating their reactive power output, more PV active power can be released while maintaining grid voltage stability. Furthermore, the capacity of power quality control devices should not be solely used for reactive power balancing but should be flexibly allocated based on actual needs. Summary of the Invention

[0006] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, the first purpose of this application is to propose a method for coordinating a photovoltaic storage converter with a dedicated power quality management device in a low-voltage distribution network.

[0008] The second purpose of this application is to propose a collaborative device for a low-voltage distribution network photovoltaic storage converter and a dedicated power quality management device.

[0009] The third objective of this application is to provide an electronic device.

[0010] The fourth object of this application is to provide a computer-readable storage medium.

[0011] A fifth object of this application is to provide a computer program product.

[0012] To achieve the above objectives, the first embodiment of the present application proposes a method for coordinating a photovoltaic storage converter and a dedicated power quality management device in a low-voltage distribution network, including:

[0013] In response to the grid connection point voltage monitoring module detecting that the current voltage exceeds the set voltage upper limit or lower limit, starting the collaborative control process;

[0014] If the current voltage exceeds the upper limit, the reactive power control module of the energy storage system will first output reactive power to support the voltage;

[0015] In response to the voltage still exceeding the limit, the power quality dedicated management device control module is activated to output reactive power at a preset ratio to participate in voltage support; if voltage fluctuation or flicker occurs, the power quality dedicated management device control module performs dynamic management based on the reserved capacity space;

[0016] In response to the voltage still exceeding the limit, switching the reactive power control module of the energy storage system to an active power control module to output active power to further regulate the voltage;

[0017] If the voltage still has not recovered, the reactive power is output through the photovoltaic inverter reactive power control module to assist in increasing the photovoltaic active power;

[0018] When the voltage returns to within the set range, the photovoltaic inverter control module switches to the flexible power point tracking mode and determines the photovoltaic output power based on the voltage limit condition.

[0019] Optionally, the preset ratio is 90% of the rated capacity of the power quality dedicated treatment equipment for active support, and 10% for treating voltage fluctuations or flickers.

[0020] Optionally, the reactive power control module of the energy storage system outputs reactive power at rated capacity in the initial stage, and when switched to the active power control module, its active power output is half of the reactive power output capacity.

[0021] Optionally, when the photovoltaic inverter control module switches to the FPPT mode, its reference power is the maximum power that keeps the grid connection point voltage within a limit.

[0022] Optionally, the power quality control device includes a static VAR generator and / or an active filter, and its control module dynamically adjusts the reserved capacity ratio according to the device type and application scenario.

[0023] To achieve the above objectives, the second embodiment of the present application proposes a collaborative device for a low-voltage distribution network photovoltaic storage converter and a dedicated power quality management device, comprising:

[0024] The voltage monitoring and response unit is used to start the coordinated control process in response to the grid connection point voltage monitoring module detecting that the current voltage exceeds the set voltage upper limit or lower limit;

[0025] The reactive power control unit of the energy storage system is used to output reactive power through the reactive power control module of the energy storage system to support the voltage if the current voltage exceeds the upper limit;

[0026] The reactive power control unit of the power quality control device is used to activate the power quality control device control module in response to the voltage still exceeding the limit, and output reactive power at a preset ratio to participate in voltage support; if voltage fluctuation or flicker occurs, the power quality control device control module performs dynamic control based on the reserved capacity space;

[0027] An active power control unit of the energy storage system is configured to, in response to the voltage still exceeding the limit, switch the reactive power control module of the energy storage system to an active power control module, output active power to further regulate the voltage;

[0028] The photovoltaic inverter reactive power control unit is used to output reactive power through the photovoltaic inverter reactive power control module if the voltage has not yet recovered, thereby assisting in increasing the photovoltaic active power;

[0029] The photovoltaic inverter flexible power point tracking unit is used to control the photovoltaic inverter control module to switch to a flexible power point tracking mode when the voltage returns to a set range, and determine the photovoltaic output power based on the voltage limit condition.

[0030] To achieve the above-mentioned purpose, a third embodiment of the present application provides an electronic device, comprising: a processor, and a memory communicatively connected to the processor;

[0031] The memory stores computer-executable instructions;

[0032] The processor executes the computer-executable instructions stored in the memory to implement the method as described in any one of the first aspects.

[0033] To achieve the above-mentioned purpose, the fourth embodiment of the present application proposes a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, they are used to implement the method as described in any one of the first aspects.

[0034] To achieve the above-mentioned objectives, the fifth embodiment of the present application proposes a computer program product, which implements any one of the methods in the first aspect when executed by a processor.

[0035] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects: by fully utilizing the reactive capacity of energy storage and photovoltaics to achieve voltage support, compared with the existing method that only utilizes reactive power under voltage-exceeding conditions, the absorption of photovoltaic active power is increased; by reserving a certain limit of rated capacity for SVG, it enables it to participate in governance even when system flicker and fluctuation conditions occur, compared with the existing SVG that uses all its power to support photovoltaic active power, the stability of the system voltage is improved.

[0036] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0038] Figure 1 A flowchart of a method for coordinating a photovoltaic storage converter and a power quality control device in a low-voltage distribution network provided by an embodiment of the present application;

[0039] Figure 2 This is a schematic diagram of photovoltaic-energy storage-SVG connected to a low-voltage distribution network according to the first embodiment of the present invention;

[0040] Figure 3 Schematic diagram of power control during the first embodiment of the collaborative method proposed in the present invention;

[0041] Figures 4(a)-(d) are comparison diagrams of the collaborative control effect during the rapid increase of illumination according to the first embodiment of the present invention;

[0042] Figure 5 This is a comparison diagram of the collaborative control effect in the process of rapidly increasing and then decreasing light intensity in Example 1 of the present invention;

[0043] Figure 6 This is a schematic diagram of photovoltaic-energy storage-SVG-APF access to a low-voltage distribution network according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0045] In response to the problems existing in the prior art, the embodiments of the present application provide a method for coordinating photovoltaic storage converters and power quality control equipment in a low-voltage distribution network, aiming to improve the voltage quality of the low-voltage distribution network. This strategy reserves more capacity space for power quality control equipment by effectively and collaboratively utilizing the reactive power of photovoltaic power generation and energy storage systems, enabling it to respond more flexibly to various voltage quality issues. At the same time, by optimizing the charge and discharge management of the energy storage system, unnecessary charge and discharge operations are reduced and the service life of the energy storage equipment is extended. Simulation results show that compared with traditional control strategies, the improved strategies proposed in these three embodiments have significant advantages in improving voltage quality and improving energy utilization efficiency, providing new solutions for the stable operation and sustainable development of low-voltage distribution networks.

[0046] Figure 1 This is a flow chart of a method for coordinating a low-voltage distribution network photovoltaic converter and a power quality control device provided in an embodiment of the present application. Figure 1 As shown, the method includes the following steps:

[0047] Step S1: In response to the grid connection point voltage monitoring module detecting that the current voltage exceeds the set voltage upper limit or lower limit, the collaborative control process is started.

[0048] In the embodiment of the present application, step S1 is mainly used to monitor and determine the voltage status of the grid connection point to determine whether to start the collaborative control process of the photovoltaic storage converter and the power quality management equipment.

[0049] Specifically, the system uses the grid-connected point voltage monitoring module to obtain the current grid-connected voltage value in real time and compares it with the system's preset upper and lower voltage thresholds. If the monitoring results show that the current voltage has exceeded the preset upper or lower voltage threshold, i.e., a voltage over-limit condition has occurred, the system immediately activates the coordinated control logic and enters step S2 to take appropriate measures to maintain voltage stability.

[0050] If the monitoring results show that the current voltage is within the set range, that is, the grid connection point voltage does not exceed the set upper and lower limits, the system determines that the current operating state is normal and no additional voltage support control is required. In this case, the photovoltaic system continues to operate in maximum power point tracking (MPPT) mode to maximize the output of photovoltaic energy. At the same time, dedicated power quality management equipment can be used to deal with other types of power quality issues, such as harmonics, voltage fluctuations, voltage imbalance, etc., to achieve multi-dimensional power quality optimization without interfering with the operating status of the photovoltaic and energy storage systems.

[0051] Through the above settings, this application has the ability to respond quickly when the voltage at the grid connection point is abnormal, and achieve optimal resource allocation under normal voltage conditions, thereby improving the system's operating efficiency and the flexibility of power quality management.

[0052] Step S2: If the current voltage exceeds the upper limit, reactive power is first output through the reactive power control module of the energy storage system to support the voltage.

[0053] In the embodiment of the present application, step S2 is used to prioritize the reactive power regulation capability of the energy storage system (ESS) to provide rapid voltage support when the grid connection point voltage exceeds an upper limit.

[0054] Specifically, when the voltage detected by the grid-connected point voltage monitoring module exceeds the set voltage upper threshold, the system first maintains the photovoltaic system in maximum power point tracking (MPPT) mode to maintain the maximum active power output of the photovoltaic output without interference. Based on this, it determines whether the current voltage exceeds the upper limit.

[0055] If the voltage exceeds the upper limit, the energy storage system's reactive power control module is immediately activated, causing the energy storage converter to output reactive power to inject inductive reactive power into the grid, thereby suppressing the high voltage. The energy storage system's reactive power output offers fast response and strong regulation capabilities, providing timely support when the voltage exceeds the upper limit, preventing the system from entering higher-level control logic.

[0056] After reactive power support is activated, the system re-evaluates in real time whether the grid connection point voltage has returned to the set range. If the voltage has returned to between the upper and lower limits, the reactive power regulation of the energy storage system has achieved the desired effect. The control process then returns to step S1 to continue voltage monitoring and normal photovoltaic operation.

[0057] If the voltage still does not recover after performing energy storage reactive support, that is, the voltage still exceeds the upper limit, the system enters the next stage of control logic, namely step S3, to introduce other equipment to further support the grid connection point voltage.

[0058] By setting this step, the application can prioritize the use of the reactive power regulation capability of the energy storage system itself for rapid response at the initial stage of voltage rise, reducing the frequency of intervention in photovoltaic output and other equipment, thereby improving the stability and economy of the overall system operation.

[0059] Step S3: In response to the voltage still exceeding the limit, the power quality dedicated management device control module is activated to output reactive power at a preset ratio to participate in voltage support; if voltage fluctuation or flicker occurs, the power quality dedicated management device control module performs dynamic management based on the reserved capacity space;

[0060] In an embodiment of the present application, step S3 is used to further call on power quality dedicated management equipment to participate in support when the reactive support of the energy storage system fails to restore the grid connection point voltage to the set range, so as to enhance the voltage regulation capability and ensure stable system operation.

[0061] Specifically, if the energy storage system has already output reactive power in step S2 but the grid connection point voltage is still above the upper limit, the system will activate the power quality control device control module. This control device may include, but is not limited to, a static VAR generator (SVG), an active power filter (APF), or other equipment with rapid reactive power regulation capabilities. In this step, the control device outputs reactive power at a preset ratio or power level to cooperate with the energy storage system to support the voltage and reduce the overvoltage condition at the grid connection point.

[0062] Furthermore, in the embodiments of the present application, the power quality management device reserves a portion of its rated capacity during design and operation. This capacity is not directly used to balance the photovoltaic system's generated power, but is instead specifically used to address dynamic power quality issues such as short-term voltage fluctuations and voltage flicker. When the system detects a voltage fluctuation or flicker event, the management device can quickly and dynamically respond based on this reserved capacity to improve the system's short-term voltage stability and power quality.

[0063] After the treatment equipment intervenes, the system again determines whether the grid connection point voltage is still out of limit. If the voltage has returned to normal (i.e., no longer exceeds the set voltage upper limit), the coordinated regulation of the energy storage system and the treatment equipment has been effective. The process then returns to step S1 to continue with normal voltage monitoring and equipment coordination.

[0064] If the voltage still does not recover, it indicates that the reactive power regulation capability of the current system has reached a critical point and the voltage cannot be controlled within a reasonable range through reactive power support means. The system will continue to enter the next stage of the control process, namely step S4.

[0065] The setting of this step enables this application to have a stronger hierarchical response capability when dealing with voltage over-limit problems, reasonably allocates the resources of energy storage and management equipment, and improves the overall system's coordination and regulation capabilities and the level of response to sudden power quality problems.

[0066] Step S4: In response to the voltage still exceeding the limit, the reactive power control module of the energy storage system is switched to an active power control module to output active power to further regulate the voltage.

[0067] In an embodiment of the present application, step S4 is used to further mobilize the active power regulation capability of the energy storage system to enhance the voltage control effect when the energy storage system and the power quality management equipment have completed reactive support and the voltage has not yet returned to normal.

[0068] Specifically, after the energy storage system's reactive power support in step S2 and the power quality control equipment's reactive power support in step S3, the system detects that the grid connection point voltage is still above the upper limit, indicating that the current reactive power regulation measures are no longer sufficient to meet voltage control requirements. At this point, the system control logic switches the energy storage system's reactive power control module to an active power control module, causing the energy storage system to begin outputting active power to further regulate the grid connection point voltage level.

[0069] In this embodiment, the energy storage system's active power output startup capacity is set at half its original reactive capacity to prevent excessive discharge of the energy storage device, which could affect its lifespan, while also ensuring relatively smooth regulation of active power support. By outputting active power, the local bus voltage can be effectively reduced, suppressing further voltage increases and achieving stronger voltage regulation capabilities.

[0070] At the same time, dedicated power quality management equipment remains operational, its support functions working in conjunction with the active power output of the energy storage system to jointly regulate voltage at the grid connection point. This combined control of active and reactive power enables the system to maintain efficient regulation capabilities even under more severe voltage disturbances.

[0071] After the energy storage system outputs active power, the system again determines whether the grid connection point voltage has returned to the set range. If the voltage has returned to normal, the system process returns to step S1 and resumes normal monitoring and operation.

[0072] If the voltage still exceeds the limit, even if the energy storage system has already output active power, it is still insufficient to restore the voltage to the set range. The system will then proceed to the next stage of control, step S5, to further guide the photovoltaic inverter to participate in reactive power regulation and active power limitation.

[0073] Through the setting of this step, the present application provides a dynamic switching mechanism from reactive power regulation to active power regulation, realizes the optimal response of the energy storage system in different regulation stages, and improves the processing depth and recovery capability of the entire system in the case of continuous voltage exceeding the limit.

[0074] Step S5: If the voltage has not recovered, the reactive power is output through the photovoltaic inverter reactive power control module to assist in increasing the photovoltaic active power.

[0075] In an embodiment of the present application, step S5 is used to further call the reactive power regulation capability of the photovoltaic inverter to achieve deeper voltage optimization control when the system voltage has not yet recovered to the set range after the energy storage system has switched from reactive support to active support and the power quality management equipment has also participated in the regulation.

[0076] Specifically, when executing this step, the system determines that the current voltage problem has not been resolved and that the traditional reactive power support and active power output of the energy storage system are no longer sufficient to achieve voltage recovery. At this point, the control strategy of this application calls on the reactive power control module of the photovoltaic inverter, causing the photovoltaic system to begin outputting reactive power to help improve the voltage condition.

[0077] In the embodiment of the present application, the photovoltaic inverter, on the basis of having a certain reactive power regulation capability, outputs reactive power mainly for local voltage support, forming a coupled control relationship with the output of active power. After the photovoltaic provides reactive support, it can effectively improve the response capability of the photovoltaic inverter to voltage changes, thereby assisting in increasing the active power output capacity of the photovoltaic, so that the photovoltaic power generation system can release as much active power as possible within the voltage control range, thereby achieving an improvement in energy utilization efficiency. At the same time, the system switches the photovoltaic inverter from the traditional MPPT mode to the flexible power point tracking (FPPT) mode, and dynamically adjusts the photovoltaic output power to stabilize it at the maximum value within the voltage allowable range, while ensuring that the voltage does not exceed the limit.

[0078] Through the control logic of this step, the present application can introduce the deep participation of the photovoltaic system under extreme working conditions where multiple rounds of reactive and active power regulation of the system have failed to work, and further release the active power output potential by means of reactive power regulation, thereby improving the flexibility of the overall voltage control and resource utilization efficiency, and avoiding the waste of renewable energy caused by forced power generation restrictions in traditional strategies.

[0079] If the grid connection point voltage recovers to within the set range after reactive power support and power adjustment by the photovoltaic inverter, the process returns to step S1 to continue normal operation and voltage monitoring.

[0080] Step S6: When the voltage returns to within the set range, the photovoltaic inverter control module switches to the flexible power point tracking mode and determines the photovoltaic output power based on the voltage limit condition.

[0081] In the embodiment of the present application, step S6 is used to adjust the operating mode of the photovoltaic system after the system voltage returns to the set range, so that it can maximize the output of active power while maintaining voltage stability, thereby further improving the utilization efficiency of renewable energy.

[0082] Specifically, after the voltage regulation and coordinated control measures in the aforementioned steps (S1 to S5) take effect, the system detects that the grid connection point voltage has returned to within the preset upper and lower limits, at which point it deems the voltage problem to have been temporarily alleviated. To further unleash the PV system's power generation capacity and improve power generation utilization, the system switches the PV inverter's control mode from conventional maximum power point tracking (MPPT) to flexible power point tracking (FPPT).

[0083] In FPPT mode, the PV system no longer blindly tracks the maximum power output point. Instead, it dynamically sets a "safety reference power" based on the current real-time status of the grid-connected voltage, provided that voltage stability permits. This reference power corresponds to the maximum allowable PV output power that will keep the voltage within the specified limits under current network conditions.

[0084] In this embodiment, the PV power is gradually increased in FPPT mode. During this process, the system continuously monitors the voltage changes at the grid connection point. If the voltage approaches a set upper limit, the system locks the current PV output power as the "maximum safe power generation point" and maintains operation to prevent further increases in PV output from causing the voltage to exceed the limit again.

[0085] Through this strategy setting, this application can not only ensure that the grid connection point voltage is always maintained within the set range, but also accept as much photovoltaic power generation as possible under the premise that system resources permit, improve the efficiency of new energy utilization, and take into account the dual goals of system voltage safety and renewable energy friendly access.

[0086] In addition, an embodiment is proposed for a method of coordinating a photovoltaic storage converter and a dedicated power quality management device in a low-voltage distribution network proposed in this application, see embodiment 1.

[0087] Example 2

[0088] like Figure 2 As shown in the figure, photovoltaic (PV) systems, energy storage systems, and a static VAR generator (SVG) are connected to different locations on the low-voltage distribution network. The PV system has a capacity of 100 kW, while the energy storage system (ESS) and the static VAR generator (SVG) each have a capacity of 10 kW. Their resistance-to-reactance ratio (R / X) is 2. The starting voltage at the grid connection point is within the specified limit, and the PV system is operating in maximum power point tracking (MPPT). The energy storage system and SVG are not yet involved in control.

[0089] like Figure 3 As shown in the figure, the improved photovoltaic-energy storage system-static VAR generator (PV-ESS-SVG) coordination strategy first utilizes the reactive power of the ESS during the period t2 to t3. When the reactive power of the ESS fails to achieve power balance, the SVG is put into operation in the final stage from t3 to t4, with its capacity limited to 90% of the rated power. Then, from t4 to t5, the ESS transitions to an active power control strategy. Until the ESS operates at rated power and the SVG operates at 90% capacity, reactive power from the PV inverter is injected from t5 to t6. It can be seen that compared to the PV-ESS-SVG coordination strategy based on maximum power point tracking (FPPT), the PV power is higher at this time, and the SVG still has 10% of its capacity available to cope with voltage fluctuations.

[0090] The photovoltaic system works in MPPT mode, with a light intensity of 40W / s. 2 / s slope from 600W / s 2 Increased to 1000W / s 2As the sunlight continues to increase, the current voltage at the grid connection point is read in real time and compared with the set voltage upper limit (1.05 pu) and lower limit (0.95 pu), as shown in Figure 4(a). The photovoltaic system switches to maximum power point tracking (FPPT) mode in the period from 9 seconds to 10 seconds, while the energy storage system is cut in at 4 seconds, outputting reactive power, and switches to outputting active power at around 6 seconds, as shown in Figure 4(b). This is because the static VAR generator (SVG) is cut in at 5 seconds and gradually increases its power until it reaches 0.9 times its capacity at around 6 seconds, as shown in Figure 4(c). From 9 seconds to 10 seconds, as shown in Figure 4(d), the voltage fluctuation is eliminated by the reverse capacity of the SVG. The improved coordination strategy increases the photovoltaic power, reduces the active power output of the energy storage system during the tracking process, and reduces the voltage fluctuation at the common connection point (PCC) by utilizing the reserve capacity of the SVG.

[0091] like Figure 5 The results show that under conditions where sunlight first increases and then decreases, the voltage of the proposed strategy is compared with that of the maximum power point tracking (MPPT) strategy, the fixed maximum power point tracking (FPPT) strategy, and the improved strategy. The voltage of the MPPT strategy exceeds the specified range between 3 and 21 seconds. The voltage of the fixed FPPT strategy fluctuates between 3 and 10 seconds and between 15 and 21 seconds. With the proposed strategy, the fixed maximum power point tracking (FPPT) is switched on much later, and the voltage fluctuations are suppressed by the static VAR generator (SVG) backup capacity.

[0092] Example 2

[0093] Figure 6 Another specific embodiment of the present invention is shown: PV-storage-SVG-APF integrated into a low-voltage distribution network for collaborative power quality optimization. The process for collaborative power quality optimization using PV-storage-SVG-APF integrated into a low-voltage distribution network is essentially the same as in Example 1. The difference is that both the SVG and APF are dedicated power quality management devices, and their reserved management capacity must be configured based on the actual application scenario.

[0094] To implement the above embodiment, the present application also proposes a collaborative device for a low-voltage distribution network photovoltaic power converter and a dedicated power quality control device. The device includes:

[0095] The voltage monitoring and response unit is used to start the coordinated control process in response to the grid connection point voltage monitoring module detecting that the current voltage exceeds the set voltage upper limit or lower limit;

[0096] The reactive power control unit of the energy storage system is used to output reactive power through the reactive power control module of the energy storage system to support the voltage if the current voltage exceeds the upper limit;

[0097] The reactive power control unit of the power quality control device is used to activate the power quality control device control module in response to the voltage still exceeding the limit, and output reactive power at a preset ratio to participate in voltage support; if voltage fluctuation or flicker occurs, the power quality control device control module performs dynamic control based on the reserved capacity space;

[0098] An active power control unit of the energy storage system is configured to, in response to the voltage still exceeding the limit, switch the reactive power control module of the energy storage system to an active power control module, output active power to further regulate the voltage;

[0099] The photovoltaic inverter reactive power control unit is used to output reactive power through the photovoltaic inverter reactive power control module if the voltage has not yet recovered, thereby assisting in increasing the photovoltaic active power;

[0100] The photovoltaic inverter flexible power point tracking unit is used to control the photovoltaic inverter control module to switch to a flexible power point tracking mode when the voltage returns to a set range, and determine the photovoltaic output power based on the voltage limit condition.

[0101] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0102] In order to implement the above embodiments, the present application also proposes an electronic device, comprising: a processor, and a memory communicatively connected to the processor; the memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the method provided by the above embodiments.

[0103] In order to implement the above embodiments, the present application also proposes a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the methods provided by the above embodiments.

[0104] In order to implement the above embodiments, the present application also proposes a computer program product, including a computer program, which implements the methods provided by the above embodiments when executed by a processor.

[0105] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this application are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0106] It is important to note that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold beyond these legitimate uses. Furthermore, such collection / sharing should be conducted only after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes the relevant user information before using the feature. Furthermore, any necessary steps must be taken to safeguard and secure access to such personal information and ensure that others with access to personal information comply with its privacy policy and procedures.

[0107] This application contemplates providing implementations that allow users to selectively block the use or access of personal information data. Specifically, this disclosure contemplates providing hardware and / or software to prevent or block access to such personal information data. Risks can be minimized by limiting data collection and deleting data once it is no longer needed. Furthermore, where applicable, such personal information can be de-identified to protect user privacy.

[0108] In the descriptions of the foregoing embodiments, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent.

[0109] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0110] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0111] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0112] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0113] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0114] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0115] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

[0116] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this application can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of this application can be achieved. This is not limited herein.

[0117] The above specific embodiments do not constitute a limitation on the scope of protection of this application. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A method for coordinating a photovoltaic storage converter and a power quality control device in a low-voltage distribution network, characterized in that: The following steps are involved: In response to the grid connection point voltage monitoring module detecting that the current voltage exceeds the set voltage upper limit or lower limit, starting the collaborative control process; If the current voltage exceeds the upper limit, the reactive power control module of the energy storage system will first output reactive power to support the voltage; In response to the voltage still exceeding the limit, the power quality dedicated management device control module is activated to output reactive power at a preset ratio to participate in voltage support; if voltage fluctuation or flicker occurs, the power quality dedicated management device control module performs dynamic management based on the reserved capacity space; In response to the voltage still exceeding the limit, switching the reactive power control module of the energy storage system to an active power control module to output active power to further regulate the voltage; If the voltage still has not recovered, the reactive power is output through the photovoltaic inverter reactive power control module to assist in increasing the photovoltaic active power; When the voltage returns to within the set range, the photovoltaic inverter control module switches to the flexible power point tracking mode and determines the photovoltaic output power based on the voltage limit condition.

2. The method according to claim 1, wherein The preset ratio is 90% of the rated capacity of the power quality control equipment used for active support and 10% used for controlling voltage fluctuations or flicker.

3. The method according to claim 1, wherein The reactive power control module of the energy storage system outputs reactive power at rated capacity in the initial stage. When switched to the active power control module, its active power output is half of the reactive power output capacity.

4. The method according to claim 1, wherein When the photovoltaic inverter control module switches to the FPPT mode, its reference power is the maximum power that keeps the grid connection point voltage within the limit.

5. The method according to claim 1, wherein The power quality control device includes a static VAR generator and / or an active filter, and its control module dynamically adjusts the reserved capacity ratio according to the device type and application scenario.

6. A collaborative device for a low-voltage distribution network photovoltaic converter and a power quality control device, characterized in that: include: The voltage monitoring and response unit is used to start the coordinated control process in response to the grid connection point voltage monitoring module detecting that the current voltage exceeds the set voltage upper limit or lower limit; The reactive power control unit of the energy storage system is used to output reactive power through the reactive power control module of the energy storage system to support the voltage if the current voltage exceeds the upper limit; The reactive power control unit of the power quality control device is used to activate the power quality control device control module in response to the voltage still exceeding the limit, and output reactive power at a preset ratio to participate in voltage support; if voltage fluctuation or flicker occurs, the power quality control device control module performs dynamic control based on the reserved capacity space; An active power control unit of the energy storage system is configured to, in response to the voltage still exceeding the limit, switch the reactive power control module of the energy storage system to an active power control module, output active power to further regulate the voltage; The photovoltaic inverter reactive power control unit is used to output reactive power through the photovoltaic inverter reactive power control module if the voltage has not yet recovered, thereby assisting in increasing the photovoltaic active power; The photovoltaic inverter flexible power point tracking unit is used to control the photovoltaic inverter control module to switch to a flexible power point tracking mode when the voltage returns to a set range, and determine the photovoltaic output power based on the voltage limit condition.

7. An electronic device, characterized in that: include: a processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 5 when executed by a processor.

9. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 5 when executed by a processor.

Images