Voltage reactive power control method and device, storage medium and computer device

Abstract

The voltage reactive power control method, device, storage medium and computer device provided in the application, the method comprises: acquiring an actual power factor at a gateway of a photovoltaic low-voltage grid-connected system, and determining a total load power of the photovoltaic low-voltage grid-connected system according to the actual power factor; determining a total reactive power compensation capacity according to a preset target power factor, the total load power and the actual power factor; determining a first reactive power compensation capacity and a second reactive power compensation capacity according to the total reactive power compensation capacity and a reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system; controlling the switching state of each capacitor bank based on the first reactive power compensation capacity, so that the reactive power compensation capacity of the capacitor of the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity; generating a reactive power compensation instruction based on the second reactive power compensation capacity, and sending the reactive power compensation instruction to a photovoltaic inverter of the photovoltaic low-voltage grid-connected system. By using the method, the power factor of the distributed photovoltaic low-voltage grid-connected system can be improved.

Description

Technical Field

[0001] This application relates to the field of power engineering technology, and in particular to a voltage reactive power control method, device, storage medium and computer equipment. Background Technology

[0002] With the rapid development and promotion of clean energy, distributed photovoltaic (PV) power generation systems have become a common renewable energy generation method. Currently, most distributed PV power generation systems are connected to the distribution system via a 0.4kV multi-point grid connection. Compared to the traditional 10kV high-voltage grid connection method, this low-voltage multi-point grid connection method can effectively reduce construction costs and improve power generation efficiency.

[0003] However, adopting the 0.4kV multi-point grid connection method also presents some problems. One of them is the reduction in power factor on the load side. Because grid-connected inverters in photovoltaic power generation systems typically employ MPPT (Maximum Power Point Tracking) technology, they operate purely on active power output, lacking dynamic reactive power output mechanisms. This leads to a decrease in power factor on the user side, deteriorating power quality, and potentially causing power factor assessments to fail.

[0004] As photovoltaic penetration continues to increase, the failure of power factor assessment values ​​at the grid-user boundary is becoming increasingly serious. Therefore, existing technologies suffer from low power factor in distributed photovoltaic low-voltage grid-connected systems. Summary of the Invention

[0005] The purpose of this application is to at least address one of the aforementioned technical defects, particularly the low power factor of existing distributed photovoltaic low-voltage grid-connected systems.

[0006] In a first aspect, this application provides a voltage reactive power control method, the method comprising:

[0007] Obtain the actual power factor at the junction of the photovoltaic low-voltage grid-connected system, and determine the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor;

[0008] The total reactive power compensation capacity is determined based on the preset target power factor, the total load power, and the actual power factor.

[0009] Based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system, the first reactive power compensation capacity and the second reactive power compensation capacity are determined.

[0010] Based on the first reactive power compensation capacity, the switching state of each capacitor bank is controlled respectively so that the reactive power compensation capacity of the capacitor bank in the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity.

[0011] A reactive power compensation instruction is generated based on the second reactive power compensation capacity and sent to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation instruction is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity.

[0012] In one embodiment, the step of determining the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor includes:

[0013] Based on the actual power factor, and the collected grid connection point voltage and grid connection point current, determine the total grid connection point power;

[0014] Based on the actual power factor, and the collected photovoltaic power generation voltage and photovoltaic power generation current, the total photovoltaic power generation is determined;

[0015] The total load power is determined based on the total power of the grid connection point and the total photovoltaic power generation.

[0016] In one embodiment, the step of determining the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor includes:

[0017] The active power and reactive power of the load are determined based on the total load power and the actual power factor.

[0018] The target reactive power is determined based on the load active power and the preset target power factor;

[0019] The total reactive power compensation capacity is determined based on the target reactive power and the load reactive power.

[0020] In one embodiment, if the reactive power compensation capacity of at least one capacitor bank is not equal to the reactive power compensation capacity of the other capacitor banks, then the step of determining the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system includes:

[0021] Based on the reactive power compensation capacity of each capacitor bank, the capacitor banks are sorted in descending order to determine the arrangement order of each capacitor bank.

[0022] The total reactive power compensation capacity is used as the initial unallocated reactive power compensation capacity, and the allocated reactive power compensation capacity is initialized to zero.

[0023] For each capacitor bank arranged in ascending order, if the reactive power compensation capacity of the capacitor bank is less than or equal to the unallocated reactive power compensation capacity, then the reactive power compensation capacity of the capacitor bank is increased to the allocated reactive power compensation capacity, and the reactive power compensation capacity of the capacitor bank is subtracted from the unallocated reactive power compensation capacity to update the allocated and unallocated reactive power compensation capacities. This process is repeated for the next capacitor bank until the reactive power compensation capacity of all capacitor banks has been traversed. The allocated reactive power compensation capacity is taken as the first reactive power compensation capacity, and the unallocated reactive power compensation capacity is taken as the second reactive power compensation capacity.

[0024] In one embodiment, if the reactive power compensation capacity of each capacitor bank is equal, the step of determining the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system includes:

[0025] The ratio of the total reactive power compensation capacity to the reactive power compensation capacity of a single capacitor bank is rounded to obtain the rounded result.

[0026] The rounding result is multiplied by the reactive power compensation capacity of a single capacitor bank, and the product value is used as the first reactive power compensation capacity.

[0027] The total reactive power compensation capacity is moduloed by the reactive power compensation capacity of a single capacitor, and the remainder is used as the second reactive power compensation capacity.

[0028] In one embodiment, the step of controlling the switching state of each capacitor bank based on the first reactive power compensation capacity includes:

[0029] Determine whether the difference between the capacitor reactive power compensation capacity of the photovoltaic low-voltage grid-connected system and the first reactive power compensation capacity is greater than zero;

[0030] If so, then shut down the capacitor bank corresponding to the difference between the reactive power compensation capacity and the stated value;

[0031] If not, when the difference is not zero, the capacitor bank with the reactive power compensation capacity corresponding to the difference is turned on.

[0032] In one embodiment, the step of generating a reactive power compensation command based on the second reactive power compensation capacity and sending the reactive power compensation command to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system includes:

[0033] Obtain the instruction format and communication address of the photovoltaic inverter;

[0034] The second reactive power compensation capacity is encoded according to the instruction format to generate the reactive power compensation instruction;

[0035] The reactive power compensation command is sent to the photovoltaic inverter based on the communication address.

[0036] Secondly, this application provides a voltage reactive power control device, the device comprising:

[0037] The total load power determination module is used to obtain the actual power factor at the junction of the photovoltaic low-voltage grid-connected system and determine the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor.

[0038] The reactive power compensation total capacity determination module is used to determine the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor.

[0039] The reactive power compensation capacity determination module is used to determine the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system.

[0040] The switching status control module is used to control the switching status of each capacitor bank based on the first reactive power compensation capacity, so that the reactive power compensation capacity of the capacitor bank in the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity.

[0041] The reactive power compensation instruction generation module is used to generate a reactive power compensation instruction based on the second reactive power compensation capacity and send the reactive power compensation instruction to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation instruction is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity.

[0042] Thirdly, this application provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the steps of the voltage reactive power control method described in any of the above embodiments.

[0043] Fourthly, this application provides a computer device, including: one or more processors, and a memory;

[0044] The memory stores computer-readable instructions, which, when executed by the one or more processors, perform the steps of the voltage reactive power control method described in any of the above embodiments.

[0045] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0046] The voltage reactive power control method, apparatus, storage medium, and computer equipment provided in this application include: obtaining the actual power factor at the switch of a photovoltaic low-voltage grid-connected system, and determining the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor; determining the total reactive power compensation capacity based on a preset target power factor, the total load power, and the actual power factor; determining a first reactive power compensation capacity and a second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system; controlling the switching state of each capacitor bank based on the first reactive power compensation capacity, so that the capacitor reactive power compensation capacity of the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity; generating a reactive power compensation command based on the second reactive power compensation capacity, and sending the reactive power compensation command to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation command is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity. When the actual power factor at the junction of a distributed photovoltaic low-voltage grid-connected system changes dynamically, the capacity of the capacitor bank that needs to be put into operation can be dynamically determined, the capacitor bank can be rationally allocated, the reactive power generated in the system can be effectively controlled, and the power factor can be adjusted. At the same time, appropriate reactive power compensation instructions can be generated based on the reactive power compensation margin and sent to the photovoltaic inverter. By optimizing the reactive power regulation of the inverter, it can be ensured that the photovoltaic inverter dynamically adjusts according to the system demand, so that the system power factor is maintained within the preset target range. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic flowchart illustrating the voltage reactive power control method provided in the embodiments of this application;

[0049] Figure 2 A schematic diagram illustrating the process of determining the total load power provided in an embodiment of this application;

[0050] Figure 3 A flowchart illustrating the process of determining the total reactive power compensation capacity provided in this application embodiment;

[0051] Figure 4One of the flowcharts for determining the first reactive power compensation capacity and the second reactive power compensation capacity provided in the embodiments of this application;

[0052] Figure 5 The second schematic diagram of the process for determining the first reactive power compensation capacity and the second reactive power compensation capacity provided in the embodiments of this application;

[0053] Figure 6 A flowchart illustrating the control switching state provided in an embodiment of this application;

[0054] Figure 7 This is a schematic diagram of the voltage reactive power control device provided in the embodiments of this application;

[0055] Figure 8 This is a schematic diagram of the internal structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] This application provides a method for controlling reactive power. The following embodiments illustrate this method applied to a control device in a photovoltaic low-voltage grid-connected system. It is understood that the control device can be any device with data processing capabilities, including but not limited to a single server, server cluster, personal laptop, desktop computer, etc. Figure 1 As shown, the reactive power control method of this application may include the following steps:

[0058] S101: Obtain the actual power factor at the junction of the photovoltaic low-voltage grid-connected system, and determine the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor.

[0059] In this step, the actual power factor at the junction of the photovoltaic low-voltage grid-connected system refers to the ratio of active power to apparent power in the system. Ideally, the power factor should be 1, indicating that the system has only active power and no reactive power. However, in actual operation, photovoltaic low-voltage grid-connected systems are often affected by various factors, such as changes in electrical load, losses in equipment like transformers, and the impedance of distribution lines. These factors typically introduce a certain amount of reactive power, causing the actual power factor to be less than 1.

[0060] Furthermore, to obtain the actual power factor at the switch point of the low-voltage grid-connected photovoltaic system, a power factor measuring instrument, such as a power factor meter or power factor analyzer, can be connected to the switch point. Alternatively, the actual power factor can be calculated by measuring the voltage and current values ​​at the system switch point and then analyzing the measured values.

[0061] Specifically, the information needed to determine the total load power of a photovoltaic low-voltage grid-connected system can include the rated capacity of the photovoltaic generator set, the actual power factor, and the rated capacity of the photovoltaic low-voltage grid-connected system. Based on the obtained information, the total load power of the photovoltaic low-voltage grid-connected system can be calculated.

[0062] S102: Determine the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor.

[0063] In this step, the target power factor can be determined according to the actual situation, and this application does not impose specific restrictions on it. For example, the target power factor can be 1, which means correcting all reactive power in the system. The total reactive power compensation capacity is the reactive power required to correct the system, which can be calculated from the target power factor, the total load power, and the actual power factor.

[0064] S103: Determine the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system.

[0065] In this step, the reactive power compensation capacity of each capacitor bank can be determined based on its parameters. The total reactive power compensation capacity is then allocated based on the reactive power compensation capacity of each capacitor bank to obtain the first and second reactive power compensation capacities. One approach is to determine how many capacitor banks in the system can be used for reactive power compensation, allocate the total reactive power compensation capacity to each capacitor bank according to a certain allocation rule, and then adjust the capacity based on actual needs and system configuration. For example, if a capacitor bank requires a larger reactive power compensation capacity, its capacity can be increased.

[0066] Furthermore, the first reactive power compensation capacity is the reactive power compensation capacity allocated to the capacitor bank in the photovoltaic low-voltage grid-connected system, and the second reactive power compensation capacity is the difference between the total reactive power compensation capacity and the first reactive power compensation capacity, and this difference is not less than zero.

[0067] S104: Based on the first reactive power compensation capacity, control the switching state of each capacitor bank respectively, so that the reactive power compensation capacity of the capacitor bank in the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity.

[0068] In this step, the switching status of each capacitor bank can be checked first. If all capacitor banks are in the off state, a sufficient number of capacitor banks need to be turned on to achieve the first reactive power compensation capacity. Based on the required reactive power compensation capacity, the switching status of each capacitor bank is adjusted one by one. If a capacitor bank is already in the on state and its capacity is greater than the first reactive power compensation capacity, it should be turned off until the total reactive power compensation capacity equals the first reactive power compensation capacity. After adjusting the switching status of the capacitor banks, the reactive power compensation capacity of the photovoltaic low-voltage grid-connected system can be monitored and verified to ensure that the reactive power compensation of the system reaches the required target by real-time monitoring of parameters such as current, voltage, and power factor.

[0069] Furthermore, the control method for the switching state of capacitor banks can be to turn the capacitor banks on or off at predetermined time points, so that their working time and rest time are adjusted accordingly to achieve the required reactive power compensation capacity; or it can be to set a threshold range, and automatically switch the capacitor banks on or off when the reactive power or power factor exceeds or falls below the threshold, for example, by detecting system parameters in real time through sensors or monitoring devices, and determining whether to turn the capacitor banks on or off based on the set threshold; or it can be to use an adaptive control algorithm, which calculates and makes decisions based on the real-time monitored system parameters, and continuously adjusts the switching state of the capacitor banks to make the reactive power compensation capacity of the system approach the required value, and achieve dynamic adjustment and optimization.

[0070] S105: Generate a reactive power compensation instruction based on the second reactive power compensation capacity, and send the reactive power compensation instruction to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation instruction is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity.

[0071] In this step, a control system or monitoring device can be used to convert the second reactive power compensation capacity into a corresponding reactive power compensation command. The command can be in digital or message form, representing the required reactive power value or power factor setting. The generated reactive power compensation command is sent to the photovoltaic inverter in the low-voltage grid-connected photovoltaic system. Command transmission can be accomplished through a communication interface or network connection. After receiving the reactive power compensation command, the photovoltaic inverter adjusts its voltage reactive power output according to the command requirements. The control algorithm and power electronic devices inside the photovoltaic inverter can control the current and voltage to achieve the required reactive power compensation capacity.

[0072] The voltage reactive power control method, apparatus, storage medium, and computer equipment provided in this application include: obtaining the actual power factor at the switch of a photovoltaic low-voltage grid-connected system, and determining the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor; determining the total reactive power compensation capacity based on a preset target power factor, the total load power, and the actual power factor; determining a first reactive power compensation capacity and a second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system; controlling the switching state of each capacitor bank based on the first reactive power compensation capacity, so that the capacitor reactive power compensation capacity of the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity; generating a reactive power compensation command based on the second reactive power compensation capacity, and sending the reactive power compensation command to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation command is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity. When the actual power factor of a distributed photovoltaic low-voltage grid-connected system changes dynamically, the capacity of the capacitor bank that needs to be put into operation can be dynamically determined, the capacitor bank can be rationally allocated, the reactive power generated in the system can be effectively controlled, and the power factor can be adjusted. At the same time, appropriate reactive power compensation instructions can be generated based on the reactive power compensation margin and sent to the photovoltaic inverter. By optimizing the reactive power regulation of the inverter, it can be ensured that the photovoltaic inverter dynamically adjusts according to the system demand, so that the system power factor is maintained within the preset target range.

[0073] like Figure 2 As shown, in one embodiment, the step of determining the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor includes:

[0074] S201: Determine the total power at the grid connection point based on the actual power factor, the collected grid connection point voltage and grid connection point current;

[0075] S202: Determine the total photovoltaic power generation based on the actual power factor, as well as the collected photovoltaic power generation voltage and photovoltaic power generation current;

[0076] S203: Determine the total load power based on the total power of the grid connection point and the total photovoltaic power generation.

[0077] Specifically, based on the actual power factor, and the collected grid connection point voltage and current values, the total grid connection point power is calculated using the definition of power factor and the three-phase power calculation formula, as follows:

[0078]

[0079] Where P represents total power, U represents voltage, I represents current, and PF represents actual power factor.

[0080] Similarly, based on the actual power factor, the collected photovoltaic power generation voltage and photovoltaic power generation current, the total photovoltaic power generation is determined using the above formula. Adding the total power at the grid connection point to the total photovoltaic power generation yields the total load power. Since the total photovoltaic power generation is a negative value, the total load power can represent the power consumed by other loads in the system besides the photovoltaic power generation system.

[0081] In this calculation, the grid connection point voltage, grid connection point current, photovoltaic power generation voltage, photovoltaic power generation current, and actual power factor used are all collected at the same point in time and calculated according to the same voltage and current type. Sensors or measuring instruments can be used to collect the grid connection point voltage, grid connection point current, photovoltaic power generation voltage, and photovoltaic power generation current.

[0082] Understandably, accurately calculating the total load power provides a better understanding of the system's energy consumption.

[0083] like Figure 3 As shown, in one embodiment, the step of determining the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor includes:

[0084] S301: Determine the active power and reactive power of the load based on the total load power and the actual power factor;

[0085] S302: Determine the target reactive power based on the load active power and the preset target power factor;

[0086] S303: Determine the total reactive power compensation capacity based on the target reactive power and the load reactive power.

[0087] Specifically, the active power of the load can be obtained by multiplying the total load power by the actual power factor. The reactive power of the load can be obtained by multiplying the total load power by the square root of the actual power factor, and then multiplying by the negative sign of the total load power; if the actual power factor is positive, the result is negative. The target reactive power can be obtained by multiplying the active power of the load by the square root of the target power factor, and then multiplying by the negative sign of the active power of the load; if the target power factor is positive, the result is negative. The total reactive power compensation capacity equals the target reactive power minus the load reactive power.

[0088] It is understandable that by compensating for the reactive power of the load, the power factor can be improved, the ineffective power in the system can be reduced, the energy utilization efficiency can be improved, and the stability and reliability of the power system can be improved.

[0089] like Figure 4 As shown, in one embodiment, if the reactive power compensation capacity of at least one capacitor bank is not equal to the reactive power compensation capacity of the other capacitor banks, then the step of determining the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system includes:

[0090] S401: Based on the reactive power compensation capacity of each capacitor bank, sort the capacitor banks in descending order to determine the arrangement order of each capacitor bank.

[0091] S402: Use the total reactive power compensation capacity as the initial unallocated reactive power compensation capacity, and initialize the allocated reactive power compensation capacity to zero;

[0092] S403: For each capacitor bank in ascending order of arrangement, if the reactive power compensation capacity of the capacitor bank is less than or equal to the unallocated reactive power compensation capacity, then the reactive power compensation capacity of the capacitor bank is increased to the allocated reactive power compensation capacity, and the reactive power compensation capacity of the capacitor bank is subtracted from the unallocated reactive power compensation capacity to update the allocated and unallocated reactive power compensation capacities. Then, the process is repeated for the next capacitor bank until the reactive power compensation capacity of all capacitor banks has been traversed. The allocated reactive power compensation capacity is taken as the first reactive power compensation capacity, and the unallocated reactive power compensation capacity is taken as the second reactive power compensation capacity.

[0093] Specifically, the reactive power compensation capacity of each capacitor bank is sorted in descending order. The total reactive power compensation capacity is set to the initial value of the unallocated reactive power compensation capacity, and the allocated reactive power compensation capacity is initialized to zero. For each capacitor bank in ascending order, the following operations are performed: if the reactive power compensation capacity of a capacitor bank is less than or equal to the unallocated reactive power compensation capacity, the reactive power compensation capacity of that capacitor bank is added to the allocated reactive power compensation capacity, and the reactive power compensation capacity of that capacitor bank is subtracted from the unallocated reactive power compensation capacity; the allocated and unallocated reactive power compensation capacities are then updated. The process is repeated for the next capacitor bank until the reactive power compensation capacity of all capacitor banks has been processed. Afterwards, the allocated reactive power compensation capacity will be used as the first reactive power compensation capacity, and the unallocated reactive power compensation capacity will be used as the second reactive power compensation capacity.

[0094] For example, if the reactive power compensation capacity of each capacitor bank is: Group A (2kVar), Group B (4kVar), and Group C (3kVar), the descending order is: Group B (4kVar), Group C (3kVar), Group A (2kVar). The total reactive power compensation capacity (10kVar) is set to the initial unallocated reactive power compensation capacity, and the allocated reactive power compensation capacity is initialized to 0. The capacitor banks are then processed sequentially from smallest to largest according to the order. For Group B (4kVar): Since 4kVar < 10kVar, 4kVar is added to the allocated reactive power compensation capacity, making the allocated reactive power compensation capacity 4kVar. Then, 4kVar is subtracted from the unallocated reactive power compensation capacity, making the unallocated reactive power compensation capacity 6kVar. For group C (3kVar): Since 3kVar < 6kVar, add 3kVar to the allocated reactive power compensation capacity, making the allocated reactive power compensation capacity 7kVar. Then subtract 3kVar from the unallocated reactive power compensation capacity, making the unallocated reactive power compensation capacity 3kVar. For group A (2kVar): Since 2kVar < 3kVar, add 2kVar to the allocated reactive power compensation capacity, making the allocated reactive power compensation capacity 9kVar. Then subtract 2kVar from the unallocated reactive power compensation capacity, making the unallocated reactive power compensation capacity 1kVar. Thus, the allocated reactive power compensation capacity is 9kVar, and the unallocated reactive power compensation capacity is 1kVar. That is, the first reactive power compensation capacity is 9kVar, and the second reactive power compensation capacity is 1kVar.

[0095] It is understandable that capacitor banks are sorted in descending order, and reactive power compensation capacity is allocated one by one according to the available unallocated reactive power compensation capacity. The needs of larger capacity capacitor banks are met first, so as to make full use of the available reactive power compensation capacity, thereby maximizing the power factor of the system and improving power quality.

[0096] like Figure 5 As shown, in one embodiment, if the reactive power compensation capacity of each capacitor bank is equal, the step of determining the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system includes:

[0097] S501: The ratio of the total reactive power compensation capacity to the reactive power compensation capacity of a single capacitor bank is rounded to obtain the rounded result;

[0098] S502: Multiply the rounding result with the reactive power compensation capacity of a single capacitor bank, and use the product value as the first reactive power compensation capacity.

[0099] S503: Perform a remainder operation on the total reactive power compensation capacity and the reactive power compensation capacity of a single capacitor, and use the remainder result as the second reactive power compensation capacity.

[0100] Specifically, by comparing the total reactive power compensation capacity with the reactive power compensation capacity of a single capacitor bank and rounding the result, an integer value is obtained. This integer value reflects how many complete single capacitor banks' reactive power compensation capacity requirements can be met under a given capacity condition. The rounded result is then multiplied by the reactive power compensation capacity of a single capacitor bank to obtain a product value, which serves as the first reactive power compensation capacity. This product value represents the sum of the reactive power compensation capacities of the capacitor banks met after rounding, and is a multiple of the rounded result. Finally, by taking the remainder between the total reactive power compensation capacity and the reactive power compensation capacity of a single capacitor bank, a remainder value is obtained as the second reactive power compensation capacity. This remainder value represents the remaining unmet reactive power compensation capacity after rounding.

[0101] Understandably, this approach ensures that the reactive power compensation capacity requirements of the capacitor bank are met as much as possible, clearly distinguishes between the met and unmet requirements, and the rounding and remainder operations help optimize the configuration of the reactive power compensation system, making it more reasonable and efficient.

[0102] like Figure 6 As shown, in one embodiment, the step of controlling the switching state of each capacitor bank based on the first reactive power compensation capacity includes:

[0103] S601: Determine whether the difference between the reactive power compensation capacity of the capacitor in the photovoltaic low-voltage grid-connected system and the first reactive power compensation capacity is greater than zero;

[0104] S602: If so, then shut down the capacitor bank corresponding to the difference between the reactive power compensation capacity and the value mentioned above;

[0105] S603: If not, when the difference is not zero, turn on the capacitor bank with the reactive power compensation capacity corresponding to the difference.

[0106] Specifically, the existence of unmet reactive power compensation capacity demand is determined by comparing the difference between the capacitor's reactive power compensation capacity and the first reactive power compensation capacity. If the difference is greater than zero, it indicates unmet demand; if the difference is equal to or less than zero, it indicates that the reactive power compensation capacity has met or exceeded the demand. If the difference is greater than zero, meaning there is unmet reactive power compensation capacity demand, the corresponding capacitor bank needs to be shut down to reduce the reactive power compensation capacity. Shutting down the capacitor bank can be achieved by disconnecting its power supply or cutting its connection wires. If the difference is less than zero but not zero, meaning the reactive power compensation capacity is not fully utilized or exceeds the demand, the corresponding capacitor bank needs to be turned on to increase the reactive power compensation capacity. Turning on the capacitor bank can be achieved by turning on its power supply or connecting its connection wires.

[0107] Understandably, this approach allows for dynamic adjustment of the capacitor bank's switching status based on actual reactive power compensation capacity requirements, ensuring that the system's reactive power compensation capacity matches actual needs, further improving the stability and efficiency of the photovoltaic low-voltage grid-connected system, and ensuring reasonable control of power quality.

[0108] In one embodiment, the step of generating a reactive power compensation command based on the second reactive power compensation capacity and sending the reactive power compensation command to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system includes:

[0109] Obtain the instruction format and communication address of the photovoltaic inverter;

[0110] The second reactive power compensation capacity is encoded according to the instruction format to generate the reactive power compensation instruction;

[0111] The reactive power compensation command is sent to the photovoltaic inverter based on the communication address.

[0112] Specifically, communication between the photovoltaic inverter and the control equipment of the photovoltaic low-voltage grid-connected system can employ common communication protocols such as Modbus or OPC, using a specific command format. Based on the command format, the second reactive power compensation capacity can be encoded to generate corresponding reactive power compensation commands. The specific encoding method and command generation method need to be determined according to the specific command format. Finally, the generated reactive power compensation command can be sent to the photovoltaic inverter based on the communication address. The communication address is generally used to uniquely identify the inverter, ensuring that the command is sent to the correct device.

[0113] Understandably, by adjusting the reactive power output of the photovoltaic inverter, the system can be made to operate at its optimal operating point, optimize energy utilization efficiency, and improve power generation efficiency.

[0114] The voltage and reactive power control device provided in the embodiments of this application is described below. The voltage and reactive power control device described below can be referred to in correspondence with the voltage and reactive power control method described above. For example Figure 7 As shown, this application provides a voltage reactive power control device, which may include the following structure:

[0115] The total load power determination module 701 is used to obtain the actual power factor at the junction of the photovoltaic low-voltage grid-connected system and determine the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor.

[0116] The reactive power compensation total capacity determination module 702 is used to determine the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor.

[0117] The reactive power compensation capacity determination module 703 is used to determine the first reactive power compensation capacity and the second reactive power compensation capacity based on the total reactive power compensation capacity and the reactive power compensation capacity of each capacitor bank in the photovoltaic low-voltage grid-connected system.

[0118] The switching status control module 704 is used to control the switching status of each capacitor bank based on the first reactive power compensation capacity, so that the reactive power compensation capacity of the capacitor bank in the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity.

[0119] The reactive power compensation instruction generation module 705 is used to generate a reactive power compensation instruction based on the second reactive power compensation capacity and send the reactive power compensation instruction to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation instruction is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity.

[0120] In one embodiment, the total load power determination module 701 includes:

[0121] The grid connection point total power determination unit is used to determine the grid connection point total power based on the actual power factor and the collected grid connection point voltage and grid connection point current.

[0122] The photovoltaic power generation total power determination unit is used to determine the total photovoltaic power generation based on the actual power factor and the collected photovoltaic power generation voltage and photovoltaic power generation current.

[0123] The total load power determination unit is used to determine the total load power based on the total power at the grid connection point and the total photovoltaic power generation.

[0124] In one embodiment, the total reactive power compensation capacity determination module 702 includes:

[0125] The load active power determination unit is used to determine the load active power and load reactive power based on the total load power and the actual power factor.

[0126] The target reactive power determination unit is used to determine the target reactive power based on the load active power and the preset target power factor.

[0127] The reactive power compensation total capacity determination unit is used to determine the total reactive power compensation capacity based on the target reactive power and the load reactive power.

[0128] In one embodiment, the reactive power compensation capacity determination module 703 includes:

[0129] The arrangement order determination unit is used to sort the capacitor groups in descending order according to the reactive power compensation capacity of each capacitor group, so as to determine the arrangement order of each capacitor group.

[0130] An initialization unit is used to set the total reactive power compensation capacity as the initial unallocated reactive power compensation capacity and to initialize the allocated reactive power compensation capacity to zero.

[0131] The reactive power compensation capacity determination unit is used to sequentially determine the reactive power compensation capacity of each capacitor bank in ascending order of arrangement. If the reactive power compensation capacity of the capacitor bank is less than or equal to the unallocated reactive power compensation capacity, the reactive power compensation capacity of the capacitor bank is increased to the allocated reactive power compensation capacity, and the reactive power compensation capacity of the capacitor bank is subtracted from the unallocated reactive power compensation capacity to update the allocated and unallocated reactive power compensation capacities. The unit then iterates through the next capacitor bank until the reactive power compensation capacity of all capacitor banks has been traversed. The allocated reactive power compensation capacity is used as the first reactive power compensation capacity, and the unallocated reactive power compensation capacity is used as the second reactive power compensation capacity.

[0132] In one embodiment, the reactive power compensation capacity determination module 703 includes:

[0133] The rounding result acquisition unit is used to round the ratio of the total reactive power compensation capacity to the reactive power compensation capacity of a single capacitor bank to obtain the rounding result.

[0134] The first reactive power compensation capacity determination unit is used to multiply the rounding result with the reactive power compensation capacity of a single capacitor bank, and use the product value as the first reactive power compensation capacity.

[0135] The second reactive power compensation capacity determination unit is used to perform a remainder operation on the total reactive power compensation capacity and the reactive power compensation capacity of a single capacitor, and use the remainder result as the second reactive power compensation capacity.

[0136] In one embodiment, the switching state control module 704 includes:

[0137] The difference judgment unit is used to determine whether the difference between the reactive power compensation capacity of the capacitor in the photovoltaic low-voltage grid-connected system and the first reactive power compensation capacity is greater than zero.

[0138] A capacitor bank shutdown unit is used to shut down the capacitor bank corresponding to the difference in reactive power compensation capacity if the condition is met.

[0139] The capacitor bank opening unit is used to open the capacitor bank with the reactive power compensation capacity corresponding to the difference if, no, the difference is not zero.

[0140] In one embodiment, the reactive power compensation instruction generation module 705 includes:

[0141] The instruction format acquisition unit is used to acquire the instruction format and communication address of the photovoltaic inverter.

[0142] A reactive power compensation instruction generation unit is used to encode the second reactive power compensation capacity according to the instruction format and generate the reactive power compensation instruction.

[0143] The reactive power compensation instruction sending unit is used to send the reactive power compensation instruction to the photovoltaic inverter according to the communication address.

[0144] In one embodiment, this application also provides a storage medium storing computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the voltage reactive power control method as described in any of the above embodiments.

[0145] In one embodiment, this application also provides a computer device storing computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the voltage reactive power control method as described in any of the above embodiments.

[0146] Indicatively, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the internal structure of a computer device 800 provided in an embodiment of this application. The computer device 800 can be provided as a server. (Refer to...) Figure 8The computer device 800 includes a processing component 802, which further includes one or more processors, and memory resources represented by memory 801 for storing instructions, such as application programs, that can be executed by the processing component 802. The application programs stored in memory 801 may include one or more modules, each corresponding to a set of instructions. Furthermore, the processing component 802 is configured to execute instructions to perform the voltage reactive power control method of any of the above embodiments.

[0147] The computer device 800 may also include a power supply component 803 configured to perform power management of the computer device 800, a wired or wireless network interface 804 configured to connect the computer device 800 to a network, and an input / output (I / O) interface 805. The computer device 800 may operate on an operating system stored in memory 801, such as Windows Server™, Mac OS X™, Unix™, Linux™, Free BSD™, or similar.

[0148] Those skilled in the art will understand that Figure 8 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0149] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, "a," "an," "the," "the," and "its" may also include plural forms unless the context clearly indicates otherwise. "Multiple" refers to at least two, such as 2, 3, 5, or 8, etc. "And / or" includes any and all combinations of the related listed items.

[0150] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0151] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A voltage reactive power control method, characterized in that, The method includes: Obtain the actual power factor at the junction of the photovoltaic low-voltage grid-connected system, and determine the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor; The total reactive power compensation capacity is determined based on the preset target power factor, the total load power, and the actual power factor. If, in each capacitor bank, the reactive power compensation capacity of at least one capacitor bank is not equal to the reactive power compensation capacity of the other capacitor banks, then, based on the reactive power compensation capacity of each capacitor bank, the capacitor banks are sorted in descending order to determine the arrangement order of each capacitor bank; the total reactive power compensation capacity is used as the initial unallocated reactive power compensation capacity, and the allocated reactive power compensation capacity is initialized to zero; in ascending order of arrangement, for each capacitor bank, if the reactive power compensation capacity of the capacitor bank is less than or equal to the unallocated reactive power compensation capacity, then the reactive power compensation capacity of the capacitor bank is increased to the allocated reactive power compensation capacity, and the reactive power compensation capacity of the capacitor bank is subtracted from the unallocated reactive power compensation capacity to update the allocated and unallocated reactive power compensation capacities, and the process is repeated for the next capacitor bank until the reactive power compensation capacity of all capacitor banks has been traversed, with the allocated reactive power compensation capacity used as the first reactive power compensation capacity and the unallocated reactive power compensation capacity used as the second reactive power compensation capacity; If the reactive power compensation capacity of each capacitor bank is equal, the ratio of the total reactive power compensation capacity to the reactive power compensation capacity of a single capacitor bank is rounded down to obtain the rounded result; the rounded result is multiplied by the reactive power compensation capacity of a single capacitor bank, and the product value is used as the first reactive power compensation capacity; the remainder of the total reactive power compensation capacity and the reactive power compensation capacity of a single capacitor bank is calculated, and the remainder result is used as the second reactive power compensation capacity. Based on the first reactive power compensation capacity, the switching state of each capacitor bank is controlled respectively so that the reactive power compensation capacity of the capacitor bank in the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity. A reactive power compensation instruction is generated based on the second reactive power compensation capacity and sent to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation instruction is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity.

2. The voltage reactive power control method according to claim 1, characterized in that, The step of determining the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor includes: Based on the actual power factor, and the collected grid connection point voltage and grid connection point current, determine the total grid connection point power; Based on the actual power factor, and the collected photovoltaic power generation voltage and photovoltaic power generation current, the total photovoltaic power generation is determined; The total load power is determined based on the total power of the grid connection point and the total photovoltaic power generation.

3. The voltage reactive power control method according to claim 1, characterized in that, The step of determining the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor includes: The active power and reactive power of the load are determined based on the total load power and the actual power factor. The target reactive power is determined based on the load active power and the preset target power factor; The total reactive power compensation capacity is determined based on the target reactive power and the load reactive power.

4. The voltage reactive power control method according to claim 1, characterized in that, The step of controlling the switching state of each capacitor bank based on the first reactive power compensation capacity includes: Determine whether the difference between the capacitor reactive power compensation capacity of the photovoltaic low-voltage grid-connected system and the first reactive power compensation capacity is greater than zero; If so, then shut down the capacitor bank corresponding to the difference between the reactive power compensation capacity and the stated value; If not, when the difference is not zero, the capacitor bank with the reactive power compensation capacity corresponding to the difference is turned on.

5. The voltage reactive power control method according to any one of claims 1 to 4, characterized in that, The step of generating a reactive power compensation command based on the second reactive power compensation capacity and sending the reactive power compensation command to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system includes: Obtain the instruction format and communication address of the photovoltaic inverter; The second reactive power compensation capacity is encoded according to the instruction format to generate the reactive power compensation instruction; The reactive power compensation command is sent to the photovoltaic inverter based on the communication address.

6. A voltage reactive power control device, characterized in that, The device includes: The total load power determination module is used to obtain the actual power factor at the junction of the photovoltaic low-voltage grid-connected system and determine the total load power of the photovoltaic low-voltage grid-connected system based on the actual power factor. The reactive power compensation total capacity determination module is used to determine the total reactive power compensation capacity based on the preset target power factor, the total load power, and the actual power factor. The reactive power compensation capacity determination module is used to determine the order of capacitor banks by sorting them in descending order based on their reactive power compensation capacity if, in each capacitor bank, the reactive power compensation capacity of at least one capacitor bank is not equal to that of the other capacitor banks; using the total reactive power compensation capacity as the initial unallocated reactive power compensation capacity and initializing the allocated reactive power compensation capacity to zero; and sequentially processing each capacitor bank in ascending order, if the reactive power compensation capacity of that capacitor bank is less than or equal to the unallocated reactive power compensation capacity, increasing the reactive power compensation capacity of that capacitor bank to the allocated reactive power compensation capacity, and subtracting the reactive power compensation capacity of that capacitor bank from the unallocated reactive power compensation capacity. The reactive power compensation capacity is updated by updating the allocated and unallocated reactive power compensation capacities, and then iterates through the next capacitor bank until the reactive power compensation capacity of all capacitor banks has been traversed. The allocated reactive power compensation capacity is taken as the first reactive power compensation capacity, and the unallocated reactive power compensation capacity is taken as the second reactive power compensation capacity. If the reactive power compensation capacity of each capacitor bank is equal, the ratio of the total reactive power compensation capacity to the reactive power compensation capacity of a single capacitor bank is rounded to obtain the rounded result. The rounded result is multiplied by the reactive power compensation capacity of a single capacitor bank, and the product value is taken as the first reactive power compensation capacity. The remainder of the total reactive power compensation capacity and the reactive power compensation capacity of a single capacitor bank is taken as the second reactive power compensation capacity. The switching status control module is used to control the switching status of each capacitor bank based on the first reactive power compensation capacity, so that the reactive power compensation capacity of the capacitor bank in the photovoltaic low-voltage grid-connected system is equal to the first reactive power compensation capacity. The reactive power compensation instruction generation module is used to generate a reactive power compensation instruction based on the second reactive power compensation capacity and send the reactive power compensation instruction to the photovoltaic inverter of the photovoltaic low-voltage grid-connected system; the reactive power compensation instruction is used to instruct the photovoltaic inverter to control the voltage reactive power output of the photovoltaic inverter according to the second reactive power compensation capacity.

7. A storage medium, characterized in that: The storage medium stores computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the voltage reactive power control method as described in any one of claims 1 to 5.

8. A computer device, characterized in that, include: One or more processors, and memory; The memory stores computer-readable instructions, which, when executed by the one or more processors, perform the steps of the voltage reactive power control method as described in any one of claims 1 to 5.

Images