A distributed photovoltaic reactive voltage regulation method and system

Abstract

The present invention discloses a distributed photovoltaic reactive voltage regulation method and system, which fits the voltage / reactive sensitivity relationship matrix of each distributed photovoltaic node; calculates the voltage / reactive droop curve of each distributed photovoltaic node and the reactive power required to support other nodes; calculates the expected reactive power output of the photovoltaic inverter based on the voltage / reactive droop curve and the reactive power required to support other nodes; when the expected reactive power output of each photovoltaic inverter is lower than or equal to the reactive power upper limit, and the expected reactive power output of each photovoltaic inverter is higher than or equal to the reactive power lower limit, the expected reactive power is used as the reactive power instruction value of the photovoltaic inverter; when the expected reactive power output of each photovoltaic inverter is lower than the reactive power lower limit or higher than the reactive power upper limit, the reactive power output of the photovoltaic inverter is adjusted to the reactive power lower limit or the reactive power upper limit, and the reactive power shortage caused by capacity limitation is calculated as the input information of the next cycle.

Description

Technical Field

[0001] The present invention belongs to the technical field of voltage control, and in particular relates to a distributed photovoltaic reactive voltage regulation method and system. Background Art

[0002] At present, the global economy is developing rapidly, energy demand is growing, and the structure of distribution network is becoming more and more complex. At the same time, photovoltaic power generation, as a renewable and clean energy, has been widely connected to the distribution network. However, the large-scale access of distributed photovoltaics breaks the unidirectional power flow mode in the traditional distribution network. When the output power of photovoltaic power generation exceeds the load demand, a power reverse flow will occur in the distribution network, causing the voltage limit problem. Voltage / Var Control (Volt / Var Control, VVC) uses the remaining capacity of the photovoltaic inverter to adjust the voltage by outputting reactive power. The current VVC mainly includes local control and centralized control, and both require corresponding control parameter design based on line impedance parameters. The research on local control mainly focuses on designing a reasonable voltage / reactive droop curve so that the reactive power can be adjusted quickly and reasonably according to the local voltage fluctuation to achieve real-time voltage regulation. Centralized control aims to find the optimal working point of the photovoltaic inverter to achieve multi-objective optimization of the distribution network.

[0003] Most existing technical studies have used transparent distribution systems as research objects to design voltage / reactive power control strategies, and the accuracy of their strategies is highly dependent on the precise measurement of impedance, power flow, voltage amplitude and phase within the distribution network. However, in low-voltage distribution networks with a high proportion of photovoltaic power generation access, due to the complex network structure, it becomes very difficult to obtain real-time impedance parameters and voltage phase information. At this time, the voltage / reactive power control strategy based on transparent network information will no longer be applicable due to the lack of parameters. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a distributed photovoltaic reactive voltage regulation method and system in view of the deficiencies in the above-mentioned prior art, which utilizes the limited monitoring data in the distribution network to fit the voltage / reactive sensitivity of each node, and designs a voltage / reactive control strategy that is both local and centralized based on the fitted voltage / reactive sensitivity, so as to solve the technical problem of distributed photovoltaic effective reactive voltage regulation when impedance information is incomplete.

[0005] The present invention adopts the following technical solutions:

[0006] A distributed photovoltaic reactive voltage regulation method comprises the following steps:

[0007] Fit the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node based on historical voltage and reactive power information;

[0008] Based on the obtained voltage / reactive power sensitivity relationship matrix, the voltage / reactive power droop curve of each distributed photovoltaic node and the reactive power required to support other nodes are calculated in combination with the reactive power shortage of each distributed photovoltaic node;

[0009] Calculate the expected reactive power of the PV inverter based on the voltage / reactive power droop curve and the reactive power required to support other nodes;

[0010] The expected reactive power obtained by output is used as the reactive power command value of the photovoltaic inverter when the expected reactive power output of each photovoltaic inverter is lower than or equal to the upper limit of the reactive power under the actual capacity limitation of the inverter, and the expected reactive power output of each photovoltaic inverter is higher than or equal to the lower limit of the reactive power under the actual capacity limitation of the inverter;

[0011] When the expected reactive power output of each PV inverter is lower than the reactive power lower limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle;

[0012] When the expected reactive power output of each PV inverter is higher than the reactive power upper limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle.

[0013] Preferably, the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node is as follows:

[0014]

[0015] Among them, S ij is the influence coefficient of the reactive power of the node where the photovoltaic inverter j is located on the voltage amplitude of the node where the photovoltaic inverter i is located, i,j∈K, K={1,2,…,n}, represents the number of the distributed photovoltaic inverter, and They are the difference between the voltage amplitude and reactive power of the nth distributed photovoltaic inverter at the most recent t moments in the historical database and the current moment.

[0016] Preferably, the difference between the voltage amplitude and reactive power at the most recent t moments in the historical database and the current moment and They are:

[0017]

[0018] Among them, T = {1, 2, ..., t}, represents the t time series closest to the current moment in the historical database, U i0 and Qi0 are the voltage amplitude and reactive power of the installation node of PV inverter i at the current moment respectively.

[0019] Preferably, the voltage / reactive power droop curve of each distributed photovoltaic node is The details are as follows:

[0020]

[0021] Among them, -ω i / s ii is the slope of the voltage / reactive power droop curve of PV inverter i, ω i is the control coefficient, U 1 , U 2 The upper and lower voltage limits.

[0022] Preferably, reactive power of other nodes needs to be supported The details are as follows:

[0023]

[0024] in, is the reactive power that PV inverter i needs to support PV inverter j, K={1,2,…,n} represents the number of distributed PV inverters.

[0025] Preferably, the expected reactive power of photovoltaic inverter i for:

[0026]

[0027] in, is the reactive power value calculated based on the slope of the voltage / reactive power droop curve of PV inverter i, K={1,2,…,n}, represents the number of distributed PV inverter, is the reactive power that PV inverter i needs to support PV inverter j.

[0028] Preferably, the inverter calculates the reactive power value Q based on the droop slope pv,i for:

[0029]

[0030] in, is the reactive power output of photovoltaic inverter i at the current moment, It is the reactive power adjustment value of PV inverter i calculated based on the voltage / reactive power droop control strategy under the current working condition.

[0031] Preferably, the reactive power output of the photovoltaic inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by the capacity limitation of the photovoltaic inverter i for:

[0032]

[0033] in, is the expected reactive power of PV inverter i, is the lower limit of reactive power capacity of PV inverter i.

[0034] Preferably, the reactive power output of the photovoltaic inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by the capacity limitation of the photovoltaic inverter i for:

[0035]

[0036] in, is the expected reactive power of PV inverter i, is the upper limit of reactive power capacity of PV inverter i.

[0037] In a second aspect, an embodiment of the present invention provides a distributed photovoltaic reactive voltage regulation system, comprising:

[0038] A fitting module fits the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node based on historical voltage and reactive power information;

[0039] The calculation module calculates the voltage / reactive power droop curve of each distributed photovoltaic node and the reactive power required to support other nodes based on the obtained voltage / reactive power sensitivity relationship matrix and the reactive power shortage of each distributed photovoltaic node;

[0040] The expected module calculates the expected reactive power of the PV inverter based on the voltage / reactive power droop curve and the reactive power required to support other nodes;

[0041] An output module outputs the expected reactive power. When the expected reactive power output of each photovoltaic inverter is lower than or equal to the upper limit of reactive power under the actual capacity limit of the inverter, and the expected reactive power output of each photovoltaic inverter is higher than or equal to the lower limit of reactive power under the actual capacity limit of the inverter, the expected reactive power is used as the reactive power command value of the photovoltaic inverter;

[0042] When the expected reactive power output of each PV inverter is lower than the reactive power lower limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle;

[0043] When the expected reactive power output of each PV inverter is higher than the reactive power upper limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle.

[0044] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned distributed photovoltaic reactive voltage regulation method when executing the computer program.

[0045] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned distributed photovoltaic reactive voltage regulation method.

[0046] In a fifth aspect, a chip includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned distributed photovoltaic reactive voltage regulation method when executing the computer program.

[0047] In a sixth aspect, an embodiment of the present invention provides an electronic device, including a computer program, which implements the steps of the above-mentioned distributed photovoltaic reactive voltage regulation method when executed by the electronic device.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] A distributed photovoltaic reactive voltage regulation method utilizes limited monitoring data in the distribution network to fit the voltage / reactive sensitivity of each node, and designs a voltage / reactive control strategy that is both local and centralized based on the fitted voltage / reactive sensitivity. This method can achieve reactive voltage regulation of distributed photovoltaics under incomplete impedance information. In a distribution network with incomplete monitoring information, it can maximize the protection of photovoltaic active output and reduce the phenomenon of abandoned light caused by photovoltaic machine cutting.

[0050] Furthermore, the voltage / reactive sensitivity relationship matrix can intuitively reflect the effect of reactive regulation of each photovoltaic inverter on the voltage deviation of each node in the entire network under the current operating conditions. On the one hand, it can provide a basis for the reasonable and effective setting of the local voltage / reactive droop coefficient of the photovoltaic inverter. On the other hand, when cross-node voltage deviation management is required, the voltage / reactive sensitivity relationship matrix also provides a quantitative calculation basis for reactive support.

[0051] Furthermore, the local voltage / reactive power droop control of distributed photovoltaic nodes can quickly and reasonably adjust the reactive power according to local voltage fluctuations, realize real-time voltage regulation, and make up for the problem that real-time voltage fluctuations are difficult to control in a timely manner due to the long central control cycle.

[0052] Furthermore, by setting the expected reactive power output of the photovoltaic inverter, it is possible to avoid the reactive power command issued exceeding the capacity constraint of the reactive power of the photovoltaic inverter, resulting in the loss of control effect.

[0053] Furthermore, when the expected reactive power output of the photovoltaic inverter is lower than the reactive power lower limit, the reactive power shortage caused by capacity limitation is calculated and uploaded to the central controller. The central controller allocates the shortage to the photovoltaic inverters of other nodes based on the voltage / reactive power sensitivity relationship matrix. When the local regulation capacity is insufficient, timely reactive power support can be provided across nodes, thereby achieving the management of voltage deviation.

[0054] Furthermore, when the expected reactive power output of the photovoltaic inverter is higher than the reactive power upper limit, the reactive power shortage caused by capacity limitation is calculated and uploaded to the central controller. The central controller allocates the shortage to the photovoltaic inverters of other nodes based on the voltage / reactive power sensitivity relationship matrix. When the local regulation capacity is insufficient, timely reactive power support can be provided across nodes, thereby achieving the management of voltage deviation.

[0055] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0056] In summary, the present invention fits the voltage / reactive sensitivity of each node in the distribution network based on the easily measurable voltage amplitude and power information, and combines the local voltage / reactive droop control strategy and the central multi-node reactive power support strategy to achieve effective reactive voltage regulation of distributed photovoltaics under incomplete impedance information. In a distribution network with incomplete monitoring information, the present invention can maximize the protection of photovoltaic active output and reduce the phenomenon of abandoned light caused by photovoltaic machine cutting; at the same time, the present invention does not have high requirements on the function of distribution network detection equipment, further improving the economy of distribution network voltage deviation management.

[0057] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 is a flow chart of the method of the present invention;

[0059] Figure 2 is the local droop control curve of distributed photovoltaic;

[0060] Figure 3 IEEE18 node topology diagram for distributed photovoltaic access;

[0061] Figure 4 It is the active power output diagram of each distributed photovoltaic system;

[0062] Figure 5 It is the voltage amplitude diagram of each node when there is no governance;

[0063] Figure 6 It is the reactive power output diagram of each distributed photovoltaic;

[0064] Figure 7 It is the voltage amplitude diagram of each node after treatment;

[0065] Figure 8 A schematic diagram of a computer device provided by an embodiment of the present invention;

[0066] Fig. 9 The block diagram of a chip provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0067] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0068] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0069] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0070] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0071] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0072] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0073] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0074] The present invention provides a distributed photovoltaic reactive voltage regulation method. When line impedance parameter information is difficult to obtain, the voltage / reactive sensitivity is linearly fitted using the least squares method according to the voltage amplitude and power monitoring information of each distributed photovoltaic node. On this basis, a local voltage / reactive droop control strategy of distributed photovoltaics and a reactive power support strategy between multiple nodes are designed. The two levels cooperate with each other at the central and local levels to achieve reactive voltage regulation of distributed photovoltaics under incomplete impedance information.

[0075] See also Figure 1 The present invention provides a distributed photovoltaic reactive voltage regulation method, comprising the following steps:

[0076] S1. Upload the node voltage amplitude and reactive power information of each distributed photovoltaic system and the reactive power shortage of each node to the central controller. The central controller fits the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node based on the historical voltage and reactive power information.

[0077] Among them, if the distributed photovoltaic inverter function supports, the node voltage and reactive power information of each distributed photovoltaic can be directly uploaded by the distributed photovoltaic inverter. If the device does not support the collection and upload of voltage and reactive power, it can be collected and uploaded by the power quality monitoring device. The voltage amplitude and reactive power of the photovoltaic inverter i installation node (i∈K, K={1,2,…,n} is the number of the distributed photovoltaic inverter) at the current moment are recorded as U i0 and Q i0 .

[0078] Reactive power shortage Q of each distributed photovoltaic sup,i (i∈K) is uploaded from distributed photovoltaic to the central controller, the initial Q sup,i Set to 0.

[0079] Calculate the difference between the voltage amplitude and reactive power at the most recent t (t>n) moments in the historical database and the current moment:

[0080] (1)

[0081] Among them, T={1,2,…,t} is the t time series closest to the current moment in the historical database.

[0082] Establish voltage / reactive power sensitivity relationship matrix:

[0083] (2)

[0084] Among them, S ij (i,j∈K) is the influence coefficient of the reactive power of the node where the photovoltaic inverter j is located on the voltage amplitude of the node where the photovoltaic inverter i is located, that is, the voltage / reactive sensitivity, and They are the difference between the voltage amplitude and reactive power of the nth distributed photovoltaic inverter at the most recent t moments in the historical database and the current moment.

[0085] Since t>n, the equation is an overdetermined equation. The sensitivity matrix is ​​solved by least squares fitting. The specific solution formula is:

[0086] (3)

[0087] S2, the central controller is based on the fitted voltage / reactive power sensitivity relationship matrix S and the received reactive power shortage Q of each node sup,i , calculate the voltage / reactive power droop parameters of each distributed photovoltaic node and the reactive power required to support other nodes, and send them to each distributed photovoltaic inverter;

[0088] Calculation of voltage / reactive power droop parameters of each distributed photovoltaic node:

[0089] The droop curve is determined by the current working point of the photovoltaic inverter, the fitted voltage / reactive sensitivity, and the upper and lower limits of reactive power. The photovoltaic inverter locally monitors voltage changes and adjusts reactive power output according to the droop curve. The droop curve diagram is shown in Figure 2 shown.

[0090] Among them, Q base is the current reactive power output of the inverter, U 1 , U 2 is the voltage upper and lower limits, Q max , -Q max are the upper and lower limits of the reactive power output of the photovoltaic inverter. The droop curve equation of the photovoltaic inverter is obtained by formula (2):

[0091] (4)

[0092] in, is the slope of the voltage / reactive power droop curve of PV inverter i, ω i is the control coefficient, which is generally set to 1 / n.

[0093] PV inverter i needs to support reactive power calculation of other nodes:

[0094] According to the reactive power shortage uploaded by each photovoltaic inverter, the photovoltaic inverter nodes with the highest voltage / reactive power sensitivity to these nodes are found respectively.

[0095] Taking photovoltaic inverter j as an example, the reactive power shortage uploaded by photovoltaic inverter j is Q sup,j First, find the photovoltaic inverter i with the highest sensitivity to the voltage / reactive power of the inverter j node. At this time, the photovoltaic inverter i needs to support the reactive power Q of the photovoltaic inverter j. req,ij The calculation formula is:

[0096] (5)

[0097] Therefore, the total reactive power that PV inverter i needs to support other nodes is:

[0098] (6)

[0099] S3, the local photovoltaic inverter calculates the expected reactive power output of the photovoltaic inverter based on the voltage / reactive power droop curve and the reactive power quota required for support received;

[0100] The expected reactive power calculation formula of photovoltaic inverter i is:

[0101] (7)

[0102] in, is the reactive power value calculated by the inverter based on the droop slope, and its expression is

[0103] (8)

[0104] S4. Determine whether the reactive power output of each photovoltaic inverter is lower than or equal to the reactive power upper limit Q max , if it is lower than or equal to, then go to step S5; when the reactive power output of each photovoltaic inverter is lower than the reactive power upper limit, adjust the reactive power output of the photovoltaic inverter to the reactive power upper limit, and calculate the reactive power shortage Q caused by capacity limitation sup , as the input information in the next cycle step S1;

[0105] At this time, the reactive power shortage of photovoltaic inverter i is:

[0106] (9)

[0107] S5. Determine whether the reactive power output of each photovoltaic inverter is higher than or equal to the reactive power lower limit. If so, use the reactive power as the reactive power command value of the photovoltaic inverter. When the reactive power output of each photovoltaic inverter is lower than the reactive power lower limit, adjust the reactive power output of the photovoltaic inverter to the reactive power lower limit, and calculate the reactive power shortage caused by capacity limitation as the input information in the next cycle step S1.

[0108] At this time, the reactive power shortage of photovoltaic inverter i is:

[0109] (10)

[0110] According to the above process, by running with a suitable control cycle, a distributed photovoltaic reactive voltage regulation method without impedance information can be finally obtained.

[0111] In another embodiment of the present invention, a distributed photovoltaic reactive voltage regulation system is provided, which can be used to implement the above-mentioned distributed photovoltaic reactive voltage regulation method. Specifically, the distributed photovoltaic reactive voltage regulation system includes a fitting module, a calculation module, an expectation module and an output module.

[0112] Among them, the fitting module fits the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node based on the historical voltage and reactive power information;

[0113] The calculation module calculates the voltage / reactive power droop curve of each distributed photovoltaic node and the reactive power required to support other nodes based on the obtained voltage / reactive power sensitivity relationship matrix and the reactive power shortage of each distributed photovoltaic node;

[0114] The expected module calculates the expected reactive power of the PV inverter based on the voltage / reactive power droop curve and the reactive power required to support other nodes;

[0115] The output module outputs the expected reactive power. When the reactive power output of each photovoltaic inverter is lower than the reactive power upper limit and the reactive power output of each photovoltaic inverter is higher than the reactive power lower limit, the reactive power is used as the reactive power command value of the photovoltaic inverter.

[0116] When the reactive power output of each photovoltaic inverter is lower than the reactive power lower limit, the reactive power output of the photovoltaic inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by capacity limitation is calculated as the input information for the next cycle;

[0117] When the reactive power output of each PV inverter is greater than the reactive power upper limit, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by capacity limitation is calculated as the input information for the next cycle.

[0118] In another embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the distributed photovoltaic reactive voltage regulation method, including:

[0119] Based on the historical voltage and reactive power information, the voltage / reactive sensitivity relationship matrix of each distributed photovoltaic node is fitted; based on the obtained voltage / reactive sensitivity relationship matrix, the voltage / reactive droop curve of each distributed photovoltaic node and the reactive power required to support other nodes are calculated in combination with the reactive power shortage of each distributed photovoltaic node; based on the voltage / reactive droop curve and the reactive power required to support other nodes, the expected reactive power of the photovoltaic inverter is calculated; the expected reactive power is output, and when the reactive power output of each photovoltaic inverter is lower than the reactive power upper limit and the reactive power of each photovoltaic inverter is When the reactive power output is higher than the reactive power lower limit, the reactive power is used as the reactive power command value of the PV inverter; when the reactive power output of each PV inverter is lower than the reactive power lower limit, the reactive power output of the PV inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by capacity limitation is calculated as the input information for the next cycle; when the reactive power output of each PV inverter is greater than the reactive power upper limit, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by capacity limitation is calculated as the input information for the next cycle.

[0120] See also Figure 8 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for calculating the composition of the fluid in the reservoir transformation wellbore in the embodiment is realized. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the distributed photovoltaic reactive voltage regulation system in the embodiment are realized. To avoid repetition, it is not described one by one here.

[0121] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 8 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0122] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0123] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0124] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0125] See also Fig. 9 The terminal device 600 is an electronic device, and the electronic device is in the form of a general computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0126] The storage unit 620 stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0127] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0128] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0129] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0130] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0131] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs. It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-VolatileMemory), such as at least one disk memory.

[0132] The processor may load and execute one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the distributed photovoltaic reactive voltage regulation method in the above embodiment; the processor may load and execute the following steps:

[0133] Based on the historical voltage and reactive power information, the voltage / reactive sensitivity relationship matrix of each distributed photovoltaic node is fitted; based on the obtained voltage / reactive sensitivity relationship matrix, the voltage / reactive droop curve of each distributed photovoltaic node and the reactive power required to support other nodes are calculated in combination with the reactive power shortage of each distributed photovoltaic node; based on the voltage / reactive droop curve and the reactive power required to support other nodes, the expected reactive power of the photovoltaic inverter is calculated; the expected reactive power is output, and when the reactive power output of each photovoltaic inverter is lower than the reactive power upper limit and the reactive power of each photovoltaic inverter is When the reactive power output is higher than the reactive power lower limit, the reactive power is used as the reactive power command value of the PV inverter; when the reactive power output of each PV inverter is lower than the reactive power lower limit, the reactive power output of the PV inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by capacity limitation is calculated as the input information for the next cycle; when the reactive power output of each PV inverter is greater than the reactive power upper limit, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by capacity limitation is calculated as the input information for the next cycle.

[0134] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0135] The corresponding program was established in Matlab for verification. Based on the IEEE18 node topology, the topology after connecting to distributed photovoltaics is as follows: Figure 3 shown.

[0136] The active power fluctuation of each distributed photovoltaic is as follows: Figure 4 As shown in Figure 2, if reactive voltage regulation is not performed at this time, the voltage amplitude of each node is as follows: Figure 5 As shown in the figure, it can be seen that the voltage of multiple nodes in the distribution network exceeds 1.05 at this time.

[0137] By using the reactive voltage regulation method of the present invention, only the voltage amplitude and power need to be collected, and the reactive output of each distributed photovoltaic in the process of governance is as follows: Figure 6 As shown, it can be seen that at 9 seconds, the photovoltaic inverter of node 7 first reaches its reactive power limit. At this time, the photovoltaic inverter of node 7 sends an upload reactive power shortage to the central controller.

[0138] Based on the fitted sensitivity matrix, the central controller selects the PV inverter of node 6 to provide support for node 7. At 11 seconds, the PV inverter of node 24 also reaches its reactive power capacity limit, and the central controller selects the PV inverter of node 23 for reactive support.

[0139] After 15 seconds, as the system stabilizes and the voltage of each node is adjusted to within the control target range, the PV inverter no longer adjusts its reactive power output.

[0140] See also Figure 7 , which is the control effect. It can be seen that after starting the voltage reactive power regulation method designed by the present invention, the voltage of each node is lower than 1.05, and the control effect is good.

[0141] In summary, the distributed photovoltaic reactive voltage regulation method and system of the present invention fits the voltage / reactive sensitivity of each node in the distribution network based on the easily measurable voltage amplitude and power information, and combines the local voltage / reactive power droop control strategy and the central multi-node reactive power support strategy to achieve effective reactive voltage regulation of distributed photovoltaics under incomplete impedance information.

[0142] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0143] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0144] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0145] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0146] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0147] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0148] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0149] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0150] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0151] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0152] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A distributed photovoltaic reactive voltage regulation method, characterized in that: The following steps are involved: Fit the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node based on historical voltage and reactive power information; Based on the obtained voltage / reactive power sensitivity relationship matrix, the voltage / reactive power droop curve of each distributed photovoltaic node is calculated in combination with the reactive power shortage of each distributed photovoltaic node and the reactive power required to support other nodes. The voltage / reactive power droop curve of each distributed photovoltaic node The details are as follows: Among them, -ω i / s ii is the slope of the voltage / reactive power droop curve of PV inverter i, ω i is the control coefficient, U1 and U2 are the upper and lower limits of voltage, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the voltage amplitude of the node; Reactive power required to support other nodes The details are as follows: in, is the reactive power that PV inverter i needs to support PV inverter j, K={1,2,…,n}, represents the number of distributed PV inverters; PV inverter i needs to support the reactive power Q of PV inverter j req,ij The calculation formula is: in, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the node voltage amplitude, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the node voltage amplitude, For photovoltaic inverter Upload reactive power shortage; Calculate the expected reactive power of the PV inverter based on the voltage / reactive power droop curve and the reactive power required to support other nodes; The expected reactive power obtained by output is used as the reactive power command value of the photovoltaic inverter when the expected reactive power output of each photovoltaic inverter is lower than or equal to the upper limit of the reactive power under the actual capacity limitation of the inverter, and the expected reactive power output of each photovoltaic inverter is higher than or equal to the lower limit of the reactive power under the actual capacity limitation of the inverter; When the expected reactive power output of each PV inverter is lower than the reactive power lower limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle; When the expected reactive power output of each PV inverter is higher than the reactive power upper limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle.

2. The distributed photovoltaic reactive voltage regulation method according to claim 1, characterized in that: The voltage / reactive sensitivity relationship matrix of each distributed photovoltaic node is as follows: in, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the node voltage amplitude, and are the difference between the voltage amplitude and reactive power of the nth distributed photovoltaic inverter at the most recent t moments in the historical database and the current moment, is the total number of inverters.

3. The distributed photovoltaic reactive voltage regulation method according to claim 2, characterized in that: The difference between the voltage amplitude and reactive power at the most recent t moments in the historical database and the current moment and They are: Among them, T = {1, 2, ..., t}, represents the t time series closest to the current moment in the historical database, U i0 and Q i0 are the voltage amplitude and reactive power of the installation node of PV inverter i at the current moment respectively.

4. The distributed photovoltaic reactive voltage regulation method according to claim 1, characterized in that: Expected reactive power of PV inverter i for: in, is the reactive power value calculated based on the slope of the voltage / reactive power droop curve of PV inverter i, K={1,2,…,n}, is the total number of inverters, indicating the number of distributed photovoltaic inverters. is the reactive power that PV inverter i needs to support PV inverter j.

5. The distributed photovoltaic reactive voltage regulation method according to claim 4, characterized in that: The reactive power value calculated by the inverter based on the droop slope for: in, is the reactive power output of photovoltaic inverter i at the current moment, It is the reactive power adjustment value of PV inverter i calculated based on the voltage / reactive power droop control strategy under the current working condition.

6. The distributed photovoltaic reactive voltage regulation method according to claim 1, characterized in that: Adjust the reactive power output of the PV inverter to the reactive power lower limit, and the reactive power shortage caused by the capacity limitation of the PV inverter for: in, is the expected reactive power of PV inverter i, is the lower limit of reactive power capacity of PV inverter i.

7. The distributed photovoltaic reactive voltage regulation method according to claim 1, characterized in that: Adjust the reactive power output of the PV inverter to the reactive power upper limit, and the reactive power shortage caused by the capacity limitation of the PV inverter for: in, is the expected reactive power of PV inverter i, is the upper limit of reactive power capacity of PV inverter i.

8. A distributed photovoltaic reactive voltage regulation system, characterized in that: include: A fitting module fits the voltage / reactive power sensitivity relationship matrix of each distributed photovoltaic node based on historical voltage and reactive power information; The calculation module calculates the voltage / reactive power droop curve of each distributed photovoltaic node based on the obtained voltage / reactive power sensitivity relationship matrix and the reactive power shortage of each distributed photovoltaic node, as well as the reactive power required to support other nodes. The voltage / reactive power droop curve of each distributed photovoltaic node The details are as follows: Among them, -ω i / s ii is the slope of the voltage / reactive power droop curve of PV inverter i, ω i is the control coefficient, U1 and U2 are the upper and lower limits of voltage, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the voltage amplitude of the node; Reactive power required to support other nodes The details are as follows: in, is the reactive power that PV inverter i needs to support PV inverter j, K={1,2,…,n}, represents the number of distributed PV inverters; PV inverter i needs to support the reactive power Q of PV inverter j req,ij The calculation formula is: in, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the node voltage amplitude, For photovoltaic inverter The reactive power of the node is used for the photovoltaic inverter The influence coefficient of the node voltage amplitude, For photovoltaic inverter Upload reactive power shortage; The expected module calculates the expected reactive power of the PV inverter based on the voltage / reactive power droop curve and the reactive power required to support other nodes; An output module outputs the expected reactive power. When the expected reactive power output of each photovoltaic inverter is lower than or equal to the upper limit of reactive power under the actual capacity limit of the inverter, and the expected reactive power output of each photovoltaic inverter is higher than or equal to the lower limit of reactive power under the actual capacity limit of the inverter, the expected reactive power is used as the reactive power command value of the photovoltaic inverter; When the expected reactive power output of each PV inverter is lower than the reactive power lower limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power lower limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle; When the expected reactive power output of each PV inverter is higher than the reactive power upper limit under the actual capacity limitation of the inverter, the reactive power output of the PV inverter is adjusted to the reactive power upper limit, and the reactive power shortage caused by the capacity limitation is calculated as the input information for the next cycle.

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