Distributed photovoltaic district voltage regulation and control method, device, equipment and product

Abstract

The invention discloses a distributed photovoltaic transformer area voltage regulation and control method and device, electronic equipment and a product, and the method carries out the rapid voltage regulation of a photovoltaic grid-connected point based on an energy storage device and a photovoltaic inverter in a transformer area energy storage system in a power distribution network. Wherein when the grid-connected voltage of the photovoltaic grid-connected point is judged to be out of limit, active power is absorbed or released through charging or discharging of energy storage equipment in a transformer area, so that the aim of regulating and controlling the grid-connected voltage is fulfilled; and then, under the condition that the adjusted grid-connected voltage is still out of limit, adjusting the grid-connected voltage again by adjusting the reactive power of the photovoltaic inverter in the transformer area, so that the grid-connected voltage is adjusted to be within the calibrated grid-connected voltage range, and stable access of the distributed photovoltaic power generation system is ensured. Therefore, the problem of voltage out-of-limit caused by abnormal voltage deviation due to access of the distributed photovoltaic power generation system to the power distribution network can be solved, so that the method is very suitable for large-scale application and popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of voltage regulation in photovoltaic areas, and specifically relates to a distributed photovoltaic area voltage regulation method, device, equipment and product. Background Art

[0002] As countries are increasingly concerned about environmental protection and energy shortages, how to resolve the contradiction between energy and environment has become an unavoidable issue in the process of energy development in various countries. Among them, photovoltaic power generation, as a green energy, has been widely used in recent years and has become one of the fastest-growing renewable energy sources. In actual application, distributed photovoltaic power generation systems use solar power generation to reduce environmental pollution and thus achieve clean energy conversion. Therefore, distributed photovoltaic power generation has become a key component of the distribution network.

[0003] However, while photovoltaic power generation brings many advantages, it also brings certain problems to the smart distribution network. Among them, photovoltaic power generation is intermittent and random. Therefore, its access to the power grid will cause abnormal voltage deviation, which can easily lead to grid stability problems such as voltage fluctuations or even over-limit. The voltage over-limit not only affects the power quality of the local load, but also limits the penetration rate of photovoltaics in the distribution network. Therefore, how to provide a photovoltaic area voltage control method that can meet the rapid voltage adjustment of photovoltaic grid-connected points has become an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to provide a distributed photovoltaic area voltage control method, device, equipment and product to solve the problem in the prior art that the distributed photovoltaic power generation system will cause voltage exceeding the limit when connected to the distribution network, thereby affecting the stability of the power grid and limiting the penetration rate of photovoltaic in the distribution network.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, a distributed photovoltaic area voltage control method is provided, which is applied to an area energy storage system corresponding to each photovoltaic grid connection point in a distribution network, wherein the method comprises:

[0007] Obtain the grid-connected power parameters of any photovoltaic grid-connected point in the distribution network;

[0008] According to the grid-connected power parameters, determining whether the grid-connected voltage of any photovoltaic grid-connected point exceeds a limit;

[0009] If so, control the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge, so as to adjust the grid-connected voltage by charging or discharging the energy storage device to obtain the adjusted grid-connected voltage;

[0010] Determining whether the adjusted grid-connected voltage exceeds a limit;

[0011] If so, the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point is adjusted according to the adjusted grid-connected voltage, so that the adjusted grid-connected voltage is adjusted to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter, so as to complete the regulation of the distributed photovoltaic area voltage after the adjustment.

[0012] Based on the above disclosed content, the present invention utilizes the substation energy storage system in the distribution network to perform voltage regulation of the photovoltaic grid-connected point in the distribution network, wherein the present invention first obtains the grid-connected power parameters of any photovoltaic grid-connected point in the distribution network, and then, based on the grid-connected power parameters, determines whether the grid-connected voltage of any photovoltaic grid-connected point exceeds the limit; if so, controls the energy storage device in the substation energy storage system corresponding to any photovoltaic grid-connected point to charge or discharge, so as to absorb the excess active power of the photovoltaic system by charging the energy storage device, thereby reducing the grid-connected voltage, or release the active power by discharging the energy storage device, thereby increasing the voltage; in this way, the grid-connected voltage can be regulated by charging and discharging the energy storage device in the substation in the distribution network; then, it continues to determine whether the adjusted grid-connected voltage is still over the limit, and if so, the grid-connected voltage is regulated again by adjusting the reactive power of the photovoltaic inverter in the substation, so as to adjust it to within the calibrated grid-connected voltage range, thereby ensuring that the voltage of the photovoltaic grid-connected point does not exceed the limit, thereby achieving the purpose of voltage regulation in the distributed photovoltaic substation.

[0013] Through the above design, the present invention relies on the energy storage equipment and photovoltaic inverter in the substation energy storage system in the distribution network to quickly adjust the voltage of the photovoltaic grid-connected point; wherein, when it is determined that the grid-connected voltage of the photovoltaic grid-connected point exceeds the limit, the active power is first absorbed or released by charging or discharging the energy storage equipment in the substation, thereby achieving the purpose of grid-connected voltage regulation; then, when the adjusted grid-connected voltage still exceeds the limit, the grid-connected voltage is adjusted again by adjusting the reactive power of the photovoltaic inverter in the substation, thereby adjusting it to within the calibrated grid-connected voltage range to ensure the stable access of the distributed photovoltaic power generation system; thus, the present invention can solve the problem that the access of the distributed photovoltaic power generation system to the distribution network will cause abnormal voltage deviation, thereby causing the voltage to exceed the limit, thereby improving the power quality of the local load and the penetration rate of photovoltaics in the distribution network; therefore, it is very suitable for large-scale application and promotion.

[0014] In a possible design, the grid-connected power parameters include: photovoltaic active power and photovoltaic reactive power of any photovoltaic grid-connected point, and load active power and load reactive power of any photovoltaic grid-connected point;

[0015] Wherein, judging whether the grid-connected voltage of any photovoltaic grid-connected point exceeds the limit according to the grid-connected power parameter includes:

[0016] Obtaining the distribution network bus voltage, distribution network bus resistance and distribution network bus impedance corresponding to any photovoltaic grid-connected point;

[0017] Calculate the lower limit of the grid-connected power according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the voltage lower limit within the calibrated grid-connected voltage range, the photovoltaic reactive power, and the load reactive power, and calculate the upper limit of the grid-connected power according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the voltage upper limit within the calibrated grid-connected voltage range, the photovoltaic reactive power, and the load reactive power;

[0018] Determining the difference between the photovoltaic active power and the load active power;

[0019] Determining whether the difference is between the grid-connected power lower limit and the grid-connected power upper limit;

[0020] If not, it is determined that the grid-connected voltage of any of the photovoltaic grid-connected points exceeds the limit.

[0021] In one possible design, the grid-connected power lower limit is calculated according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the voltage lower limit within the calibrated grid-connected voltage range, the photovoltaic reactive power, and the load reactive power, including:

[0022] According to the following formula (1), the lower limit of the grid-connected power is calculated;

[0023]

[0024] In the above formula (1), P min represents the lower limit of the grid-connected power, Indicates the lower voltage limit within the rated grid-connected voltage range, U s represents the distribution network bus voltage, Q pcc represents the photovoltaic reactive power, Q L represents the load reactive power, X represents the distribution network bus impedance value, and R represents the distribution network bus resistance value.

[0025] In a possible design, controlling the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge includes:

[0026] Obtaining the state of charge of the energy storage device, and determining whether the energy storage device has charge and discharge capabilities according to the state of charge;

[0027] If so, the over-limit state of the grid-connected voltage of any photovoltaic grid-connected point is obtained, and the energy storage device is controlled to charge or discharge according to the over-limit state; otherwise, the reactive power of the photovoltaic inverter in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point is adjusted according to the grid-connected voltage, so as to adjust the grid-connected voltage to the range of the calibrated grid-connected voltage by adjusting the reactive power of the photovoltaic inverter;

[0028] Among them, the over-limit state is lower than the voltage lower limit value within the calibrated grid-connected voltage range or higher than the voltage upper limit value within the calibrated grid-connected voltage range, and if the over-limit state is lower than the voltage lower limit value, the energy storage device is controlled to discharge to increase the grid-connected voltage, and if the over-limit state is higher than the voltage upper limit value, the energy storage device is controlled to charge to reduce the grid-connected voltage.

[0029] In a possible design, determining whether the adjusted grid-connected voltage exceeds a limit includes:

[0030] Determining whether the adjusted grid-connected voltage is within the calibrated grid-connected voltage range;

[0031] If not, it is determined that the adjusted grid-connected voltage exceeds the limit;

[0032] Correspondingly, according to the adjusted grid-connected voltage, adjusting the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point includes:

[0033] Obtaining a maximum grid-connected voltage and a minimum grid-connected voltage, wherein the calibrated grid-connected voltage range is between the maximum grid-connected voltage and the minimum grid-connected voltage;

[0034] Constructing a reactive power regulation function according to the maximum grid voltage, the minimum grid voltage, the calibrated grid voltage range and the adjusted grid voltage;

[0035] The reactive power of the photovoltaic inverter is adjusted according to the reactive power adjustment function.

[0036] In a possible design, a reactive power regulation function is constructed according to the maximum grid voltage, the minimum grid voltage, the calibrated grid voltage range, and the adjusted grid voltage, including:

[0037] According to the following formula (2), the reactive power regulation function is constructed;

[0038]

[0039] In the above formula (2), Qn represents the reactive power regulation function, Indicates the maximum reactive output capacity of the photovoltaic inverter, U′ pcc represents the adjusted grid-connected voltage, Indicates the minimum value of the grid-connected voltage, Indicates the maximum value of the grid-connected voltage, and Indicates the voltage upper limit and voltage lower limit of the calibrated grid-connected voltage range, where Q n When it is positive, it means that the photovoltaic inverter outputs reactive power. n When it is negative, it means that the PV inverter absorbs reactive power.

[0040] In one possible design, after adjusting the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point, the method further includes:

[0041] Obtaining the latest grid-connected voltage of any photovoltaic grid-connected point;

[0042] Determining whether the latest grid-connected voltage exceeds a limit;

[0043] If yes, the photovoltaic active power of any photovoltaic grid-connected point is adjusted to the upper limit of active power, and after the photovoltaic active power is adjusted to the upper limit of active power, the output active power of the photovoltaic inverter is obtained;

[0044] According to the output active power and in accordance with the following formula (3), the maximum reactive output capacity of the photovoltaic inverter is updated to obtain an updated maximum reactive output capacity;

[0045]

[0046] In the above formula (3), represents the updated maximum reactive output capacity, P s represents the output active power, δ represents the power control factor;

[0047] The reactive power of the photovoltaic inverter is adjusted according to the updated maximum reactive output capacity and the latest grid-connected voltage, so as to adjust the latest grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter.

[0048] In a second aspect, a distributed photovoltaic area voltage control device is provided, which is applied to an area energy storage system corresponding to each photovoltaic grid connection point in a distribution network, wherein the device comprises:

[0049] An acquisition unit, used to acquire grid-connected power parameters of any photovoltaic grid-connected point in the distribution network;

[0050] A judgment unit, configured to judge whether the grid-connected voltage of any photovoltaic grid-connected point exceeds a limit according to the grid-connected power parameter;

[0051] A charge and discharge control unit, configured to control the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge when the judgment unit judges that the grid-connected voltage exceeds the limit, so as to adjust the grid-connected voltage by charging or discharging the energy storage device to obtain the adjusted grid-connected voltage;

[0052] The judging unit is further used to judge whether the adjusted grid-connected voltage exceeds a limit;

[0053] The inverter control unit is used to adjust the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point according to the adjusted grid-connected voltage when the judgment unit determines that the adjusted grid-connected voltage exceeds the limit, so as to adjust the adjusted grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter, so as to complete the regulation of the distributed photovoltaic area voltage after the adjustment.

[0054] In a third aspect, another distributed photovoltaic area voltage control device is provided. Taking the device as an electronic device as an example, it includes a memory, a processor and a transceiver that are communicatively connected in sequence, wherein the memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer program to execute the distributed photovoltaic area voltage control method as described in the first aspect or any possible design of the first aspect.

[0055] In a fourth aspect, a storage medium is provided, on which instructions are stored. When the instructions are executed on a computer, the distributed photovoltaic area voltage control method as described in the first aspect or any possible design of the first aspect is executed.

[0056] In a fifth aspect, a computer program product comprising instructions is provided, which, when executed on a computer, causes the computer to execute the distributed photovoltaic area voltage control method as described in the first aspect or any possible design of the first aspect.

[0057] Beneficial effects:

[0058] (1) The present invention relies on the energy storage device and photovoltaic inverter in the substation energy storage system in the distribution network to quickly adjust the voltage of the photovoltaic grid-connected point; wherein, when it is determined that the grid-connected voltage of the photovoltaic grid-connected point exceeds the limit, the active power is first absorbed or released by charging or discharging the energy storage device in the substation, thereby achieving the purpose of grid-connected voltage regulation; then, if the adjusted grid-connected voltage still exceeds the limit, the grid-connected voltage is adjusted again by adjusting the reactive power of the photovoltaic inverter in the substation, so as to adjust it to within the calibrated grid-connected voltage range to ensure the stable access of the distributed photovoltaic power generation system; thus, the present invention can solve the problem that the voltage deviation is abnormal when the distributed photovoltaic power generation system is connected to the distribution network, thereby causing the voltage to exceed the limit, thereby improving the power quality of the local load and the penetration rate of photovoltaic in the distribution network; therefore, it is very suitable for large-scale application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A schematic diagram of the steps of the distributed photovoltaic area voltage control method provided by an embodiment of the present invention;

[0060] Figure 2 A schematic diagram of the structure of a distributed photovoltaic area voltage control device provided by an embodiment of the present invention;

[0061] Figure 3 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0063] It should be understood that although the terms first, second, etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another unit. For example, a first unit can be referred to as a second unit, and similarly, a second unit can be referred to as a first unit without departing from the scope of the exemplary embodiments of the present invention.

[0064] It should be understood that the term "and / or" that may appear in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" that may appear in this article describes another type of association object relationship, indicating that two relationships may exist. For example, A / and B can represent two situations: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0065] Example:

[0066] See also Figure 1 As shown, the distributed photovoltaic area voltage control method provided in this embodiment is applied to the area energy storage system corresponding to each photovoltaic grid-connected point in the distribution network, that is, the initial adjustment of the photovoltaic grid-connected point voltage is carried out by charging and discharging the energy storage device in the area energy storage system in the distribution network, and then combined with the photovoltaic inverter in the distribution network to realize the secondary adjustment of the photovoltaic grid-connected point voltage, so as to adjust it to within the calibrated grid-connected voltage range to ensure the stable access of the distributed photovoltaic power generation system; thus, the method can solve the problem that the voltage deviation is abnormal when the distributed photovoltaic power generation system is connected to the distribution network, thereby causing the voltage to exceed the limit, so that the power quality of the local load and the penetration rate of photovoltaic in the distribution network can be improved; therefore, it is very suitable for large-scale application and promotion; among them, for example, the method can be but not limited to running on the control end side of the area energy storage system, it can be understood that the aforementioned execution subject does not constitute a limitation on the embodiments of the present application, and accordingly, the operation steps of the method can be but not limited to the following steps S1 to S5.

[0067] S1. Obtain the grid-connected power parameters of any photovoltaic grid-connected point in the distribution network; in specific applications, the aforementioned grid-connected power parameters may include but are not limited to: the photovoltaic active power and photovoltaic reactive power of any photovoltaic grid-connected point, and the load active power and load reactive power of any photovoltaic grid-connected point; thus, after obtaining the aforementioned parameters, it may be based on this to determine whether the grid-connected voltage of any photovoltaic grid-connected point exceeds the limit, wherein the over-limit judgment process may be but is not limited to as shown in the following step S2.

[0068] S2. According to the grid-connected power parameters, determine whether the grid-connected voltage of any of the photovoltaic grid-connected points exceeds the limit; in the present embodiment, the upper limit value and the lower limit value of the grid-connected power are first calculated, and then, according to the photovoltaic active power and the load active power of any of the aforementioned photovoltaic grid-connected points, as well as the upper limit and lower limit values ​​of the aforementioned grid-connected power, determine whether the aforementioned grid-connected voltage exceeds the limit; wherein, the specific judgment process may be but is not limited to the following steps S21 to S25.

[0069] S21. Obtain the distribution network bus voltage, distribution network bus resistance and distribution network bus impedance corresponding to any of the photovoltaic grid-connected points; in the present embodiment, the distribution network bus resistance and distribution network bus impedance can be measured in advance and then stored in the control terminal; in this way, after obtaining the aforementioned data, the upper and lower limits of the grid-connected power can be calculated in combination with the grid-connected power parameters of any of the photovoltaic grid-connected points, thereby making a grid voltage over-limit judgment based on the upper and lower limits of the grid-connected power; wherein, the calculation process of the upper and lower limits of the grid-connected power can be but is not limited to the following step S22.

[0070] S22. Calculate the lower limit of the grid-connected power according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the lower limit of the voltage within the calibrated grid-connected voltage range, the photovoltaic reactive power and the load reactive power, and calculate the upper limit of the grid-connected power according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the upper limit of the voltage within the calibrated grid-connected voltage range, the photovoltaic reactive power and the load reactive power; in this embodiment, the calculation principle of the upper and lower limits of the grid-connected power is the same, and the following takes the lower limit of the grid-connected power as an example for explanation.

[0071] Optionally, the grid-connected power lower limit value may be calculated, for example but not limited to, according to the following formula (1).

[0072]

[0073] In the above formula (1), P min represents the lower limit of the grid-connected power, Indicates the lower voltage limit within the rated grid-connected voltage range, U s represents the distribution network bus voltage, Q pcc represents the photovoltaic reactive power, Q L represents the load reactive power, X represents the distribution network bus impedance value, and R represents the distribution network bus resistance value.

[0074] In this embodiment, the fundamental reason for the voltage exceeding the limit at the photovoltaic grid-connected point is the change in the power of the photovoltaic system. Therefore, the power can be used as the basis for over-limit judgment. In this way, this embodiment calculates the upper and lower limits of the aforementioned grid-connected power to make an over-limit judgment on the grid-connected voltage. At the same time, when calculating the lower limit of the grid-connected power, the lower limit of the voltage in formula (1) is replaced by the upper limit of the voltage within the calibrated grid-connected voltage range.

[0075] In this way, based on the above formula (1), after calculating the upper and lower limits of the grid-connected power, the difference between the photovoltaic active power and the load active power can be used as the power value corresponding to the grid-connected voltage of any photovoltaic grid-connected point, wherein the judgment process can be but is not limited to the following steps S23 to S25.

[0076] S23. Determine the difference between the photovoltaic active power and the load active power; in this embodiment, after calculating the difference between the photovoltaic active power and the load active power, it can be determined whether it is between the upper and lower limits of the aforementioned grid-connected power, wherein, if it is, it means that the grid-connected voltage is within the limit, otherwise, it means that it is over the limit, and the process is shown in the following steps S24 and S25.

[0077] S24. Determine whether the difference is between the grid-connected power lower limit and the grid-connected power upper limit.

[0078] S25. If not, determine that the grid-connected voltage of any of the photovoltaic grid-connected points exceeds the limit.

[0079] In this embodiment, if the difference in the aforementioned step S23 is between the lower limit value of the grid-connected power and the upper limit value of the grid-connected power, it means that the grid-connected voltage is within the aforementioned calibrated grid-connected voltage range and no voltage adjustment is required; conversely, as long as it is less than the lower limit value of the grid-connected power or greater than the upper limit value of the grid-connected power, it means that the grid-connected voltage is not within the allowable grid-connected voltage range (i.e., the calibrated grid-connected voltage range); at this time, it is determined that the grid voltage exceeds the limit and voltage adjustment is required.

[0080] Therefore, through the aforementioned steps S21 to S25, after determining that the grid-connected voltage of any photovoltaic grid-connected point exceeds the limit based on the grid-connected voltage parameters, the grid-connected voltage can be adjusted; wherein, this embodiment utilizes the charging and discharging of the energy storage device in the energy storage system of the corresponding substation of any photovoltaic grid-connected point to adjust the grid-connected voltage, and the process can be but is not limited to as shown in the following step S3.

[0081] S3. If so, control the energy storage device in the corresponding substation energy storage system of any photovoltaic grid-connected point to charge or discharge, so as to adjust the grid-connected voltage by charging or discharging the energy storage device to obtain the adjusted grid-connected voltage; in this embodiment, substation energy storage refers to an energy storage system installed in the distribution substation for dynamic capacity expansion, load fluctuation suppression and smoothing the output of new energy power generation in the substation, which can make the entire substation become a stable load or power source, improve the power quality and grid safety; that is, in actual use, in order to ensure the stable access of the distributed photovoltaic power generation system to the distribution network, the existing distribution network is mostly equipped with the substation storage system, therefore, this embodiment can use the energy storage device in the substation energy storage system to adjust the grid-connected voltage.

[0082] In this embodiment, the steps for adjusting the grid-connected voltage are:

[0083] S31. Obtain the state of charge of the energy storage device, and determine whether the energy storage device has charge and discharge capabilities based on the state of charge; in specific applications, the state of charge refers to the power of the energy storage device, wherein when the power is within a preset range, it is determined that it has charge and discharge capabilities; optionally, taking into account overcharge and overdischarge, for example, when the power is within the range of [30,70], it is determined that the energy storage device has charge and discharge capabilities.

[0084] After determining that the energy storage device has the charging and discharging capability, the charging and discharging of the energy storage device can be used to adjust the grid voltage, and the process can be but is not limited to the following step S32.

[0085] S32. If so, obtain the over-limit status of the grid-connected voltage of any photovoltaic grid-connected point, and control the energy storage device to charge or discharge according to the over-limit status; otherwise, adjust the reactive power of the photovoltaic inverter in the energy storage system of the corresponding substation of any photovoltaic grid-connected point according to the grid-connected voltage, so as to adjust the grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter.

[0086] In this embodiment, when the energy storage device does not have the charging and discharging capabilities, the grid-connected voltage is adjusted with the help of a photovoltaic inverter; the specific process of adjusting the voltage with the help of a photovoltaic inverter is described in detail below.

[0087] At the same time, the over-limit state is taken as an example of a voltage lower limit value lower than the calibrated grid-connected voltage range or a voltage upper limit value higher than the calibrated grid-connected voltage range, wherein if the over-limit state is lower than the voltage lower limit value, the energy storage device is controlled to discharge to increase the grid-connected voltage, and if the over-limit state is higher than the voltage upper limit value, the energy storage device is controlled to charge to reduce the grid-connected voltage.

[0088] In specific implementation, the principle of voltage regulation by charging and discharging the energy storage device is as follows: when the grid voltage is lower than the aforementioned voltage lower limit, the energy storage device discharges to release active power to increase the grid voltage; conversely, when the grid voltage is higher than the aforementioned voltage upper limit, the energy storage device charges to absorb excess active power of the system to reduce the grid voltage; in this way, the purpose of grid voltage regulation can be achieved; at the same time, this embodiment will monitor the grid voltage in real time during the charging and discharging process, wherein, when the grid voltage is adjusted to the aforementioned calibrated grid voltage range, charging or discharging can be stopped; at the same time, if the charged power exceeds the maximum power value (which can be pre-set) or the discharged power is lower than the minimum power value, the charging or discharging process is stopped. At this time, it is necessary to detect again whether the grid voltage after charging or discharging adjustment exceeds the limit, and the process can be but is not limited to the following step S4.

[0089] S4. Determine whether the adjusted grid-connected voltage exceeds the limit; in the present embodiment, it is to determine whether the adjusted grid-connected voltage is within the calibrated grid-connected voltage range; if it is not within the calibrated grid-connected voltage range, it is determined that the adjusted grid-connected voltage exceeds the limit; otherwise, it does not exceed the limit.

[0090] In this embodiment, when the grid-connected voltage after adjustment by the energy storage device still exceeds the limit, it is necessary to use a photovoltaic inverter to perform a secondary adjustment of the voltage, and the process may be but is not limited to the following step S5.

[0091] S5. If so, then according to the adjusted grid-connected voltage, adjust the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point, so as to adjust the adjusted grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter, so as to complete the regulation of the distributed photovoltaic area voltage after the adjustment.

[0092] In specific applications, this embodiment is based on the fact that the photovoltaic inverter has a certain amount of residual capacity while outputting a certain amount of active power to adjust the grid-connected voltage, that is, the inverter can absorb or emit reactive power, thereby achieving the purpose of regulating the grid-connected point voltage; optionally, the voltage regulation process based on the photovoltaic inverter can be but is not limited to the following steps S51 to S53.

[0093] S51. Obtain the maximum value and the minimum value of the grid-connected voltage, wherein the calibrated grid-connected voltage range is between the maximum value and the minimum value of the grid-connected voltage; in the present embodiment, the maximum value and the minimum value of the grid-connected voltage are preset values, which can be specifically set according to actual use; therefore, the present embodiment is equivalent to setting a minimum voltage and a maximum voltage allowing photovoltaic access, and then, on this basis, allowing the voltage to fluctuate to a certain extent, thereby setting a calibrated grid-connected voltage range between the minimum voltage and the maximum voltage; in this way, after obtaining the aforementioned data, the reactive power regulation function of the photovoltaic inverter can be constructed based on this, so as to regulate the reactive power of the photovoltaic inverter based on the function; wherein, the construction process of the aforementioned regulation function can be but is not limited to the following step S52.

[0094] S52. Construct a reactive power regulation function according to the maximum grid voltage, the minimum grid voltage, the calibrated grid voltage range and the adjusted grid voltage; in specific implementation, the reactive power regulation function can be constructed according to the following formula (2) for example but not limited thereto.

[0095]

[0096] In the above formula (2), Q n represents the reactive power regulation function, Indicates the maximum reactive output capacity of the photovoltaic inverter, U′ pcc represents the adjusted grid-connected voltage, Indicates the minimum value of the grid-connected voltage, Indicates the maximum value of the grid-connected voltage, and Indicates the voltage upper limit and voltage lower limit of the calibrated grid-connected voltage range, where Q n When it is positive, it means that the photovoltaic inverter outputs reactive power. n When it is negative, it means that the PV inverter absorbs reactive power.

[0097] In this way, after constructing the reactive power regulation function based on the aforementioned formula (2), the reactive power of the photovoltaic inverter can be regulated based on it, thereby achieving the purpose of re-regulating the adjusted grid-connected voltage; wherein, the power regulation process can be but is not limited to as shown in the following step S53.

[0098] S53. According to the reactive power regulation function, the reactive power of the photovoltaic inverter is regulated; in specific implementation, it is equivalent to controlling the photovoltaic inverter to output reactive power to support the voltage when the adjusted grid-connected voltage is lower than the voltage lower limit, thereby increasing the adjusted grid-connected voltage; conversely, if the adjusted grid-connected voltage is higher than the voltage upper limit, it is necessary to control the photovoltaic inverter to absorb reactive power to reduce the adjusted grid-connected power supply, thereby preventing overvoltage.

[0099] Therefore, through the aforementioned steps S51 to S53, the secondary regulation of the adjusted grid-connected voltage can be completed, so as to adjust it to within the calibrated grid-connected voltage range to ensure the stable access of the distributed photovoltaic power generation system.

[0100] Furthermore, this embodiment provides a further optimization solution based on the above adjustment, namely:

[0101] In actual use, the grid voltage can be well regulated through the above-mentioned reactive power regulation, but the reactive power regulation capacity is limited; therefore, when the grid voltage is too large, the reactive power regulation is not enough to regulate the excessive grid voltage to within the calibrated grid voltage range; therefore, this embodiment provides a voltage regulation scheme combining active power with reactive power, and its specific implementation process is as follows:

[0102] After adjusting the reactive power of the photovoltaic inverter in the energy storage system of the substation corresponding to any photovoltaic grid-connected point, it is also necessary to obtain its latest grid-connected voltage, and then judge again whether the latest grid-connected voltage exceeds the limit (that is, judge whether the latest grid-connected voltage is greater than the voltage upper limit value within the calibrated grid-connected power range), so as to adjust the active + reactive power according to the judgment result, so as to adjust the grid-connected voltage of any photovoltaic grid-connected point to within the calibrated grid-connected voltage range; wherein, the adjustment process can be but is not limited to as shown in the following steps S6 to S10.

[0103] S6. Obtain the latest grid-connected voltage of any of the photovoltaic grid-connected points; in this embodiment, after reactive power adjustment of the photovoltaic inverter, the voltage of any of the photovoltaic grid-connected points collected is the latest grid-connected voltage; then, continue to determine whether it exceeds the limit, so as to perform voltage adjustment operations based on the judgment result; wherein, the specific process can be but is not limited to the following steps S7 to S10.

[0104] S7. Determine whether the latest grid-connected voltage exceeds the limit; in specific applications, it has been explained above that the aforementioned steps S6 to S10 are mainly aimed at overvoltage behavior. Therefore, it is only necessary to determine whether the latest grid-connected voltage is greater than the voltage upper limit value. If it is greater, it is considered to be over-limit; at this time, it is necessary to adjust the active power of photovoltaic access, and at the same time combine the photovoltaic inverter to adjust the reactive power. The process can be but is not limited to the following steps S8 to S10.

[0105] S8. If so, the photovoltaic active power of any photovoltaic grid-connected point is adjusted to the upper limit of active power, and after the photovoltaic active power is adjusted to the upper limit of active power, the output active power of the photovoltaic inverter is obtained; in this embodiment, if the latest grid-connected voltage exceeds the limit, it means that when the reactive power absorption capacity of the photovoltaic inverter reaches the maximum, it is still unable to adjust the voltage to the calibrated grid-connected voltage range. At this time, it is necessary to limit the power connected to the distribution network, that is, to adjust the photovoltaic active power of any photovoltaic grid-connected point to the upper limit of active power.

[0106] Optionally, the upper limit of active power can be pre-set; specifically, the increase in photovoltaic active power is positively correlated with the increase in grid-connected point voltage, that is, as the connected photovoltaic active power increases, the grid-connected voltage also increases; therefore, the historical grid-connected voltage and the historical photovoltaic active power can be obtained, and then a function image between the historical photovoltaic active power and the historical grid-connected voltage is generated; then, the slope is calculated based on the function image; then, the slope is multiplied by the maximum grid-connected voltage to obtain the maximum active power; finally, the upper limit of active power (usually less than the maximum active power) is set based on the maximum active power.

[0107] In this way, after limiting the active power of the distributed photovoltaic power generation system connected to the distribution network through the aforementioned step S8, the latest grid-connected voltage of any photovoltaic grid-connected point can be reduced; then, the output active power of the photovoltaic inverter at this time can be obtained, and then the maximum reactive output capacity is updated, and reactive adjustment is performed again, so as to adjust the latest grid-connected voltage to within the calibrated grid-connected voltage range; wherein, the updating process of the maximum reactive output capacity can be but is not limited to as shown in the following step S9.

[0108] S9. Based on the output active power and in accordance with the following formula (3), the maximum reactive output capacity of the photovoltaic inverter is updated to obtain an updated maximum reactive output capacity.

[0109] Q n ' max =P s tan[arccos(δ)] (3)

[0110] In the above formula (3), Q n ' max represents the updated maximum reactive output capacity, P s represents the output active power, δ represents the power control factor; in this embodiment, the power control factor is a constant.

[0111] Therefore, based on the above formula (3), the maximum reactive output capacity of the photovoltaic inverter can be updated; finally, the voltage can be adjusted in combination with the latest grid-connected voltage, and the process can be but not limited to the following step S10.

[0112] S10. According to the updated maximum reactive output capacity and the latest grid-connected voltage, the reactive power of the photovoltaic inverter is adjusted, so that the latest grid-connected voltage is adjusted to the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter; in this embodiment, the aforementioned latest grid-connected voltage is actually the voltage collected by any photovoltaic grid-connected point after the photovoltaic active power is adjusted to the upper limit of the active power; at this time, Q in the aforementioned formula (2) is n max Replace with Q n ' max Then, the reactive power is adjusted according to the above formula (2); thus, after the above adjustment, the voltage of any photovoltaic grid-connected point can be adjusted to within the above calibrated grid-connected voltage range, thereby ensuring the stable access of the distributed photovoltaic power generation system.

[0113] Of course, the regulation of the grid-connected voltage of the remaining photovoltaic grid-connected points in the distribution network is the same as the regulation process of the grid-connected voltage of any of the aforementioned photovoltaic grid-connected points, and will not be repeated here.

[0114] Therefore, through the above-mentioned detailed explanation of the distributed photovoltaic area voltage control method, the present invention performs the initial regulation of the photovoltaic grid-connected point voltage through the charging and discharging of the energy storage device in the area energy storage system in the distribution network, and then combines it with the photovoltaic inverter in the distribution network to achieve secondary regulation of the photovoltaic grid-connected point voltage, thereby adjusting it to within the calibrated grid-connected voltage range to ensure the stable access of the distributed photovoltaic power generation system; thus, the present invention can solve the problem that the access of the distributed photovoltaic power generation system to the distribution network will cause abnormal voltage deviation, thereby causing voltage over-limit, so that the power quality of the local load and the penetration rate of photovoltaic in the distribution network can be improved; therefore, it is very suitable for large-scale application and promotion.

[0115] like Figure 2 As shown, the second aspect of this embodiment provides a hardware device for implementing the distributed photovoltaic area voltage control method described in the first aspect of the embodiment, including:

[0116] The acquisition unit is used to obtain the grid-connected power parameters of any photovoltaic grid-connected point in the distribution network.

[0117] A judgment unit is used to judge whether the grid-connected voltage of any photovoltaic grid-connected point exceeds a limit according to the grid-connected power parameter.

[0118] The charging and discharging control unit is used to control the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge when the judgment unit determines that the grid-connected voltage exceeds the limit, so as to adjust the grid-connected voltage by charging or discharging the energy storage device to obtain the adjusted grid-connected voltage.

[0119] The judging unit is further used to judge whether the adjusted grid-connected voltage exceeds a limit.

[0120] The inverter control unit is used to adjust the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point according to the adjusted grid-connected voltage when the judgment unit determines that the adjusted grid-connected voltage exceeds the limit, so as to adjust the adjusted grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter, so as to complete the regulation of the distributed photovoltaic area voltage after the adjustment.

[0121] The working process, working details and technical effects of the device provided in this embodiment can be found in the first aspect of the embodiment and will not be described in detail here.

[0122] like Figure 3 As shown, the third aspect of this embodiment provides another distributed photovoltaic area voltage control device, taking the device as an electronic device as an example, comprising: a memory, a processor and a transceiver that are communicatively connected in sequence, wherein the memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer program to execute the distributed photovoltaic area voltage control method as described in the first aspect of the embodiment.

[0123] For example, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out memory (FIFO) and / or first-in-last-out memory (FILO), etc. Specifically, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). At the same time, the processor may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU (Central Processing Unit); the coprocessor is a low-power processor for processing data in the standby state.

[0124] In some embodiments, the processor may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the display screen. For example, the processor may not be limited to a microprocessor of the STM32F105 series, a reduced instruction set computer (RISC) microprocessor, an X86 or other architecture processor, or a processor with an integrated embedded neural network processor (NPU); the transceiver may be, but is not limited to, a wireless fidelity (WIFI) wireless transceiver, a Bluetooth wireless transceiver, a general packet radio service technology (Genera l Packet Rad ioService, GPRS) wireless transceiver, a ZigBee protocol (a low-power LAN protocol based on the IEEE 802.15.4 standard, ZigBee) wireless transceiver, a 3G transceiver, a 4G transceiver and / or a 5G transceiver, etc. In addition, the device may also include, but is not limited to, a power module, a display screen and other necessary components.

[0125] The working process, working details and technical effects of the electronic device provided in this embodiment can be found in the first aspect of the embodiment and will not be described in detail here.

[0126] The fourth aspect of this embodiment provides a storage medium that stores instructions for the distributed photovoltaic area voltage control method described in the first aspect of the embodiment, that is, the storage medium stores instructions, and when the instructions are run on a computer, the distributed photovoltaic area voltage control method described in the first aspect of the embodiment is executed.

[0127] The storage medium refers to a carrier for storing data, which may include but is not limited to a floppy disk, a CD, a hard disk, a flash memory, a USB flash drive and / or a memory stick, etc. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0128] The working process, working details and technical effects of the storage medium provided in this embodiment can be found in the first aspect of the embodiment and will not be described in detail here.

[0129] The fifth aspect of this embodiment provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the distributed photovoltaic area voltage control method as described in the first aspect of the embodiment, wherein the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0130] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A distributed photovoltaic area voltage control method, characterized in that: Applied to the energy storage system of the substation corresponding to each photovoltaic grid-connected point in the distribution network, wherein the method comprises: Obtain the grid-connected power parameters of any photovoltaic grid-connected point in the distribution network; According to the grid-connected power parameters, determining whether the grid-connected voltage of any photovoltaic grid-connected point exceeds a limit; If so, control the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge, so as to adjust the grid-connected voltage by charging or discharging the energy storage device to obtain the adjusted grid-connected voltage; Determining whether the adjusted grid-connected voltage exceeds a limit; If so, the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point is adjusted according to the adjusted grid-connected voltage, so that the adjusted grid-connected voltage is adjusted to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter, so as to complete the regulation of the distributed photovoltaic area voltage after the adjustment.

2. The method according to claim 1, characterized in that The grid-connected power parameters include: the photovoltaic active power and photovoltaic reactive power of any photovoltaic grid-connected point, and the load active power and load reactive power of any photovoltaic grid-connected point; Wherein, judging whether the grid-connected voltage of any photovoltaic grid-connected point exceeds the limit according to the grid-connected power parameter includes: Obtaining the distribution network bus voltage, distribution network bus resistance and distribution network bus impedance corresponding to any photovoltaic grid-connected point; Calculate the lower limit of the grid-connected power according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the voltage lower limit within the calibrated grid-connected voltage range, the photovoltaic reactive power, and the load reactive power, and calculate the upper limit of the grid-connected power according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the voltage upper limit within the calibrated grid-connected voltage range, the photovoltaic reactive power, and the load reactive power; Determining the difference between the photovoltaic active power and the load active power; Determining whether the difference is between the grid-connected power lower limit and the grid-connected power upper limit; If not, it is determined that the grid-connected voltage of any of the photovoltaic grid-connected points exceeds the limit.

3. The method according to claim 2, characterized in that The grid-connected power lower limit is calculated according to the distribution network bus voltage, the distribution network bus resistance, the distribution network bus impedance, the voltage lower limit within the calibrated grid-connected voltage range, the photovoltaic reactive power and the load reactive power, including: According to the following formula (1), the lower limit of the grid-connected power is calculated; In the above formula (1), P min represents the lower limit of the grid-connected power, Indicates the lower voltage limit within the rated grid-connected voltage range, U s represents the distribution network bus voltage, Q pcc represents the photovoltaic reactive power, Q L represents the load reactive power, X represents the distribution network bus impedance value, and R represents the distribution network bus resistance value.

4. The method according to claim 1, characterized in that: Controlling the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge, including: Obtaining the state of charge of the energy storage device, and determining whether the energy storage device has charge and discharge capabilities according to the state of charge; If so, the over-limit state of the grid-connected voltage of any photovoltaic grid-connected point is obtained, and the energy storage device is controlled to charge or discharge according to the over-limit state; otherwise, the reactive power of the photovoltaic inverter in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point is adjusted according to the grid-connected voltage, so as to adjust the grid-connected voltage to the range of the calibrated grid-connected voltage by adjusting the reactive power of the photovoltaic inverter; Among them, the over-limit state is lower than the voltage lower limit value within the calibrated grid-connected voltage range or higher than the voltage upper limit value within the calibrated grid-connected voltage range, and if the over-limit state is lower than the voltage lower limit value, the energy storage device is controlled to discharge to increase the grid-connected voltage, and if the over-limit state is higher than the voltage upper limit value, the energy storage device is controlled to charge to reduce the grid-connected voltage.

5. The method according to claim 1, characterized in that Determining whether the adjusted grid-connected voltage exceeds a limit includes: Determining whether the adjusted grid-connected voltage is within the calibrated grid-connected voltage range; If not, it is determined that the adjusted grid-connected voltage exceeds the limit; Correspondingly, according to the adjusted grid-connected voltage, adjusting the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point includes: Obtaining a maximum grid-connected voltage and a minimum grid-connected voltage, wherein the calibrated grid-connected voltage range is between the maximum grid-connected voltage and the minimum grid-connected voltage; Constructing a reactive power regulation function according to the maximum grid voltage, the minimum grid voltage, the calibrated grid voltage range and the adjusted grid voltage; The reactive power of the photovoltaic inverter is adjusted according to the reactive power adjustment function.

6. The method according to claim 5, characterized in that According to the maximum grid-connected voltage, the minimum grid-connected voltage, the calibrated grid-connected voltage range and the adjusted grid-connected voltage, a reactive power regulation function is constructed, including: According to the following formula (2), the reactive power regulation function is constructed; In the above formula (2), Q n represents the reactive power regulation function, Indicates the maximum reactive output capacity of the photovoltaic inverter, U′ pcc represents the adjusted grid-connected voltage, Indicates the minimum value of the grid-connected voltage, Indicates the maximum value of the grid-connected voltage, and Indicates the voltage upper limit and voltage lower limit of the calibrated grid-connected voltage range, where Q n When it is positive, it means that the photovoltaic inverter outputs reactive power. n When it is negative, it means that the PV inverter absorbs reactive power.

7. The method according to claim 1, characterized in that After adjusting the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point, the method further includes: Obtaining the latest grid-connected voltage of any photovoltaic grid-connected point; Determining whether the latest grid-connected voltage exceeds a limit; If yes, the photovoltaic active power of any photovoltaic grid-connected point is adjusted to the upper limit of active power, and after the photovoltaic active power is adjusted to the upper limit of active power, the output active power of the photovoltaic inverter is obtained; According to the output active power and in accordance with the following formula (3), the maximum reactive output capacity of the photovoltaic inverter is updated to obtain an updated maximum reactive output capacity; Q n ′ max =P s tan[arccos(δ)] (3) In the above formula (3), Q n ' max represents the updated maximum reactive output capacity, P s represents the output active power, δ represents the power control factor; The reactive power of the photovoltaic inverter is adjusted according to the updated maximum reactive output capacity and the latest grid-connected voltage, so as to adjust the latest grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter.

8. A distributed photovoltaic area voltage control device, characterized in that: Applicable to the energy storage system of the substation corresponding to each photovoltaic grid-connected point in the distribution network, wherein the device comprises: An acquisition unit, used to acquire grid-connected power parameters of any photovoltaic grid-connected point in the distribution network; A judgment unit, configured to judge whether the grid-connected voltage of any photovoltaic grid-connected point exceeds a limit according to the grid-connected power parameter; A charge and discharge control unit, configured to control the energy storage device in the energy storage system of the corresponding area of ​​any photovoltaic grid-connected point to charge or discharge when the judgment unit judges that the grid-connected voltage exceeds the limit, so as to adjust the grid-connected voltage by charging or discharging the energy storage device to obtain the adjusted grid-connected voltage; The judging unit is further used to judge whether the adjusted grid-connected voltage exceeds a limit; The inverter control unit is used to adjust the reactive power of the photovoltaic inverter in the energy storage system of the area corresponding to any photovoltaic grid-connected point according to the adjusted grid-connected voltage when the judgment unit determines that the adjusted grid-connected voltage exceeds the limit, so as to adjust the adjusted grid-connected voltage to within the calibrated grid-connected voltage range by adjusting the reactive power of the photovoltaic inverter, so as to complete the regulation of the distributed photovoltaic area voltage after the adjustment.

9. An electronic device, characterized in that: include: A memory, a processor and a transceiver that are sequentially connected in communication, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program to execute the distributed photovoltaic area voltage control method as described in any one of claims 1 to 7.

10. A computer program product comprising instructions, characterized in that When the instructions are executed on a computer, the computer is caused to execute the distributed photovoltaic area voltage control method as described in any one of claims 1 to 7.

Images