Voltage out-of-limit treatment method, system and device for power distribution network and medium

Abstract

The invention discloses a voltage out-of-limit treatment method, system and device for a power distribution network and a medium, and the method comprises the steps: obtaining a voltage out-of-limit event and a topological relation of a distribution transformer, and a power distribution region where a reactive compensation device belongs, and determining whether interval continuous voltage out-of-limit or line continuous voltage out-of-limit exists according to the voltage out-of-limit event and the topological relation, if the interval contiguous voltage out-of-limit or the line contiguous voltage out-of-limit exists, determining a target reactive power compensation device according to the power distribution area to which the reactive power compensation device belongs, and if the interval contiguous voltage out-of-limit does not occur or the treatment capability of the target reactive power compensation device on the line is insufficient, determining the reactive power compensation device. And determining whether voltage out-of-limit caused by photovoltaic power generation exists or not according to the voltage out-of-limit time period and the photovoltaic power generation time period, and if the voltage out-of-limit caused by photovoltaic power generation exists, determining the photovoltaic reactive compensation amount according to the voltage out-of-limit deviation of the distribution transformer and the generated power of the photovoltaic group under the distribution transformer. The method can effectively treat voltage out-of-limit, and is applied to the technical field of power distribution network control.

Description

Technical Field

[0001] The present invention relates to the field of power distribution network control technology, and in particular to a method, system, device and medium for controlling voltage over-limit in a power distribution network. Background Art

[0002] In recent years, the scale of distributed photovoltaic power generation connected to the distribution network has continued to expand, and the grid capacity has continued to increase, presenting a pattern of "many points, wide coverage, and high-density grid connection in local areas". Large-scale distributed photovoltaic grid connection can increase the proportion of clean energy and alleviate energy pressure and environmental problems. However, after distributed photovoltaics are connected to the distribution network, the distribution network has gradually developed from a "passive network" to an "active network", increasing the difficulty of voltage control in the distribution network. When the photovoltaic power generation power is too large and cannot be fully consumed on site, the remaining power will be fed back to the power grid system through the line, causing the voltage to exceed the limit, which will affect the safe and stable operation of the power grid.

[0003] In the prior art, the voltage over-limit problem of the distribution network is attributed to photovoltaic access, and the voltage over-limit problem of the distribution network cannot be effectively managed. Summary of the invention

[0004] In order to solve one of the above problems, the purpose of the present invention is to provide a method, system, device and medium for voltage over-limit management of a distribution network, which can specifically analyze the causes of voltage over-limit and effectively manage the voltage over-limit problem.

[0005] In one aspect, the present invention provides a method for managing voltage over-limit in a distribution network, comprising the following steps:

[0006] Obtain voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong for distribution transformers;

[0007] Determine whether there is an over-limit voltage in an area or an over-limit voltage in a line according to the over-limit voltage event and the topological relationship;

[0008] If the section-connected voltage exceeds the limit or the line-connected voltage exceeds the limit, determine a target reactive compensation device according to the power distribution area to which the reactive compensation device belongs, and determine the compensation amount of the target reactive compensation device;

[0009] If there is no voltage over-limit in the section or the control capacity of the target reactive power compensation device on the line is insufficient, an assistance instruction is issued to the terminal, so that the terminal obtains the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, and determines whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period;

[0010] If there is a voltage over-limit caused by the photovoltaic power generation, the photovoltaic reactive power compensation amount is determined according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer.

[0011] Optionally, the determining whether there is an interval-connected voltage over-limit or a line-connected voltage over-limit according to the voltage over-limit event and the topological relationship specifically includes:

[0012] If the number of distribution transformers with the voltage over-limit event under the line is greater than the first threshold, the line section is divided, and the distribution transformers that are continuous in the line section in the topological relationship are retrieved. If the number of continuous distribution transformers is greater than or equal to the first threshold, it is determined that there is a continuous voltage over-limit in the section; the distribution transformer is the distribution transformer with the voltage over-limit event;

[0013] The line section where the section voltage exceeds the limit is recorded as a section voltage exceeding the limit area. If the number of distribution transformers in the section voltage exceeding the limit area is greater than or equal to the second threshold, it is determined that the line section voltage exceeds the limit.

[0014] Optionally, if the section-connected voltage exceeds the limit or the line-connected voltage exceeds the limit, determining a target reactive power compensation device according to a power distribution area to which the reactive power compensation device belongs specifically includes:

[0015] If the line segment voltage exceeds the limit, determine that the reactive power compensation device on the busbar of the substation where the line is located is the target reactive power compensation device;

[0016] If there is an over-limit of the section-connected voltage and there is no over-limit of the line-connected voltage, the reactive compensation device in the over-limited section of the section is determined as the target reactive compensation device according to the distribution area to which the reactive compensation device belongs;

[0017] If the reactive power compensation device in the contiguous voltage over-limit area has insufficient governance capacity, reactive power compensation devices in other line sections on the line are added as the target reactive power compensation devices; other line sections refer to line sections different from the contiguous voltage over-limit area;

[0018] If the reactive compensation devices in the area where the continuous voltage exceeds the limit and the reactive compensation devices in other line sections have insufficient management capabilities, a reactive compensation device on the busbar of the substation where the line is located is added as the target reactive compensation device.

[0019] Optionally, the sending of an assistance instruction to the terminal so that the terminal obtains the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction specifically includes:

[0020] issuing an assistance instruction to the terminal, so that the terminal analyzes the assistance instruction after receiving the assistance instruction, and obtains the occurrence time of the voltage over-limit event, the recovery time of the voltage over-limit event and the photovoltaic power generation curve according to the analysis result;

[0021] The voltage over-limit period is obtained by taking the occurrence time of the voltage over-limit event as the beginning of each period and the recovery time of the voltage over-limit event as the end of each period;

[0022] The initial power generation period of all photovoltaics under the distribution transformer is obtained according to the photovoltaic power generation curve, and the initial power generation period of all photovoltaics is summarized to obtain the photovoltaic power generation period.

[0023] Optionally, determining whether there is voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period specifically includes:

[0024] Projecting the voltage over-limit period onto the photovoltaic power generation period to obtain the voltage over-limit probability caused by photovoltaic power generation;

[0025] If the voltage over-limit probability is greater than a second threshold, it is determined that the voltage over-limit is caused by the photovoltaic power generation.

[0026] Optionally, determining the photovoltaic reactive compensation amount according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer specifically includes:

[0027] Calculate the reactive power compensation demand according to the voltage over-limit deviation of the distribution transformer, and calculate the total available reactive power compensation of the photovoltaic group according to the power generation power of the photovoltaic group under the distribution transformer;

[0028] If the total amount of reactive power compensation available is greater than or equal to the reactive power compensation demand, the reactive power compensation amount of each photovoltaic is equal to the reactive power compensation available amount of each photovoltaic;

[0029] If the total amount of reactive power compensation available is less than the required amount of reactive power compensation, the reactive power compensation amount of each photovoltaic is equal to the average value of the total amount of reactive power compensation available.

[0030] Optionally, if there is no voltage over-limit caused by photovoltaic power generation, the gear of the distribution transformer where the voltage over-limit event occurs is adjusted. If the distribution transformer does not drop to a preset voltage range after adjustment, reactive compensation is performed according to the reactive compensation amount of the photovoltaic group.

[0031] On the other hand, the present invention provides a voltage over-limit management system for a distribution network, comprising a master station and a fusion terminal, wherein:

[0032] The fusion terminal is used to collect voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution transformers, and upload voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution transformers to the master station;

[0033] The master station is used to obtain the voltage over-limit event, topological relationship and distribution area to which the reactive compensation device belongs of the distribution transformer; determine whether there is an interval-connected voltage over-limit or a line-connected voltage over-limit according to the voltage over-limit event and the topological relationship; if there is an interval-connected voltage over-limit or a line-connected voltage over-limit, determine the target reactive compensation device according to the distribution area to which the reactive compensation device belongs, and determine the compensation amount of the target reactive compensation device; if there is no interval-connected voltage over-limit or the governance capacity of the target reactive compensation device on the line is insufficient, send an assistance instruction to the terminal;

[0034] The fusion terminal is also used to obtain the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, and determine whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period; if there is a voltage over-limit caused by the photovoltaic power generation, the photovoltaic reactive compensation amount is determined according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer.

[0035] On the other hand, the present invention provides a voltage over-limit management device for a distribution network, comprising:

[0036] at least one processor;

[0037] at least one memory for storing at least one program;

[0038] When the at least one program is executed by the at least one processor, the at least one processor implements the method described above.

[0039] In another aspect, the present invention provides a computer-readable storage medium storing a program executable by a processor. When the program executable by the processor is executed by the processor, it is used to perform the method as described above.

[0040] The implementation of the present invention includes the following beneficial effects: This embodiment obtains the voltage over-limit event, topological relationship and distribution area to which the reactive compensation device belongs of the distribution transformer; determines whether there is an interval-connected voltage over-limit or a line-connected voltage over-limit according to the voltage over-limit event and the topological relationship; if there is an interval-connected voltage over-limit or a line-connected voltage over-limit, determines the target reactive compensation device according to the distribution area to which the reactive compensation device belongs, and determines the compensation amount of the target reactive compensation device; if there is no interval-connected voltage over-limit or the target reactive compensation device on the line has insufficient governance capacity, sends an assistance instruction to the terminal so that the terminal obtains the voltage according to the assistance instruction During the voltage over-limit period and photovoltaic power generation period, determine whether there is voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and photovoltaic power generation period; if there is voltage over-limit caused by photovoltaic power generation, determine the photovoltaic reactive compensation amount according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer. The present invention confirms the specific cause of the voltage over-limit, identifies different management scenarios such as the photovoltaic-induced voltage over-limit at the distribution transformer outlet and the voltage over-limit of multiple distribution transformers caused by the line-connected voltage over-limit, and serves as an important basis for supporting the voltage over-limit management strategy. Selecting a reactive compensation device according to the cause of the voltage over-limit can effectively manage the voltage over-limit problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the application environment of a voltage over-limit management method for a distribution network provided by the present invention;

[0042] Figure 2 It is a flow chart of the steps of a method for over-limit voltage control of a distribution network provided by the present invention;

[0043] Figure 3 The present invention provides a flowchart of the steps of determining whether there is an over-limit voltage in an area or an over-limit voltage in a line;

[0044] Figure 4 It is a flow chart of steps for obtaining voltage over-limit period and photovoltaic power generation period provided by the present invention;

[0045] Figure 5 A flowchart of steps for determining voltage over-limit caused by photovoltaic power generation provided by the present invention;

[0046] Figure 6 It is a flow chart of steps for determining the amount of photovoltaic reactive compensation provided by the present invention;

[0047] Figure 7 It is a structural schematic diagram of a voltage over-limit management system for a distribution network provided by the present invention;

[0048] Figure 8It is a structural schematic diagram of a voltage over-limit management device for a distribution network provided by the present invention. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only provided for the convenience of explanation and description, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0050] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0051] When the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it is necessary to understand that the terms "first / S100", "second / S200", "third / S300", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0052] The voltage over-limit management method of the distribution network provided by the present invention can be applied to any server or device with computing capability, such as Figure 1 As shown, Figure 1 The present invention is a schematic diagram of the application environment of a voltage over-limit control method for a distribution network. The voltage over-limit control method for a distribution network can also apply a system including a master station and a fusion terminal. The fusion terminal is responsible for collecting various data of its corresponding distribution transformer, determining the reactive power compensation amount of photovoltaic power, and uploading various data of the distribution transformer to the master station. The master station determines the target reactive power compensation device according to the various data of the distribution transformer uploaded by the fusion terminal, and determines the compensation amount of the target reactive power compensation device.

[0053] like Figure 2 As shown, Figure 2 The present invention is a flowchart of a method for over-limit voltage control in a distribution network. The present invention provides a method for over-limit voltage control in a distribution network, which can be applied to a main station such as a server, and includes the following steps:

[0054] S100: Obtain voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution transformers.

[0055] Among them, the voltage over-limit event refers to the voltage over-limit of the distribution transformer.

[0056] The topological relationship includes any one or more of the structural relationship between lines in the power grid, the structural relationship between all distribution transformers on each line, or the structural relationship between all power generation equipment under the distribution transformer.

[0057] S200. Determine whether there is a voltage over-limit in a section or a voltage over-limit in a line according to a voltage over-limit event and a topological relationship.

[0058] Specifically, according to the voltage over-limit event of the distribution transformer on any line, it is determined whether there are multiple distribution transformers with voltage over-limit events on the line. When the number of distribution transformers with voltage over-limit events on the same line is greater than the threshold value N sli , indicating that the line may have a voltage over-limit, and the following line voltage over-limit analysis is initiated. Otherwise, over-limit management is performed based on a single distribution transformer, which may be but is not limited to executing S300b.

[0059] Analysis of line voltage over-limit:

[0060] Divide the line section, search for topologically continuous distribution transformers in the line section, and if the number of continuous distribution transformers is greater than or equal to a first threshold, determine that there is a voltage over-limit in a continuous section of the section; the distribution transformer is a distribution transformer with a voltage over-limit event;

[0061] The line section where the section voltage exceeds the limit is recorded as a section voltage exceeding the limit area. If the number of distribution transformers with voltage exceeding the limit events in the section voltage exceeding the limit area is greater than or equal to the second threshold, it is determined that the line section voltage exceeds the limit.

[0062] S300a: If the section-connected voltage exceeds the limit or the line-connected voltage exceeds the limit, determine the target reactive compensation device according to the distribution area to which the reactive compensation device belongs, and determine the compensation amount of the target reactive compensation device.

[0063] If there is a line segment voltage exceeding the limit, determine the reactive compensation device on the busbar of the substation where the line is located as the target reactive compensation device, and calculate the reactive compensation demand for the line segment voltage exceeding the limit and the reactive compensation amount of the target reactive compensation device until the voltage of the distribution transformer in the line segment returns to a reasonable range, or there is no adjustable capacity on the busbar, then the process ends and a command is issued to clear the data of the distribution transformer that has recovered to a reasonable voltage range.

[0064] If there is an interval voltage over-limit and no line voltage over-limit, the reactive compensation device in the area where the voltage over-limit is connected is determined as the target reactive compensation device according to the distribution area to which the reactive compensation device belongs, that is, the reactive compensation device in the area where the voltage over-limit is connected is preferentially searched for reactive compensation.

[0065] If the control capacity of the reactive power compensation device in the contiguous voltage over-limit area is insufficient, reactive power compensation devices in other line sections on the line are added as target reactive power compensation devices; other line sections refer to line sections different from the contiguous voltage over-limit area; that is, reactive power compensation devices on the same line outside the contiguous voltage over-limit area are searched for reactive power compensation.

[0066] If the reactive compensation devices in the area where the continuous voltage exceeds the limit and the reactive compensation devices in other line sections have insufficient management capabilities, the reactive compensation device on the busbar of the substation where the line is located shall be added as the target reactive compensation device, that is, reactive compensation shall be performed through the reactive compensation capacitor group on the busbar of the substation where the line is located.

[0067] Determining the compensation amount of the target reactive power compensation device belongs to the prior art and will not be described in detail here.

[0068] This step makes reasonable arrangements for the priorities of adjustable resources based on the various actual reasons for the voltage deviation, implements comprehensive management of various means under different management scenarios, and effectively responds to the impact voltage exceeding the limit problem caused by the access of distributed power sources to the distribution network.

[0069] S300b. If there is no voltage over-limit in the section or the control capacity of the target reactive power compensation device on the line is insufficient, an assistance instruction is issued to the terminal so that the terminal obtains the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, and determines whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period.

[0070] The content of the assistance instructions includes but is not limited to distribution transformers within the range of over-limit voltage with insufficient compensation capacity, distribution transformers within the line over-limit voltage, and distribution transformers within the non-over-limit voltage area.

[0071] Specifically, if the voltage over-limit does not occur in the connected section or the control capacity of the target reactive power compensation device on the line is insufficient, the master station sends an assistance instruction to the fusion terminal so that the fusion terminal can perform over-limit control of a single distribution transformer after receiving the assistance instruction. It can be used to control distribution transformers in non-contiguous areas or distribution transformers in lines or connected sections with insufficient compensation capacity. The over-limit control of a single distribution transformer includes: obtaining the voltage over-limit time period and photovoltaic power generation time period according to the assistance instruction, projecting the voltage over-limit time period onto the photovoltaic power generation time period, and obtaining the voltage over-limit probability caused by photovoltaic power generation. If the voltage over-limit probability is greater than the second threshold, it is determined that the voltage over-limit is caused by photovoltaic power generation.

[0072] S310b. If there is a voltage over-limit caused by photovoltaic power generation, determine the photovoltaic reactive compensation amount according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer.

[0073] Specifically, if there is a voltage over-limit caused by photovoltaic power generation, the reactive compensation demand is calculated based on the voltage over-limit deviation of the distribution transformer, the total available reactive compensation amount of the photovoltaic group is calculated based on the power generation power of the photovoltaic group under the distribution transformer, and the reactive compensation amount of photovoltaic is determined based on the reactive compensation demand and the total available reactive compensation amount.

[0074] The photovoltaic inverter under the photovoltaic group performs reactive power compensation according to the reactive power compensation amount of each photovoltaic.

[0075] If there is no voltage over-limit caused by photovoltaic power generation, adjust the gear of the distribution transformer with the voltage over-limit event. If the distribution transformer does not drop to the preset voltage range after adjustment, perform reactive power compensation according to the reactive power compensation amount of the photovoltaic group without affecting the photovoltaic active power processing. If the voltage over-limit of the distribution transformer cannot be eliminated, cut off the adjustable load under the distribution transformer until the voltage of the distribution transformer returns to a reasonable range.

[0076] In some embodiments, Figure 3 As shown, Figure 3 The invention is a flowchart of steps for determining whether there is an over-limit voltage in an area or an over-limit voltage in a line. Step S200 determines whether there is an over-limit voltage in an area or an over-limit voltage in a line according to a voltage over-limit event and a topological relationship, and specifically includes:

[0077] S210. If the number of distribution transformers with voltage over-limit events under the line is greater than a first threshold, divide the line into sections, and search for topologically continuous distribution transformers in the line section. If the number of continuous distribution transformers is greater than or equal to the first threshold, it is determined that there is a voltage over-limit event in the section.

[0078] Among them, the distribution transformer is a distribution transformer that has a voltage over-limit event.

[0079] The first threshold may be a natural number greater than or equal to 1.

[0080] Specifically, if the number of distribution transformers with voltage over-limit events under the line is greater than the first threshold, this line may have a continuous voltage over-limit, and the line interval is divided and marked: the line is divided into intervals surrounded by automatic switches according to the topological relationship to obtain several line intervals. The range mark of each line interval is that the power supply side switch under the standard state is marked as the beginning of the interval, and the remaining switches are marked as the end of the interval.

[0081] Search for topologically continuous distribution transformers in the line section: Starting from the first line section at the head end of the line, search each line section in turn: If all distribution transformers in the line section have voltage over-limit events, it is determined that there is a continuous voltage over-limit in the line section; otherwise, starting from the standard power supply side of the line section, search for distribution transformers with voltage over-limit events in the section according to the topological relationship. When the first distribution transformer with voltage over-limit events is retrieved, set the continuous judgment start mark, and continue to search downward until a distribution transformer without voltage over-limit events is retrieved or all distribution transformers in the line section are retrieved, set the continuous judgment end, and obtain a group of continuous distribution transformers, and record and count the number of distribution transformers. If there are still distribution transformers in the line section that have not been retrieved, start from the aforementioned distribution transformer without voltage over-limit events, and continue to search according to the aforementioned method until all distribution transformers in the line section have not been retrieved, and obtain several groups of continuous distribution transformers.

[0082] If there is a group of continuous distribution transformers with a number ≥ the first threshold (connected voltage over-limit threshold), it is determined that the line section has experienced an interval connected voltage over-limit, and the interval connected voltage over-limit event is recorded and the distribution transformers involved are recorded; otherwise, the line section has not experienced an interval connected voltage over-limit.

[0083] S220. Record the line section where the section voltage exceeds the limit as a section voltage exceeding the limit area. If the number of distribution transformers in the section voltage exceeding the limit area is greater than or equal to a second threshold, determine that the line section voltage exceeds the limit.

[0084] The second threshold may be, but is not limited to, half of the number of all distribution transformers on the line.

[0085] Specifically, the line section where the section-to-section voltage exceeds the limit in step S210 is recorded as a section-to-section voltage exceeding area; if the number of distribution transformers in the section-to-section voltage exceeding area is greater than or equal to the second threshold, it is determined that the line section-to-section voltage exceeds the limit, and the line section-to-section voltage exceeding event and the distribution transformer on the line having the voltage exceeding event are recorded.

[0086] If the number of distribution transformers in all the segment voltage-over-limit areas is less than the second threshold, it is determined that there is no segment voltage over-limit in the line.

[0087] If the number of distribution transformers with voltage over-limit events under the line is less than or equal to the first threshold, it is determined that there is no section-connected voltage over-limit and line-connected voltage over-limit.

[0088] In some embodiments, Figure 4 As shown, Figure 4 The invention is a flowchart of steps for obtaining a voltage over-limit period and a photovoltaic power generation period. Step S300b sends an assistance instruction to a terminal so that the terminal obtains the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, specifically including:

[0089] S320b, sending an assistance instruction to the terminal, so that the terminal analyzes the assistance instruction after receiving the assistance instruction, and obtains the occurrence time of the voltage over-limit event, the recovery time of the voltage over-limit event and the photovoltaic power generation curve according to the analysis result.

[0090] Specifically, the information of distribution transformers in line segments with insufficient compensation capacity, distribution transformers in line interval segments, and distribution transformers in non-separate areas is formed into assistance instructions, so that after receiving the assistance instructions, the terminal parses the assistance instructions to obtain the occurrence time of voltage over-limit events, the recovery time of voltage over-limit events, and the photovoltaic power generation curve within a cycle, and analyzes the voltage over-limit period of distribution transformers in a certain period, such as one day, one week, one month, or one quarter. The occurrence time of voltage over-limit events, the recovery time of voltage over-limit events, and the photovoltaic power generation curve of all distribution transformers within the cycle are obtained.

[0091] S330b: Take the occurrence time of the voltage over-limit event as the beginning of each period and the recovery time of the voltage over-limit event as the end of each period to obtain the voltage over-limit period.

[0092] Specifically, there may be multiple voltage over-limit periods every day, and there are multiple voltage over-limit periods in a cycle. For each distribution transformer, the voltage over-limit event of the distribution transformer is started at the time of occurrence and ends at the time of recovery of the voltage over-limit event of the distribution transformer, which is recorded as a voltage over-limit period. If there are M voltage over-limit periods in a cycle, then the voltage over-limit period set T of a single distribution transformer is u Denoted as formula (1):

[0093] T u ={T u (s1, e1), T u (s2, e2), ..., T u(s M , e M )) (1)

[0094] Among them, s1 to s M The beginning of each period, e1 to e M At the end of each period, T u (s1, e1) represents a voltage-out-of-limit period.

[0095] It is worth noting that if the distribution transformer has a voltage over-limit time at the first time point within the calculation cycle (this time point is not necessarily the time when the voltage over-limit event occurs), the start time of the calculation cycle will be used as the start time of the first voltage over-limit period; if the distribution transformer has a voltage over-limit event at the last time point within the calculation cycle, the end time of the calculation cycle will be used as the end time of the last voltage over-limit period (this time point is not necessarily the recovery time of the voltage over-limit event).

[0096] S340b, obtaining the initial power generation period of all photovoltaics under the distribution transformer according to the photovoltaic power generation curve, and summarizing the initial power generation period of all photovoltaics to obtain the photovoltaic power generation period.

[0097] Among them, one distribution transformer can include N photovoltaic households.

[0098] Specifically, the set of all photovoltaics under a distribution transformer is represented by PV = {PV1, PV2, ..., PV N )}, taking a photovoltaic unit as a unit, the power generation curve state of the photovoltaic power generation curve is analyzed day by day, and the power generation state B at each time point on the power generation curve i The analysis is shown in formula (2):

[0099]

[0100] Among them, P m is the power generation threshold, P i Indicates the active power of the photovoltaic at time i, 0 means no power generation at time i, and 1 means power generation at time i. On the power generation curve, forward search in the time axis sequence within a preset time, for example, within a day, to obtain the time when the photovoltaic first generated power and the time when the photovoltaic last generated power.

[0101] The time when the power generation state first occurs is the power generation start time s n The last time the power generation state occurs is the power generation end time e n , we get the power generation period of a single photovoltaic on the dth day in a cycle, recorded as T d (s n , e n), if we want to be more refined, the dth day can also be a preset time period, then under a distribution transformer, all photovoltaics in the power generation period T on the dth day pd As shown in formula (3):

[0102] T pd ={T d (s1, e1), T d (s2, e2), ..., T d (s N , e N )) (3)

[0103] The distribution transformer's power generation start time on day d is recorded as T ds , which is equal to the minimum value of all photovoltaic power generation start times, and the power generation end time is recorded as T de , that is, the maximum value of the end time of power generation of all photovoltaics. According to the power generation period of all photovoltaics on the dth day and formula (4), the initial power generation period T (s pv1 , e pv1 ):

[0104]

[0105] Among them, T ds1 Equal to s1, T ds2 -T dsN By analogy, T de1 Equal to e1, T de2 -T deN And so on, s pv1 is the time when the distribution transformer starts generating electricity on day d, e pv1 is the time when the distribution transformer ends power generation on day d.

[0106] Therefore, the initial power generation period T(s) of the distribution transformer in one cycle is summarized as pv1 , e pv1 ), the photovoltaic power generation period is shown in formula (5):

[0107] T pv ={T(s pv1 , e pv1 ), T(s pv2 , e pv2 ), ..., T(s pvD , e pvD )} (5)

[0108] In some embodiments, Figure 5 As shown, Figure 5The invention is a flowchart of the steps of determining voltage over-limit caused by photovoltaic power generation, wherein step S300b determines whether there is voltage over-limit caused by photovoltaic power generation according to the period of the voltage over-limit event and the photovoltaic power generation period, and specifically includes:

[0109] S350b, projecting the time period of the voltage over-limit event onto the photovoltaic power generation time period to obtain the voltage over-limit probability caused by the photovoltaic power generation.

[0110] Specifically, the time period T of the voltage limit-crossing event can be u Projection during photovoltaic power generation period T pv The overlap between the two is calculated as the voltage over-limit probability R of the distribution transformer during the photovoltaic power generation period. pv .

[0111] It can also be based on the time period T of the voltage limit event u Get the total duration of the distribution transformer voltage exceeding the limit, record it as T uo , according to the photovoltaic power generation period T pv and the period T of voltage over-limit event u The voltage over-limit event occurs during the photovoltaic power generation period T pv The duration within is recorded as T in , then the voltage over-limit probability caused by photovoltaic power generation is R pv =(T in / T uo )*100%.

[0112] S360b: If the voltage over-limit probability is greater than the second threshold, determine that there is a voltage over-limit caused by photovoltaic power generation.

[0113] Specifically, the second threshold R is set b , when R pv ≥R b , it is determined that there is a voltage over-limit caused by photovoltaic power generation, otherwise it can be determined that there is no voltage over-limit caused by photovoltaic power generation. And record the distribution transformer voltage over-limit event and cause: photovoltaic power generation / non-photovoltaic power generation.

[0114] In some embodiments, Figure 6 As shown, Figure 6 The invention is a flowchart of the steps for determining the reactive power compensation amount of photovoltaic power generation. Step S310b determines the reactive power compensation amount of photovoltaic power generation according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer, and specifically includes:

[0115] S311b, calculating the reactive power compensation demand according to the voltage over-limit deviation of the distribution transformer, and calculating the total available reactive power compensation of the photovoltaic group according to the power generation power of the photovoltaic group under the distribution transformer.

[0116] Specifically, the reactive power compensation demand is calculated according to the voltage over-limit deviation of the distribution transformer, and the available reactive power compensation of a single photovoltaic user is calculated under the condition of unchanged active power output according to the photovoltaic power generation power of each photovoltaic power generation under the distribution transformer, and the available reactive power compensation of all photovoltaics under the distribution transformer is summarized to obtain the total available reactive power compensation of the photovoltaic group.

[0117] S312b. If the total available amount of reactive compensation is greater than or equal to the reactive compensation demand, the reactive compensation amount of each photovoltaic is equal to the available amount of reactive compensation of each photovoltaic; if the total available amount of reactive compensation is less than the reactive compensation demand, the reactive compensation amount of each photovoltaic is equal to the average value of the total available amount of reactive compensation.

[0118] Specifically, if the total amount of reactive compensation available is greater than or equal to the reactive compensation demand, the reactive compensation amount of each photovoltaic is equal to the reactive compensation available amount of each photovoltaic, and the reactive compensation amount of each photovoltaic is sent to its corresponding photovoltaic inverter; if the total amount of reactive compensation available is less than the reactive compensation demand, the reactive compensation demand is taken as the total target, the average value of the reactive compensation demand is calculated as the reactive compensation adjustment amount of a photovoltaic, and the reactive compensation amount of each photovoltaic is sent to its corresponding photovoltaic inverter. At the same time, if the reactive compensation amount of a single photovoltaic is greater than the reactive compensation available amount, the active loss of the photovoltaic for reactive compensation adjustment is calculated.

[0119] The implementation of the present invention includes the following beneficial effects: the present invention confirms the specific causes of voltage over-limit, identifies different management scenarios such as voltage over-limit at the distribution transformer outlet caused by photovoltaics, voltage over-limit in the inter-section connection, and voltage over-limit in multiple distribution transformers caused by voltage over-limit in the inter-section connection. As an important basis for supporting the voltage over-limit management strategy, it follows the principle of "whoever pollutes, whoever manages", and can effectively manage the problem of voltage over-limit.

[0120] The present invention reasonably arranges the priority of adjustable resources according to various situations of actual causes of voltage deviation, realizes comprehensive management of various means under different management scenarios, and effectively copes with the impact voltage over-limit problem caused by the access of distributed power sources to the distribution network.

[0121] like Figure 7 As shown, Figure 7 The present invention is a schematic diagram of the structure of a voltage over-limit management system of a distribution network. The present invention also provides a voltage over-limit management system of a distribution network, including a master station and a fusion terminal, wherein:

[0122] The fusion terminal is used to collect voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution network transformers, and upload such events, topological relationships, and distribution areas to which reactive power compensation devices belong to the master station;

[0123] The master station is used to obtain voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution network transformers; determine whether there is a voltage over-limit in a section or a voltage over-limit in a line according to the voltage over-limit events and topological relationships;

[0124] If the voltage of the section is over the limit or the voltage of the line is over the limit, determine the target reactive compensation device according to the distribution area to which the reactive compensation device belongs, and determine the compensation amount of the target reactive compensation device; if the voltage of the section is not over the limit or the management capacity of the target reactive compensation device on the line is insufficient, send an assistance instruction to the terminal;

[0125] The fusion terminal is also used to obtain the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, and determine whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period; if there is a voltage over-limit caused by the photovoltaic power generation, the photovoltaic reactive compensation amount is determined according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer.

[0126] Specifically, Figure 7 The distribution transformer voltage over-limit data includes but is not limited to voltage over-limit events, topological relationships and the distribution area to which the reactive power compensation device belongs, voltage over-limit period and photovoltaic power generation period, occurrence time of voltage over-limit events, recovery time of voltage over-limit events and photovoltaic power generation power curve.

[0127] The master station is specifically used for steps S100 (obtaining from the fusion terminal), S200, S300a and their subordinate steps, and the fusion terminal is specifically used for steps S100 (obtaining from the distribution transformer), S300b, S310b and their subordinate steps.

[0128] It can be seen that the contents of the above method embodiments are all applicable to the present system embodiments, the functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0129] like Figure 8 As shown, Figure 8 The present invention is a schematic diagram of the structure of a voltage over-limit management device for a distribution network. The present invention also provides a voltage over-limit management device for a distribution network, comprising:

[0130] at least one processor;

[0131] at least one memory for storing at least one program;

[0132] When the at least one program is executed by the at least one processor, the at least one processor implements the steps of the method for managing voltage over-limit in the distribution network described in the above method embodiment.

[0133] Among them, the memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. The memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a remote memory remotely arranged relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0134] It can be seen that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0135] In addition, the embodiment of the present application also discloses a computer program product or a computer program, and the computer program product or the computer program is stored in a computer-readable storage medium. The processor of the computer device can read the computer program from the computer-readable storage medium, and the processor executes the computer program, so that the computer device performs the above method. Similarly, the contents in the above method embodiment are all applicable to the storage medium embodiment, and the functions specifically implemented by the storage medium embodiment are the same as those in the above method embodiment, and the beneficial effects achieved are also the same as those achieved by the above method embodiment.

[0136] The present invention also provides a computer-readable storage medium, which stores a program executable by a processor. The program executable by the processor is used to implement the above method when executed by the processor.

[0137] It is understood that all or some steps and systems in the disclosed method above can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, and the computer-readable medium can include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0138] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0139] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for controlling voltage over-limit in a distribution network, characterized in that: The following steps are involved: Obtain voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong for distribution transformers; Determine whether there is an over-limit voltage in an area or an over-limit voltage in a line according to the over-limit voltage event and the topological relationship; If the section-connected voltage exceeds the limit or the line-connected voltage exceeds the limit, determine a target reactive compensation device according to the power distribution area to which the reactive compensation device belongs, and determine the compensation amount of the target reactive compensation device; If there is no voltage over-limit in the section or the control capacity of the target reactive power compensation device on the line is insufficient, an assistance instruction is issued to the terminal, so that the terminal obtains the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, and determines whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period; If there is a voltage over-limit caused by the photovoltaic power generation, the photovoltaic reactive power compensation amount is determined according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer.

2. The method according to claim 1, characterized in that The determining, according to the voltage over-limit event and the topological relationship, whether there is an interval-connected voltage over-limit or a line-connected voltage over-limit specifically includes: If the number of distribution transformers with the voltage over-limit event under the line is greater than the first threshold, the line section is divided, and the distribution transformers that are continuous in the line section in the topological relationship are retrieved. If the number of continuous distribution transformers is greater than or equal to the first threshold, it is determined that there is a continuous voltage over-limit in the section; the distribution transformer is the distribution transformer with the voltage over-limit event; The line section where the section voltage exceeds the limit is recorded as a section voltage exceeding the limit area. If the number of distribution transformers in the section voltage exceeding the limit area is greater than or equal to the second threshold, it is determined that the line section voltage exceeds the limit.

3. The method according to claim 2, characterized in that If the voltage of the section is over the limit or the voltage of the line is over the limit, determining the target reactive power compensation device according to the power distribution area to which the reactive power compensation device belongs specifically includes: If the line segment voltage exceeds the limit, determine that the reactive power compensation device on the busbar of the substation where the line is located is the target reactive power compensation device; If there is an over-limit of the section-connected voltage and there is no over-limit of the line-connected voltage, the reactive compensation device in the over-limited section of the section is determined as the target reactive compensation device according to the distribution area to which the reactive compensation device belongs; If the reactive power compensation device in the contiguous voltage over-limit area has insufficient governance capacity, reactive power compensation devices in other line sections on the line are added as the target reactive power compensation devices; other line sections refer to line sections different from the contiguous voltage over-limit area; If the reactive compensation devices in the area where the continuous voltage exceeds the limit and the reactive compensation devices in other line sections have insufficient management capabilities, a reactive compensation device on the busbar of the substation where the line is located is added as the target reactive compensation device.

4. The method according to claim 1, characterized in that: The sending of the assistance instruction to the terminal so that the terminal obtains the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction specifically includes: issuing an assistance instruction to the terminal, so that the terminal analyzes the assistance instruction after receiving the assistance instruction, and obtains the occurrence time of the voltage over-limit event, the recovery time of the voltage over-limit event and the photovoltaic power generation curve according to the analysis result; The voltage over-limit period is obtained by taking the occurrence time of the voltage over-limit event as the beginning of each period and the recovery time of the voltage over-limit event as the end of each period; The initial power generation period of all photovoltaics under the distribution transformer is obtained according to the photovoltaic power generation curve, and the initial power generation period of all photovoltaics is summarized to obtain the photovoltaic power generation period.

5. The method according to claim 1, characterized in that The determining whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period specifically includes: Projecting the voltage over-limit period onto the photovoltaic power generation period to obtain the voltage over-limit probability caused by photovoltaic power generation; If the voltage over-limit probability is greater than a second threshold, it is determined that the voltage over-limit is caused by the photovoltaic power generation.

6. The method according to any one of claims 1 to 4, characterized in that: Determining the photovoltaic reactive compensation amount according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer specifically includes: Calculate the reactive power compensation demand according to the voltage over-limit deviation of the distribution transformer, and calculate the total available reactive power compensation of the photovoltaic group according to the power generation power of the photovoltaic group under the distribution transformer; If the total amount of reactive power compensation available is greater than or equal to the reactive power compensation demand, the reactive power compensation amount of each photovoltaic is equal to the reactive power compensation available amount of each photovoltaic; If the total amount of reactive power compensation available is less than the required amount of reactive power compensation, the reactive power compensation amount of each photovoltaic is equal to the average value of the total amount of reactive power compensation available.

7. The method according to any one of claims 1 to 4, characterized in that: If there is no voltage over-limit caused by photovoltaic power generation, adjust the gear of the distribution transformer where the voltage over-limit event occurs. If the distribution transformer does not drop to the preset voltage range after adjustment, perform reactive compensation according to the reactive compensation amount of the photovoltaic group.

8. A voltage over-limit management system for a distribution network, characterized in that: It includes the main station and the fusion terminal, among which, The fusion terminal is used to collect voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution transformers, and upload voltage over-limit events, topological relationships, and distribution areas to which reactive power compensation devices belong of distribution transformers to the master station; The master station is used to obtain the voltage over-limit event, topological relationship and distribution area to which the reactive compensation device belongs of the distribution transformer; determine whether there is an interval-connected voltage over-limit or a line-connected voltage over-limit according to the voltage over-limit event and the topological relationship; if there is an interval-connected voltage over-limit or a line-connected voltage over-limit, determine the target reactive compensation device according to the distribution area to which the reactive compensation device belongs, and determine the compensation amount of the target reactive compensation device; if there is no interval-connected voltage over-limit or the governance capacity of the target reactive compensation device on the line is insufficient, send an assistance instruction to the terminal; The fusion terminal is also used to obtain the voltage over-limit period and the photovoltaic power generation period according to the assistance instruction, and determine whether there is a voltage over-limit caused by photovoltaic power generation according to the voltage over-limit period and the photovoltaic power generation period; if there is a voltage over-limit caused by the photovoltaic power generation, the photovoltaic reactive compensation amount is determined according to the voltage over-limit deviation of the distribution transformer and the power generation power of the photovoltaic group under the distribution transformer.

9. A voltage over-limit control device for a distribution network, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a program executable by a processor, characterized in that: The processor-executable program is used to perform the method according to any one of claims 1 to 7 when executed by the processor.

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