Power distribution network voltage control method and device based on photovoltaic access, terminal equipment and storage medium

Abstract

The invention discloses a photovoltaic access-based power distribution network voltage control method, a photovoltaic access-based power distribution network voltage control device, terminal equipment and a storage medium. Adjusting the reactive power output of a second distributed photovoltaic which is located on the same outgoing line with the first distributed photovoltaic of which the voltage exceeds the upper limit under the constraint, and then determining that the reactive power output of the second distributed photovoltaic reaches the limit value and the voltage of the first photovoltaic access point still exceeds the upper limit; adjusting the reactive power output of the first centralized photovoltaic under the constraint; and when it is determined that the reactive power output of the first centralized photovoltaic unit reaches the limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, calculating an out-of-limit reactive capacity value of a main transformer located on the low-voltage side in the substation, and adjusting the reactive power output of the main transformer according to the out-of-limit reactive capacity value. By implementing the method, photovoltaic absorption can be guaranteed preferentially, and meanwhile, the voltage of the power grid is effectively prevented from exceeding the upper limit.

Description

Technical Field

[0001] The present invention relates to the field of power systems, and in particular to a method, device, terminal equipment and storage medium for controlling voltage of a distribution network based on photovoltaic access. Background Art

[0002] As the power grid develops towards activeness, the proportion of distributed renewable energy to grid load is increasing. During the day, when distributed renewable energy generates a large amount of electricity, the operating state of the traditional 220 / 110 kV plant step-down transformer and 35 / 10 kV outgoing line gradually changes from long-term pure load input to light load, and sometimes even reverse power transmission to the main grid. However, the current power grid is mainly designed and constructed based on the characteristics of passive and nearly pure load, and its reactive configuration mostly focuses on capacitive reactive power to meet the voltage support requirements under heavy load conditions.

[0003] In view of the current status of the above-mentioned grid construction, when a large number of distributed photovoltaics are connected to the grid, the grid will change from a passive state to an active state. This change makes the original reactive power balance design principle no longer applicable. The fluctuation of photovoltaic power will cause voltage fluctuations, and due to the lack of sufficient inductive reactive power sources, it is difficult to effectively suppress overvoltage conditions. Summary of the invention

[0004] The present invention provides a distribution network voltage control method based on photovoltaic access. When voltage fluctuation occurs in a substation, the method controls the voltage of distributed photovoltaics, centralized photovoltaics and main transformers in the substation in turn, thereby effectively suppressing the problem of grid voltage exceeding the upper limit while giving priority to photovoltaic consumption through a hierarchical and step-by-step control principle.

[0005] An embodiment of the present invention provides a method for controlling voltage of a distribution network based on photovoltaic access, comprising:

[0006] Real-time monitoring of the voltage at the access point of distributed photovoltaics in the substation;

[0007] When it is monitored that the voltage of the first photovoltaic access point of at least one distributed photovoltaic exceeds the upper limit, under the preset first voltage and power factor dual control constraints, the reactive power output of the second distributed photovoltaic located on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit is adjusted; wherein the voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic is in a normal state;

[0008] When it is determined that the reactive power output of the second distributed photovoltaic has reached the limit and the voltage of the first photovoltaic access point still exceeds the upper limit, a centralized photovoltaic whose reactive power dynamic adjustment capability meets the preset first sensitivity condition is selected as the first centralized photovoltaic, and the reactive power output of the first centralized photovoltaic is adjusted under the preset second voltage and power factor dual control constraint; wherein the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line;

[0009] When it is determined that the reactive power output of the first centralized photovoltaic has reached the limit value and the voltage of the first photovoltaic access point is still above the upper limit, the over-limit reactive capacity value of the main transformer on the low-voltage side of the substation is calculated, and the reactive power output of the main transformer is adjusted according to the over-limit reactive capacity value; wherein the online active power of the main transformer is greater than a preset judgment threshold.

[0010] Furthermore, the step of selecting a centralized photovoltaic system whose reactive power dynamic regulation capability satisfies a preset first sensitivity condition as the first centralized photovoltaic system includes:

[0011] Calculate the first reactive power-voltage sensitivity of each centralized photovoltaic power station relative to the photovoltaic access point voltage;

[0012] For each of the centralized photovoltaic systems, determining whether a first reactive power-voltage sensitivity corresponding to the centralized photovoltaic system is not less than a first threshold value,

[0013] If so, it is determined that the reactive power dynamic adjustment capability of the centralized photovoltaic system meets the preset first sensitivity condition, and the centralized photovoltaic system is used as the first centralized photovoltaic system.

[0014] If not, it is determined that the reactive power dynamic regulation capability of the centralized photovoltaic system does not meet a preset first sensitivity condition.

[0015] Further, the calculating of the over-limit reactive capacity value of the main transformer on the low voltage side in the substation and adjusting the reactive power output of the main transformer according to the over-limit reactive capacity value includes:

[0016] Calculating a first voltage-voltage sensitivity of a low-voltage side voltage of the main transformer relative to a voltage of the first photovoltaic access point;

[0017] Calculating a second reactive-voltage sensitivity of the low-voltage side reactive compensation capacity of the main transformer relative to the low-voltage side voltage;

[0018] Determine, according to the first voltage-voltage sensitivity and the second reactive-voltage sensitivity, a third reactive-voltage sensitivity of the low-voltage side reactive compensation capacity of the main transformer relative to the voltage of the first photovoltaic access point;

[0019] Calculate the over-limit reactive capacity value of the low-voltage side of the main transformer according to the preset photovoltaic access point over-limit threshold, the third reactive-voltage sensitivity and the first photovoltaic access point voltage;

[0020] According to the over-limit reactive capacity value, the reactive power output of the main transformer is adjusted.

[0021] Furthermore, the first voltage and power factor dual control constraint is specifically:

[0022] The voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic does not exceed the lower limit and the first photovoltaic power factor corresponding to the second distributed photovoltaic is within a preset power factor range.

[0023] Furthermore, the second voltage and power factor dual control constraint is specifically:

[0024] The voltage of the third photovoltaic access point corresponding to the first centralized photovoltaic does not exceed a lower limit and the second photovoltaic power factor corresponding to the first centralized photovoltaic is within the power factor range.

[0025] Furthermore, the distribution network voltage control method based on photovoltaic access also includes:

[0026] When it is determined that the reactive power output of the main transformer has reached the limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, a second distributed photovoltaic whose active power dynamic regulation capability meets the preset second sensitivity condition is selected as the third distributed photovoltaic, and the second photovoltaic access point voltage corresponding to the second distributed photovoltaic whose active power dynamic regulation capability meets the preset second sensitivity condition is used as the fourth photovoltaic access point voltage;

[0027] When the voltage of the fourth photovoltaic access point does not exceed a lower limit, the active power output of the third distributed photovoltaic is adjusted.

[0028] Furthermore, the selecting of the second distributed photovoltaic system whose active power dynamic regulation capability meets the preset second sensitivity condition as the third distributed photovoltaic system includes:

[0029] Calculating the active power-voltage sensitivity of each second distributed photovoltaic active power output relative to the corresponding second photovoltaic access point voltage;

[0030] For each of the second distributed photovoltaics, determining whether the active power-voltage sensitivity corresponding to the second distributed photovoltaics is not less than a second threshold,

[0031] If so, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic meets the preset second sensitivity condition, the second distributed photovoltaic is used as the third distributed photovoltaic, and the second photovoltaic access point voltage corresponding to the third distributed photovoltaic is used as the fourth photovoltaic access point voltage,

[0032] If not, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic system does not meet a preset second sensitivity condition.

[0033] An embodiment of the present invention further provides a distribution network voltage control device based on photovoltaic access, comprising: an access point voltage monitoring module, a first reactive power output adjustment module, a second reactive power output adjustment module, and a third reactive power output adjustment module;

[0034] The access point voltage monitoring module is used to monitor the access point voltage of the distributed photovoltaic in the substation in real time;

[0035] The first reactive power output adjustment module is used to adjust the reactive power output of the second distributed photovoltaic on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit under the preset first voltage and power factor dual control constraint when the voltage of the first photovoltaic access point of at least one distributed photovoltaic exceeds the upper limit; wherein the voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic is in a normal state;

[0036] The second reactive power output adjustment module is used to select a centralized photovoltaic whose reactive power dynamic adjustment capability meets a preset first sensitivity condition as the first centralized photovoltaic when it is determined that the reactive power output of the second distributed photovoltaic has reached a limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, and adjust the reactive power output of the first centralized photovoltaic under the preset second voltage and power factor dual control constraint; wherein the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line;

[0037] The third reactive power output adjustment module is used to calculate the over-limit reactive capacity value of the main transformer on the low-voltage side in the substation when it is determined that the reactive power output of the first centralized photovoltaic has reached the limit and the voltage of the first photovoltaic access point is still over the upper limit, and adjust the reactive power output of the main transformer according to the over-limit reactive capacity value; wherein the online active power of the main transformer is greater than the preset judgment threshold.

[0038] The present application also provides a terminal device, including:

[0039] one or more processors;

[0040] A memory, coupled to the processor, for storing one or more programs;

[0041] When the one or more programs are executed by the one or more processors, the one or more processors implement the distribution network voltage control method based on photovoltaic access as described in the above-mentioned embodiment of the invention.

[0042] The present application also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for controlling the voltage of a distribution network based on photovoltaic access as described in the above-mentioned embodiment of the invention is implemented.

[0043] The following beneficial effects are achieved by implementing the present invention:

[0044] The present invention provides a distribution network voltage control method, device, terminal equipment and storage medium based on photovoltaic access. When the voltage of a first photovoltaic access point of at least one distributed photovoltaic is monitored to exceed an upper limit, the method adjusts the reactive power output of a second distributed photovoltaic located on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit under the preset first voltage and power factor dual control constraints, thereby increasing or reducing reactive power by using the regulation capability of the distributed photovoltaic itself, and pulling the voltage back to the normal range as much as possible;

[0045] Since centralized photovoltaics usually have a larger adjustment range and stronger adjustment capability, and can more effectively control the grid voltage, when it is determined that the reactive power output of the second distributed photovoltaic has reached the limit and the voltage of the first photovoltaic access point is still above the upper limit, the reactive power output of the first centralized photovoltaic is adjusted under the preset second voltage and power factor dual control constraints;

[0046] As a key device in the power grid, the adjustment of the reactive power output of the main transformer will have a significant impact on the voltage stability of the entire system. Therefore, when both distributed photovoltaic and centralized photovoltaic cannot return the voltage to the normal range, the voltage is adjusted through the main transformer, that is, the over-limit reactive capacity value of the main transformer on the low-voltage side of the substation is calculated, and the reactive power output of the main transformer is adjusted according to the over-limit reactive capacity value;

[0047] In summary, when it is necessary to take control operations against the grid exceeding the upper limit caused by distributed photovoltaic power fluctuations, this application gives priority to adjusting the reactive power output of distributed photovoltaics and centralized photovoltaics, and finally considers adjusting the reactive power output of the main transformer. This hierarchical and step-by-step approach control method effectively suppresses the problem of grid voltage exceeding the upper limit while giving priority to photovoltaic absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the implementation manner will be briefly introduced below. Obviously, the drawings described below are only some implementation manners of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 It is a flowchart of a method for controlling voltage of a distribution network based on photovoltaic access provided by a certain embodiment of the present application;

[0050] Figure 2 is a first substation simulation system diagram provided by a certain embodiment of the present application;

[0051] Figure 3 is a simulation system diagram of a second substation after voltage control is completed provided by a certain embodiment of the present application;

[0052] Figure 4 It is a structural schematic diagram of a distribution network voltage control device based on photovoltaic access provided by a certain embodiment of the present application;

[0053] Figure 5 is a structural schematic diagram of a distribution network voltage control device based on photovoltaic access provided by another embodiment of the present application;

[0054] Figure 6 It is a structural diagram of a terminal device provided in a certain embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0057] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0058] 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 application. The appearance of the phrase in various locations 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.

[0059] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0060] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0061] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0062] See also Figure 1 , is a flow chart of a method for controlling voltage of a distribution network based on photovoltaic access provided by an embodiment of the present invention, comprising:

[0063] S1, real-time monitoring of the voltage at the access point of distributed photovoltaics in the substation;

[0064] S2. When it is monitored that the voltage of the first photovoltaic access point of at least one distributed photovoltaic exceeds the upper limit, under the preset first voltage and power factor dual control constraint, adjust the reactive power output of the second distributed photovoltaic located on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit; wherein the voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic is in a normal state;

[0065] Indicatively, it is assumed that the voltage of at least one photovoltaic access point of distributed photovoltaic in the current substation exceeds the upper limit U pv_Hset When the voltage of the distributed photovoltaic power plant exceeds the upper limit, the distributed photovoltaic power plant with the voltage exceeding the upper limit is taken as the first distributed photovoltaic power plant pv_1, and the voltage of the first photovoltaic access point corresponding to the first distributed photovoltaic power plant pv_1 is taken as U pv_1 ;

[0066] At this time, it is necessary to find a second distributed photovoltaic pv_2 located on the same outlet line as the first distributed photovoltaic pv_1, wherein the second photovoltaic access point voltage U corresponding to the second distributed photovoltaic pv_2 pv_2 be in a normal state;

[0067] After finding the second distributed photovoltaic pv_2, adjusting the reactive power output of the second distributed photovoltaic pv_2 under the preset first voltage and power factor dual control constraints;

[0068] It should be noted that the second distributed photovoltaic can be one or more;

[0069] In a preferred embodiment, the first voltage and power factor dual control constraint is specifically:

[0070] The voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic does not exceed the lower limit and the first photovoltaic power factor corresponding to the second distributed photovoltaic is within a preset power factor range;

[0071] Specifically, the expression of the first voltage and power factor dual control constraint is as follows:

[0072]

[0073] Where U pv_Lest is the voltage lower limit; is the upper limit of the power factor range; is the lower limit of the power factor range; is the photovoltaic power factor of the second distributed photovoltaic.

[0074] S3. When it is determined that the reactive power output of the second distributed photovoltaic has reached the limit and the voltage of the first photovoltaic access point is still above the upper limit, a centralized photovoltaic whose reactive power dynamic adjustment capability meets the preset first sensitivity condition is selected as the first centralized photovoltaic, and the reactive power output of the first centralized photovoltaic is adjusted under the preset second voltage and power factor dual control constraint; wherein the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line;

[0075] In a preferred embodiment, the step of selecting a centralized photovoltaic system whose reactive power dynamic regulation capability satisfies a preset first sensitivity condition as the first centralized photovoltaic system includes:

[0076] Calculate the first reactive power-voltage sensitivity of each centralized photovoltaic power station relative to the photovoltaic access point voltage;

[0077] For each of the centralized photovoltaic systems, determining whether a first reactive power-voltage sensitivity corresponding to the centralized photovoltaic system is not less than a first threshold value,

[0078] If so, it is determined that the reactive power dynamic adjustment capability of the centralized photovoltaic system meets the preset first sensitivity condition, and the centralized photovoltaic system is used as the first centralized photovoltaic system.

[0079] If not, it is determined that the reactive power dynamic regulation capability of the centralized photovoltaic system does not meet a preset first sensitivity condition;

[0080] Specifically, simulate the reactive power output change dQ of each centralized photovoltaic pv_10 , and obtain the voltage change dU of the photovoltaic access point corresponding to each centralized photovoltaic pv_10 , thus obtaining the first reactive power-voltage sensitivity

[0081] For each centralized photovoltaic, determine the first reactive power-voltage sensitivity corresponding to the centralized photovoltaic Is it not less than the first threshold th_1? If so, it is determined that the reactive power dynamic regulation capability of the centralized photovoltaic meets the preset first sensitivity condition, and the centralized photovoltaic is used as the first centralized photovoltaic pv_10; if not, it is determined that the reactive power dynamic regulation capability of the centralized photovoltaic does not meet the preset first sensitivity condition;

[0082] After sensitivity determination, each centralized photovoltaic obtains the first centralized photovoltaic pv_10 whose final reactive power dynamic regulation capability meets the preset first sensitivity condition;

[0083] It should be noted that the first centralized photovoltaic can be one or more; the operation of reactive power output change of each centralized photovoltaic can be simulated by simulation analysis, and the available simulation analysis includes but is not limited to PSASP, BPA, DIgSilent, and ETAP;

[0084] After obtaining the first centralized photovoltaic pv_10, under the preset second voltage and power factor dual control constraints, adjusting the reactive power output of the first centralized photovoltaic pv_10;

[0085] It should be noted that the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line;

[0086] In a preferred embodiment, the second voltage and power factor dual control constraint is specifically:

[0087] The voltage of the third photovoltaic access point corresponding to the first centralized photovoltaic does not exceed the lower limit and the second photovoltaic power factor corresponding to the first centralized photovoltaic is within the power factor range;

[0088] Specifically, the expression of the second voltage and power factor dual control constraint is as follows:

[0089]

[0090] Where U pv_Lest is the voltage lower limit; U pv_10 is the voltage of the third photovoltaic access point; is the upper limit of the power factor range; is the lower limit of the power factor range; is the photovoltaic power factor of the first concentrated photovoltaic.

[0091] S4. When it is determined that the reactive power output of the first centralized photovoltaic has reached the limit value and the voltage of the first photovoltaic access point is still above the upper limit, the over-limit reactive capacity value of the main transformer on the low-voltage side of the substation is calculated, and the reactive power output of the main transformer is adjusted according to the over-limit reactive capacity value; wherein the online active power of the main transformer is greater than the preset judgment threshold;

[0092] In a preferred embodiment, the calculating of the over-limit reactive capacity value of the main transformer on the low voltage side in the substation and adjusting the reactive power output of the main transformer according to the over-limit reactive capacity value include:

[0093] Calculating a first voltage-voltage sensitivity of a low-voltage side voltage of the main transformer relative to a voltage of the first photovoltaic access point;

[0094] Calculating a second reactive-voltage sensitivity of the low-voltage side reactive compensation capacity of the main transformer relative to the low-voltage side voltage;

[0095] Determine, according to the first voltage-voltage sensitivity and the second reactive-voltage sensitivity, a third reactive-voltage sensitivity of the low-voltage side reactive compensation capacity of the main transformer relative to the voltage of the first photovoltaic access point;

[0096] Calculate the over-limit reactive capacity value of the low-voltage side of the main transformer according to the preset photovoltaic access point over-limit threshold, the third reactive-voltage sensitivity and the first photovoltaic access point voltage;

[0097] According to the over-limit reactive capacity value, adjusting the reactive power output of the main transformer;

[0098] Indicatively, before performing reactive power output adjustment in step S3, it is necessary to screen out the main transformers whose online active power is greater than the preset judgment threshold, that is, it is necessary to obtain the online active power P of the main transformer and determine whether the online active power P is greater than the judgment threshold P. set If the judgment result is yes, it is determined that the main transformer can be used for the current reactive power output regulation. If the judgment result is no, the main transformer does not participate in the voltage control and the current main transformer is not selected;

[0099] Assuming that the current active power of the main transformer tr is greater than the preset judgment threshold, at this time, the low-voltage side voltage change dU of the main transformer tr is simulated. tr , obtain the voltage change dU of the first photovoltaic access point corresponding to the first distributed photovoltaic pv_1 , thus calculating the first voltage-voltage sensitivity

[0100] Then simulate the reactive power compensation capacity change dQ of the low-voltage side of the main transformer tr to obtain the low-voltage side voltage change dU corresponding to the main transformer tr tr , and thus the second reactive power-voltage sensitivity is calculated

[0101] Finally, according to the first voltage-voltage sensitivity And the second reactive power-voltage sensitivity Determine a third reactive power-voltage sensitivity of the low-voltage side reactive power compensation capacity of the main transformer relative to the voltage of the first photovoltaic access point

[0102] According to the preset PV access point exceeding the upper threshold U pv_Hset , the third reactive power-voltage sensitivity And the first photovoltaic access point voltage U pv_1, calculating the over-limit reactive capacity value ΔQ of the low-voltage side of the main transformer, and adjusting the reactive power output of the main transformer according to the over-limit reactive capacity value ΔQ;

[0103] Specifically, the over-limit reactive capacity value ΔQ on the low-voltage side of the main transformer is calculated by the following formula:

[0104]

[0105] It should be noted that the operation of reactive power output changes of each centralized photovoltaic system can be simulated through simulation analysis, and the available simulation analysis includes but is not limited to PSASP, BPA, DIgSilent, and ETAP.

[0106] In a preferred embodiment, the distribution network voltage control method based on photovoltaic access further includes:

[0107] When it is determined that the reactive power output of the main transformer has reached the limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, a second distributed photovoltaic whose active power dynamic regulation capability meets the preset second sensitivity condition is selected as the third distributed photovoltaic, and the second photovoltaic access point voltage corresponding to the second distributed photovoltaic whose active power dynamic regulation capability meets the preset second sensitivity condition is used as the fourth photovoltaic access point voltage;

[0108] When the voltage of the fourth photovoltaic access point does not exceed the lower limit, adjusting the active power output of the third distributed photovoltaic;

[0109] Indicatively, when it is determined that the reactive power output of the main transformer has reached the limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, at this time, it is necessary to select a second distributed photovoltaic whose active power dynamic adjustment capability meets a preset second sensitivity condition as the third distributed photovoltaic;

[0110] In a preferred embodiment, the selecting of the second distributed photovoltaic system whose active power dynamic regulation capability meets the preset second sensitivity condition as the third distributed photovoltaic system includes:

[0111] Calculating the active power-voltage sensitivity of each second distributed photovoltaic active power output relative to the voltage of the corresponding second photovoltaic access point;

[0112] For each of the second distributed photovoltaics, determining whether the active power-voltage sensitivity corresponding to the second distributed photovoltaics is not less than a second threshold,

[0113] If so, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic meets the preset second sensitivity condition, the second distributed photovoltaic is used as the third distributed photovoltaic, and the second photovoltaic access point voltage corresponding to the third distributed photovoltaic is used as the fourth photovoltaic access point voltage,

[0114] If not, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic system does not meet the preset second sensitivity condition;

[0115] Specifically, simulate the active output change dP of each second distributed photovoltaic pv_2 pv_10 , and obtain the voltage change dU of the second photovoltaic access point corresponding to the second distributed photovoltaic pv_2 pv_2 , and thus the active power-voltage sensitivity is calculated For each second distributed photovoltaic pv_2, determine the active power-voltage sensitivity corresponding to the second distributed photovoltaic pv_2 Is it not less than the second threshold th_2? If so, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic pv_2 meets the preset second sensitivity condition, and the second distributed photovoltaic pv_2 is used as the third distributed photovoltaic pv_3, and the second photovoltaic access point voltage U corresponding to the third distributed photovoltaic pv_3 is pv_2 As the fourth photovoltaic access point voltage U pv_4 If not, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic pv_2 does not meet the preset second sensitivity condition;

[0116] After sensitivity determination, each second distributed photovoltaic pv_2 obtains a third distributed photovoltaic pv_3 whose final active power dynamic adjustment capability meets the preset second sensitivity condition, and at the fourth photovoltaic access point voltage U pv_4 Do not exceed the lower limit U pv_Lset In the case of, adjusting the active power output of the third distributed photovoltaic pv_3;

[0117] It should be noted that the operation of reactive power output changes of each centralized photovoltaic system can be simulated through simulation analysis, and the available simulation analysis includes but is not limited to PSASP, BPA, DIgSilent, and ETAP.

[0118] See also Figure 2 , is a first substation simulation system diagram provided by a certain embodiment of the present application. The high-voltage side of the main transformer of the substation is 220kV, and the low-voltage side is 10kV. The low-voltage side bus is "bus 00", including 1 10kV outgoing line of bus 00~bus 01~bus 02~bus 03~bus 04. The centralized photovoltaic "Light 01" has a capacity of 3MW, which is connected to "bus 01" through a step-up transformer. The capacity of distributed photovoltaic "Light 02" and "Light 03" are both 0.5MW, which are connected to the 400V low-voltage side of "bus 04". The 400V low-voltage sides of bus "02", "bus 03" and "bus 04" are all connected to a load of 0.2MW+j0.08Mvar.

[0119] See also Figure 2 as well as Figure 3 , centralized photovoltaic and distributed photovoltaic are fully powered, and the photovoltaic power factor is 1.0. At this time, the 400V bus voltage in the system is 0.44~0.45kV, which is 1.1 times higher than the rated voltage of 400V. The minimum photovoltaic power factor is considered to be 0.9.

[0120] To control the voltage on the 400V side of the power grid not to exceed 1.1 times the rated voltage, the voltage control is performed according to the method of this application. The power flow diagram of the power grid after the control target is achieved is as follows: Figure 3 It can be seen that the centralized photovoltaic and distributed photovoltaic absorb reactive power at a power factor of 0.9, and a 2.17Mvar reactor is put into the "bus 00" side. After the distributed photovoltaic output drops to 0.3MW, the 400V bus voltage does not exceed 1.1 times the rated voltage.

[0121] See also Figure 4 , is a distribution network voltage control device based on photovoltaic access provided by an embodiment of the present invention, comprising: an access point voltage monitoring module, a first reactive power output adjustment module, a second reactive power output adjustment module and a third reactive power output adjustment module;

[0122] The access point voltage monitoring module is used to monitor the access point voltage of the distributed photovoltaic in the substation in real time;

[0123] The first reactive power output adjustment module is used to adjust the reactive power output of the second distributed photovoltaic on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit under the preset first voltage and power factor dual control constraint when the voltage of the first photovoltaic access point of at least one distributed photovoltaic exceeds the upper limit; wherein the voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic is in a normal state;

[0124] The second reactive power output adjustment module is used to select a centralized photovoltaic whose reactive power dynamic adjustment capability meets a preset first sensitivity condition as the first centralized photovoltaic when it is determined that the reactive power output of the second distributed photovoltaic has reached a limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, and adjust the reactive power output of the first centralized photovoltaic under the preset second voltage and power factor dual control constraint; wherein the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line;

[0125] The third reactive power output adjustment module is used to calculate the over-limit reactive capacity value of the main transformer on the low-voltage side in the substation when it is determined that the reactive power output of the first centralized photovoltaic has reached the limit and the voltage of the first photovoltaic access point is still over the upper limit, and adjust the reactive power output of the main transformer according to the over-limit reactive capacity value; wherein the online active power of the main transformer is greater than the preset judgment threshold.

[0126] See also Figure 5 , In a preferred embodiment, the photovoltaic access-based distribution network voltage control device further includes: a first active power output adjustment module;

[0127] The first active power output adjustment module is used to select the second distributed photovoltaic whose active power dynamic adjustment capability meets the preset second sensitivity condition as the third distributed photovoltaic when it is determined that the reactive power output of the main transformer has reached the limit and the voltage of the first photovoltaic access point still exceeds the upper limit, and use the second photovoltaic access point voltage corresponding to the second distributed photovoltaic whose active power dynamic adjustment capability meets the preset second sensitivity condition as the fourth photovoltaic access point voltage; and adjust the active power output of the third distributed photovoltaic when the voltage of the fourth photovoltaic access point does not exceed the lower limit;

[0128] See also Figure 6 , a certain embodiment of the present application further provides a terminal device, including:

[0129] one or more processors;

[0130] A memory, coupled to the processor, for storing one or more programs;

[0131] When the one or more programs are executed by the one or more processors, the one or more processors implement the distribution network voltage control method based on photovoltaic access as described above.

[0132] The processor is used to control the overall operation of the terminal device to complete all or part of the steps of the above-mentioned distribution network voltage control method based on photovoltaic access. The memory is used to store various types of data to support the operation of the terminal device, and these data may include, for example, instructions for any application or method used to operate on the terminal device, and application-related data. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, referred to as EPROM), programmable read-only memory (Programmable Read-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, disk or optical disk.

[0133] In an exemplary embodiment, the terminal device can be implemented by one or more application specific integrated circuits (Application Specific Integrated Circuit, ASIC), digital signal processors (Digital Signal Processor, DSP), digital signal processing devices (Digital Signal Processing Device, DSPD), programmable logic devices (Programmable Logic Device, PLD), field programmable gate arrays (Field Programmable Gate Array, FPGA), controllers, microcontrollers, microprocessors or other electronic components, and is used to execute the distribution network voltage control method based on photovoltaic access as described in any of the above embodiments, and achieve the same technical effect as the above method.

[0134] In another exemplary embodiment, a computer-readable storage medium including a computer program is also provided, and when the computer program is executed by a processor, the steps of the method for controlling the voltage of a distribution network based on photovoltaic access as described in any of the above embodiments are implemented. For example, the computer-readable storage medium may be the above-mentioned memory including the computer program, and the above-mentioned computer program may be executed by a processor of a terminal device to complete the method for controlling the voltage of a distribution network based on photovoltaic access as described in any of the above embodiments, and achieve the technical effect consistent with the above-mentioned method.

[0135] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A distribution network voltage control method based on photovoltaic access, characterized in that: include: Real-time monitoring of the voltage at the access point of distributed photovoltaics in the substation; When it is monitored that the voltage of the first photovoltaic access point of at least one distributed photovoltaic exceeds the upper limit, under the preset first voltage and power factor dual control constraints, the reactive power output of the second distributed photovoltaic located on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit is adjusted; wherein the voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic is in a normal state; When it is determined that the reactive power output of the second distributed photovoltaic has reached the limit and the voltage of the first photovoltaic access point still exceeds the upper limit, a centralized photovoltaic whose reactive power dynamic adjustment capability meets the preset first sensitivity condition is selected as the first centralized photovoltaic, and the reactive power output of the first centralized photovoltaic is adjusted under the preset second voltage and power factor dual control constraint; wherein the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line; When it is determined that the reactive power output of the first centralized photovoltaic has reached the limit value and the voltage of the first photovoltaic access point is still above the upper limit, the over-limit reactive capacity value of the main transformer on the low-voltage side of the substation is calculated, and the reactive power output of the main transformer is adjusted according to the over-limit reactive capacity value; wherein the online active power of the main transformer is greater than a preset judgment threshold.

2. The method for controlling voltage of a distribution network based on photovoltaic access according to claim 1, characterized in that: The step of selecting a centralized photovoltaic system whose reactive power dynamic regulation capability satisfies a preset first sensitivity condition as the first centralized photovoltaic system comprises: Calculate the first reactive power-voltage sensitivity of each centralized photovoltaic power station relative to the photovoltaic access point voltage; For each of the centralized photovoltaic systems, determining whether a first reactive power-voltage sensitivity corresponding to the centralized photovoltaic system is not less than a first threshold value, If so, it is determined that the reactive power dynamic regulation capability of the centralized photovoltaic system meets the preset first sensitivity condition, and the centralized photovoltaic system is used as the first centralized photovoltaic system. If not, it is determined that the reactive power dynamic regulation capability of the centralized photovoltaic system does not meet a preset first sensitivity condition.

3. The method for controlling voltage of a distribution network based on photovoltaic access according to claim 1, characterized in that: The calculating of the over-limit reactive capacity value of the main transformer on the low voltage side in the substation and adjusting the reactive power output of the main transformer according to the over-limit reactive capacity value includes: Calculating a first voltage-voltage sensitivity of a low-voltage side voltage of the main transformer relative to a voltage of the first photovoltaic access point; Calculating a second reactive-voltage sensitivity of the low-voltage side reactive compensation capacity of the main transformer relative to the low-voltage side voltage; Determine, according to the first voltage-voltage sensitivity and the second reactive-voltage sensitivity, a third reactive-voltage sensitivity of the low-voltage side reactive compensation capacity of the main transformer relative to the voltage of the first photovoltaic access point; Calculate the over-limit reactive capacity value of the low-voltage side of the main transformer according to the preset photovoltaic access point over-limit threshold, the third reactive-voltage sensitivity and the first photovoltaic access point voltage; According to the over-limit reactive capacity value, the reactive power output of the main transformer is adjusted.

4. The method for controlling voltage of a distribution network based on photovoltaic access according to claim 1, characterized in that: The first voltage and power factor dual control constraint is specifically: The voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic does not exceed the lower limit and the first photovoltaic power factor corresponding to the second distributed photovoltaic is within a preset power factor range.

5. The method for controlling voltage of a distribution network based on photovoltaic access according to claim 4, characterized in that: The second voltage and power factor dual control constraint is specifically: The voltage of the third photovoltaic access point corresponding to the first centralized photovoltaic does not exceed a lower limit and the second photovoltaic power factor corresponding to the first centralized photovoltaic is within the power factor range.

6. The method for controlling voltage of a distribution network based on photovoltaic access according to claim 1, characterized in that: Also includes: When it is determined that the reactive power output of the main transformer has reached the limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, a second distributed photovoltaic whose active power dynamic regulation capability meets the preset second sensitivity condition is selected as the third distributed photovoltaic, and the second photovoltaic access point voltage corresponding to the second distributed photovoltaic whose active power dynamic regulation capability meets the preset second sensitivity condition is used as the fourth photovoltaic access point voltage; When the voltage of the fourth photovoltaic access point does not exceed a lower limit, the active power output of the third distributed photovoltaic is adjusted.

7. The method for controlling voltage of a distribution network based on photovoltaic access according to claim 6, characterized in that: The selecting a second distributed photovoltaic power plant whose active power dynamic regulation capability meets a preset second sensitivity condition as the third distributed photovoltaic power plant comprises: Calculating the active power-voltage sensitivity of each second distributed photovoltaic active power output relative to the voltage of the corresponding second photovoltaic access point; For each of the second distributed photovoltaics, determining whether the active power-voltage sensitivity corresponding to the second distributed photovoltaics is not less than a second threshold, If so, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic meets the preset second sensitivity condition, the second distributed photovoltaic is used as the third distributed photovoltaic, and the second photovoltaic access point voltage corresponding to the third distributed photovoltaic is used as the fourth photovoltaic access point voltage, If not, it is determined that the active power dynamic adjustment capability of the second distributed photovoltaic system does not meet a preset second sensitivity condition.

8. A distribution network voltage control device based on photovoltaic access, characterized in that: include: An access point voltage monitoring module, a first reactive power output adjustment module, a second reactive power output adjustment module, and a third reactive power output adjustment module; The access point voltage monitoring module is used to monitor the access point voltage of the distributed photovoltaic in the substation in real time; The first reactive power output adjustment module is used to adjust the reactive power output of the second distributed photovoltaic on the same output line as the first distributed photovoltaic whose voltage exceeds the upper limit under the preset first voltage and power factor dual control constraint when the voltage of the first photovoltaic access point of at least one distributed photovoltaic exceeds the upper limit; wherein the voltage of the second photovoltaic access point corresponding to the second distributed photovoltaic is in a normal state; The second reactive power output adjustment module is used to select a centralized photovoltaic whose reactive power dynamic adjustment capability meets a preset first sensitivity condition as the first centralized photovoltaic when it is determined that the reactive power output of the second distributed photovoltaic has reached a limit value and the voltage of the first photovoltaic access point still exceeds the upper limit, and adjust the reactive power output of the first centralized photovoltaic under the preset second voltage and power factor dual control constraint; wherein the first centralized photovoltaic and the first distributed photovoltaic are located on the same outgoing line; The third reactive power output adjustment module is used to calculate the over-limit reactive capacity value of the main transformer on the low-voltage side in the substation when it is determined that the reactive power output of the first centralized photovoltaic has reached the limit and the voltage of the first photovoltaic access point is still over the upper limit, and adjust the reactive power output of the main transformer according to the over-limit reactive capacity value; wherein the online active power of the main transformer is greater than the preset judgment threshold.

9. A terminal device, characterized in that: include: one or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the distribution network voltage control method based on photovoltaic access as described in any one of claims 1 to 7.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for controlling voltage of a distribution network based on photovoltaic access as described in any one of claims 1 to 7 is implemented.

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