Method and apparatus for site selection and capacity determination of voltage regulating devices in distribution network lines based on voltage spatiotemporal distribution characteristics

Abstract

This invention relates to a method and apparatus for site selection and capacity determination of voltage regulating devices in distribution network lines based on the spatiotemporal distribution characteristics of voltage. The method includes: screening out the lowest and highest voltage values ​​of the line throughout the year, and extracting the distribution outlet voltage at the corresponding time segment; constructing voltage distribution models from the distribution outlet to the users corresponding to the lowest and highest voltage values ​​of the year, respectively; calculating the installation distance under different operating conditions based on the critical voltage values ​​of the voltage regulating device; determining the target installation location based on the distribution network line's over-limit conditions using a first installation distance and / or a second installation distance; locating towers near the target installation location along the distribution network line as the installation towers for the voltage regulating device, and determining the capacity of the voltage regulating device based on the load of the line downstream of the installation tower. This invention can effectively solve the voltage over-limit problem in medium-voltage or low-voltage lines caused by factors such as increased power supply radius and distributed power source access.

Description

Technical Field

[0001] This invention relates to the field of voltage regulation technology for power distribution networks, and in particular to a method and apparatus for site selection and capacity determination of voltage regulating devices for power distribution network lines based on the spatiotemporal distribution characteristics of voltage. Background Technology

[0002] In modern power distribution systems, qualified voltage quality is the core guarantee for user power safety. With the expansion of power supply radius, the problem of low voltage at the end caused by line impedance is becoming increasingly prominent. At the same time, the large-scale connection of distributed power sources such as photovoltaics can easily cause high voltage at the end during peak power generation, forming a complex scenario of "bidirectional voltage exceeding limit", which seriously reduces the voltage qualification rate and threatens equipment safety.

[0003] Two-way voltage regulation devices (such as UPQC) are the core means to solve this problem, but existing site selection and capacity determination methods have the following drawbacks:

[0004] 1. Relying on manual experience or simple power flow calculations, ignoring the characteristics of line voltage gradient distribution;

[0005] 2. Design based on fixed load distribution or single scenario, for example, document CN107039983B discloses a method for selecting and determining the capacity of a low-voltage line voltage regulator. This method only considers the design of a unidirectional over-limit scenario, and determines the installation point by the distance of the boundary point and the load increase coefficient, without considering the bidirectional over-limit caused by the fluctuation of distributed power sources.

[0006] 3. The complexity of optimization schemes leads to high costs. For example, document CN119250384A discloses a location and capacity planning method based on improved multi-objective differential evolution. Although the two-stage robust optimization method used in this method can handle uncertainty, it requires iterative solution of mixed integer second-order cone programming, which has high computational cost and relies on high-speed communication systems, making it difficult to promote in grassroots distribution networks.

[0007] 4. Traditional methods select equipment based on 1.0-1.1 times the peak load, without considering the statistical laws of load growth and distributed power source fluctuations. Case studies show that within 5 years, a 12% increase in load caused the equipment to burn out due to overload, increasing replacement costs by 50%. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a method and device for selecting and determining the location and capacity of voltage regulating device for distribution network lines based on the spatiotemporal distribution characteristics of voltage, which can effectively solve the problem of voltage exceeding the limit caused by factors such as the increase of power supply radius and the access of distributed power sources in medium-voltage or low-voltage lines.

[0009] The technical solution adopted by this invention to solve its technical problem is: providing a method for site selection and capacity determination of voltage regulating devices in distribution network lines based on the spatiotemporal distribution characteristics, comprising:

[0010] The voltage data of each monitoring point on the distribution network line is obtained, the lowest voltage value and the highest voltage value of the year are selected, and the distribution outlet voltage under the corresponding time section is extracted to obtain the first distribution outlet voltage and the second distribution outlet voltage.

[0011] Based on the first distribution outlet voltage and the annual minimum voltage value, a first voltage distribution model is constructed from the distribution outlet to the user corresponding to the annual minimum voltage value of the line. Then, based on the critical voltage value of the voltage regulating device under the voltage boosting condition, the first installation distance is calculated using the first voltage distribution model.

[0012] Based on the second distribution outlet voltage and the highest voltage value of the year, a second voltage distribution model is constructed from the distribution outlet to the user corresponding to the highest voltage value of the year. Then, based on the critical voltage value of the voltage regulating device under the voltage reduction condition, the second installation distance is calculated using the second voltage distribution model.

[0013] The over-limit situation is determined based on the lowest and highest voltage values ​​of the year, and the target installation location is determined based on the over-limit situation and the first installation distance and / or the second installation distance.

[0014] Locate the poles near the target installation location along the power distribution network line as the installation poles for the voltage regulating device, and determine the capacity of the voltage regulating device based on the load of the line downstream of the installation pole.

[0015] Furthermore, based on the distribution network line exceeding the limit, the target installation location is determined according to the first installation distance and / or the second installation distance, including:

[0016] If the distribution network line only has low-voltage over-limit issues, the target installation location is determined based on the first installation distance;

[0017] If the distribution network line only has high voltage over-limit issues, then the target installation location is determined based on the second installation distance;

[0018] If both low-voltage and high-voltage over-limits exist in the distribution network line, the target installation location shall be determined based on the shorter of the first installation distance and the second installation distance.

[0019] Furthermore, a first voltage distribution model and a second voltage distribution model are constructed based on the load distribution characteristics of the distribution network lines and the distribution characteristics of distributed power sources.

[0020] Furthermore, the first voltage distribution model is expressed as:

[0021]

[0022] in, This is the voltage at the first power distribution outlet. This is the critical voltage value of the voltage regulator under boosting conditions. This is the lowest voltage value throughout the year. The first installation distance, This refers to the distance from the power distribution outlet to the user corresponding to the lowest voltage value throughout the year.

[0023] Furthermore, the second voltage distribution model is expressed as:

[0024]

[0025] in, This is the voltage output of the second power distribution outlet. This is the critical voltage value of the voltage regulator under step-down operation. This is the highest voltage value of the year. For the second installation distance, This refers to the distance from the power distribution outlet to the user corresponding to the highest voltage value throughout the year.

[0026] Furthermore, the load on the line behind the pole is obtained by collecting data from the load monitoring device on the line or by estimating the rated power of the user's electrical equipment.

[0027] Furthermore, the capacity of the voltage regulating device should be no less than 1.2 times the load of the line at the rear end of the installation tower.

[0028] Furthermore, the critical voltage values ​​for the voltage regulating device under boost and buck conditions are set to 205V and 230V, respectively.

[0029] The present invention also provides a voltage regulation device location and capacity determination device for distribution network lines based on voltage spatiotemporal distribution characteristics, used to perform the method described above, including:

[0030] The data acquisition module is used to acquire voltage data from monitoring points on the distribution network line, filter out the lowest and highest voltage values ​​of the year, and extract the distribution outlet voltage at the corresponding time section to obtain the first distribution outlet voltage and the second distribution outlet voltage.

[0031] The first calculation module is used to calculate the first installation distance based on the first power distribution outlet voltage, the lowest voltage value throughout the year, and the critical voltage value of the voltage regulating device under the voltage boosting condition.

[0032] The second calculation module is used to calculate the second installation distance based on the second power distribution outlet voltage, the highest voltage value throughout the year, and the critical voltage value of the voltage regulating device under voltage reduction conditions.

[0033] The location selection module is used to determine the over-limit situation based on the lowest voltage value and the highest voltage value throughout the year, and to determine the target installation location based on the over-limit situation and the first installation distance and / or the second installation distance.

[0034] The capacity-determining module is used to determine the capacity of the voltage regulating device based on the line load at the rear end of the installed tower.

[0035] Furthermore, it also includes:

[0036] The statistics module is used to estimate the load on the line behind the installation tower based on the load on the distribution network line or the rated power of the user's electrical equipment.

[0037] Beneficial effects

[0038] By adopting the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0039] This invention combines spatiotemporal voltage profile analysis with a dual-mode critical voltage mechanism, fully considering the actual voltage changes in low-voltage distribution areas and the distribution characteristics of loads and distributed power sources. It determines the installation distance based on different over-limit situations of distribution network lines through a dual-mode model, and performs scientific capacity calculations based on load conditions, avoiding secondary over-limit situations of front-end voltage caused by empirical methods. It is compatible with both low-voltage and high-voltage management scenarios and avoids the problem of insufficient dynamic adaptability of traditional methods.

[0040] The data acquisition and analysis process of this invention can be realized based on existing power monitoring systems. The calculation based on the linear voltage distribution model does not require iterative solutions. The voltage drop calculation and capacity calculation methods are simple and in line with the basic principles of power systems. It has high feasibility in practical engineering applications. It can be implemented under the existing low-voltage distribution network architecture without complex equipment and high costs, thus solving the cost defects of complex optimization methods.

[0041] This invention can specifically address voltage exceedance issues: in addressing low voltage problems, it can effectively increase the terminal voltage to the acceptable range; in addressing high voltage problems, it can reduce excessively high voltage to a reasonable range, thereby significantly improving the voltage qualification rate, ensuring the stable operation of the low-voltage distribution network, improving power supply quality, and having good economic and social benefits. Attached Figure Description

[0042] Figure 1 This is a flowchart illustrating the first embodiment of the present invention;

[0043] Figure 2 This is a flowchart of Embodiment 1 of the present invention. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] The first embodiment of the present invention relates to a method for site selection and capacity determination of voltage regulating devices in distribution network lines based on the spatiotemporal distribution characteristics, which mainly includes three parts:

[0046] Voltage data acquisition and analysis based on spatiotemporal voltage profiles;

[0047] Dual-mode critical voltage adaptive addressing method;

[0048] Load margin correction constant volume method.

[0049] Specifically, the following methods can be used for voltage data acquisition and analysis:

[0050] Using existing smart meters or power monitoring terminals, the voltage information of each user or monitoring point will be continuously monitored for one year.

[0051] The monitoring data is uploaded to the data processing center in real time, and the lowest and highest voltage values, as well as the corresponding times, are filtered out from all the data in the area through data analysis software.

[0052] The monitoring system obtains the output voltage of the substation (for medium-voltage lines) or low-voltage distribution area (for low-voltage lines) at the corresponding time section.

[0053] By filtering out the lowest and highest voltage values, the worst operating conditions throughout the year can be used to avoid insufficient or redundant equipment configuration.

[0054] like Figure 1 As shown, this embodiment implements dual-mode critical voltage adaptive addressing for low-voltage, high-voltage, and bidirectional over-limit modes. Assuming the line load and distributed power source access are uniformly distributed, the specific method includes:

[0055] Low voltage control mode (lowest voltage in the line) (When the lower limit is exceeded): At this time, the voltage regulator is operating in boost mode. To ensure that the voltage at the front end of the equipment is not lower than the minimum voltage standard of 198V after equipment installation, the critical voltage value at the equipment installation point is determined as follows: Typically around 205V. The distance from the starting point (substation or low-voltage distribution area) to the user with the lowest voltage is known to be... According to the formula for uniform voltage drop:

[0056]

[0057] in, This is the voltage drop value. For distance variables, For the output voltage at the first end, when At that time, the calculation yielded That is, the voltage drops to the critical voltage. The distance from the beginning. This refers to the initial location of the voltage regulating device installed on the line under boosting conditions.

[0058] High voltage control mode (highest voltage in the line) (When exceeding the upper limit): At this time, the voltage regulator operates in step-down mode. To ensure that the voltage at the front end of the equipment does not exceed 235.4V after installation, the critical voltage is... The value is typically around 230V. The distance from the starting point (substation or low-voltage distribution area) to the highest voltage user is known to be... According to the formula for uniform voltage rise:

[0059]

[0060] in, This is the voltage drop value. For distance variables, For the output voltage at the first end, when At that time, the calculation yielded That is, the voltage drops to the critical voltage. The distance from the beginning. This refers to the initial location of the voltage regulating device installed on the line under the voltage reduction condition.

[0061] When a transformer area experiences a bidirectional overvoltage situation—daytime overvoltage and evening low voltage when there is no solar power—(i.e., and (Both exceed limits): Calculate the corresponding installation point locations using the low-voltage mitigation mode and high-voltage mitigation mode methods respectively. The smaller value is selected as the final address value, thereby ensuring that the voltage regulator can play a more effective regulatory role under different operating conditions and solving the bidirectional over-limit problem.

[0062] Then, based on the tower number and actual location, locate the tower near the installation point along the line and identify it as the tower for installing the voltage regulating device (the nearest tower).

[0063] Load statistics are performed on the lines behind the preliminarily determined installation towers. The total load value of this section of the line is obtained by using load monitoring devices on the line or by estimating based on the rated power of the user's electrical equipment. Calculate the capacity of the voltage regulating device:

[0064]

[0065] Based on the calculation results, select a voltage regulator with an appropriate capacity for installation. This method ensures that the device capacity meets the actual voltage regulation requirements without over-configuration.

[0066] The second embodiment of the present invention relates to a voltage regulation device location and capacity determination device for distribution network lines based on the spatiotemporal distribution characteristics, used to perform the method described above, including:

[0067] The data acquisition module is used to acquire voltage data from various monitoring points on the distribution network line, filter out the lowest and highest voltage values ​​of the year, and extract the distribution outlet voltage of the corresponding time section.

[0068] The location selection module is used to determine the over-limit situation based on the lowest and highest voltage values ​​in the distribution network line, and to determine the target installation location based on the over-limit situation;

[0069] The capacity-determining module is used to determine the capacity of the voltage regulating device based on the line load at the rear end of the installed tower.

[0070] The address selection module includes:

[0071] The first calculation module, for low-voltage management mode, is used to calculate the installation distance based on the distribution outlet voltage, the lowest voltage value throughout the year, and the critical voltage value of the voltage regulating device under voltage boosting conditions.

[0072] The second calculation module, for high-voltage management mode, is used to determine the installation distance based on the distribution outlet voltage, the highest voltage value throughout the year, and the critical voltage value of the voltage regulating device under voltage reduction conditions.

[0073] Furthermore, it also includes a statistics module, which is used to estimate the load of the line behind the installation tower based on the load on the distribution network line or based on the rated power of the user's electrical equipment.

[0074] like Figure 2 The low-voltage distribution area shown:

[0075] Voltage at the first end of the distribution area (transformer outlet) Total power supply radius (Straight-line distance from the first end to the last load 6);

[0076] Line loads 1-6 are uniformly distributed residential loads, with the lowest voltage value collected throughout the year for the terminal load 6. If the voltage is lower than the minimum low-voltage user voltage of 198V specified in GB / T 22387, it is judged as a low voltage over-limit and triggers the boost control mode.

[0077] Set the critical target voltage for boost operation. .

[0078] Calculate the installation distance under low voltage conditions:

[0079]

[0080] Substitute into the formula:

[0081]

[0082] That is, the voltage regulating device should be installed at a distance of approximately from the beginning of the transformer area. The location of the line.

[0083] The line in this area adopts The towers are arranged at equal intervals, with the transformer outlet at the first end being tower number 0. Towers are installed as close as possible to the calculated location.

[0084] This corresponds to tower number 8, which was selected as the installation platform. The deviation between the installation location and the calculated value is... This meets the engineering accuracy requirements.

[0085] Compare the line voltage changes before and after voltage regulation using the voltage distribution curves in the attached diagram:

[0086] Before voltage regulation: Line voltage starts from the beginning. Linear drop, voltage at point 6 of the terminal load drops to This falls under the category of low voltage exceeding limits, with a voltage qualification rate of only [percentage missing]. ;

[0087] After voltage regulation: The voltage regulator will reduce the input voltage at the installation location (originally dropped to approximately) The voltage is steadily boosted to the target voltage. The subsequent route starts from A linear drop occurred, and the voltage at the final terminal load 6 increased to... (Meets the acceptable voltage range of GB / T 22387), and the voltage qualification rate of the distribution area has been improved to... This successfully resolved the low voltage over-limit problem.

[0088] Taking a 20-node distribution network in Hebei Province as an example, its low-voltage distribution substation has a power supply radius of 800 meters and is connected to a distributed photovoltaic capacity of 200kVA. The load is mainly residential and commercial, with significant peak-valley fluctuations. At the end of the substation line, the voltage rises to 255V (rated 220V) during peak photovoltaic power generation, and drops to 185V during off-peak hours at night. Furthermore, the traditional UPQC device frequently trips due to overcurrent protection during sudden load changes, resulting in a voltage qualification rate of only 75%.

[0089] Step 1: Data Collection and Limit-Exceeding Scene Identification

[0090] Monitor the voltage of all users in the monitoring area, record the lowest voltage V2 and the highest voltage V4 throughout the year and the time when they occur, and simultaneously obtain the first-end voltage V1 at that time (example: V1=220V, V2=190V; V1=221V, V4=247V).

[0091] Step 2: Critical Voltage Mode Selection

[0092] If V2 < 198V, enable low voltage mode (V3 = 205V).

[0093] If V4 > 235.4V, enable high voltage mode (V3 = 230V);

[0094] If both conditions exist, a two-way over-limit processing procedure will be initiated.

[0095] Step 3: Installation distance calculation and tower positioning

[0096] Assume L = 500m (distance from the transformer substation to the user with the lowest voltage), V1 = 219V, V2 = 190V:

[0097] Low voltage mode: L1 = 500*(220 - 205) / (220 - 190) = 250m;

[0098] High voltage mode: L1 = 500*(230-221) / (247-221) = 173m.

[0099] The nearest tower, located 173m from the transformer substation, was selected as the installation point.

[0100] Step 4: Capacity Configuration

[0101] If the total downstream load capacity of the installation point is S=50kVA, then the voltage regulating device capacity SN=1.2 * 50 = 60kVA.

[0102] Example effect:

[0103] The voltage qualification rate increased from 82.3% to 98.1%;

[0104] The solar curtailment rate decreased by 8.72% (compared to the fixed-weight method);

[0105] The capacity configuration accuracy of the voltage regulating device is improved by 15%, avoiding the risk of overload.

Claims

1. A method for site selection and capacity determination of voltage regulating devices in distribution network lines based on the spatiotemporal distribution characteristics, characterized in that, include: Obtain voltage data from each monitoring point on the distribution network line, filter out the lowest and highest voltage values ​​of the year, and extract the distribution outlet voltage at the corresponding time section to obtain the first and second distribution outlet voltages. Based on the first distribution outlet voltage and the lowest annual voltage value, a first voltage distribution model is constructed from the distribution outlet to the user corresponding to the lowest annual voltage value. Then, based on the critical voltage value of the voltage regulating device under boosting conditions, the first installation distance is calculated using the first voltage distribution model. The first voltage distribution model is expressed as follows: ， in, This is the voltage at the first power distribution outlet. This is the critical voltage value of the voltage regulator under boosting conditions. This is the lowest voltage value throughout the year. The first installation distance, The distance from the distribution outlet to the user corresponding to the lowest voltage value throughout the year; Based on the second distribution outlet voltage and the highest annual voltage value, a second voltage distribution model is constructed from the distribution outlet to the user corresponding to the highest annual voltage value. Then, based on the critical voltage value of the voltage regulating device under step-down conditions, the second installation distance is calculated using the second voltage distribution model. The second voltage distribution model is expressed as follows: , in, This is the voltage at the second power distribution outlet. This is the critical voltage value of the voltage regulator under step-down operation. This is the highest voltage value of the year. For the second installation distance, This refers to the distance from the distribution outlet to the user corresponding to the highest voltage value of the line throughout the year. The over-limit situation is determined based on the lowest and highest voltage values ​​of the year, and the target installation location is determined based on the over-limit situation and the first installation distance and / or the second installation distance. If the distribution network line only has low-voltage over-limit, the target installation location is determined based on the first installation distance. If the distribution network line only has high-voltage over-limit, the target installation location is determined based on the second installation distance. If the distribution network line has both low-voltage and high-voltage over-limit, the target installation location is determined based on the shorter of the first installation distance and the second installation distance. Locate the towers near the target installation location along the power distribution network line as the installation towers for the voltage regulating device, and determine the capacity of the voltage regulating device based on the load of the line downstream of the installation tower.

2. The site selection and volume determination method according to claim 1, characterized in that, The first voltage distribution model and the second voltage distribution model are constructed based on the load distribution characteristics of the distribution network lines and the distribution characteristics of distributed power sources.

3. The site selection and volume determination method according to claim 1, characterized in that, The load on the line behind the installed tower is obtained by collecting data from the load monitoring device on the line or by estimating the rated power of the user's electrical equipment.

4. The site selection and volume determination method according to claim 1, characterized in that, The capacity of the voltage regulating device should be no less than 1.2 times the load of the line at the rear end of the installation tower.

5. The site selection and volume determination method according to claim 1, characterized in that, The critical voltage values ​​for the voltage regulator under boost and buck conditions are set to 205V and 230V respectively.

6. A location and capacity determination device for voltage regulation devices in distribution networks based on the spatiotemporal distribution characteristics, used to perform the method described in any one of claims 1-5, characterized in that, include: The data acquisition module is used to acquire voltage data from monitoring points on the distribution network line, filter out the lowest and highest voltage values ​​of the year, and extract the distribution outlet voltage at the corresponding time section to obtain the first distribution outlet voltage and the second distribution outlet voltage. The first calculation module is used to calculate the first installation distance based on the first power distribution outlet voltage, the lowest voltage value throughout the year, and the critical voltage value of the voltage regulating device under the voltage boosting condition. The second calculation module is used to calculate the second installation distance based on the second power distribution outlet voltage, the highest voltage value throughout the year, and the critical voltage value of the voltage regulating device under voltage reduction conditions. The location selection module is used to determine the over-limit situation based on the lowest voltage value and the highest voltage value throughout the year, and to determine the target installation location based on the over-limit situation and the first installation distance and / or the second installation distance. The capacity-determining module is used to determine the capacity of the voltage regulating device based on the line load at the rear end of the installed tower.

7. The site selection and volume control device according to claim 6, characterized in that, Also includes: The statistics module is used to estimate the load on the line behind the installed tower based on the load on the distribution network line or the rated power of the user's electrical equipment.

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