Current status of photovoltaic access to layered and zoned distribution networks and evaluation methods of their carrying capacity

Abstract

The present invention relates to a method for evaluating the photovoltaic access status and carrying capacity of a layered and zoned distribution network, comprising the following steps: dividing the distribution network into a power supply area, a feeder power supply area and a substation power supply area according to the level to which the power supply area belongs; respectively obtaining the regional photovoltaic capacity penetration rate, the regional photovoltaic energy penetration rate, the regional photovoltaic power upload rate, the regional photovoltaic power on-site consumption rate and the power supply area abandonment rate indicators of the power supply area, and performing a multi-dimensional photovoltaic power generation status evaluation on the power supply area according to the above indicators; after obtaining the photovoltaic power generation status of the power supply area, obtaining the photovoltaic consumption capacity indicator and the photovoltaic acceptance capacity indicator of the power supply area, and evaluating the photovoltaic carrying potential of the power supply area according to the indicators; and realizing the photovoltaic access planning and design of the power supply area according to the photovoltaic power generation status and the photovoltaic carrying potential of the power supply area; the present invention can better obtain the real photovoltaic consumption level of the distribution network, and then guide the construction of distributed photovoltaic and energy storage in my country's distribution network.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution network evaluation, and in particular relates to a method for evaluating the photovoltaic access status and carrying capacity of a layered and zoned distribution network. Background Art

[0002] my country's long-term high-proportion fossil energy consumption has brought great security risks to my country's future energy supply. Distributed photovoltaic refers to a form of photovoltaic power generation that is built and operated at or near the user's site, and the generated electricity is consumed in the distribution network system. It has the principles of nearby power generation, nearby grid connection, nearby conversion, and nearby use. It fully utilizes idle rooftop resources, improves the utilization rate of renewable solar energy resources, and avoids the disadvantages of high loss in the traditional high-voltage long-distance transmission mode.

[0003] Photovoltaic carrying capacity refers to the maximum capacity of photovoltaic power that the distribution network can absorb or accept under the conditions that the power grid is continuously not overloaded and the short-circuit current, voltage deviation, and harmonics do not exceed the standard. It has two meanings: absorption capacity and acceptance capacity. Distributed photovoltaic power is usually located at the end of the distribution network, with a low access voltage level and poor observability and measurability. For the grid dispatching department, its disorderly access often exceeds the photovoltaic carrying capacity of the distribution network, resulting in safety risks. Therefore, in order to ensure the coordinated development of distributed photovoltaic power, loads, and power grids, it is necessary to calculate the photovoltaic carrying capacity of each power supply area of ​​the distribution network, realize the evaluation of the current status of photovoltaic access, and calculate the margin of photovoltaic capacity that can be accessed in the future, so as to provide guidance for the planning and construction of photovoltaic and distribution networks. Summary of the invention

[0004] The purpose of this invention is to propose a method for evaluating the photovoltaic status and carrying capacity of a layered and zoned distribution network, so as to solve the problems of rough calculation of the photovoltaic carrying capacity of the distribution network, poor accuracy and practicality, and to guide the distribution network planners and operators to scientifically plan and construct distributed photovoltaics in their jurisdiction.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] The evaluation method of photovoltaic access status and carrying capacity of hierarchical and zoned distribution network includes the following steps:

[0007] The distribution network is divided into power supply area, feeder power supply area and substation power supply area according to the level of power supply area;

[0008] Obtain the regional photovoltaic capacity penetration rate, regional photovoltaic energy penetration rate, regional photovoltaic power upload rate, regional photovoltaic power local consumption rate, and power supply area abandonment rate indicators of the power supply area respectively, and conduct a multi-dimensional photovoltaic access power generation status assessment of the power supply area based on the above indicators;

[0009] After obtaining the current status of photovoltaic access power generation in the power supply area, obtaining the photovoltaic absorption capacity index and photovoltaic acceptance capacity index of the power supply area, and evaluating the photovoltaic carrying potential of the power supply area according to the photovoltaic absorption capacity index and photovoltaic acceptance capacity index;

[0010] Based on the photovoltaic power generation status and photovoltaic carrying potential of the power supply area, the photovoltaic access planning and design of the power supply area is implemented.

[0011] Furthermore, the photovoltaic absorption capacity indicators of the power supply area include the regional source-load power supply-demand ratio, regional photovoltaic absorption capacity, regional photovoltaic absorption capacity margin, and regional photovoltaic increased absorption capacity ratio; the photovoltaic acceptance capacity indicators of the power supply area include regional photovoltaic acceptance capacity, regional photovoltaic acceptance margin, and regional photovoltaic increased absorption capacity ratio.

[0012] Furthermore, the regional photovoltaic capacity penetration rate is the ratio of the regional photovoltaic installed capacity to the regional maximum load, which is used to characterize the development trend of the regional photovoltaic installed capacity;

[0013] The regional photovoltaic energy penetration rate is the ratio of the regional annual photovoltaic power generation to the regional annual load power, which can be used to characterize the development trend of regional photovoltaic power generation;

[0014] The regional photovoltaic power upload rate is the proportion of photovoltaic power transmitted to the high voltage level through the transformer to the total power generation;

[0015] The local consumption rate of regional photovoltaic power is the proportion of the photovoltaic power generation that can be consumed locally in the power supply area to the total power generation;

[0016] The abandonment rate of photovoltaic power in the power supply area is the ratio of the abandoned photovoltaic power to the sum of the total photovoltaic power generation and the abandoned photovoltaic power.

[0017] Furthermore, the regional source-load power supply-demand ratio is the ratio of the photovoltaic power generated in the power supply area per unit time to the regional load power consumption, which can reflect the degree of absorption of the photovoltaic power generated by the regional load per unit time;

[0018] The regional photovoltaic absorption capacity is the ratio of the current regional photovoltaic access capacity to the maximum regional source-load power supply-demand ratio within a certain time span;

[0019] The regional photovoltaic absorptive capacity margin is the difference between the regional photovoltaic absorptive capacity and the current regional photovoltaic access capacity, which can reflect the potential for improving the regional photovoltaic absorptive capacity;

[0020] The ratio of the regional photovoltaic incremental capacity is the proportion of the regional photovoltaic capacity margin to the current regional photovoltaic access capacity.

[0021] Furthermore, the regional photovoltaic acceptance capacity is the sum of the maximum photovoltaic capacity that can be absorbed by the photovoltaic power supply area and the maximum external power transmission of the power supply area; wherein the photovoltaic external power transmission power of different power supply areas is determined by different equipment;

[0022] The regional photovoltaic acceptance margin is the difference between the regional photovoltaic acceptance capacity of the power supply area and the current regional photovoltaic access capacity; it can reflect the potential for improvement of the photovoltaic acceptance capacity of the power supply area;

[0023] The ratio of the regional photovoltaic capacity that can be increased is the proportion of the regional photovoltaic acceptance margin in the power supply area to the current regional photovoltaic access capacity.

[0024] The advantages and positive effects of the present invention are:

[0025] The layered and zoned assessment method for the dual carrying capacity of photovoltaic absorption and acceptance in distribution networks for substations, feeders and substations of the present invention can better obtain the actual photovoltaic absorption level of the distribution network, and then guide the construction of distributed photovoltaic and energy storage in my country's distribution network, playing an important role in promoting the large-scale development of photovoltaics and achieving the national dual carbon goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0027] Figure 1 A schematic diagram of a process for evaluating the photovoltaic access status and carrying capacity of a hierarchical and partitioned distribution network provided by an embodiment of the present invention; DETAILED DESCRIPTION

[0028] First of all, it should be noted that the specific structure, features and advantages of the present invention will be specifically described below by way of example, but all descriptions are only for illustration and should not be understood as limiting the present invention in any way. In addition, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the drawings, can still be combined or deleted between these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned herein.

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0030] like Figure 1The method for evaluating the photovoltaic access status and carrying capacity of the hierarchical and partitioned distribution network provided in this embodiment includes the following steps:

[0031] The distribution network is divided into power supply area, feeder power supply area and substation power supply area according to the level of power supply area;

[0032] Obtain the regional photovoltaic capacity penetration rate, regional photovoltaic energy penetration rate, regional photovoltaic power upload rate, regional photovoltaic power local consumption rate, and power supply area abandonment rate indicators of the power supply area respectively, and conduct a multi-dimensional photovoltaic access power generation status assessment of the power supply area based on the above indicators;

[0033] After obtaining the current status of photovoltaic access power generation in the power supply area, obtaining the photovoltaic absorption capacity index and photovoltaic acceptance capacity index of the power supply area, and evaluating the photovoltaic carrying potential of the power supply area according to the photovoltaic absorption capacity index and photovoltaic acceptance capacity index;

[0034] Based on the photovoltaic power generation status and photovoltaic carrying potential of the power supply area, the photovoltaic access planning and design of the power supply area is implemented.

[0035] Specifically, the regional photovoltaic capacity penetration rate is the ratio of the regional photovoltaic installed capacity to the regional maximum load, which is used to characterize the development trend of the regional photovoltaic installed capacity. Different photovoltaic penetration rates can be obtained by considering different time spans, such as the daily photovoltaic capacity penetration rate. Monthly photovoltaic capacity penetration rate Quarterly PV Capacity Penetration Rate Annual photovoltaic capacity penetration rate Etc., can be expressed as:

[0036]

[0037]

[0038]

[0039]

[0040] Among them, φ represents the power supply area such as the power supply station area, feeder power supply area and substation power supply area. They represent the maximum load power demand on the Dth day, the Mth month, the Qth quarter, and the Yth year, respectively. is the photovoltaic installed capacity of region φ;

[0041] The regional photovoltaic energy penetration rate is the ratio of the regional annual photovoltaic power generation to the regional annual load power, which can be used to characterize the development trend of regional photovoltaic power generation. Different photovoltaic energy penetration rates can be obtained by considering different time spans, such as the daily photovoltaic energy penetration rate. Monthly photovoltaic energy penetration rate Quarterly PV energy penetration Annual photovoltaic energy penetration rate Etc., can be expressed as:

[0042]

[0043]

[0044]

[0045]

[0046] in, and are the photovoltaic output and regional load demand of the power supply area at time t on day D, D M , D Q , D Y They represent the total number of days in the Mth month, Qth quarter, and Yth year respectively.

[0047] The regional photovoltaic power upload rate is the proportion of photovoltaic power transmitted to the high voltage level through the transformer to the total power generation; considering different time spans, different photovoltaic power upload rates can be obtained, such as the daily photovoltaic power upload rate Monthly photovoltaic power upload rate Quarterly photovoltaic power upload rate Annual photovoltaic power upload rate Can be expressed as:

[0048]

[0049]

[0050]

[0051]

[0052] Among them, S T ,S L are the actual operating limits of transformer and line respectively, is the photovoltaic upload coefficient, if or but otherwise,

[0053] The local consumption rate of regional photovoltaic power is the proportion of photovoltaic power generation that can be consumed locally in the power supply area to the total power generation. Different local consumption rates can be obtained by considering different time spans, such as the local consumption rate of photovoltaic power in the power supply area on a daily basis. Monthly photovoltaic power local consumption rate Quarterly photovoltaic power local consumption rate Annual photovoltaic power local consumption rate Can be expressed as:

[0054]

[0055]

[0056]

[0057]

[0058] in, The maximum charging power configured for regional energy storage, and is a Boolean variable used to represent and The size relationship between when hour, on the contrary,

[0059] The abandonment rate of the power supply area is the ratio of the abandoned photovoltaic power to the sum of the total photovoltaic power generation and the abandoned photovoltaic power. Different abandonment rates can be obtained by considering different time spans, such as the daily abandonment rate Monthly abandonment rate Quarterly abandonment rate Annual abandoned light rate Can be expressed as:

[0060]

[0061]

[0062]

[0063]

[0064] in, They represent the amount of abandoned photovoltaic power in region φ on the Dth day, the Mth month, the Qth quarter, and the Yth year, respectively. They represent the photovoltaic power generation of region φ on the Dth day, the Mth month, the Qth quarter, and the Yth year, respectively.

[0065] After constructing the above-mentioned evaluation indicators, and knowing the typical annual load data and photovoltaic power generation data of different power supply areas, the current status of photovoltaic power generation in different power supply areas can be evaluated separately; among which, the annual abandonment rate of power supply areas shall not be greater than 5% according to national standards.

[0066] On the basis of the evaluation of the current status of photovoltaic power generation, the photovoltaic carrying potential of each power supply area of ​​the distribution network can be evaluated from the two aspects of photovoltaic absorption capacity and photovoltaic acceptance capacity. Specifically, photovoltaic absorption capacity refers to the ability of the power supply area (substation, substation, substation) to consume and use the electricity generated by photovoltaics locally, reflecting the balance of power supply and demand in the power supply area considering the temporal and spatial matching of local source-load power. The photovoltaic absorption capacity indicators of the power supply area include the regional source-load power supply and demand ratio, the regional photovoltaic absorption capacity, the regional photovoltaic absorption capacity margin, and the regional photovoltaic increased absorption capacity ratio.

[0067] The regional source-load power supply-demand ratio is the ratio of photovoltaic power generation to regional load power consumption per unit time in the power supply area, which can reflect the degree of absorption of photovoltaic power generation by regional load per unit time; it can be expressed as:

[0068]

[0069] Among them, φ represents the power supply area such as the power supply station area, feeder power supply area and substation power supply area. and They are the photovoltaic power output and regional load time variables at time t respectively;

[0070] If within a period of time, This means that under the premise that the peak-shaving capacity of the large power grid meets the requirements, the instantaneous power generated by distributed photovoltaics can be absorbed within the access area and the required voltage level range, and the system still has room to connect more photovoltaics; if This means that the load in the power supply area connected to the photovoltaic power plant is unable to absorb the instantaneous power generated by the photovoltaic power plant, resulting in power oversupply.

[0071] The regional photovoltaic absorption capacity is the ratio of the current regional photovoltaic access capacity to the maximum regional source-load power supply-demand ratio within a certain time span; it can be expressed as:

[0072]

[0073] This is because the moment when the power supply area has the largest source-load supply-demand ratio is the most severe moment for the local photovoltaic consumption in the area. If the photovoltaic output at this time is equal to the load power demand, it can be guaranteed that the photovoltaic output at all other times of the year is less than the load demand, that is, the photovoltaic is fully consumed. Therefore, the existing photovoltaic capacity in the region is expanded. times, which can ensure that photovoltaic power reaches the optimal full absorption capacity.

[0074] The regional photovoltaic absorptive capacity margin is the difference between the regional photovoltaic absorptive capacity and the current regional photovoltaic access capacity, which can reflect the potential for improving the regional photovoltaic absorptive capacity and can be expressed as:

[0075]

[0076] The ratio of the regional photovoltaic capacity that can be increased and absorbed is the ratio of the regional photovoltaic capacity margin to the current regional photovoltaic access capacity, which can be expressed as:

[0077]

[0078] After obtaining the ratio of regional photovoltaic capacity that can be increased and absorbed, the lower limit of the photovoltaic access capacity range in the region can be determined.

[0079] The photovoltaic acceptance capacity of the power supply area refers to the maximum photovoltaic capacity allowed to be connected in the power supply area (substation, feeder or substation) under the premise of meeting various safety operation constraints. It is mainly restricted by the load level of the region, the power transmission capacity limit of the equipment, the power reception bottleneck of the upper area, etc.; the photovoltaic acceptance capacity indicators of the power supply area include regional photovoltaic acceptance capacity, regional photovoltaic acceptance margin, and regional photovoltaic increaseable acceptance capacity ratio.

[0080] Furthermore, the regional photovoltaic acceptance capacity is the sum of the maximum photovoltaic capacity that can be absorbed by the power supply area photovoltaic and the maximum external power transmission of the power supply area; wherein the photovoltaic external power transmission power of different power supply areas is determined by different equipment; wherein:

[0081] The photovoltaic transmission power in the substation power supply area is mainly determined by the transformer capacity; the photovoltaic transmission power in the feeder power supply area is mainly determined by the capacity of the line where the root node is located; the photovoltaic transmission power in the substation power supply area is mainly determined by the distribution transformer capacity.

[0082] Therefore, the photovoltaic acceptance capacity of the substation power supply area, feeder power supply area and station power supply area can be expressed as:

[0083]

[0084] The regional photovoltaic acceptance margin is the difference between the regional photovoltaic acceptance capacity of the power supply area and the current regional photovoltaic access capacity; it can reflect the potential for improving the photovoltaic acceptance capacity of the power supply area; it can be expressed as:

[0085]

[0086] The ratio of the regional photovoltaic capacity that can be increased is the ratio of the regional photovoltaic capacity margin in the power supply area to the current regional photovoltaic access capacity, which can be expressed as:

[0087]

[0088] The regional photovoltaic acceptance margin of the power supply area (station area, feeder or substation) is obtained separately and the ratio of regional photovoltaic capacity that can be increased After that, the lower and upper limits of the photovoltaic carrying potential of the power supply area can be obtained, thereby guiding the photovoltaic access planning in different power supply areas.

[0089] The above embodiments describe the present invention in detail, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. The current status and carrying capacity assessment method of photovoltaic access to the hierarchical and partitioned distribution network is characterized by: The steps include: The distribution network is divided into power supply area, feeder power supply area and substation power supply area according to the level of power supply area; Obtain the regional photovoltaic capacity penetration rate, regional photovoltaic energy penetration rate, regional photovoltaic power upload rate, regional photovoltaic power local consumption rate, and power supply area abandonment rate indicators of the power supply area respectively, and conduct a multi-dimensional photovoltaic access power generation status assessment of the power supply area based on the above indicators; After obtaining the current status of photovoltaic access power generation in the power supply area, obtaining the photovoltaic absorption capacity index and photovoltaic acceptance capacity index of the power supply area, and evaluating the photovoltaic carrying potential of the power supply area according to the photovoltaic absorption capacity index and photovoltaic acceptance capacity index; According to the photovoltaic access power generation status and photovoltaic load potential of the power supply area, realize the photovoltaic access planning and design of the power supply area; The photovoltaic absorption capacity indicators of the power supply area include the regional source-load power supply-demand ratio, the regional photovoltaic absorption capacity, the regional photovoltaic absorption capacity margin, and the regional photovoltaic increased absorption capacity ratio; the photovoltaic acceptance capacity indicators of the power supply area include the regional photovoltaic acceptance capacity, the regional photovoltaic acceptance margin, and the regional photovoltaic increased acceptance capacity ratio.

2. The method for evaluating the photovoltaic access status and carrying capacity of the hierarchical and zoned distribution network according to claim 1 is characterized by: The regional photovoltaic capacity penetration rate is the ratio of the regional photovoltaic installed capacity to the regional maximum load, which is used to characterize the development trend of the regional photovoltaic installed capacity; The regional photovoltaic energy penetration rate is the ratio of the regional annual photovoltaic power generation to the regional annual load power, which can be used to characterize the development trend of regional photovoltaic power generation; The regional photovoltaic power upload rate is the proportion of photovoltaic power transmitted to the high voltage level through the transformer to the total power generation; The local consumption rate of regional photovoltaic power is the proportion of the photovoltaic power generation that can be consumed locally in the power supply area to the total power generation; The abandonment rate of photovoltaic power in the power supply area is the ratio of the abandoned photovoltaic power to the sum of the total photovoltaic power generation and the abandoned photovoltaic power.

3. The method for evaluating the photovoltaic access status and carrying capacity of the hierarchical and zoned distribution network according to claim 1 is characterized by: The regional source-load power supply-demand ratio is the ratio of photovoltaic power generation to regional load power consumption per unit time in the power supply area, which can reflect the degree of absorption of photovoltaic power generation by regional load per unit time. The regional photovoltaic absorption capacity is the ratio of the current regional photovoltaic access capacity to the maximum regional source-load power supply-demand ratio within a certain time span; The regional photovoltaic absorptive capacity margin is the difference between the regional photovoltaic absorptive capacity and the current regional photovoltaic access capacity, which can reflect the potential for improving the regional photovoltaic absorptive capacity; The ratio of the regional photovoltaic incremental capacity is the proportion of the regional photovoltaic capacity margin to the current regional photovoltaic access capacity.

4. The method for evaluating the photovoltaic access status and carrying capacity of the hierarchical and zoned distribution network according to claim 1 is characterized by: The regional photovoltaic acceptance capacity is the sum of the maximum photovoltaic capacity that can be absorbed by the photovoltaic power supply area and the maximum external power transmission of the power supply area; wherein the photovoltaic external power transmission power of different power supply areas is determined by different equipment; The regional photovoltaic acceptance margin is the difference between the regional photovoltaic acceptance capacity of the power supply area and the current regional photovoltaic access capacity; it can reflect the potential for improvement of the photovoltaic acceptance capacity of the power supply area; The ratio of the regional photovoltaic capacity that can be increased is the proportion of the regional photovoltaic acceptance margin in the power supply area to the current regional photovoltaic access capacity.

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