Method for determining power supply capacity of multi-voltage-class power grid

Abstract

The invention provides a method for determining the power supply capacity of a multi-voltage-class power grid. The method comprises the following steps: S1, determining a power grid topological structure; S2, determining the power supply capacity of a low-voltage power distribution network; s3, determining the medium-voltage power distribution network capability based on the low-voltage power distribution network power supply capability; and S4, the power supply capability of the regional substations and the power supply capability of the high-voltage power distribution network are considered, and the relative independence of the power supply capability of each subarea and the mutual constraint and mutual support of the power supply capabilities of the power distribution networks with different voltage classes are considered, so that the power supply capability of the power distribution network with multiple voltage classes can be accurately evaluated. And the whole algorithm is simple in process and high in efficiency, and provides accurate data support for subsequent power grid planning and scheduling.

Description

Technical Field

[0001] The present invention relates to a power grid analysis method, and in particular to a method for determining the power supply capacity of a multi-voltage level power grid. Background Art

[0002] Power supply capacity is an important indicator to measure whether the distribution network can meet future load demand, and plays an important guiding role in network structure optimization and distribution network planning and operation. At the same time, power supply capacity is also the basic data for electricity allocation in the economic evaluation of distribution network projects.

[0003] At present, the calculation of the power supply capacity of the distribution network usually transforms the problem into linear or nonlinear programming, and often uses complex algorithms such as genetic algorithms to solve it, which makes the calculation difficult and time-consuming, and is not conducive to practical application. In addition, most existing methods are based on grid structure and equipment capacity limitations to obtain an ideal load distribution to obtain the maximum power supply capacity of the system, but this load distribution is difficult to achieve in the actual distribution network, so it is not suitable for distribution network planning.

[0004] Therefore, in order to solve the above technical problems, it is urgent to propose a new technical means. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for determining the power supply capacity of a multi-voltage level power grid, which takes into account the relative independence of the power supply capacity of each partition and the mutual constraints and mutual support of the power supply capacities between distribution networks of different voltage levels, so as to accurately evaluate the power supply capacity of the multi-voltage level distribution network, and the whole algorithm process is simple and efficient, providing accurate data support for subsequent power grid planning and scheduling.

[0006] The present invention provides a method for determining the power supply capacity of a multi-voltage power grid, comprising the following steps:

[0007] S1. Determine the grid topology, which includes a power plant side, a regional substation, and a low-voltage user side. The high-voltage electricity generated by the power plant side is input to the regional substation for processing. The regional substation steps down the high-voltage electricity and then inputs it to the low-voltage user side for processing before providing it to the user.

[0008] S2. Determine the power supply capacity of the low voltage distribution network;

[0009] S3. Determine the capacity of the medium voltage distribution network based on the power supply capacity of the low voltage distribution network;

[0010] S4. The power supply capacity of regional substations and high-voltage distribution network.

[0011] Furthermore, the power supply capacity of the low voltage distribution network is determined by the following method:

[0012]

[0013] Where: C TQ,i It represents the power supply capacity of the distribution station area i of the low-voltage distribution network, S DT Indicates the capacity of the distribution transformer of the low-voltage distribution network, Expressed as the continuous limit transmission capacity of the lth low-voltage line, L LV,i Represents the low-voltage outgoing line number set of the low-voltage distribution network, N TQ Represents a set of area numbers.

[0014] Furthermore, the power supply capacity of the medium voltage distribution network is determined by the following method:

[0015]

[0016] in: is the power supply capacity of the low voltage distribution network supplied by the medium voltage typical connection i, The power supply capacity of the medium voltage distribution network, A collection of numbers for typical medium voltage connections. Indicates the maximum transmission capacity of the medium voltage line l.

[0017] Furthermore, the maximum transmission capacity of the medium voltage line 1 is Determined by:

[0018]

[0019]

[0020] in: is the continuous limit transmission capacity of the medium voltage line l, is the maximum load rate; It represents the maximum load rate of medium voltage line l without considering the low voltage power supply capacity constraint; It is the set of medium voltage line numbers in the medium voltage typical wiring i; and They are respectively the power supply capacity of the medium voltage connection i before and after considering the power supply capacity constraint of the low voltage distribution network.

[0021] Furthermore, the power supply capacity of the regional substation is determined by the following method:

[0022] Determine the main transformer in the area and construct the main transformer connection relationship matrix L link :

[0023]

[0024] L i,j is the connection relationship between the i-th main transformer and the j-th main transformer (i=1,2,3,…,NΣ ,j=1,2,3,…,N Σ ), if there is a contact relationship, use L i,j =1, otherwise L i,j =0; main transformer connection matrix L link The i-th row or i-th column in the system represents a group of main transformers that have a communication relationship with the i-th main transformer in the system, which is defined as a main transformer communication unit with the i-th main transformer as the center;

[0025] Determine the maximum load rate matrix T of the main transformer contact unit:

[0026]

[0027] The element T in the matrix T i,j for:

[0028]

[0029] Determine the minimum value T in the matrix T i(N-1) :

[0030]

[0031] Determine the power supply capacity of the i-th main transformer:

[0032] S i(N-1) =T i(N-1) R i ;

[0033] The power supply capacity of the regional substation is:

[0034] C Sub,i is the power supply capacity of substation i; Ω T,i is the set of main transformer numbers in substation i.

[0035] Furthermore, the power supply capacity of the high-voltage distribution network is:

[0036] is the number of typical high-voltage connections in the power grid;

[0037] When the high-voltage distribution network is a single substation single radial connection:

[0038]

[0039] When the high voltage distribution network is a single substation with double radial wiring

[0040] J i The substation number of the typical single-station dual-radiation connection i, For substation J i Power supply capacity; and They are respectively the continuous limit transmission capacity of the two radial lines in the single-station dual-radial structure i.

[0041] The beneficial effects of the present invention are as follows: through the present invention, the relative independence of the power supply capacity of each partition and the mutual constraints and mutual support of the power supply capacities between distribution networks of different voltage levels are taken into account, so that the power supply capacity of the multi-voltage level distribution network can be accurately evaluated, and the whole algorithm process is simple and efficient, providing accurate data support for subsequent power grid planning and scheduling. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0043] Figure 1 It is a flow chart of the present invention.

[0044] Figure 2 It is a schematic diagram of the topological structure of the distribution network of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described below:

[0046] The present invention provides a method for determining the power supply capacity of a multi-voltage power grid, comprising the following steps:

[0047] S1. Determine the grid topology, which includes the power plant side, the regional substation and the low-voltage user side. The high-voltage electricity generated by the power plant side is input to the regional substation for processing. The regional substation steps down the high-voltage electricity and then inputs it to the low-voltage user side for processing before providing it to the user. The specific topology is as follows: Figure 2 As shown;

[0048] S2. Determine the power supply capacity of the low-voltage distribution network;

[0049] S3. Determine the capacity of the medium voltage distribution network based on the power supply capacity of the low voltage distribution network;

[0050] S4. The power supply capacity of the regional substation and the power supply capacity of the high-voltage distribution network. Through the above method, the relative independence of the power supply capacity of each partition and the mutual constraints and mutual support of the power supply capacities between distribution networks of different voltage levels are taken into account, so that the power supply capacity of the multi-voltage level distribution network can be accurately evaluated. Moreover, the entire algorithm process is simple and efficient, providing accurate data support for subsequent power grid planning and scheduling.

[0051] In this embodiment, the power supply capacity of the low-voltage distribution network is determined by the following method:

[0052]

[0053] Where: CTQ,i It represents the power supply capacity of the distribution station area i of the low-voltage distribution network, S DT Indicates the capacity of the distribution transformer of the low-voltage distribution network, Expressed as the continuous limit transmission capacity of the lth low-voltage line, L LV,i Represents the low-voltage outgoing line number set of the low-voltage distribution network, N TQ Represents a set of area numbers.

[0054] In this embodiment, for the medium voltage distribution network, the medium voltage wiring group is defined as a medium voltage local interconnection network, in which each feeder supports each other through a tie switch (such as each typical wiring mode), and the power supply capacity of the medium voltage distribution network is determined by the following method:

[0055]

[0056] in: is the power supply capacity of the low voltage distribution network supplied by the medium voltage typical connection i, The power supply capacity of the medium voltage distribution network, A collection of numbers for typical medium voltage connections. Indicates the maximum transmission capacity of the medium voltage line l.

[0057] Where: the maximum transmission capacity of the medium voltage line l Determined by:

[0058]

[0059] in: is the continuous limit transmission capacity of the medium voltage line l, is the maximum load rate; It represents the maximum load rate of medium voltage line l without considering the low voltage power supply capacity constraint; It is the set of medium voltage line numbers in the medium voltage typical wiring i; and They are respectively the power supply capacity of the medium voltage connection i before and after considering the power supply capacity constraint of the low voltage distribution network.

[0060] In this embodiment, the power supply capacity of the regional substation is determined by the following method:

[0061] The power supply capacity of a substation refers to the maximum power supply capacity of a substation under the condition of N-1, which can meet the power demand of users. When the incoming line capacity meets the main transformer capacity, the main analysis can be made on the maximum power supply capacity of the substation under the condition of N-1. In the "N-1" case, if the load of a main transformer can be transferred to another main transformer through the contact switch, it can be said that there is a contact relationship between the two main transformers; therefore,

[0062] Assume that there are n substations in the study area, which can be numbered 1, 2, ..., n, and the number of main transformers in each substation is N1, N2, ..., N respectively. n The number of the jth main transformer of the i-th station is and will Marked as N iΣ , take N Σ =N1+N2+…+N n , indicating the total number of main transformers in the area. i Represents the capacity of the i-th main transformer; determines the main transformer in the area and constructs the main transformer connection relationship matrix L link :

[0063]

[0064] L i,j is the connection relationship between the i-th main transformer and the j-th main transformer (i=1,2,3,…,N Σ ,j=1,2,3,…,N Σ ), if there is a contact relationship, use L i,j =1, otherwise L i,j =0; main transformer connection matrix L link The i-th row or i-th column in the system represents a group of main transformers that have a communication relationship with the i-th main transformer in the system, which is defined as a main transformer communication unit with the i-th main transformer as the center;

[0065] Determine the maximum load rate matrix T of the main transformer contact unit:

[0066]

[0067] The element T in the matrix T i,j for:

[0068] Where, k is the overload factor;

[0069] Determine the minimum value T in the matrix T i(N-1) :

[0070]

[0071] Determine the power supply capacity of the i-th main transformer:

[0072] S i(N-1) =T i(N-1) R i ;

[0073] The power supply capacity of the regional substation is:

[0074] C Sub,i is the power supply capacity of substation i; Ω T,iis the set of main transformer numbers in substation i.

[0075] In this embodiment, the power supply capacity of the high-voltage distribution network is:

[0076] is the number of typical high-voltage connections in the power grid;

[0077] When the high-voltage distribution network is a single substation single radial connection:

[0078]

[0079] When the high voltage distribution network is a single substation with double radial wiring

[0080] J i The substation number of the typical single-station dual-radiation connection i, For substation J i Power supply capacity; and They are respectively the continuous limit transmission capacity of the two radial lines in the single-station dual-radial structure i.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for determining the power supply capacity of a multi-voltage power grid, characterized in that: The following steps are involved: S1. Determine the grid topology, which includes a power plant side, a regional substation, and a low-voltage user side. The high-voltage electricity generated by the power plant side is input to the regional substation for processing. The regional substation steps down the high-voltage electricity and then inputs it to the low-voltage user side for processing before providing it to the user. S2. Determine the power supply capacity of the low-voltage distribution network; S3. Determine the capacity of the medium voltage distribution network based on the power supply capacity of the low voltage distribution network; S4. The power supply capacity of regional substations and high-voltage distribution network.

2. The method for determining the power supply capacity of a multi-voltage power grid according to claim 1, characterized in that: The power supply capacity of the low-voltage distribution network is determined by the following method: Where: C TQ,i It represents the power supply capacity of the distribution station area i of the low-voltage distribution network, S DT Indicates the capacity of the distribution transformer of the low-voltage distribution network, Expressed as the continuous limit transmission capacity of the lth low-voltage line, L LV,i Represents the low-voltage outgoing line number set of the low-voltage distribution network, N TQ Represents a set of area numbers.

3. The method for determining the power supply capacity of a multi-voltage power grid according to claim 2, characterized in that: The power supply capacity of the medium voltage distribution network is determined by the following method: in: is the power supply capacity of the low voltage distribution network supplied by the medium voltage typical connection i, The power supply capacity of the medium voltage distribution network, A collection of numbers for typical medium voltage connections. Indicates the maximum transmission capacity of the medium voltage line l.

4. The method for determining the power supply capacity of a multi-voltage power grid according to claim 3, characterized in that: The maximum transmission capacity of the medium voltage line 1 Determined by: in: is the continuous limit transmission capacity of the medium voltage line l, is the maximum load rate; It represents the maximum load rate of medium voltage line l without considering the low voltage power supply capacity constraint; It is the set of medium voltage line numbers in the medium voltage typical wiring i; and They are respectively the power supply capacity of the medium voltage connection i before and after considering the power supply capacity constraint of the low voltage distribution network.

5. The method for determining the power supply capacity of a multi-voltage power grid according to claim 1, characterized in that: The power supply capacity of the regional substation is determined by the following method: Determine the main transformer in the area and construct the main transformer connection relationship matrix L link : L i,j is the connection relationship between the i-th main transformer and the j-th main transformer (i=1,2,3,…,N Σ ,j=1,2,3,…,N Σ ), if there is a contact relationship, use L i,j =1, otherwise L i,j =0; main transformer connection matrix L link The i-th row or i-th column in the system represents a group of main transformers that have a communication relationship with the i-th main transformer in the system, which is defined as a main transformer communication unit with the i-th main transformer as the center; Determine the maximum load rate matrix T of the main transformer contact unit: The element T in the matrix T i,j for: Determine the minimum value T in the matrix T i(N-1) : Determine the power supply capacity of the i-th main transformer: S i(N-1) =T i(N-1) R i ; The power supply capacity of the regional substation is: C Sub,i is the power supply capacity of substation i; Ω T,i is the set of main transformer numbers in substation i.

6. The method for determining the power supply capacity of a multi-voltage power grid according to claim 1, characterized in that: The power supply capacity of the high-voltage distribution network is: is the number of typical high-voltage connections in the power grid; When the high-voltage distribution network is a single substation single radial connection: When the high voltage distribution network is a single substation with double radial wiring J i The substation number of the typical single-station dual-radiation connection i, For substation J i Power supply capacity; and They are respectively the continuous limit transmission capacity of the two radial lines in the single-station dual-radial structure i.

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