A method and calculation device for blocking surplus sharing considering circulation effect

Abstract

The present invention provides a congestion surplus sharing method and a calculation device considering the loop flow effect. The congestion surplus sharing method considering the loop flow effect is applied to a multi-region power system, and specifically includes the following steps: S1, establish and solve an economic dispatch model of the multi-region power system; S2, distribute and recover the node marginal price; S3, quantify the impacts of intra-region transactions and inter-region transactions on line congestion; S4, share the congestion surplus among multiple regions. Based on the clearing result of cross-region power transactions obtained by using the generalized coordinated transaction scheduling, the present invention proposes a distributed method to recover the global node price, quantifies and prices the impacts caused by the loop flow, and each region shares the congestion surplus according to its contribution to line congestion, improving the cross-region transaction mechanism, properly considering the impact of the loop flow effect, protecting the data privacy of each region, and having important engineering application value in the multi-region power market.

Description

Technical Field

[0001] The present invention relates to the field of multi - regional electricity market transactions, and particularly to a congestion surplus sharing method and a calculation device considering the loop flow effect. Background Art

[0002] Under the goal of "carbon peak and carbon neutrality", a new power system mainly based on new energy will be constructed. In China, considering the reverse distribution of new energy power generation and load centers and the needs of each region to cope with extreme weather changes, it is more important to develop and improve the cross - regional power trading mechanism and realize the interconnection and mutual assistance of different power systems. In the United States and Europe, regional electricity markets have been widely studied and have been operating for decades, and the Location Marginal Price (LMP) mechanism has been widely applied. Each regional Independent System Operator (ISO) settles with power generators and users within the region through LMP, and the remaining amount is used for auctions of financial transmission rights, etc. In a multi - regional power system, how to share the congestion surplus generated by inter - regional tie - lines among multi - regional ISOs is an unsolved problem because not only will inter - regional power transactions pass through tie - lines, but internal transactions in each region will also affect line congestion, which is also called the loop flow effect. In engineering, the New York ISO (NYISO) and the ISO New England (ISO - NE) evenly divide the congestion surplus of inter - regional tie - lines, which may not be the best solution under various operating conditions. Therefore, it is necessary to study decomposing the power flow of congested lines into the contributions of different types of transactions and appropriately pricing each part of the loop flow contribution, so as to scientifically and reasonably allocate the congestion surplus among regions.

[0003] Currently, in the United States and Europe, the loop flow effect has caused economic losses in cross - regional transaction clearing and settlement. The Southern Power Pool (SPP) company in the United States and the European Commission have tried to solve this problem by installing phase shifters, further dividing pricing regions, optimizing network topologies, etc., but the effects are not ideal and are accompanied by high economic costs.

[0004] In terms of the market clearing model, the solution to the joint economic dispatch problem of the multi - regional electricity market usually adopts distributed algorithms. Currently, there are algorithms based on Lagrangian relaxation, fully distributed algorithms based on consensus, edge equivalent decomposition algorithms, and critical region projection methods. Traditional distributed algorithms may encounter problems of slow convergence and calculation speed, thus limiting their application in engineering.

[0005] In the aspect of the new market mechanism for cross - regional power trading, the New York Independent System Operator (NYISO) and ISO - New England (ISO - NE) in the United States have adopted the methods of tie optimization (TO) and coordinated transaction scheduling (CTS). However, they rely on the selection of proxy nodes, which will cause significant errors. The subsequently proposed generalized CTS (GCTS) model solves the deviation problem of proxy nodes. But in all studies, how to jointly allocate the congestion surplus of multi - regional power systems remains an unsolved problem. Summary of the Invention

[0006] To solve the technical problem of how to jointly allocate the congestion surplus of multi - regional power systems in the prior art, the present invention proposes a congestion surplus allocation method and a calculation device considering the loop - current effect.

[0007] Therefore, the congestion surplus allocation method considering the loop - current effect proposed by the present invention is applied to a multi - regional power system, and specifically includes the following steps:

[0008] S1. Establish and solve an economic dispatch model for the multi - regional power system;

[0009] S2. Distributively recover the nodal marginal price;

[0010] S3. Quantify the impact of intra - regional transactions and inter - regional transactions on line congestion;

[0011] S4. Allocate the congestion surplus among multiple regions.

[0012] Further, the step S1 specifically includes:

[0013] S11. Establish a network structure;

[0014] S12. Establish an economic dispatch model for the multi - regional power system;

[0015] S13. Solve the clearing price of cross - regional transactions.

[0016] Further, the multi - regional power system includes multiple transmission grids, inter - regional tie lines, intra - regional lines, internal transactions within each region, and cross - regional transactions.

[0017] Further, the step S2 specifically includes:

[0018] S21. Distributively solve the power transfer distribution factor;

[0019] S22. Solve the global nodal marginal price.

[0020] Further, in step S21, the power transfer distribution factors for lines and nodes in multiple regions are divided into two categories: intra-region factors and inter-region factors. The intra-region factors refer to cases where the line and the node are in the same region, and the inter-region factors refer to cases where the line and the node are in different regions.

[0021] Further, in step S21, the independent system operator of each region directly calculates the intra-region factors according to the DC optimal power flow model and the equivalent network of other regions.

[0022] Further, step S3 specifically includes:

[0023] S31. Calculate the impact of inter-region transactions on the power flow of internal transmission lines in each region;

[0024] S32. Calculate the impact of inter-region transactions on the tie-line power flow;

[0025] S33. Calculate the impact of intra-region transactions on the power flow of internal lines in this region;

[0026] S34. The impact of intra-region transactions on the tie-line or the power flow of internal lines in other regions is all reflected through inter-region transactions and does not need to be calculated separately.

[0027] Further, in step S4, the congestion surplus borne by the region is the remaining funds after the independent system operator of the region settles with internal generators, internal loads, and inter-region bidders.

[0028] The present invention proposes a computing device applied to a multi-region power system, which specifically includes a memory and a central processing unit. A computer program is stored in the memory. By running the computer program, the central processing unit can implement the above congestion surplus sharing method considering the circulating current effect.

[0029] The present invention proposes a computer-readable storage medium storing a computer program that can be run by a central processing unit. During the process of being run by the central processing unit, the computer program can implement the congestion surplus sharing method considering the circulating current effect according to any one of claims 1-8.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] A distributed method is proposed to recover the global LMP, and the impact caused by the circulating current is quantified and priced. Each region shares the congestion surplus according to its contribution to line congestion, improving the inter-region trading mechanism, properly considering the impact of the circulating current effect, protecting the data privacy of each region, and having important engineering application value in the multi-region power market. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flowchart of the congestion surplus sharing method according to an embodiment of the present invention;

[0033] Figure 2 It is a schematic diagram of the network structure of the multi - area power system economic dispatch model according to an embodiment of the present invention;

[0034] Figure 3 It is a schematic diagram of the settlement process of the cross - regional transaction GCTS mechanism according to an embodiment of the present invention. Detailed implementation manners

[0035] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific implementation manners of the present invention will now be described with reference to the accompanying drawings.

[0036] As Figure 1 shown, an embodiment of the present invention proposes a congestion surplus sharing method considering the loop - flow effect, which is applied to a multi - area power system and specifically includes the following steps:

[0037] S1. Establish and solve the economic dispatch model of the multi - area power system. Taking the multi - area including three areas as an example for detailed description, it specifically includes the following steps:

[0038] S11. Establish the network structure. As Figure 2 shown, the solid arrows represent cross - regional transactions, and the dashed arrows represent intra - regional transactions. The multi - area power system includes multiple transmission grids. The inter - regional tie lines l i-j , l i-m and l j-m , the intra - regional lines l i , l m and l j , the internal transactions p i , p m and p j , as well as the cross - regional transactions s i-j , s i-m and s j-m . Adopt the GCTS mechanism and introduce inter - regional bidders between different regions. Its bidding format is:

[0039]

[0040] In the formula, <B pm , B qn > represents that the inter - regional bidder purchases electricity from node p in area m and sells it at node q in area n. The parameter Δπ b represents the expected price difference between nodes p and q by the inter - regional bidder, and the parameter represents the upper limit of the capacity reported by the inter - regional bidder.

[0041] S12. Establish an economic dispatch model for a multi - area power system, and the model is defined by the following formula:

[0042]

[0043] 1 T g = 1 T d

[0044]

[0045] In the model, the decision variables are the generator output g and the contract clearing volume s of the inter - area bidders. The vectors c i , d i , f i , g i , are the generator cost coefficient, load value, tie - line capacity upper limit, upper and lower limits of power generation output of area i respectively. The vector f t represents the capacity constraint of the tie - line, and the vector represents the capacity upper limit of the inter - area bidders. The vectors and B ii represent the mutual susceptance matrix and self - susceptance matrix respectively. The vector S i,i represents the power transfer distribution factor between the internal lines and internal nodes of area i. The vector S i,-Bi represents the power transfer distribution factor between the internal lines of area i and the boundary nodes of all areas except area i. The vector S t,i represents the power transfer distribution factor between the tie - line and the internal nodes of area i. The matrix M is the incidence matrix of the inter - area bids. If the inter - area bid buys at node i and sells at node j, then the i - th and j - th items in its incidence matrix column vector [..., i,..., j,...] T are 1 and - 1 respectively, and the others are 0. The dual multipliers λ, μ i , μ t , η i , γ , and ρ i .

[0046] S13. Solve the clearing price of cross - regional transactions. The generators and loads within area i will be settled according to the LMP of each node. According to the envelope theorem, the LMP of each node within area i is:

[0047]

[0048] Cross - regional transactions will be settled according to the marginal price of s based on the optimal cost of area i:

[0049]

[0050] In the formula, matrix A is the incidence matrix of the nodes and branches in region i, and vector is the susceptance matrix between the boundary nodes of region i and the boundary nodes of region j, is the self-susceptance matrix of the boundary nodes of region i after network equivalence. The definitions of other subscript vectors in the formula are the same.

[0051] S2. Distributed recovery of LMP, which specifically includes the following steps:

[0052] S21. Distributed solution of the power transfer distribution factor. Before recovering the global LMP, it is necessary to use a distributed method to solve the power transfer distribution factor matrix of the entire network. Generally, the common boundary node is selected as the reference node. The power transfer distribution factors of line l and node n in multiple regions can be divided into two categories: intra-region factors (transmission line l is an internal line or a tie line in region i, and node n is in region i) and inter-region factors (transmission line l is in region i, and node n is in region j). Each ISO can directly calculate the intra-region factors according to the direct current optimal power flow (DCOPF) model and the equivalent network of other regions. For the inter-region factors of branch l and node n, they will be calculated through the following steps:

[0053] S211. Calculate the intra-region power transfer distribution factor S between line l in region i and the boundary node set Bj of region j l,Bj ;

[0054] S212. Calculate the admittance coefficient matrix matrix W Bj establishes the relationship between the boundary equivalent injection power and the injection power of the internal nodes of the system;

[0055] S213. Calculate the inter-region power transfer distribution factor S through the following formula l,n

[0056] S l,n = S l,Bj ×W Bj,n

[0057] In the formula, vector W Bj,n is the column vector related to the boundary node set Bj and node n.

[0058] Through the above three steps, the value of the inter-region power transfer distribution factor can be calculated. Using network equivalence in the process can protect the data privacy of each region. The inter-region power transfer distribution factor does not need to be calculated and stored on a large scale in advance. When recovering the global LMP, it can be calculated as needed.

[0059] S22. Solve the global LMP, and separately solve the dual multiplier λ of the power balance equation, the dual multiplier μ of the line capacity constraint i , μ t , and the dual multiplier ρ of the boundary constraint equation i . Since the LMP at the node where the marginal unit is located is equal to the marginal cost of the unit, and the marginal price in the region where the inter-regional bidder is located is equal to the marginal bid of the inter-regional bidder, the following linear equations can be written

[0060]

[0061] where L is the Lagrangian function, and the subscript m represents the set of marginal units and inter-regional bidders. In the case of non-degenerate model solution, the number of independent equations in the above linear equations is equal to the number of variables to be solved, so that the unique solution of the linear equations can be obtained through the existing distributed solution methods. Based on the solved multipliers and power transfer distribution factors, each ISO can separately solve the LMP value within the region and the settlement price of the inter-regional bidder, so as to conduct settlements with generators, loads, and inter-regional bidders.

[0062] S3. Quantify the impact of intra-regional transactions and inter-regional transactions on line congestion, which specifically includes the following steps:

[0063] S31. Calculate the impact of inter-regional transactions on the power flow of the internal transmission lines in each region. For example, for the transaction s between region i and region j i-j the contribution ψ to the power flow of the internal lines in region i i，i-j is

[0064] ψ i,i-j =(S i,i -S i,j )×s i-j

[0065] where the elements in the matrix S i,j are obtained through the method of distributed power transfer distribution factors, and other similarly defined contributions ψ j，i-j , ψ m，i-j , ψ i，i-m , φ j，i-m , ψ m，i-m , ψ i，j-m , ψ j，j-m , ψ m，j-m can also be obtained through similar methods.

[0066] S32. Calculate the impact of inter-regional transactions on the tie-line power flow. For example, for the transaction s between region i and region j i-j the contribution ψ to the tie-line power flow between regions i and j i-j，i-j is

[0067] ψ i-j,i-j = (S i-j,i - S i-j,j ) × s i-j

[0068] Other contribution values φ of the same type j-m，i-j , ψ i-m，i-j , ψ i-j，i-m , ψ j-m，i-m , φ i-m，i-m , φ i-j，j-m , φ j-m，j-m , ψ i-m，j-m can also be calculated in the same way.

[0069] S33. Calculate the impact of intra-regional transactions on the power flow of internal lines in this region. For example, the contribution ψ of intra-regional transactions in region i to the power flow of internal lines in region i i，i is

[0070] ψ i,i = ψ i - ψ i,i-j - ψ i,j-m - ψ i,i-m

[0071] In the formula, the vector ψ i represents the branch power flow in region i, and other contribution values ψ of the same type j，j , ψ m，m can also be calculated in the same way.

[0072] S34. Under the GCTS trading mechanism, the impact of intra-regional transactions on the power flow of tie lines or internal lines in other regions is reflected through cross-regional transactions and does not need to be calculated separately.

[0073] S4. Multi-regional congestion surplus sharing. The congestion surplus borne by region i is the remaining funds after settlement between the ISO i and internal generators, internal loads, and inter-regional bidders, and can be calculated through the following formula. The congestion surplus shared by other regions can also be settled using the same method.

[0074]

[0075] The congestion surplus that needs to be borne by the bidders between region i and region j can be calculated through the following formula. The congestion surplus that needs to be borne by bidders between other regions can also be settled using the same method.

[0076]

[0077] Taking region i and region j as an example, in the case where region j purchases electricity from region i Figure 3It shows the settlement process of the GCTS mechanism for cross - regional transactions. Figure 3 The pentagram in it represents the proxy node. Through Figure 3 It can be seen that the independent system operator in region j trades with the independent system operator in region i through the external market participant A. The independent system operator in region i expends the internal generator / load B, and the independent system operator in region j receives the internal generator / load B. The tie - line power flow from region i to region j is realized between region j and region i through the proxy node.

[0078] In addition, according to the contribution value of various types of transactions to the transmission line power flow, the unit capacity of the line is priced using the shadow price of the transmission line capacity constraint, and the congestion surplus that region i needs to bear is:

[0079]

[0080] where μ i is the shadow price vector of the line capacity constraint in region i. The congestion surplus borne by regions j and m can also be obtained by the same method. The congestion surplus that the inter - regional bidder between region i and region j needs to bear is:

[0081]

[0082] where, μ j , μ m , μ i-j , μ i-m , μ j-m are the shadow price vectors corresponding to the internal transmission line and tie - line capacity constraints. These shadow price vectors have been obtained in the process of distributed recovery of the global LMP. The congestion surplus that the bidders between region i and region m, and between region j and region m need to bear can be calculated by the same method.

[0083] An embodiment of the present invention proposes a computing device, including a memory and a central processing unit. A computer program is stored in the memory. By running the computer program, the central processing unit can implement the above - mentioned congestion surplus sharing method considering the circulation effect.

[0084] An embodiment of the present invention proposes a computer - readable storage medium storing a computer program that can be run by a central processing unit. During the process of being run by the central processing unit, the computer program can implement the above - mentioned congestion surplus sharing method considering the circulation effect.

[0085] Based on the cross-regional electricity trading clearing results obtained by the GCTS mechanism, the congestion surplus sharing method considering the loop flow effect proposed by the present invention proposes a distributed method to restore the global LMP, quantifies and prices the impact caused by the loop flow. Each region shares the congestion surplus according to its contribution to line congestion, improves the cross-regional trading mechanism, properly considers the impact of the loop flow effect, protects the data privacy of each region, and has important engineering application value in the multi-region electricity market.

[0086] Compared with the prior art, the present invention has the following technical contributions:

[0087] 1) A quantification and pricing framework for the loop flow effect is proposed. By classifying the loop flow effect, the contributions of intra-regional transactions and cross-regional transactions to line congestion in each region are obtained respectively.

[0088] 2) Aiming at the settlement problem of multi-region power systems, a distributed LMP restoration method is proposed. Under the assumptions of the DC optimal power flow model and no degeneracy, the results of distributed LMP restoration are the same as those calculated centrally by the GCTS model.

[0089] 3) According to network equivalence and power transfer distribution factors, the contributions of intra-regional transactions and cross-regional transactions in each region to line congestion are quantified and priced distributively. In the case of considering the loop flow, all regions and inter-regional bidders will jointly share the congestion surplus.

[0090] The above-disclosed are only the preferred embodiments of the present invention, and of course, the scope of rights of the present invention cannot be limited thereby. It should be pointed out that for those skilled in the art of this technology, any equivalent changes made to the present invention without departing from the design structure and principle of the present invention are regarded as the protection scope of the present invention.

Claims

1. A method for determining the allocation of congestion surplus considering the loop flow effect, which is applied to a multi-region power system. Characterized in that , the method specifically includes the following steps: S1. Establish and solve an economic dispatch model for the multi-region power system; specifically including: S11. Establish the network structure; S12. Establish an economic dispatch model for the multi-region power system; the multi-region power system includes multiple transmission grids, inter-regional tie lines, intra-regional lines, internal transactions within each region, and cross-regional transactions; S13. Solve the clearing price of cross-regional transactions; S2. Distribute the recovery nodal marginal price; specifically including: S21. Distributively solve the power transfer distribution factors; the power transfer distribution factors regarding lines and nodes in the multi-region are divided into two categories: intra-regional factors and inter-regional factors. The intra-regional factors refer to the situation where the line and the node are in the same region, and the inter-regional factors refer to the situation where the line and the node are in different regions; S22. Solve the global nodal marginal price; S3. Quantify the impacts of intra-regional transactions and cross-regional transactions on line congestion; specifically including: S31. Calculate the impact of cross-regional transactions on the power flow of intra-regional transmission lines in each region; S32. Calculate the impact of cross-regional transactions on the power flow of tie lines; S33. Calculate the impact of intra-regional transactions on the power flow of intra-regional lines in this region; The impacts of intra-regional transactions on the power flow of tie lines or intra-regional lines in other regions are all reflected through cross-regional transactions and do not need to be calculated separately; S4. Determine the allocation of congestion surplus among multiple regions according to the impact of cross-regional transactions on the power flow of intra-regional transmission lines in each region, the impact of cross-regional transactions on the power flow of tie lines, and the impact of intra-regional transactions on the power flow of intra-regional lines in this region.

2. The method for determining the allocation of congestion surplus according to claim 1, Characterized in that, in step S21, the independent system operator of each region directly calculates the intra-regional factors according to the DC optimal power flow model and the equivalent network of other regions.

3. The method for determining the allocation of congestion surplus according to claim 1, Characterized in that, in step S4, the congestion surplus borne by the region is the remaining funds after the independent system operator of the region settles with internal generators, internal loads, and cross-regional bidders.

4. A computing device, which is applied to a multi-region power system, Characterized in that , it specifically includes a memory and a central processing unit. A computer program is stored in the memory, and the central processing unit can implement the method for determining the allocation of congestion surplus considering the loop flow effect according to any one of claims 1-3 by running the computer program.

5. A computer-readable storage medium, Characterized in that , it stores a computer program that can be run by a central processing unit, and the computer program can implement the method for determining the allocation of congestion surplus considering the loop flow effect according to any one of claims 1-3 during the process of being run by the central processing unit.

Images