Power transmission side operation loss and power transmission and distribution boundary power coordination method and device

Abstract

The invention provides a power transmission side operation loss and power transmission and distribution boundary power coordination method and device, and relates to the technical field of power system operation and control. The method comprises the following steps: defining loss in operation of a power transmission side as conventional unit power generation loss, reserved standby loss and dynamic line capacity expansion loss, and constructing an objective function of the operation loss of the power transmission side; establishing a direct current power flow constraint of power transmission side operation loss; according to the method, boundary power consistency constraints of a power distribution side and a power transmission side are established, an optimization objective function of the power transmission side and the power distribution side is constructed and serves as an iteration basis, the boundary power of the power transmission side and the boundary power of the power distribution side are gradually close through a decoupling method and an iteration coordination mechanism, the operation loss of the power transmission side is minimized, and power transmission side electric energy market clearing optimization is achieved. According to the method, the complexity of centralized optimization and the dispersity of distributed optimization are effectively balanced, the operation loss of the power transmission side can be better minimized, and collaborative optimization of the power transmission side and the power distribution side can be further deepened.

Description

Technical Field

[0001] The present invention relates to the field of power system operation and control technology, and in particular to a method and device for coordinating transmission-side operation loss and transmission and distribution boundary power. Background Art

[0002] In the current power system architecture, the operations of the transmission and distribution sides are gradually becoming a focus of industry attention. The transmission side plays a key role in large-scale power transmission and system scheduling, while the distribution side focuses on supplying power to end users and providing high-quality power services. With the continuous deepening of power market opening, the competition mechanism has been fully integrated into market operations, making the coordinated optimization of the transmission and distribution sides particularly critical. This requires not only ensuring the safety, stability, and efficiency of power transmission, but also achieving the scientific and rational allocation of power resources to meet the diverse needs of different market players in power trading, supply demand, and operational loss control.

[0003] In recent years, the rapid adoption of electric vehicles and the continuous innovation of virtual power plant (VPP) technology have led to the emergence of EV VPPs, a new player in the electricity market. By integrating the battery resources of numerous electric vehicles to create a massive energy storage system, EV VPPs are deeply involved in electricity market dispatch and trading. This innovation has not only brought new vitality to the electricity market, but has also posed a series of new challenges. For example, the security and stability of grid operations have been impacted, and coordination between distributed energy resources and the centralized grid is required. Therefore, in the collaborative optimization of the transmission and distribution energy market, how to fully consider the profound impact of EV VPP bidding strategies on the clearing of the transmission-side electricity market has become a key topic that urgently needs in-depth exploration and research.

[0004] Currently, most research uses centralized optimization methods, integrating the optimization problems on the transmission and distribution sides into a unified model for solution. While this approach can achieve global optimization, it faces challenges in practical applications, such as high computational complexity, large data requirements, and long solution times. Other studies have proposed distributed optimization methods, which decompose large problems into multiple smaller ones, each solved separately, and then achieve global optimization through iterative coordination. This approach reduces computational complexity to a certain extent, but suffers from slow or even non-convergence. In large-scale power systems, as the number of devices connected to the power system increases, the requirements for models increase to ensure the power system's responsiveness. As installed capacity continues to expand, ensuring coordination between the transmission and distribution energy market clearing models while enabling them to be solved independently to a certain extent will undoubtedly significantly benefit the power system's responsiveness. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and device for coordinating the operating losses on the transmission side and the transmission and distribution boundary power, which is used to solve how to achieve coordinated optimization of the transmission side and the distribution side and minimize the operating losses on the transmission side. The existing optimization methods have problems such as high computational complexity and difficulty in solving. The present invention can achieve coordinated optimization of the transmission side and the distribution side and minimize the operating losses on the transmission side, and the calculation process is simple and easy to solve.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a method for coordinating transmission-side operating losses and transmission and distribution boundary power, comprising: The losses in transmission-side operation are defined as conventional unit power generation losses, reserved standby losses, and dynamic line expansion losses, and the objective function of transmission-side operation losses is constructed. Establish DC power flow constraints for transmission side operating losses; Establish boundary power consistency constraints between the distribution side and the transmission side, construct optimization objective functions for the transmission side and the distribution side, and use decoupling methods and iterative coordination mechanisms as the basis for iteration to gradually approach the boundary power of the transmission side and the distribution side, minimize the operating loss of the transmission side, and achieve coordination between the operating loss of the transmission side and the boundary power of transmission and distribution, that is, optimize the clearing of the electricity energy market on the transmission side.

[0007] According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the calculation formula for conventional unit power generation losses, reserved standby losses, and dynamic line expansion losses is: (1) (2) (3) in, is the power generation loss of conventional units, For conventional units In the time period of efforts, is the fitting parameter; To reserve spare loss, and Conventional units In the time period Reserve loss coefficients for upward and downward backup; and Conventional units In the time period Upward and downward spares provided; All are coefficients; Dynamic line expansion loss; is the dynamic expansion coefficient, indicating that the line In the time period Capacity adjustment ratio; For the line The basic maximum transmission capacity of For the line In the time period The actual transmission power; is the marginal loss coefficient of expansion; For the line The load rate maintenance loss coefficient.

[0008] According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the objective function of transmission-side operating losses is: (4) Where, is the total number of time periods, is the number of conventional units on the transmission side, is the number of lines on the transmission side.

[0009] According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the DC power flow constraints of transmission-side operating losses include: (5) (6) (7) (8) (9) (10) (11) (12) in, is the boundary power on the transmission side; Access Node A collection of conventional units, For the node The set of connected transmission and distribution boundaries, N i is the set of nodes directly connected to node i, For nodes The load demand, For the line The susceptance between For nodes Voltage phase angle, For nodes Voltage phase angle, is the set of all nodes; They are the lower and upper limits of conventional unit output respectively; They are the lower and upper limits of the output ramp of conventional units, For conventional units In the time period contribution; and Conventional units The maximum upward and downward reserve values ​​provided; They are the minimum and maximum values ​​of the dynamic expansion coefficient respectively; For the line Node The active power limit value transmitted between.

[0010] According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the boundary power consistency constraint between the distribution side and the transmission side is: (13) Where, is the boundary power on the distribution side, is the set of all transmission and distribution boundaries.

[0011] According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the optimization objective function on the transmission side is: (14) The optimization objective function on the distribution side is: (15) in, (16) (17) (18) (19) Where, and are the charging power and discharging power of charging station n respectively, is the number of charging stations, N dist is the node set on the distribution side, is the day-ahead clearing marginal electricity price at the node where charging station n is located, is the penalty coefficient; is the transmission and distribution boundary power, which represents the power exchange target value between the transmission side and the distribution side at the boundary node k and time period t; is a dual variable used to coordinate the boundary power consistency between the transmission side and the distribution side; is the maximum charging power of the charging station, is the maximum discharge power of the charging station; when the charging station is in the charging state, , ; When the charging station is in the discharging state, , ; are the minimum and maximum day-ahead clearing marginal electricity prices at the node where charging station n is located.

[0012] According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the decoupling method is an alternating direction multiplier method.

[0013] According to the present invention, a method for coordinating transmission-side operating losses and transmission and distribution boundary power is provided. The method uses a decoupling method and an iterative coordination mechanism as an iterative basis to gradually approach the boundary power of the transmission side and the distribution side, thereby minimizing the transmission-side operating losses. The method includes: Set the initial values ​​of the transmission and distribution boundary power, dual variables, and penalty coefficients; The boundary power of the transmission side and the distribution side is gradually approached through the preset iterative formula; Calculate the difference between the boundary power of the transmission side and the distribution side. When the difference is less than a predetermined value, stop the iteration and output the minimum value of the transmission side operating loss. According to a method for coordinating transmission-side operating losses and transmission and distribution boundary power provided by the present invention, the preset iterative formula is: (20) (twenty one) (twenty two) (twenty three) The calculation formula for the difference in boundary power between the transmission side and the distribution side is: (twenty four) Where, It represents the boundary power of the transmission side after the number of iterations is N+1, It represents the boundary power of the distribution side after the number of iterations is N+1. is the transmission boundary power after N iterations, is the dual variable after the number of iterations is N, is the transmission boundary power after the number of iterations is N+1, is the dual variable after the number of iterations is N+1, is the difference between the boundary power on the transmission side and the distribution side.

[0014] In a second aspect, the present invention provides a transmission-side operating loss and transmission and distribution boundary power coordination device, comprising: A construction unit is used to define the losses in the operation of the transmission side as the power generation loss of conventional units, the reserved standby loss and the dynamic line expansion loss, and to construct an objective function of the operation loss of the transmission side; Establishing a unit for establishing DC power flow constraints for transmission side operation losses; The optimization unit is used to establish the boundary power consistency constraint between the distribution side and the transmission side, construct the optimization objective function of the transmission side and the distribution side, and use the decoupling method and iterative coordination mechanism as the iteration basis to gradually make the boundary power of the transmission side and the distribution side close to each other, thereby minimizing the operating loss of the transmission side.

[0015] The technical solution of the present invention has at least the following technical effects: The present invention provides a method and device for coordinating transmission side operating losses and transmission and distribution boundary power. The method includes: defining the losses in transmission side operation as conventional unit power generation losses, reserved standby losses, and dynamic line expansion losses, and constructing an objective function for transmission side operating losses; establishing a DC power flow constraint for transmission side operating losses; establishing a boundary power consistency constraint between the distribution side and the transmission side, constructing an optimization objective function for the transmission side and the distribution side, and using the decoupling method and iterative coordination mechanism as an iteration basis to gradually approach the boundary power of the transmission side and the distribution side, minimize the transmission side operating losses, and achieve coordination between the transmission side operating losses and the transmission and distribution boundary power. The present invention effectively balances the complexity of centralized optimization and the decentralization of distributed optimization, helps to better minimize the transmission side operating losses, and allows the collaborative optimization of the transmission side and the distribution side to be further deepened; it can achieve collaborative optimization of the transmission side and the distribution side and minimize the transmission side operating losses, and the calculation process is simple and easy to solve. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] In the attached figure: Figure 1 This is a graph showing the power difference between the transmission side and the distribution side obtained by the alternating direction multiplier method of the present invention; Figure 2 This is a graph showing how the transmission power of the boundary node 1 on the transmission side of the present invention changes with the number of iterations; Figure 3 This is a graph showing how the transmission power of the boundary node 2 on the transmission side of the present invention changes with the number of iterations; Figure 4 This is a graph showing how the transmission power of the boundary node 1 on the distribution side of the present invention changes with the number of iterations; Figure 5 This is a graph showing how the transmission power of the boundary node 2 on the power distribution side changes with the number of iterations; Figure 6 This is a flow chart of the method for coordinating transmission-side operating losses and transmission and distribution boundary power of the present invention. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0019] The following will describe some embodiments of the present invention in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0020] This invention combines the advantages of centralized and distributed optimization approaches, introducing a hybrid collaborative optimization method that combines a decoupling approach with an iterative coordination mechanism. By setting boundary power consistency constraints, it can, to a certain extent, decompose the transmission and distribution price optimization problem into independent subproblems that can be solved separately. The transmission system operator (TSO, on the transmission side) uses conventional generators, system reserve capacity, dynamic line expansion losses, and boundary exchange power with the distribution system operator (DSO, on the distribution side) as decision variables. By receiving bids from various market participants, the transmission energy market is cleared to minimize total transmission-side operating losses. The TSO then sends the resulting LMP (Local Minimum Power Price) at the transmission and distribution boundary node to the DSO, which serves as the price at which the DSO purchases power from the TSO. This method effectively balances the complexity of centralized optimization with the decentralization of distributed optimization, helping to better minimize transmission-side operating losses and further deepening collaborative optimization between the transmission and distribution sides. At the same time, in order to simplify the calculation while ensuring the accuracy of the model, based on the fact that the reactance of the high-voltage transmission network side circuit is much greater than the resistance, the transmission side line resistance and its resulting effects such as network losses are ignored in the calculation, and the DC power flow model is directly used to constrain the power flow state. This is reasonable under the premise of focusing on minimizing system operating losses and quickly solving the problem. It can improve the response speed of the model while keeping the error within a controllable range.

[0021] See also Figure 6 The embodiment of the present invention provides a method for coordinating transmission-side operating losses and transmission and distribution boundary power, including: Step 1: Define the losses in transmission-side operation as conventional unit power generation losses, reserved standby losses, and dynamic line expansion losses, and construct an objective function for transmission-side operation losses; The calculation formula for conventional unit power generation loss, reserved standby loss and dynamic line expansion loss is: (1) (2) (3) Where, (1) is the power generation loss of conventional units using exponential function to simulate increasing marginal loss, For conventional units In the time period of efforts, are the fitting parameters: The size of the exponential term determines the degree of influence. Will make the loss function grow steeper; Used to control the rate of exponential growth, it must satisfy To maintain the loss increasing characteristic; represents fixed or linear loss, ensuring that basic loss exists even at lower loads. (2) represents nonlinear reserve capacity loss, and Conventional units In the time period Reserve loss coefficients for upward and downward backup; and Conventional units In the time period Upward and downward reserves provided; coefficient It needs to be greater than 1 to reflect the increasing characteristics of the marginal loss of spare capacity, and needs to be determined according to actual conditions. Formula (3) is the dynamic line expansion loss, is the marginal loss term of expansion, is the dynamic expansion coefficient, indicating that the line In the time period The capacity adjustment ratio (for example, Indicates a 10% capacity expansion); For the line The basic maximum transmission capacity of For the line In the time period The actual transmission power; is the marginal loss coefficient of capacity expansion, which represents the cost of capacity expansion per unit capacity expansion; is the load factor related loss term, For the line The load factor loss coefficient is calculated by separating the expansion loss and the load factor loss to ensure that all items are non-negative.

[0022] The objective function of transmission side operation loss is: (4) Where, is the total number of time periods, is the number of conventional units on the transmission side, is the number of lines on the transmission side. By solving equation (4), we can obtain the minimum loss required for transmission-side operation, temporarily ignoring the interaction with the distribution side. By integrating the above loss terms, we construct an objective function for transmission-side operating losses, aiming to minimize operating losses and providing an economic model foundation for subsequent optimization.

[0023] Step 2: Establish DC power flow constraints for transmission side operating losses; Based on the parameters given in step 1, the DC power flow constraint is established as: (5) (6) (7) (8) (9) (10) (11) (12) Among them, equation (5) is the node power balance equation, which ensures that power generation, transmission and load demand are matched. is the boundary power on the transmission side, Access Node A collection of conventional units, For the node The set of connected transmission and distribution boundaries, N i is the set of nodes directly connected to node i, For nodes The load demand, For the line The susceptance between For nodes Voltage phase angle, For nodes Voltage phase angle, is the set of all nodes. It should be noted that Including all lines , in step 1, This parameter represents a line. Here, two nodes i and j are used to represent a line. Since the node power is used here, the line and lines Essentially the same.

[0024] Equations (6) and (7) are constraints on the operation of conventional units, where (6) is the upper and lower limits of the unit output, and (7) is the limit on the unit output ramp. Equations (8) and (9) are constraints on the reserve capacity, where (8) is the upward reserve capacity limit, and (9) is the downward reserve capacity limit. Equation (10) is a constraint on the dynamic expansion coefficient. By limiting the expansion range, it can prevent excessive adjustment from causing equipment overload or resource waste. Equation (11) is a constraint on the actual transmission power of the line. Equation (12) is a constraint on the line transmission power, which controls the active power transmitted by each line within a certain range. They are the lower and upper limits of conventional unit output respectively; They are the lower and upper limits of the output ramp of conventional units, For conventional units In the time period contribution; and Conventional units The maximum upward and downward reserve values ​​provided; They are the minimum and maximum values ​​of the dynamic expansion coefficient respectively; For the line Node The active power limit value transmitted between.

[0025] The calculation is simplified by using the DC power flow model (ignoring resistance), ensuring that the optimization model conforms to the actual grid operation rules and sets the physical constraints of the power system operation.

[0026] Step 3: Establish boundary power consistency constraints between the distribution side and the transmission side, construct optimization objective functions for the transmission side and the distribution side, and use the decoupling method and iterative coordination mechanism as the iteration basis to gradually approach the boundary power of the transmission side and the distribution side, minimize the operating loss of the transmission side, and achieve coordination between the operating loss of the transmission side and the boundary power of transmission and distribution, that is, optimize the clearing of the electric energy market on the transmission side.

[0027] Specifically, the boundary power consistency constraint between the distribution side and the transmission side is: (13) Where, is the boundary power on the distribution side, is the set of all transmission and distribution boundaries.

[0028] After decoupling the transmission side and the distribution side so that they can be solved independently, the alternating direction multiplier method is used to continuously update the boundary power through an iterative coordination mechanism until the required convergence level is reached.

[0029] The optimization objective function on the transmission side is: (14) The optimization objective function on the distribution side is: (15) in, (16) (17) (18) (19) Where, and are the charging power and discharging power of charging station n, is the number of charging stations, N dist is the node set on the distribution side, is the day-ahead clearing marginal electricity price at the node where charging station n is located, is the penalty coefficient; is the transmission and distribution boundary power, which represents the power exchange target value between the transmission side and the distribution side at the boundary node k and time period t; is a dual variable used to coordinate the boundary power consistency between the transmission side and the distribution side; is the maximum charging power of the charging station, is the maximum discharge power of the charging station; when the charging station is in the charging state, , ; When the charging station is in the discharging state, , ; are the minimum and maximum day-ahead clearing marginal electricity prices at the node where charging station n is located.

[0030] Among them, (14) and (15) are the TSO and DSO optimization objective functions after considering the boundary exchange power between TSO and DSO. (16), (17), (18), and (19) are the constraints of these variables, where and A 0-1 variable indicating whether the charging station is charging or discharging, ensuring that the same charging station will not be charging or discharging at the same time.

[0031] In some embodiments, in step 3, the decoupling method and the iterative coordination mechanism are used as an iteration basis to gradually approach the boundary power of the transmission side and the distribution side, thereby minimizing the operation loss of the transmission side, including: Set the initial values ​​of the transmission and distribution boundary power, dual variables, and penalty coefficients; The boundary power of the transmission side and the distribution side is gradually approached through the preset iterative formula; The difference between the boundary powers of the transmission side and the distribution side is calculated, and the iteration is stopped when the difference is less than a predetermined value, and the minimum value of the transmission side operating loss is output.

[0032] The preset iteration formula is: (20) (twenty one) (twenty two) (twenty three) The calculation formula for the difference in boundary power between the transmission side and the distribution side is: (twenty four) Where, It represents the boundary power of the transmission side after the number of iterations is N+1, It represents the boundary power of the distribution side after the number of iterations is N+1. is the transmission boundary power after N iterations, is the dual variable after the number of iterations is N, is the transmission boundary power after the number of iterations is N+1, is the dual variable after the number of iterations is N+1, is the difference between the boundary power on the transmission side and the distribution side.

[0033] Among them, (20), (21), (22), and (23) are iterative formulas. First, the initial shared variables are set. , dual variables , penalty coefficient After that, the boundary power of the transmission side and the distribution side can be gradually approached through iteration, and formula (24) is used to calculate the gap between the two. If it is less than a predetermined value, the iteration will stop and the optimized and The optimization objectives of both TSO and DSO include a quadratic penalty term for the shared variable deviation, ensuring that the global optimal solution is gradually approached during the iteration process.

[0034] By establishing a boundary power consistency constraint, the exchange power on the transmission and distribution sides at the boundary node k is forced to be equal. The alternating direction multiplier method (ADMM) is used to decompose the optimization problem on the transmission and distribution sides into independent subproblems (Equations 14 and 15), which are solved separately. By iteratively updating the boundary power (Equation 23), the optimization results of both sides are coordinated until convergence (Equation 24). A penalty term ( ) and the dual variable ( ), ensuring that the boundary power gradually approaches consistency.

[0035] It should be noted that the loss function constructed in step 1 (Equation 4) serves as the optimization objective, and the DC power flow constraint added in step 2 (Equation 5) is a physical constraint. Together, they constitute the transmission-side optimization model. The boundary consistency constraint in step 3 (Equation 13) links the optimization problems on the transmission and distribution sides, ensuring consistency in their boundary power. Furthermore, step 3 decomposes the global optimization into independent subproblems on the transmission and distribution sides (for which steps 1 and 2 provide the objective functions and constraints). An iterative mechanism (Equations 20-24) enables distributed computing, avoiding the high complexity of centralized optimization. The DC power flow model in step 2 simplifies the computation, while the decomposition method in step 3 reduces the solution size. This combination of methods improves computational speed while maintaining model accuracy, adapting to the real-time requirements of large-scale power systems. Steps 1 to 3 form a closed loop: step 1 defines the economic objective, step 2 adds physical constraints, and step 3 achieves global optimization through boundary coordination. Ultimately, transmission-side operating losses are minimized while ensuring grid security and stability.

[0036] Based on the same inventive concept, another embodiment of the present invention provides a transmission-side operating loss and transmission and distribution boundary power coordination device, which corresponds to the method of the aforementioned embodiment and includes: A construction unit is used to define the losses in the operation of the transmission side as the power generation loss of conventional units, the reserved standby loss and the dynamic line expansion loss, and to construct an objective function of the operation loss of the transmission side; Establishing a unit for establishing DC power flow constraints for transmission side operation losses; The optimization unit is used to establish the boundary power consistency constraints between the distribution side and the transmission side, construct the optimization objective functions of the transmission side and the distribution side, and use the decoupling method and iterative coordination mechanism as the iteration basis to gradually make the boundary power of the transmission side and the distribution side approach each other, minimize the operating loss of the transmission side, and achieve coordination between the operating loss of the transmission side and the transmission and distribution boundary power, that is, optimize the clearing of the electric energy market on the transmission side.

[0037] The following is a specific embodiment of the present invention.

[0038] In this embodiment, there are 5 nodes on the transmission side and the distribution side, of which 2 nodes are boundary nodes. Boundary node 1 on the transmission side corresponds to boundary node 1 on the distribution side, and boundary node 2 on the transmission side corresponds to boundary node 2 on the distribution side. Two time periods are set: time period 1 and time period 2. The loads of each node in the two time periods are different, and the corresponding boundary transmission powers are also different.

[0039] Figure 1 The variation of the boundary power difference between the transmission side and the distribution side with the continuous iteration of the alternating direction multiplier method (ADMM) is shown. Figure 2 It shows the change of the transmission power of the boundary node 1 on the transmission side with the number of iterations. Figure 3 The figure shows how the transmission power of the boundary node 2 on the transmission side changes with the number of iterations. Figure 4 The figure shows how the transmission power of the boundary node 1 on the distribution side changes with the number of iterations. Figure 5 The figure shows how the transmission power of the boundary node 2 on the distribution side changes with the number of iterations. Finally, the difference in the transmission power of the corresponding boundary nodes on the transmission side and the distribution side is less than the set value, and the iteration process ends.

[0040] After the iteration is completed, the optimized boundary power value is: The power of boundary node 1 in time period 1 is 25.893662MW, the power of boundary node 1 in time period 2 is 33.124933MW, the power of boundary node 2 in time period 1 is 24.106324MW, and the power of boundary node 2 in time period 2 is 33.125049MW.

[0041] The transmission power at the transmission side boundary is: The power of boundary node 1 in time period 1 is 25.893673MW, the power of boundary node 1 in time period 2 is 33.124945MW, the power of boundary node 2 in time period 1 is 24.106327MW, and the power of boundary node 2 in time period 2 is 33.125055MW.

[0042] The transmission power at the distribution side boundary is: The power of boundary node 1 in time period 1 is 25.893652MW, the power of boundary node 1 in time period 2 is 33.124922MW, the power of boundary node 2 in time period 1 is 24.106321MW, and the power of boundary node 2 in time period 2 is 33.125042MW.

[0043] From the final output results, it can be seen that the transmission side and the distribution side continuously update the boundary power through an iterative coordination mechanism until the boundary power gap is reduced and the required convergence level is reached. In this embodiment, the boundary power gap is less than 0.0001MW.

[0044] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the embodiments disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and variations can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for coordinating transmission-side operating losses and transmission and distribution boundary power, characterized in that: include: The losses in transmission-side operation are defined as conventional unit power generation losses, reserved standby losses, and dynamic line expansion losses, and the objective function of transmission-side operation losses is constructed. Establishing DC power flow constraints for transmission side operating losses; Establish boundary power consistency constraints between the distribution side and the transmission side, construct optimization objective functions of the transmission side and the distribution side, and use decoupling methods and iterative coordination mechanisms as the iteration basis to gradually approach the boundary power of the transmission side and the distribution side, thereby minimizing the operating loss of the transmission side.

2. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 1, characterized in that: The calculation formula for the conventional unit power generation loss, reserved standby loss and dynamic line expansion loss is: (1) (2) (3) in, is the power generation loss of conventional units, For conventional units In the time period of efforts, is the fitting parameter; To reserve spare loss, and Conventional units In the time period Reserve loss coefficients for upward and downward backup; and Conventional units In the time period Upward and downward spares provided; All are coefficients; Dynamic line expansion loss; is the dynamic expansion coefficient, indicating that the line In the time period Capacity adjustment ratio; For the line The basic maximum transmission capacity of For the line In the time period The actual transmission power; is the marginal loss coefficient of expansion; For the line The load rate maintenance loss coefficient.

3. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 2, characterized in that: The objective function of the transmission side operation loss is: (4) Where, is the total number of time periods, is the number of conventional units on the transmission side, is the number of lines on the transmission side.

4. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 3, characterized in that: The DC power flow constraints for transmission side operating losses include: (5) (6) (7) (8) (9) (10) (11) (12) in, is the boundary power on the transmission side; Access Node A collection of conventional units, For the node The set of connected transmission and distribution boundaries, N i is the set of nodes directly connected to node i, For nodes The load demand, For the line The susceptance between For nodes Voltage phase angle, For nodes Voltage phase angle, is the set of all nodes; They are the lower and upper limits of conventional unit output respectively; They are the lower and upper limits of the output ramp of conventional units, For conventional units In the time period contribution; and Conventional units The maximum upward and downward reserve values ​​provided; They are the minimum and maximum values ​​of the dynamic expansion coefficient respectively; For the line Node The active power limit value transmitted between.

5. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 4, characterized in that: The boundary power consistency constraint between the distribution side and the transmission side is: (13) Where, is the boundary power on the distribution side, is the set of all transmission and distribution boundaries.

6. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 5, characterized in that: The optimization objective function of the transmission side is: (14) The optimization objective function of the distribution side is: (15) in, (16) (17) (18) (19) Where, and are the charging power and discharging power of charging station n respectively, is the number of charging stations, N dist is the node set on the distribution side, is the day-ahead clearing marginal electricity price at the node where charging station n is located, is the penalty coefficient; is the transmission and distribution boundary power, which represents the power exchange target value between the transmission side and the distribution side at the boundary node k and time period t; is a dual variable used to coordinate the boundary power consistency between the transmission side and the distribution side; is the maximum charging power of the charging station, is the maximum discharge power of the charging station; when the charging station is in the charging state, , ; When the charging station is in the discharging state, , ; are the minimum and maximum day-ahead clearing marginal electricity prices at the node where charging station n is located.

7. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 6, characterized in that: The decoupling method is the alternating direction multiplier method.

8. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 7, characterized in that: The above-mentioned method is used as an iteration basis to gradually approach the boundary power of the transmission side and the distribution side through a decoupling method and an iterative coordination mechanism, thereby minimizing the operating loss of the transmission side, including: Set the initial values ​​of the transmission and distribution boundary power, dual variables, and penalty coefficients; The boundary power of the transmission side and the distribution side is gradually approached through the preset iterative formula; The difference between the boundary powers of the transmission side and the distribution side is calculated, and the iteration is stopped when the difference is less than a predetermined value, and the minimum value of the transmission side operating loss is output.

9. The method for coordinating transmission-side operating losses and transmission and distribution boundary power according to claim 8, characterized in that: The preset iteration formula is: (20) (21) (22) (23) The calculation formula for the difference between the boundary power of the transmission side and the distribution side is: (24) Where, It represents the boundary power of the transmission side after the number of iterations is N+1, It represents the boundary power of the distribution side after the number of iterations is N+1. is the transmission boundary power after N iterations, is the dual variable after the number of iterations is N, is the transmission boundary power after the number of iterations is N+1, is the dual variable after the number of iterations is N+1, is the difference between the boundary power on the transmission side and the distribution side.

10. A transmission side operation loss and transmission and distribution boundary power coordination device, characterized in that: include: A construction unit is used to define the losses in the operation of the transmission side as the power generation loss of conventional units, the reserved standby loss and the dynamic line expansion loss, and to construct an objective function of the operation loss of the transmission side; An establishing unit, configured to establish a DC power flow constraint for the transmission side operation loss; The optimization unit is used to establish the boundary power consistency constraint between the distribution side and the transmission side, construct the optimization objective function of the transmission side and the distribution side, and use the decoupling method and iterative coordination mechanism as the iteration basis to gradually make the boundary power of the transmission side and the distribution side close to each other, thereby minimizing the operating loss of the transmission side.

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