A distributed consistent real-time economic dispatch method for smart grid

Abstract

The present invention relates to the field of renewable energy power generation, and in particular to a distributed consistency real-time economic dispatch method for a smart grid. The present invention realizes communication and coordination between generator nodes in a smart grid through a distributed consistency algorithm, while taking into account pollutant gas emissions and transmission losses, thereby improving the practicability of the economic dispatch method. The present invention can monitor the mismatch between power demand and generator power output in real time, and update the output power of the generator in real time. In addition, the present invention has plug-and-play capabilities, effectively optimizes the operating cost and reliability of the smart grid, and improves the management and operation efficiency of the smart grid.

Description

Technical Field

[0001] The present invention belongs to the field of renewable energy power generation, and in particular to a distributed consistent real-time economic dispatching method for a smart grid. Background Art

[0002] Smart grid is a power supply system that integrates advanced information and communication technologies and intelligent control methods, aiming to achieve real-time monitoring, precise control and intelligent dispatching of all aspects of the power system. The development goal of smart grid is to improve the efficiency, reliability and sustainability of the power system, meet the growing power demand through optimized resource allocation and flexible regulation, and promote the widespread application of clean energy.

[0003] In the context of economic dispatch, the generators in the smart grid need to generate enough electricity to meet the overall load demand, which gives rise to the economic dispatch problem. The economic dispatch problem is one of the core energy management problems in the power system. Its goal is to minimize the operating cost by reasonably dispatching the output power of each generator while meeting the load demand and system constraints.

[0004] Traditional economic dispatch methods usually use centralized algorithms, such as genetic algorithms, particle swarm optimization, evolutionary programming, differential evolution, and simulated annealing. These algorithms rely on a central controller to collect global information for large amounts of data processing and require high storage capacity and fast processing speed. However, centralized methods are costly and prone to single point failures, lacking robustness. When generators or loads need to be added or subtracted in a smart grid, the entire system needs to be reconfigured, which is not flexible enough.

[0005] In recent years, distributed economic dispatch methods have gradually gained attention. Distributed economic dispatch emphasizes the autonomous decision-making and intelligence of each unit. Through the information exchange protocol, each unit communicates with neighboring nodes and makes independent decisions after integrating information to adjust its own output, thereby achieving the economic dispatch goal. Compared with centralized methods, distributed economic dispatch has higher robustness and scalability, more balanced computing and communication burdens, and also has obvious advantages in information confidentiality and security. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a distributed consistent real-time economic dispatch method for a smart grid in view of the defects of the above-mentioned prior art.

[0007] The present invention is implemented by the following scheme: a distributed consistent real-time economic dispatch method for a smart grid, comprising the following steps:

[0008] Step 1: Construct an economic dispatch model for smart grid based on pollutant gas emissions and transmission losses. The model includes: the types of generators in the smart grid and their output power costs, the objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power;

[0009] Step 2: Determine the Laplace matrix C according to the communication topology diagram of the smart grid, and then normalize the Laplace matrix C to obtain the matrix θ;

[0010] Step 3: Initialize the relevant parameters required by the algorithm;

[0011] Step 4: In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emission and transmission loss, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information.

[0012] Step 5: Check the output power of all generators. If the output power of any generator does not meet the predetermined output power constraint condition, process its output power;

[0013] Step 6: Determine whether the supply and demand balance constraint of the generator output power is met; if so, output the optimal incremental cost and the optimal generator output power; if not, return to step 4.

[0014] Furthermore, the step 1 is specifically as follows:

[0015] The types of generators in smart grids include fuel energy generators and renewable energy generators;

[0016] The output power cost of the generator in the smart grid is:

[0017]

[0018] Wherein, i = 1, 2, ..., n; n is the number of generators in the smart grid; k is the number of iterations; is the kth iteration generator output power cost of the i-th generator under the condition of considering pollutant gas emissions and transmission losses; p i(k) is the output power of the i-th generator at the k-th iteration; α i , β i , γ i , l i and δ i K is the cost coefficient of the i-th generator based on the emission of polluting gases; i is the penalty parameter of the i-th generator;

[0019] The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power are:

[0020]

[0021] p i_min ≤p i(k) ≤p i_max

[0022] in, is the objective function of the economic dispatch problem; p i_sh is the transmission loss of the output power of the i-th generator, which is specifically p i_sh =σ×p i(k) , σ is the transmission loss coefficient of the generator output power, σ∈[5%,10%]; is the supply and demand balance constraint of the generator output power; p i_min ≤p i(k) ≤p i_max is the constraint condition for the generator output power; p d is the total required power; p i_min is the minimum output power of the i-th generator; p i_max is the maximum output power of the i-th generator.

[0023] Furthermore, the method for normalizing the Laplace matrix C in step 2 is:

[0024]

[0025] Among them, c ij is the i-th row and j-th column element of the Laplace matrix C; θ ij Represented as the element in the i-th row and j-th column of the matrix θ.

[0026] Furthermore, the step three is specifically as follows:

[0027] The initial value of the output power of the i-th generator is set to p based on the transmission loss condition. i(0) , then the initial output power mismatch value of all generators is The initial incremental cost of the i-th generator is

[0028] Furthermore, the step 4 is specifically as follows:

[0029] In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emissions and transmission losses, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information. The specific calculation method is as follows:

[0030] The incremental cost iteration formula for the leading generator is:

[0031]

[0032] The incremental cost iteration formula for following a generator is:

[0033]

[0034] in, represents the incremental cost of the i-th generator at the k+1th iteration; ε is the convergence coefficient, which determines the rate at which the incremental cost converges to a consistent value; D p(k) represents the mismatch of the output power of all generators at the kth iteration. The specific calculation method is:

[0035]

[0036] The calculation method of generator output power is:

[0037]

[0038] Among them, p i(k+1) represents the output power of the i-th generator at the k+1-th iteration; Y i(k+1) is an auxiliary variable, specifically W 0 (·) is the Lambert W function.

[0039] Furthermore, the step five is specifically as follows:

[0040] Check the output power of all generators. If the output power of any generator does not meet the preset output power constraint condition, process its output power:

[0041]

[0042] The present invention provides a distributed consistent real-time economic dispatch method for a smart grid. Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The present invention uses a distributed algorithm for economic dispatch problems based on pollutant gas emissions and transmission losses to dynamically calculate the incremental cost of each generator, the output power mismatch and output power of all generators. This process belongs to a fully distributed method.

[0044] 2. The present invention combines the advantages of distributed consistency algorithms, greatly reducing communication costs and making smart grid economic dispatch more economical and safer.

[0045] 3. Since the method of the present invention does not rely on a central controller, the smart grid can also achieve the optimal solution to the economic dispatch problem when expanding new generators or adjusting the existing structure. This means that the smart grid can seamlessly connect new generators at any time without large-scale modifications to the existing dispatch strategy, making the expansion of the smart grid easier. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A flow chart of a distributed consistent real-time economic dispatch method for smart grid;

[0047] Figure 2 The IEEE 30-node standard power network of the present invention;

[0048] Figure 3 A communication topology diagram of the smart grid of the present invention;

[0049] Figure 4 This is the incremental cost change diagram of the present invention without adding a generator;

[0050] Figure 5 This is a diagram showing the variation of the output power of a generator without adding a generator in the middle of the present invention;

[0051] Figure 6 This is a total mismatch variation diagram without adding a generator in the middle of the present invention;

[0052] Figure 7 This is a graph showing the incremental cost change after adding a generator midway in the present invention;

[0053] Figure 8 This is a diagram showing the change in generator output power after a generator is added midway in the present invention;

[0054] Fig. 9 This is a diagram showing the total mismatch change after a generator is added midway in the present invention. DETAILED DESCRIPTION

[0055] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0056] Embodiment 1:

[0057] The process of the smart grid real-time economic dispatch method based on the distributed consensus algorithm under the conditions of pollutant gas emissions and transmission losses provided in this embodiment is as follows: Figure 1 As shown, the following steps are included:

[0058] Step 1: Construct an economic dispatch model for smart grid based on pollutant gas emissions and transmission losses. The model includes: the types of generators in the smart grid and their output power costs, the objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power;

[0059] Step 2: Determine the Laplace matrix C according to the communication topology diagram of the smart grid, and then normalize the Laplace matrix C to obtain the matrix θ;

[0060] Step 3: Initialize the relevant parameters required by the algorithm;

[0061] Step 4: In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emission and transmission loss, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information.

[0062] Step 5: Check the output power of all generators. If the output power of any generator does not meet the predetermined output power constraint condition, process its output power;

[0063] Step 6: Determine whether the supply and demand balance constraint of the generator output power is met; if so, output the optimal incremental cost and the optimal generator output power; if not, return to step 4.

[0064] In this embodiment, the step 1 is specifically as follows:

[0065] The types of generators in smart grids include fuel energy generators and renewable energy generators;

[0066] The output power cost of the generator in the smart grid is:

[0067]

[0068] Wherein, i = 1, 2, ..., n; n is the number of generators in the smart grid; k is the number of iterations; is the kth iteration generator output power cost of the i-th generator under the condition of considering pollutant gas emissions and transmission losses; p i(k) is the output power of the i-th generator at the k-th iteration; α i , β i , γ i, l i and δ i K is the cost coefficient of the i-th generator based on the emission of polluting gases; i is the penalty parameter of the i-th generator;

[0069] The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power are:

[0070]

[0071] p i_min ≤p i(k) ≤p i_max

[0072] in, is the objective function of the economic dispatch problem; p i_sh is the transmission loss of the output power of the i-th generator, which is specifically p i_sh =σ×p i(k) , σ is the transmission loss coefficient of the generator output power, σ∈[5%,10%]; is the supply and demand balance constraint of the generator output power; p i_min ≤p i(k) ≤p i_max is the constraint condition for the generator output power; p d is the total required power; p i_min is the minimum output power of the i-th generator; p i_max is the maximum output power of the i-th generator.

[0073] In this embodiment, the method for normalizing the Laplace matrix C in step 2 is:

[0074]

[0075] Among them, c ij is the i-th row and j-th column element of the Laplace matrix C; θ ij Represented as the element in the i-th row and j-th column of the matrix θ.

[0076] In this embodiment, the step three is specifically as follows:

[0077] The initial value of the output power of the i-th generator is set to p based on the transmission loss condition. i(0) , then the initial output power mismatch value of all generators is The initial incremental cost of the i-th generator is

[0078] In this embodiment, the step 4 is specifically as follows:

[0079] In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emissions and transmission losses, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information. The specific calculation method is as follows:

[0080] The incremental cost iteration formula for the leading generator is:

[0081]

[0082] The incremental cost iteration formula for following a generator is:

[0083]

[0084] in, represents the incremental cost of the i-th generator at the k+1th iteration; ε is the convergence coefficient, which determines the rate at which the incremental cost converges to a consistent value; D p(k) represents the mismatch of the output power of all generators at the kth iteration. The specific calculation method is:

[0085]

[0086] The calculation method of generator output power is:

[0087]

[0088] Among them, p i(k+1) represents the output power of the i-th generator at the k+1-th iteration; Y i(k+1) is an auxiliary variable, specifically W 0 (·) is the Lambert W function.

[0089] In this embodiment, the step five is specifically as follows:

[0090] Check the output power of all generators. If the output power of any generator does not meet the preset output power constraint condition, process its output power:

[0091]

[0092] Embodiment 2:

[0093] Example 2 uses the proposed smart grid real-time economic dispatch method based on distributed consensus algorithm to perform numerical simulation on the IEEE 30-node standard power network, with a total of 6 generators. Figure 2 It is an IEEE 30-node standard power network; Figure 3 Communication topology diagram of smart grid.

[0094] The specific process is described as follows:

[0095] The types of generators in smart grids include fuel energy generators and renewable energy generators;

[0096] The output power cost of the generator in the smart grid is:

[0097]

[0098] Wherein, i = 1, 2, ..., n; n is the number of generators in the smart grid; k is the number of iterations; is the kth iteration generator output power cost of the i-th generator under the condition of considering pollutant gas emissions and transmission losses; p i(k) is the output power of the i-th generator at the k-th iteration; α i , β i , γ i , l i and δ i K is the cost coefficient of the i-th generator based on the emission of polluting gases; i is the penalty parameter of the i-th generator;

[0099] The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power are:

[0100]

[0101] p i_min ≤p i(k) ≤p i_max (2c)

[0102] Where (2a) is the objective function of the economic dispatch problem; p i_sh is the transmission loss of the output power of the i-th generator, which is specifically p i_sh =σ×p i(k) , σ is the transmission loss coefficient of the generator output power, σ∈[5%,10%]; (2b) is the supply and demand balance constraint of the generator output power; (2c) is the limit constraint of the generator output power; p d is the total required power; p i_min is the minimum output power of the i-th generator; p i_max is the maximum output power of the i-th generator.

[0103] The Laplace matrix C is determined according to the communication topology diagram of the smart grid, and then the Laplace matrix C is normalized. The specific method for normalizing the Laplace matrix C is as follows:

[0104]

[0105] Among them, c ij is the i-th row and j-th column element of the Laplace matrix C; θ ij Represented as the element in the i-th row and j-th column of the matrix θ.

[0106] The initial value of the output power of the i-th generator is set to p based on the transmission loss condition. i(0) , then the initial output power mismatch value of all generators is The initial incremental cost of the i-th generator is

[0107] In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emissions and transmission losses, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information. The specific calculation method is as follows:

[0108] The incremental cost iteration formula for the leading generator is:

[0109]

[0110] The incremental cost iteration formula for following a generator is:

[0111]

[0112] in, represents the incremental cost of the i-th generator at the k+1th iteration; ε is the convergence coefficient, which determines the rate at which the incremental cost converges to a consistent value; D p(k) represents the mismatch of the output power of all generators at the kth iteration. The specific calculation method is:

[0113]

[0114] The calculation method of generator output power is:

[0115]

[0116] Among them, p i(k+1) represents the output power of the i-th generator at the k+1-th iteration; Y i(k+1) is an auxiliary variable, specifically W 0 (·) is the Lambert W function.

[0117] Check the output power of all generators. If the output power of any generator does not meet the preset output power constraint condition, process its output power:

[0118]

[0119] Determine whether the supply and demand balance constraint conditions of the generator output power are met; if so, output the optimal incremental cost and the optimal generator output power; if not, return to step 4.

[0120] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0121] The relevant parameters of the generator are shown in Table 1:

[0122] Table 1

[0123]

[0124] The initial values ​​of the output power of the i-th generator under the transmission loss condition are set to be p 1(0) =70MW, p 2(0) =70MW, p 3(0) =70MW, p 4(0) =70MW, p 5(0) =70MW, p 6(0) =70MW; total power demand p d =500MW; the initial value of the output power mismatch of all generators is D p(0) =80MW; the transmission loss coefficient σ of the generator output power is taken as 5%; the Laplace matrix C is determined according to the communication topology diagram of the smart grid as shown in formula (9); the matrix As shown in formula (10). Based on the given data, this numerical simulation shows that the optimal incremental cost converges to the same value of 791.13$ / MW. In the transient response, we noticed that after reaching the upper limit of the predetermined output power constraint, generator 5 maintains the maximum output power of 75.00MW and no longer increases. According to the results, the final output power of the generator is 64.43MW, 74.14MW, 85.40MW, 123.41MW, 75.00MW and 77.55MW, and the output power of all generators is within the range of the generator output power constraint.

[0125]

[0126] In order to verify the plug-and-play characteristics of the algorithm in the economic dispatch of smart grids, a new generator was added to the smart grid at the 70th iteration. The simulation verified that the smart grid can effectively maintain the supply and demand balance of the generator output power.

[0127] The simulation of the present invention adopts MATLAB2022a, and the computer configuration is COREi7, 2.80GHz; Figure 4 This is the incremental cost change diagram of the present invention without adding a generator; Figure 5 This is a diagram showing the variation of the output power of a generator without adding a generator in the middle of the present invention; Figure 6 This is a total mismatch variation diagram without adding a generator in the middle of the present invention; Figure 7 This is a graph showing the incremental cost change after adding a generator midway in the present invention; Figure 8 This is a diagram showing the change in generator output power after a generator is added midway in the present invention; Fig. 9 This is a diagram showing the total mismatch change after a generator is added midway in the present invention.

[0128] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A distributed consistent real-time economic dispatch method for smart grid, characterized in that The following steps are involved: Step 1: Construct an economic dispatch model for smart grid based on pollutant gas emissions and transmission losses. The model includes: the types of generators in the smart grid and their output power costs, the objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power; Step 2: Determine the Laplace matrix C according to the communication topology diagram of the smart grid, and then normalize the Laplace matrix C to obtain the matrix θ; Step 3: Initialize the relevant parameters required by the algorithm; Step 4: In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emission and transmission loss, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information. Step 5: Check the output power of all generators. If the output power of any generator does not meet the predetermined output power constraint condition, process its output power; Step 6: Determine whether the supply and demand balance constraint condition of the generator output power is met; if so, output the optimal incremental cost and the optimal generator output power; if not, return to step 4; The step 1 is specifically as follows: The types of generators in smart grids include fuel energy generators and renewable energy generators; The output power cost of the generator in the smart grid is: Wherein, i = 1, 2, ..., n; n is the number of generators in the smart grid; k is the number of iterations; is the kth iteration generator output power cost of the i-th generator under the condition of considering pollutant gas emissions and transmission losses; p i(k) is the output power of the i-th generator at the k-th iteration; α i , β i , γ i , l i and δ i K is the cost coefficient of the i-th generator based on the emission of polluting gases; i is the penalty parameter of the i-th generator; The objective function of the economic dispatch problem, the supply and demand balance constraints of the generator output power, and the limit constraints of the generator output power are: p i_min ≤p i(k) ≤p i_max in, is the objective function of the economic dispatch problem; p i_sh is the transmission loss of the output power of the i-th generator, which is specifically p i_sh =σ×p i(k) , σ is the transmission loss coefficient of the generator output power, σ∈[[5%,10%]; is the supply and demand balance constraint of the generator output power; p i_min ≤p i(k) ≤p i_max is the constraint condition for the generator output power; p d is the total required power; p i_min is the minimum output power of the i-th generator; p i_max is the maximum output power of the i-th generator; The method for normalizing the Laplace matrix C in step 2 is: Among them, c ij is the i-th row and j-th column element of the Laplace matrix C; θ ij Represented as the i-th row and j-th column element of the matrix θ; The step three is specifically as follows: The initial value of the output power of the i-th generator is set to p based on the transmission loss condition. i(0) , then the initial output power mismatch value of all generators is The initial incremental cost of the i-th generator is The step 4 is specifically as follows: In the smart grid, any generator is selected as the leading generator and the other generators are selected as follower generators. Based on the distributed algorithm of economic dispatch problem under the conditions of environmental pollution emissions and transmission losses, the incremental cost of each generator, the output power mismatch and output power of all generators are dynamically calculated without the need for global information. The specific calculation method is as follows: The incremental cost iteration formula for the leading generator is: The incremental cost iteration formula for following a generator is: in, represents the incremental cost of the i-th generator at the k+1th iteration; ε is the convergence coefficient, which determines the rate at which the incremental cost converges to a consistent value; D p(k) represents the mismatch of the output power of all generators at the kth iteration. The specific calculation method is: The calculation method of generator output power is: Among them, p i(k+1) represents the output power of the i-th generator at the k+1-th iteration; Y i(k+1) is an auxiliary variable, specifically W0(·) is the Lambert W function; The step five is specifically as follows: Check the output power of all generators. If the output power of any generator does not meet the preset output power constraint condition, process its output power:

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