Event-triggered micro-grid distributed economic dispatching method considering main power grid

Abstract

The invention discloses an event-triggered micro-grid distributed economic dispatching method considering a main power grid, and belongs to the field of energy-saving and environment-friendly economic dispatching of intelligent power grids. According to the method, the situation that whether the micro-grid is connected into the main power grid or not is fully considered, the more general incremental cost model is established, the finite time consistency economic dispatching algorithm triggered by the distributed event is designed, and the incremental cost of the generator is finally consistent under the condition that the topological structure is kept switched through the algorithm. Meanwhile, an auxiliary variable is introduced, the auxiliary variable is updated by applying a finite time consistency economic dispatching algorithm, and then the increment cost is updated by applying the auxiliary variable, so that the optimal increment cost and the output power of the generator can be obtained under the power limitation of the generator. In addition, when the micro-grid is connected into the main grid, the algorithm can enable the micro-grid to output power required by the main grid. According to the invention, economic dispatching can be carried out on the micro-grid under the condition of switching the topological structure within finite time, and meanwhile, power required by a main power grid can be output by being connected into the main power grid.

Description

Technical Field

[0001] The invention belongs to the field of energy-saving and economic dispatching of smart grids, and in particular to an event-triggered microgrid distributed economic dispatching method considering the main grid. Background Art

[0002] A microgrid is a modern power system that combines advanced sensor technology, information technology, communication technology, and control technology. It optimizes power production, transmission, distribution, and use through real-time monitoring, automated control, and data analysis, improving the operating efficiency and reliability of the power grid. The microgrid can integrate renewable energy, support distributed generation, and achieve two-way interaction, making the power supply and demand more flexible.

[0003] Initially, the dispatching of microgrids mainly relied on centralized economic dispatching methods. In this dispatching mode, all the power generation resources and load demand data of the power system are concentrated in a central control center, which formulates power generation plans and dispatching strategies based on real-time data and prediction information. For example, genetic algorithms and particle swarm optimization. Although these methods are effective, due to their dependence on the central controller, the system cost is high and it is vulnerable to single-point failures. Therefore, distributed economic dispatching algorithms have become a new choice to solve this problem. The distributed method realizes dispatching through information exchange between various devices without a central controller, thus improving the anti-interference ability and information security of the system. At the same time, the topological structure is crucial in modern network and system design. First of all, it improves the flexibility and scalability of the network, enabling resources to be allocated and utilized more efficiently. Through different topological structures, the system can be dynamically adjusted according to actual needs to ensure optimal performance and reliability. Secondly, switching the topological structure can enhance the fault tolerance of the system. When a certain node or path fails, the network can quickly re-route traffic and reduce the service interruption time. This is particularly important for critical applications and services, ensuring business continuity. Finally, switching the topological structure also supports the compatibility of multiple network protocols and technologies, promoting technological innovation and development. Generally speaking, switching the topological structure not only improves the network performance but also provides a basis for future technological evolution, and is the key to realizing an efficient, reliable, and flexible network.

[0004] In addition, the microgrid can be connected to the main grid to help the main grid generate electricity or relieve the burden. During the low electricity consumption period, the microgrid stores excess electricity through the energy storage system and releases the stored electricity during the high electricity consumption period, thereby reducing the load fluctuation of the main grid. When the main grid generates electricity in remote areas, it can demand the microgrid to provide stable power, reducing the dependence on long-distance power transmission of the main grid. When a fault or load overload occurs in the main grid, the microgrid can help the main grid generate electricity or relieve the burden while reducing the dependence on the main grid. Summary of the Invention

[0005] (1) Technical problem to be solved

[0006] The object of the present invention is to provide an event-triggered microgrid distributed economic dispatch method considering the main power grid. When the communication network topology of the generator is periodically and fixedly switched, the algorithm can meet the constraints of minimum generator power generation cost and supply-demand balance of generator output power, and operate stably and economically. At the same time, when the microgrid is incorporated into the main power grid, it can also make the generator generate electricity according to the leader's demand at the incremental cost specified by the main power grid.

[0007] (2) Technical solution

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] Step S1: Model the microgrid economic dispatch problem, mainly including establishing a generator power generation cost model, supply-demand balance constraints at the power generation end and the power consumption end, and upper and lower limits constraints of the generator output power. Set the initial value of the output power of each generator and calculate the initial value of the incremental cost, which specifically includes the following steps:

[0010] Step S1-1: Establish the power generation cost model of the i-th generator in the microgrid economic dispatch as:

[0011]

[0012] where i = 1, 2,..., n; n is the number of generators in the microgrid; C i (P i (t)) is the power generation cost objective function of the i-th generator; P i (t) is the output power of the i-th generator; α i > 0, β i > 0 and γ i > 0 are the power generation cost coefficients of the i-th generator;

[0013] Step S1-2: Model the microgrid economic dispatch problem as:

[0014]

[0015]

[0016]

[0017] where, is the objective function; is the supply-demand balance constraint at the power generation end and the power consumption end and is the upper and lower limits constraint of the output power of the i-th generator, P D is the total power demand, is the minimum output power limit of the i-th generator, is the maximum output power limit of the i-th generator;

[0018] Step S1-3: Calculate the initial incremental cost based on the initial output power of each generator. Specifically: According to the initial output power of the i-th generator being P i (0), the initial incremental cost of the i-th generator is calculated through the initial output power of the generator as λ i (0) = 2α i P i (0) + β i .

[0019] Step S2: Select the incremental cost of the generator as the consensus variable, establish a more general incremental cost model, and design an event-triggered consensus algorithm based on periodically switched topologies to make the incremental cost reach consensus. The specific steps are as follows:

[0020] Step S2-1: Establish a more general incremental cost model:

[0021]

[0022] where m > 0 represents the control gain; sig(x) θ = [sign(x1)|x1| θ , …, sign(x n )|x n | θ T ; is the adjacency weight between generator i and generator j under the communication network topology switch; the communication network topology is periodically switched, and σ(t) ∈ Z (Z = {1, 2, ..., F}), where F is the number of communication network topologies; indicates that the microgrid is not connected to the main grid, indicates that the microgrid is connected to the main grid; ω i ∈ {0, 1}, ω i = 0 indicates that there is no direct communication between the i-th generator and the main grid, ω i = 1 indicates that there is direct communication between the i-th generator and the main grid; θ ∈ (0, 1); is the incremental cost of the i-th generator at time, is the incremental cost of the j-th generator at time; and ​They represent the latest event triggering time of the i-th generator and the j-th generator respectively, and the next event triggering time is defined as:

[0023]

[0024]

[0025] Among them, f i (t.σ(t)) and f j (t,σ(t)) are the event triggering functions of the i-th and j-th generators respectively;

[0026] Step S2-2: Design an event-triggered consensus algorithm based on periodic switching topology; establish a distributed event trigger condition f i (t.σ(t))>0; for The event trigger function of the i-th generator is

[0027]

[0028] in, The event triggering mechanism of the jth generator is the same as that of the i-th generator.

[0029] Step S2-3: updating the incremental cost of the generator and determining whether the incremental cost reaches consistency;

[0030] When the microgrid is not integrated into the main grid, it is determined whether the incremental cost reaches average consistency; if the incremental cost reaches average consistency, that is, in If Ω1>0 is a very small deviation coefficient, then go to step 3, otherwise continue to use the finite time consistency economic dispatch algorithm to update the incremental cost of the generator;

[0031] When the microgrid is connected to the main grid, it is determined whether the incremental cost reaches the leader-follower consistency; if the incremental cost reaches the leader-follower consistency, that is, |λ i (t)-D∣≤Ω1, then go to step 3, otherwise continue to use the finite time consistency economic dispatch algorithm to update the incremental cost of the generator;

[0032] Step S3: Calculate the power output of the generator through incremental cost; when the generator is not connected to the main power grid, at the moment when the incremental cost reaches the average consistency, set the initial value of the auxiliary variable according to the output power, set the auxiliary variable model, update the incremental cost with the auxiliary variable, and then calculate the generator output power with the incremental cost, and adjust the generator output power until all auxiliary variables reach consistency; when the generator is connected to the main power grid, reassign the output power of the generator according to the constraints of the maximum and minimum values of the generator, and then calculate the total output power, and the power mismatch is compensated by the main power grid.

[0033] Step S4: Output the incremental cost and output power of the generator.

[0034] Furthermore, step S3 specifically includes the following steps:

[0035] Step S3-1: Let the moment when the incremental cost reaches the average consistency be t * , and the power output of the generator can be calculated through the incremental cost λ i (t * ) as:

[0036]

[0037] Step S3-2: Adjust the output power of the generator according to the constraint conditions; first, determine whether the microgrid is connected to the main power grid. If the microgrid is not connected to the main power grid, then introduce auxiliary variables * and φ (t i ) at the moment of t * , and set the initial values of the two auxiliary variables as:

[0038]

[0039]

[0040] Among them, when let when let Furthermore, for t≥t * , establish the auxiliary variable model as:

[0041]

[0042]

[0043] Update the incremental cost of the generator with the auxiliary variable as Calculate the output power of the generator with the incremental cost as Adjust the output power of the generator; specifically: determine whether the output power of each generator exceeds the maximum and minimum output powers; when the generator power output is, set the generator power output to When the generator power output is, set the generator power output to When the generator power output is, keep the generator power output unchanged Determine whether all auxiliary variables reach consistency; if all auxiliary variables reach consistency, that is, simultaneously satisfy and where are the average values of the auxiliary variables and φ i (t); then enter step 4, otherwise continue to update the incremental cost;

[0044] If the microgrid is connected to the main grid, adjust the output power of the generator, specifically: determine whether the output power of each generator exceeds the maximum and minimum output powers; when the generator power output is, set the generator power output to When the generator power output is, set the generator power output to When the generator power output is, keep the generator power output unchanged P i (t * ) = P i (t); calculate the total output power based on the output powers of each generator Power mismatch is compensated by the main grid; the total power generation, when is, the microgrid can transmit the excess power to the main grid or store it; when is, the microgrid obtains the missing power generation from the main grid.

[0045] (III) Beneficial effects

[0046] The present invention provides an event-triggered microgrid distributed economic dispatch method considering the main grid. Compared with the prior art, the beneficial effects of the present invention are:

[0047] 1. The microgrid distributed economic dispatch algorithm proposed by the present invention simultaneously considers two cases of being connected to the main grid and not being connected to the main grid. The established incremental cost model is more general and can achieve average consistency and leader-follower consistency through parameter settings.

[0048] 2. The proposed solution of the present invention is event-triggered. The sampling signal sent by each generator to adjacent generators is determined by the error between the current sampling state and the most recently sent sampling state. The event-triggered mechanism proposed by the present invention reduces the number of state signals transmitted through the multi-agent network, thereby saving communication resources and reducing the communication burden. Moreover, the distributed economic dispatch method proposed by the present invention satisfies both the generator supply-demand balance constraint and the generator output power limit.

[0049] 3. The proposed microgrid distributed economic dispatch algorithm of the present invention can still achieve consistency in the incremental cost of generators even when the topology of the generator communication network is variable. That is to say, even if the topology structure changes, it can still output the actual optimal incremental cost to complete the economic dispatch problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is the IEEE 30-bus standard power network;

[0051] Figure 2 is the switching topology diagram of each generator when the microgrid of the present invention is not connected to the main grid;

[0052] Figure 3 is the variation diagram of the incremental cost λ i (t) of each generator with time when the microgrid of the present invention is not connected to the main grid;

[0053] Figure 4 is the variation diagram of the output power P i (t) of each generator with time when the microgrid of the present invention is not connected to the main grid;

[0054] Figure 5 is the total output power of the generators when the microgrid of the present invention is not connected to the main grid and the total power demand P D with time;

[0055] Figure 6 is the event trigger time diagram of each generator when the microgrid of the present invention is not connected to the main grid;

[0056] Figure 7 is the variation diagram of the auxiliary variable with time when the microgrid of the present invention is not connected to the main grid;

[0057] Figure 8 is the variation diagram of the auxiliary variable φ i (t) with time when the microgrid of the present invention is not connected to the main grid;

[0058] Figure 9 is the variation of the total cost with time when the microgrid of the present invention is not connected to the main grid;

[0059] Figure 10 For the IEEE 30 - node standard power network when the micro - grid is integrated into the main grid in the present invention;

[0060] Figure 11 For the switching topology diagram of each generator when the micro - grid is integrated into the main grid in the present invention;

[0061] Figure 12 For the incremental cost λ i (t) of each generator over time when the micro - grid is integrated into the main grid in the present invention;

[0062] Figure 13 For the output power P i (t) of each generator over time when the micro - grid is integrated into the main grid in the present invention;

[0063] Figure 14 For the total output power of the generators when the micro - grid is integrated into the main grid in the present invention and the total power demand P D over time in the present invention;

[0064] Figure 15 For the event - trigger time diagram of each generator when the micro - grid is integrated into the main grid in the present invention;

[0065] Figure 16 For the flow chart of a distributed economic dispatch method for a micro - grid based on finite - time event - triggered in the present invention. Detailed implementation manners

[0066] The following details the implementation manners of the present invention. Examples of the implementation manners are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The implementation manners described by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0067] Example 1:

[0068] The flow of an event - triggered micro - grid distributed economic dispatch method considering the main grid provided in this example is as Figure 16 shown and specifically includes the following steps

[0069] Step S1: Model the micro - grid economic dispatch problem, mainly including establishing a generator power generation cost model, supply - demand balance constraints at the power generation end and the power consumption end, and upper and lower limits constraints on the output power of the generators, setting the initial values of the output power of each generator and calculating the initial values of the incremental costs.

[0070] In this example, step S1 specifically includes:

[0071] Step S1-1: Establish the power generation cost model of the i-th generator in the microgrid economic dispatch as follows:

[0072]

[0073] where i = 1, 2,..., n; n is the number of generators in the microgrid; C i (P i (t)) is the power generation cost objective function of the i-th generator; P i (t) is the output power of the i-th generator; α i > 0, β i > 0, and γ i > 0 are the power generation cost coefficients of the i-th generator;

[0074] Step S1-2: Model the microgrid economic dispatch problem as follows:

[0075]

[0076]

[0077]

[0078] where, is the objective function; is the supply-demand balance constraint between the power generation side and the power consumption side, and is the upper and lower limit constraint of the output power of the i-th generator, P D is the total power demand, is the minimum output power limit of the i-th generator, is the maximum output power limit of the i-th generator;

[0079] Step S1-3: Calculate the initial value of the incremental cost according to the initial value of the output power of each generator. Specifically, according to the initial value of the output power of the i-th generator being P i (0), calculate the initial value of the incremental cost of the i-th generator as λ i (0) = 2α i P i (0) + β i .

[0080] Step S2: Select the incremental cost of the generator as the consensus variable, establish a more general incremental cost model, and design an event-triggered consensus algorithm based on periodic switching topology to make the incremental cost reach consensus.

[0081] In this embodiment, Step S2 specifically includes:

[0082] Step S2-1: Establish a more general incremental cost model:

[0083]

[0084] where m > 0 represents the control gain; sig(x) θ = [sign(x1)|x1| θ ,…,sign(x n )|x n | θ T ; is the adjacency weight between generator i and generator j under the communication network topology switch; the communication network topology is periodically switched, and σ(t) ∈ Z (Z = {1,2,...,F}), where F is the number of communication network topologies; indicates that the microgrid is not connected to the main grid, indicates that the microgrid is connected to the main grid; ω i ∈ {0, 1}, ω i = 0 indicates that there is no direct communication between the i-th generator and the main grid, and ω i = 1 indicates that there is direct communication between the i-th generator and the main grid; θ ∈ (0, 1); is the incremental cost of the i-th generator at time, is the incremental cost of the j-th generator at time; and respectively represent the latest event trigger times of the i-th generator and the j-th generator, and the next event trigger time is defined as:

[0085]

[0086]

[0087] where f i (t,σ(t)) and f j (t,σ(t)) are the event trigger functions of the i-th and j-th generators respectively;

[0088] Step S2-2: Design an event-triggered consensus algorithm based on periodically switched topologies; establish a distributed event trigger condition as f i (t,σ(t)) > 0; for the event trigger function of the i-th generator is

[0089]

[0090] where,​ The event trigger mechanism of the j-th generator is the same as that of the i-th generator.

[0091] Step S2-3: Update the incremental cost of the generator and determine whether the incremental cost reaches consistency.

[0092] When the microgrid is not connected to the main grid, determine whether the incremental cost reaches average consistency; if the incremental cost reaches average consistency, that is where Ω1>0 is a very small deviation coefficient, then go to step 3, otherwise continue to use the finite-time consensus economic dispatch algorithm to update the incremental cost of the generator.

[0093] When the microgrid is connected to the main grid, determine whether the incremental cost reaches leader-follower consistency; if the incremental cost reaches leader-follower consistency, that is ∣λ i (t)-D∣≤Ω1, then go to step 3, otherwise continue to use the finite-time consensus economic dispatch algorithm to update the incremental cost of the generator.

[0094] Step S3: Calculate the power output of the generator through the incremental cost; when the generator is not connected to the main grid, at the moment when the incremental cost reaches average consistency, set the initial value of the auxiliary variable according to the output power, set the auxiliary variable model, update the incremental cost with the auxiliary variable, and then calculate the generator output power with the incremental cost, and adjust the generator output power until all the auxiliary variables reach consistency; when the generator is connected to the main grid, reassign the output power of the generator according to the constraints of the maximum and minimum values of the generator, and then calculate the total output power, and the power mismatch is compensated by the main grid.

[0095] In this embodiment, step S3 specifically includes:

[0096] Step S3-1: Let the moment when the incremental cost reaches average consistency be t * , and the power output of the generator can be calculated through the incremental cost λ i (t * ) as:

[0097]

[0098] Step S3-2: First, determine whether the microgrid is connected to the main grid. If the microgrid is not connected to the main grid, then introduce auxiliary variables * and φ and φ i (t * ) at time t, and set the initial values of the two auxiliary variables as:

[0099]

[0100]

[0101] Among them, when let When let Furthermore, for t≥t * , establish an auxiliary variable model as:

[0102]

[0103]

[0104] Update the incremental cost of the generator with the auxiliary variable as Calculate the output power of the generator with the incremental cost as Adjust the output power of the generator; specifically: judge whether the output power of each generator exceeds the maximum and minimum output powers; when the generator power output is, let the generator power output be When the generator power output is, let the generator power output be When the generator power output is, let the generator power output remain unchanged Judge whether the auxiliary variables all reach consistency; if the auxiliary variables all reach consistency, that is, simultaneously satisfy and where are the average values of the auxiliary variables and φ i (t) respectively; then enter step 4, otherwise continue to update the incremental cost;

[0105] If the microgrid is connected to the main grid, then adjust the output power of the generator, specifically: judge whether the output power of each generator exceeds the maximum and minimum output powers; when the generator power output is, let the generator power output be When the generator power output is, let the generator power output be When the generator power output is, let the generator power output remain unchanged P i (t * ) = P i (t); Calculate the total output power based on the output powers of each generator Power mismatch is compensated by the main grid; total power generation, when When there is excess power, the microgrid can transmit the excess power to the main grid or store it; when there is a shortage, the microgrid obtains the missing generated power from the main grid.

[0106] Step S4: Output the incremental cost of the generator and the output power.

[0107] Embodiment 2:

[0108] Embodiment 2 uses an event-triggered distributed economic dispatch method for a microgrid considering the main grid to perform numerical simulation on a power network with the IEEE 30-node standard. There are a total of 6 generators. Figure 1 is the IEEE 30-node standard power network, and its communication topology is as Figure 2 shown.

[0109] When the microgrid is not connected to the main grid, the objective function of the power generation cost is Table 1 shows the power generation cost coefficients α i , β i and γ i values, and Table 2 shows the generator output power limit values; input the initial values and system-related parameters, the total power demand P D = 180 MW, the initial values of the generator output powers are P1(0) = 30 MW, P2(0) = 40 MW, P3(0) = 30 MW, P4(0) = 30 MW, P5(0) = 40 MW, and P6(0) = 10 MW. From the calculation formula λ i (0) = 2α i P i (0)+β i , the initial values of the incremental costs can be obtained as λ1(0) = 6.86 $ / MW, λ2(0) = 9.65 $ / MW, λ3(0) = 8.83 $ / MW, λ4(0) = 8.94 $ / MW, λ5(0) = 9.09 $ / MW, and λ6(0) = 5.20 $ / MW; after convergence at t = 2.63 s, auxiliary variables are introduced, and the initial values of the auxiliary variables are φ1(2.64) = 5.32, φ2(2.64) = 6.14, φ3(2.64) = 4.76, φ4(2.64) = 6.10, φ5(2.64) = 6.76, and φ6(2.64) = 0; the coefficient m = 20; k i = [2, 8, 3, 1, 4, 1]; θ = 99 / 101; the constraint parameter Ω1 = 0.001.

[0110] According to the communication topology diagram, the adjacency matrix is obtained:

[0111]

[0112]

[0113] Table 1

[0114]

[0115]

[0116] Table 2

[0117]

[0118] Substitute the above parameters into the event-triggered microgrid distributed economic dispatch method. From the given data, verify the effectiveness of the present invention through numerical simulation. From Figure 3 it can be seen that at the convergence time t = 2.64 s, the optimal incremental cost values are obtained as λ1 = λ2 = λ3 = λ4 = λ5 = λ6 = 8.10 $ / MW. From Figure 4 it can be seen that at t = 2.64 s, the generator output powers are respectively P1 = 36.60 MW, P2 = 30.06 MW, P3 = 26.52 MW, P4 = 24.88 MW, P5 = 33.31 MW, and P6 = 28.13 MW. From Figure 4 it can be seen that P6 = 28.13 MW exceeds the output power limit of generator 6. After 2.64 seconds, introduce auxiliary variables to adjust the generator output power. At t = 3.04 s, the auxiliary variables and φ i (t) both reach consistency. The optimal incremental cost values are λ1 = λ2 = λ3 = λ4 = λ5 = 8.38 $ / MW and λ6 = 6.80 $ / MW, and the obtained values are P1 = 38.09 MW, P2 = 31.86 MW, P3 = 27.86 MW, P4 = 26.59 MW, P5 = 35.20 MW, and P6 = 20 MW, satisfying the generator output power limit constraint. Figure 5 Shows the total output power of the generators The total power demand P D = 180 MW, satisfying the generator supply-demand balance constraint. Figure 6 Shows the trigger moments of each generator under event-triggered conditions. Figure 7 Shows the auxiliary variable changing with time, achieving average consistency. Figure 8 Shows the change of the auxiliary variable φ i (t) with time, achieving consistency convergence. Figure 9 Shows the change of the total cost with time, achieving average consistency.

[0119] Example 3:

[0120] Example 3 uses the algorithm proposed by the finite-time distributed event-triggered economic dispatch of the microgrid to perform numerical simulation on the IEEE 30-node standard power network. There are a total of 6 generators. Figure 10 It is the IEEE 30-node standard power network, and its communication topology is as Figure 11 shown.

[0121] In the case where the microgrid is connected to the main grid, the objective function of the generation cost is Input the initial values and system-related parameters. The coefficient m = 20, k i = [0.2, 0.2, 0.2, 0.2, 0.2, 0.2], θ = 99 / 101, the constraint parameter Ω1 = 0.001, the total power demand P D = 180 MW, the initial values of the generator output powers are P1(0) = 30 MW, P2(0) = 40 MW, P3(0) = 30 MW, P4(0) = 30 MW, P5(0) = 40 MW, and P6(0) = 10 MW. From the calculation formula λ i (0) = 2α i P i (0) + β i , the initial values of the incremental costs can be obtained as λ1(0) = 6.86 $ / MW, λ2(0) = 9.65 $ / MW, λ3(0) = 8.83 $ / MW, λ4(0) = 8.94 $ / MW, λ5(0) = 9.09 $ / MW, and λ6(0) = 5.20 $ / MW. Introduce the leader D = 10. Based on the given data, the effectiveness of the present invention is verified through numerical simulation. Figure 12 In it, the convergence time t = 14.1 s, and all the incremental costs converge to the leader D, λ1 = λ2 = λ3 = λ4 = λ5 = λ6 = 10 $ / MW. λ6 = 10 exceeds the incremental cost limit of generator 6, and λ6 is limited to 6.8. From Figure 13 it can be seen the change situation of the generator output power. λ6 = 10 exceeds the incremental cost limit of generator 6. After 14.1 seconds, adjust the incremental cost of the generator. The incremental costs are λ1 = λ2 = λ3 = λ4 = λ5 = 10 $ / MW, λ6 = 6.80 $ / MW, and P1 = 46.69 MW, P2 = 42.23 MW, P3 = 35.56 MW, P4 = 36.45 MW, P5 = 46.13 MW, P6 = 20 MW are obtained, which satisfy the constraints of the generator output power limit. Figure 14 shows the change of the total power. The total power is initially 180 MV, and the main grid requires D = 10. The total power generation delivers 46.91 MW to the main grid. Figure 15 shows the trigger moments under the event-triggering conditions of each generator.

[0122] It should be noted that the above are only preferred examples of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for distributed economic dispatch of microgrids triggered by events taking into account the main grid, characterized in that: The following steps are involved: Step S1: Modeling the economic dispatch problem of the microgrid mainly includes establishing the generator power generation cost model, the supply and demand balance constraints at the power generation end and the power consumption end, and the upper and lower limits of the generator output power, setting the initial value of each generator output power and calculating the initial value of the incremental cost, which specifically includes the following steps: Step S1-1: Establish the power generation cost model of the i-th generator in the microgrid economic dispatch as follows: Where i = 1, 2, ..., n; n is the number of generators in the microgrid; C i (P i (t)) is the power generation cost objective function of the i-th generator; P i (t) is the output power of the i-th generator; α i >0, β i >0 and γ i >0 is the power generation cost coefficient of the i-th generator; Step S1-2: The microgrid economic dispatch problem is modeled as: in, is the objective function; To balance the supply and demand of power generation and consumption is the upper and lower limit constraints of the output power of the i-th generator, P D is the total power demand, is the minimum output power limit of the i-th generator, is the maximum output power limit of the i-th generator; Step S1-3: Calculate the initial value of the incremental cost according to the initial value of the output power of each generator, specifically: according to the initial value of the output power of the i-th generator, P i (0), the initial value of the incremental cost of the i-th generator is calculated by the initial value of the generator output power as λ i (0) = 2α i P i (0)+β i ; Step S2: Select the incremental cost of the generator as the consistency variable, establish a more general incremental cost model, and design an event-triggered consistency algorithm based on periodic switching topology to make the incremental cost consistent. The specific steps are as follows: Step S2-1: Establish a more general incremental cost model: Where m>0 indicates control gain; sig(x) θ =[sign(x1)|x1| θ ,…,sign(x n )|x n | θ ] T ; is the adjacency weight between generator i and generator j under the switching of communication network topology; is switched periodically, and σ(t)∈Z(Z={1,2,...,F}), where F is the number of communication network topologies; It means that the microgrid is not connected to the main grid. Indicates that the microgrid is connected to the main grid; ω i ∈{0, 1}, ω i =0 means that there is no direct communication between the i-th generator and the main grid, ω i =1 means that there is direct communication between the i-th generator and the main grid; θ∈(0,1); For the i-th generator The incremental cost of time, For the jth generator The incremental cost of the moment; and They represent the latest event triggering time of the i-th generator and the j-th generator respectively, and the next event triggering time is defined as: Among them, f i (t.σ(t)) and f j (t,σ(t)) are the event triggering functions of the i-th and j-th generators respectively; Step S2-2: Design an event-triggered consensus algorithm based on periodic switching topology; establish a distributed event trigger condition f i (t.σ(t))>0; for The event trigger function of the i-th generator is in, The event triggering mechanism of the jth generator is the same as that of the ith generator; Step S2-3: updating the incremental cost of the generator and determining whether the incremental cost reaches consistency; When the microgrid is not integrated into the main grid, it is determined whether the incremental cost reaches average consistency; if the incremental cost reaches average consistency, that is, in If Ω1>0 is a very small deviation coefficient, then go to step 3, otherwise continue to use the finite time consistency economic dispatch algorithm to update the incremental cost of the generator; When the microgrid is connected to the main grid, it is determined whether the incremental cost reaches the leader-follower consistency; if the incremental cost reaches the leader-follower consistency, that is, |λ i (t)-D∣≤Ω1, then go to step 3, otherwise continue to use the finite time consistency economic dispatch algorithm to update the incremental cost of the generator; Step S3: Calculate the power output of the generator by using the incremental cost; when the generator is not connected to the main grid, at the moment when the incremental cost reaches the average consistency, set the initial value of the auxiliary variable according to the output power, set the auxiliary variable model, update the incremental cost with the auxiliary variable, and then calculate the generator output power with the incremental cost, and adjust the generator output power until the auxiliary variables are consistent; when the generator is connected to the main grid, re-assign the output power of the generator according to the constraints of the maximum and minimum values ​​of the generator, and then calculate the total output power, and the power mismatch is compensated by the main grid; Step S4: Output the incremental cost and output power of the generator.

2. The method for distributed economic dispatching of microgrids triggered by events taking into account the main power grid according to claim 1, characterized in that: Step S3 specifically includes the following steps: Step S3-1: Let the time when the incremental cost reaches the average consistency be t * , through the incremental cost λ i (t * ) can be calculated that the power output of the generator is: Step S3-2: First determine whether the microgrid is integrated into the main grid. If the microgrid is not integrated into the main grid, then * Always introduce auxiliary variables and φ i (t * ), set the initial values ​​of the two auxiliary variables as follows: Among them, when make when make Then for t≥t * , the auxiliary variable model is established as: The incremental cost of updating the generator with the auxiliary variable is The output power of the generator is calculated using the incremental cost as Adjust the generator output power; specifically: determine whether the output power of each generator exceeds the maximum and minimum output power values; when the generator power output When the generator power output is When the generator power output When the generator power output is When the generator power output When the generator power output remains unchanged Determine whether the auxiliary variables are consistent; if the auxiliary variables are consistent, that is, they satisfy and in Auxiliary variables and φ i (t); then go to step 4, otherwise continue to update the incremental cost; If the microgrid is connected to the main grid, the generator output power is adjusted. Specifically, the output power of each generator is determined to be greater than the maximum and minimum output power values. When the generator power output is When the generator power output When the generator power output is When the generator power output When the generator power output is set to remain unchanged, P i (t * )=P i (t); Calculate the total output power based on the output power of each generator Power Mismatch Compensated by the main grid; total power generation, when When the microgrid can transmit the excess electricity to the main grid or store it; when When the power is off, the microgrid obtains the missing power from the main grid.

Images