An operation method of an electricity-hydrogen coupled distribution system considering comprehensive demand response

Abstract

The present invention relates to the technical field of new energy power systems, and in particular to an operation method of an electric-hydrogen coupled distribution system considering comprehensive demand response, comprising establishing a three-stage model of production, storage and use of a hydrogen energy storage system; establishing a comprehensive demand response strategy for the electric-hydrogen coupled distribution system; establishing and solving an optimized operation model of the electric-hydrogen coupled distribution system with the goal of minimizing system operation cost; establishing a wind-solar unit, a hydrogen energy storage system, and a power output situation diagram of the upper power grid connection and a load comparison curve before and after demand response to judge the system operation economy and the effectiveness of demand response; changing the demand response strategy of the electric-hydrogen coupled distribution system and the proportion of loads participating in demand response, calculating the system economic operation cost and the amount of new energy consumption under different demand response strategies and proportions of loads participating in demand response, thereby judging the feasibility and effectiveness of the comprehensive demand response strategy, and providing guidance for coordinating the economic and flexible operation of the distribution system and the new energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy power systems, and in particular to an operation method of an electric-hydrogen coupled distribution system taking comprehensive demand response into consideration. Background Art

[0002] Since the "carbon peak" and "carbon neutrality" goals were proposed, my country has vigorously promoted energy transformation and actively built a green, low-carbon, safe and efficient energy system. The development of renewable energy, mainly wind and solar energy, is an important support for my country's energy transformation. It can fundamentally promote the clean and low-carbonization of the power system. The access of a high proportion of renewable energy is an important feature of the future power system construction. The access of a large number of distributed renewable energy sources has put forward higher requirements for the exploration of the flexibility resource potential of the distribution network, promoting the consumption of renewable energy, and ensuring the safe and economical operation of the distribution system. Hydrogen energy, as a green, carbon-free, flexible and efficient secondary energy with rich application scenarios, is an ideal medium to promote the large-scale development of distributed renewable energy in the distribution network. As hydrogen energy storage technology continues to mature, the coupling relationship between the distribution network and the hydrogen energy system is becoming closer.

[0003] As a flexible means of regulation, the demand-side response of electric load can effectively improve the renewable energy absorption capacity and promote the efficient and economic operation of the distribution system. With the development of clean and efficient hydrogen energy storage technology, the user-side hydrogen demand does not need to meet the real-time supply and demand balance, which makes the hydrogen load also have certain flexibility and meet the conditions for participating in demand response. However, most of the existing studies on the optimized operation of distribution systems only regard the demand response of electric load as a flexible regulation resource, and do not consider the impact of the flexible characteristics of hydrogen load on the optimized operation of distribution systems. In addition, the existing studies that consider the flexible characteristics of hydrogen load do not comprehensively consider the different flexible characteristics of various types of hydrogen loads. In the existing actual distribution system, hydrogen loads come from different fields, and the industrial and transportation fields are the main sources. At present, there is a lack of an optimized operation method for the electric-hydrogen coupled distribution system that comprehensively considers the flexible characteristics of various types of hydrogen loads and the comprehensive demand response of electric-hydrogen. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an operation method of an electric-hydrogen coupled distribution system considering comprehensive demand response. The specific technical solution is as follows:

[0005] An operation method of an electric-hydrogen coupled power distribution system considering comprehensive demand response is characterized by comprising the following steps: Step S1, establishing a three-stage model of production-storage-use of a hydrogen energy storage system based on the electric-hydrogen coupled power distribution system architecture;

[0006] Step S2, based on the flexible characteristics of electric and hydrogen loads, establish a comprehensive demand response strategy for the electric and hydrogen coupled distribution system; based on the different characteristics of electric loads, divide the electric loads into rigid electric loads, interruptible electric loads and transferable electric loads according to their ability to participate in demand response, and establish different electric load demand response strategies; based on the transferability of hydrogen loads, establish a hydrogen load demand response strategy;

[0007] Step S3, considering the comprehensive demand response strategy, based on the three-stage model of hydrogen energy storage system production-storage-use, and aiming at minimizing the system operation cost, establish an optimization operation model of the electric-hydrogen coupled distribution system;

[0008] Step S4, solving the optimal operation model of the electric-hydrogen coupled power distribution system under the operating constraints of the electric-hydrogen coupled power distribution system, and optimizing the scheduling of the electric-hydrogen coupled power distribution system;

[0009] Step S5, according to the optimization dispatch result of the electric-hydrogen coupled distribution system, establish a system wind-solar unit, hydrogen energy storage system, and upper-level power grid interconnection power output diagram and a load comparison curve before and after demand response in the electric-hydrogen coupled distribution system, so as to judge the operation economy of the electric-hydrogen coupled distribution system and the effectiveness of demand response;

[0010] Step S6, change the demand response strategy of the electric-hydrogen coupled distribution system and the proportion of load participating in demand response, and repeat steps S4 and S5 to calculate the economic operation cost and new energy consumption of the electric-hydrogen coupled distribution system under different demand response strategies and proportions of load participating in demand response, so as to judge the feasibility and effectiveness of the comprehensive demand response strategy.

[0011] Preferably, the step S1 specifically includes the following steps:

[0012] Step S11, establish a hydrogen energy storage system hydrogen production stage equipment model - a proton exchange membrane based electrolyzer hydrogen production model:

[0013] H P2H,t =P P2H,t α P2H ; (1)

[0014]

[0015] Where: H P2H,t , P P2H,t They represent the equivalent hydrogen production power of the electrolyzer at time t and the energy consumption power of the electrolyzer at time t respectively; α P2H It represents the conversion efficiency of electrolyzer; Indicates the maximum operating power of the electrolyzer at time t.

[0016] Step S12, establishing a hydrogen storage tank hydrogen storage model, a hydrogen storage stage equipment model of a hydrogen energy storage system:

[0017] The amount of hydrogen stored in the hydrogen storage tank is expressed as follows:

[0018]

[0019] In the formula, SOH i,t Indicates the hydrogen storage capacity of hydrogen storage tank i during period t; SOH i,t-1 represents the hydrogen storage capacity of hydrogen storage tank i during period t-1; is a binary variable, indicating the hydrogen filling state of hydrogen storage tank i during period t. When it is equal to 1, it means that hydrogen storage tank i is in the hydrogen filling state during period t; when it is equal to 0, it means that hydrogen storage tank i is not in the hydrogen filling state during period t. de,t represents the hydrogen load demand during period t; H H2P,t It represents the equivalent hydrogen consumption of the fuel cell at time t; △t represents the unit time period.

[0020] The hydrogen storage tank capacity constraints and operation constraints are expressed as follows:

[0021]

[0022]

[0023]

[0024] in, Respectively represent the upper and lower limits of the capacity of hydrogen storage tank i; It represents the initial hydrogen storage capacity ratio of hydrogen storage tank i in period t; They represent the hydrogen storage capacity of hydrogen storage tank i at the initial period and the end period of time t respectively;

[0025] Step S13, establishing a hydrogen energy storage system hydrogen consumption stage equipment model - a hydrogen fuel cell hydrogen consumption model:

[0026]

[0027]

[0028] Among them, P H2P,t Indicates the electric power generated by burning the battery at time t; β H2P represents the fuel cell conversion efficiency, Indicates the maximum operating power of the hydrogen fuel cell at time t.

[0029] Preferably, the step S2 specifically includes the following steps:

[0030] Step S21, according to different electric load demand response strategies, the electric loads participating in demand response include interruptible electric loads and transferable electric loads, as follows:

[0031]

[0032]

[0033] in, They represent the electric load of user i participating in demand response, the electric load after demand response, and the electric load before demand response in period t respectively; They represent the interruptible load and transferable load of user i participating in demand response in period t respectively;

[0034] Step S22, two types of electric load demand response models, namely, interruptible electric load and transferable electric load, are established as follows:

[0035]

[0036]

[0037]

[0038] in, They represent the proportion of interruptible load and transferable load participating in the response respectively; They represent the interruptible load and transferable load of user i in period t respectively; A positive value indicates an outgoing load, and a negative value indicates an incoming load; T is the total time period of the dispatch cycle;

[0039] Step S23, according to the hydrogen load demand response strategy, a hydrogen load demand response model is established as follows:

[0040]

[0041]

[0042]

[0043] in, They represent the hydrogen load of user i participating in demand response, the hydrogen load after demand response, and the hydrogen load before demand response during period t respectively; Positive means outgoing load, negative means incoming load; Indicates the proportion of hydrogen load participating in demand response.

[0044] Preferably, step S3 comprises the following steps:

[0045] Step S31, the optimization operation model of the electricity-hydrogen coupled distribution system is as follows:

[0046] minC tol =C upgrid +C loss +C DR +C p ; (17)

[0047] Among them, C tol represents the total economic operation cost of the distribution network-hydrogen energy system; C upgrid , C loss , C DR , C p They represent the cost of purchasing and selling electricity from the superior power grid, the cost of distribution network loss, the cost of compensation for hydrogen demand response, and the penalty cost for wind and solar power abandonment;

[0048] Cost of purchasing and selling electricity to the upper-level power grid C upgrid As shown below:

[0049]

[0050] Among them, P grid,t Indicates the amount of electricity traded between the system and the superior power grid during period t. A positive value indicates that the system purchases electricity from the superior power grid, and a negative value indicates that the system sells electricity to the superior power grid. They represent the price of electricity purchased or sold by the system from the upper power grid during period t; the distribution network loss cost C loss As shown below:

[0051]

[0052] Among them, c loss Indicates the unit energy loss cost; U i,t , U j,t ,θ ij,t , G ij They represent the voltage of node i, the voltage of node j, the phase angle difference between the voltages of nodes i and j, and the conductance of branch ij during period t respectively; N is the number of nodes;

[0053] The demand response compensation cost includes the electric hydrogen demand response compensation cost, the interruptible electric load demand response compensation cost, and the transferable wind and solar power abandonment penalty cost C p As shown below:

[0054]

[0055] In the formula, c p,PV 、c p,WT They represent the penalty costs for unit solar power abandonment and wind power abandonment respectively; They represent the predicted output and actual output of photovoltaic i at time t, They represent the predicted output and actual output of wind turbine i at time t respectively; N PV 、N WT Respectively represent the number of photovoltaic and wind turbines;

[0056] Electric hydrogen demand response compensation cost C DR As shown below:

[0057] C DR=C DR,int +C DR,shif +C HDR ; (twenty one)

[0058] Among them, C DR,int , C DR,shif , C HDR They respectively represent the demand response compensation cost for interruptible electric load, the demand response compensation cost for transferable electric load, and the demand response compensation cost for hydrogen load.

[0059] Preferably, the interruptible electric load demand response compensation cost C DR,int As shown below:

[0060]

[0061] in, represents the unit compensation cost of demand response for user i’s interruptable load, represents the interruptible load of user i participating in demand response during period t;

[0062] The compensation cost of shiftable electric load demand response C DR,shif As shown below:

[0063]

[0064] represents the unit compensation cost of user i’s transferable electric load demand response; represents the transferable load of user i participating in demand response during period t;

[0065] Hydrogen load demand response compensation cost C HDR As shown below:

[0066]

[0067] represents the unit compensation cost of hydrogen load demand response for user i, It indicates that user i participates in demand response hydrogen load during period t.

[0068] Preferably, the operating constraints of the electric-hydrogen coupled distribution system in step S4 include network flow constraints, wind and solar power unit output constraints, demand response constraints, and hydrogen energy storage system equipment constraints;

[0069] The network power flow constraint is described by a branch power flow model based on second-order cone relaxation, as follows:

[0070]

[0071] Where v(j) and w(j) represent the first node set and the last node set of the branch connected to node j respectively; Pij,t represents the active power of branch ij at time t, P jk,t represents the active power of branch jk at time t; r ij represents the line resistance of branch ij, represents the square of the current in branch ij at time t; P j,t represents the active power injected into node j during period t; Q ij,t represents the reactive power of branch ij at time t, Q jk,t represents the reactive power of branch jk at time t; x ij represents the line reactance of branch ij, Q j,t represents the reactive power injected into node j during period t; It represents the power consumption of the electrolytic cell during period t, It indicates that the combustion battery j node is connected to generate electric power at time t; represents the square of the voltage at node j during period t, represents the square of the voltage at node i during period t, represents the active power provided by the upper power grid to node j during period t, represents the active power connected by photovoltaic power to node j in period t; represents the active power connected by the wind turbine at node j during period t; represents the active load of node j in period t; represents the reactive power provided by the upper power grid to node j during period t, represents the reactive power connected by the wind turbine to node j during period t; represents the reactive load of node j in period t; They represent the upper and lower limits of the square of the voltage at node i during period t respectively; They represent the upper and lower limits of the square of the current of branch ij at time t respectively; the output constraints of the wind and solar generator set are as follows:

[0072]

[0073] Among them, P i PV,max , P i WT,max They represent the upper limits of active power connected to the i-node by photovoltaic and wind turbines respectively;

[0074] The demand response constraint is as follows:

[0075]

[0076] The equipment constraints of the hydrogen energy storage system are as follows:

[0077]

[0078] Preferably, in step S4, the MOSEK commercial solver is called by using the MATLAB platform to solve the optimization operation model of the electric-hydrogen coupled distribution system.

[0079] Preferably, the calculation method of the load participation demand response effect in step S5 is as follows:

[0080]

[0081] Among them, P t LDR , P t 0 They represent the electric load after participating in demand response and the electric load before demand response in period t respectively; They represent the hydrogen load after participating in demand response and the hydrogen load before demand response in period t respectively; ξ, ξ H They respectively represent the effects of participating in the electric load demand response and participating in the hydrogen load demand response.

[0082] Preferably, the step S6 specifically includes the following steps:

[0083] Step S61, change the demand response strategy and the proportion of electric and hydrogen loads participating in the demand response. The proportion of loads participating in the demand response is as follows:

[0084]

[0085] Among them, P t DR , P t 0 They represent the electric load participating in demand response and the electric load before demand response in period t respectively; They represent the hydrogen load participating in demand response and the hydrogen load before demand response in period t, respectively; λ, λ H They respectively represent the proportion of participating in electric load demand response and participating in hydrogen load demand response.

[0086] Change λ, λ H Select values ​​to establish the electric and hydrogen loads not participating in demand response, only the electric loads participating in demand response, only the hydrogen loads participating in demand response, electric and hydrogen loads combined demand response, high ratio (λ, λ H ≥30%) participate in different demand response strategies for comprehensive demand response of demand response electricity and hydrogen load;

[0087] Step S62, using the optimization operation model of the electric-hydrogen coupled power distribution system to calculate the total economic operation cost of the system and the amount of new energy consumption;

[0088] Step S63, compare the total economic operation cost and new energy consumption of the system under different demand response participation ratios and demand response strategies, and determine the optimization effect of the comprehensive demand response strategy on the economic operation of the system.

[0089] Compared with the prior art, the present invention has the following beneficial effects:

[0090] This invention aims at the economic operation of the electric-hydrogen coupled distribution system and the consumption of renewable energy, proposes an operation method for the electric-hydrogen coupled distribution system considering comprehensive demand response, analyzes the relationship between different demand response strategies and the proportion of participating demand response and the economic operation of the distribution system, and thus provides guidance for the overall coordination of the economic and flexible operation of the distribution system and the consumption of new energy.

[0091] The optimization operation method of the present invention can guide the rational development of the electric-hydrogen coupled distribution system; it fully considers the flexibility of the electric-hydrogen load in the system, and considers the equipment constraints and network flow constraints of the system, analyzes the relationship between different demand response strategies and the proportion of participation in demand response and the economic operation of the distribution system, and can provide guidance for the actual work of flexible and economic operation of the electric-hydrogen coupled distribution system.

[0092] The present invention is suitable for distribution systems containing electric-hydrogen coupling parts in areas with rich wind and solar resources. Through the optimized scheduling of the hydrogen energy storage system, a high proportion of new energy in the region can be absorbed, solving the problems of wind and solar abandonment. The method fully considers the flexibility of electric-hydrogen load in the system, improves the new energy absorption capacity and the economic operation level of the distribution system.

[0093] The present invention comprehensively considers the safe operating conditions and comprehensive demand response strategy of the electric-hydrogen coupled distribution system, optimizes and solves the optimal economic operating cost of the system under the comprehensive demand response strategy, and analyzes the relationship between different demand response strategies and the proportion of participating demand response and the economic operation of the distribution system, laying the foundation for guiding the rational development of the electric-hydrogen coupled distribution system and ensuring the economic and flexible operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0095] Figure 1 is a flow chart of the method of the present invention;

[0096] Figure 2 This is the architecture diagram of the electric-hydrogen coupled distribution system;

[0097] Figure 3 It is the topological structure diagram of IEEE 69 nodes;

[0098] Figure 4 This is a typical regional daily load curve;

[0099] Figure 5 This is the output distribution diagram of the electric-hydrogen coupled distribution system;

[0100] Figure 6 This is a comparison curve of electric hydrogen load before and after demand response;

[0101] Figure 7 This is the electric load curve under strategy 2;

[0102] Figure 8 This is the hydrogen load curve under strategy 3. DETAILED DESCRIPTION

[0103] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0104] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0105] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0106] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0107] like Figure 1 As shown, this embodiment provides an operation method of an electric-hydrogen coupled distribution system considering comprehensive demand response, characterized in that it includes the following steps:

[0108] Step S1, based on the electricity-hydrogen coupled distribution system architecture, establish a three-stage model of hydrogen energy storage system production-storage-use. Specifically, it includes the following steps:

[0109] Step S11, establish a hydrogen energy storage system hydrogen production stage equipment model - a proton exchange membrane based electrolyzer hydrogen production model:

[0110] HP2H,t =P P2H,t α P2H ; (1)

[0111]

[0112] Where: H P2H,t , P P2H,t Respectively represent the equivalent hydrogen production power of the electrolyzer at time t and the energy consumption power of the electrolyzer at time t, unit: MW; α P2H Indicates the electrolytic cell conversion efficiency, %; Indicates the maximum operating power of the electrolyzer at time t;

[0113] Step S12, establishing a hydrogen storage tank hydrogen storage model, a hydrogen storage stage equipment model of a hydrogen energy storage system:

[0114] The amount of hydrogen stored in the hydrogen storage tank is expressed as follows:

[0115]

[0116] In the formula, SOH i,t Indicates the hydrogen storage capacity of hydrogen storage tank i during period t, unit: MWh; SOH i,t-1 represents the hydrogen storage capacity of hydrogen storage tank i during period t-1; is a binary variable, indicating the hydrogen filling state of hydrogen storage tank i during period t. When it is equal to 1, it means that hydrogen storage tank i is in the hydrogen filling state during period t; when it is equal to 0, it means that hydrogen storage tank i is not in the hydrogen filling state during period t. de,t represents the hydrogen load demand during period t, MW; H H2P,t represents the equivalent hydrogen consumption of the fuel cell at time t; △t represents the unit time period, h; the hydrogen storage tank capacity constraint and operation constraint are expressed as follows:

[0117]

[0118]

[0119]

[0120] in, Respectively represent the upper and lower limits of the capacity of hydrogen storage tank i, MWh; It represents the initial hydrogen storage capacity ratio of hydrogen storage tank i in period t; Respectively represent the hydrogen storage capacity of the hydrogen storage tank i in the initial period and the end period of time t; Step S13, establish the hydrogen storage system hydrogen use stage equipment model - hydrogen fuel cell hydrogen use model:

[0121]

[0122]

[0123] Among them, P H2P,t Indicates the electric power generated by the combustion battery at time t, unit: MW; β H2P Represents the fuel cell conversion efficiency, %, Indicates the maximum operating power of the hydrogen fuel cell at time t, unit: MW.

[0124] The electric-hydrogen coupled power distribution system architecture of this embodiment is as follows Figure 2 The power supply structure, grid structure, actual operation mode and other information of the improved IEEE 69 node 10kV distribution standard test system are used as the original data of the embodiment. The example topology diagram is shown in Figure 3 The distribution system is connected to three new energy power plants, each with a capacity of 5MW, and is equipped with a hydrogen energy storage system with a capacity of 2.5MWh. The typical maximum power of the daily load in this area is 13.4MW, and the maximum power of the hydrogen load is 5.2MW. Figure 4 shown.

[0125] Step S2, based on the flexible characteristics of electric and hydrogen loads, establish a comprehensive demand response strategy for the electric and hydrogen coupled distribution system; based on the different characteristics of electric loads, divide the electric loads into rigid electric loads, interruptible electric loads and transferable electric loads according to their ability to participate in demand response, and establish different electric load demand response strategies: rigid electric loads do not have adjustable capabilities and do not participate in demand response at all; interruptible electric loads are allowed to interrupt part of the load during certain periods (such as peak load periods) through contracts to ensure the safe operation of the system, and the distribution system gives certain economic compensation based on the amount of interrupted load; transferable electric loads allow part of the load to be transferred to other periods while ensuring that the total load remains unchanged, and the distribution system only gives users certain economic compensation based on the amount of transferred load when users transfer out the load.

[0126] Based on the transferable characteristics of hydrogen load, a hydrogen load demand response strategy is established: the hydrogen load user side allows part of the hydrogen load to be transferred to other time periods while ensuring that the total load remains unchanged. When the user transfers the hydrogen load, the distribution system gives the user a certain amount of economic compensation based on the transferred hydrogen load amount, thereby encouraging the user to independently transfer the hydrogen load during peak load periods.

[0127] The specific steps include:

[0128] Step S21, according to different electric load demand response strategies, the electric loads participating in demand response include interruptible electric loads and transferable electric loads, as follows:

[0129]

[0130]

[0131] in, They represent the electric load of user i participating in demand response, the electric load after demand response, and the electric load before demand response in period t respectively; They represent the interruptible load and transferable load of user i participating in demand response in period t respectively;

[0132] Step S22, two types of electric load demand response models, namely, interruptible electric load and transferable electric load, are established as follows:

[0133]

[0134]

[0135]

[0136] in, They represent the proportion of interruptible load and transferable load participating in the response respectively; They represent the interruptible load and transferable load of user i in period t respectively; A positive value indicates a load transfer out, and a negative value indicates a load transfer in; T is the total period of the dispatch cycle; Formulas (11) and (12) indicate the proportion limit of interruptible load and transferable load participating in demand response. Formula (13) indicates that the total amount of transferable load transfer in the total dispatch cycle is equal to the total amount of transferable load.

[0137] Step S23, according to the hydrogen load demand response strategy, a hydrogen load demand response model is established as follows:

[0138]

[0139]

[0140]

[0141] in, They represent the hydrogen load of user i participating in demand response, the hydrogen load after demand response, and the hydrogen load before demand response during period t respectively; Positive means outgoing load, negative means incoming load; Indicates the proportion of hydrogen load participating in demand response.

[0142] Step S3, considering the comprehensive demand response strategy, based on the three-stage model of hydrogen energy storage system production-storage-use, and aiming at minimizing the system operation cost, establishes an optimization operation model of the electric-hydrogen coupled distribution system; comprising the following steps:

[0143] Step S31, the optimization operation model of the electricity-hydrogen coupled distribution system is as follows:

[0144] minC tol =C upgrid +Closs +C DR +C p ; (17)

[0145] Among them, C tol represents the total economic operation cost of the distribution network-hydrogen energy system; C upgrid , C loss , C DR , C p They represent the cost of purchasing and selling electricity from the superior power grid, the cost of distribution network loss, the cost of compensation for hydrogen demand response, and the penalty cost for wind and solar power abandonment;

[0146] Cost of purchasing and selling electricity to the upper-level power grid C upgrid As shown below:

[0147]

[0148] Among them, P grid,t Indicates the amount of electricity traded between the system and the superior power grid during period t. A positive value indicates that the system purchases electricity from the superior power grid, and a negative value indicates that the system sells electricity to the superior power grid. They represent the price of electricity purchased or sold by the system from the upper power grid during period t; the distribution network loss cost C loss As shown below:

[0149]

[0150] Among them, c loss Indicates the unit energy loss cost; U i,t , U j,t ,θ ij,t , G ij They represent the voltage of node i, the voltage of node j, the phase angle difference between the voltages of nodes i and j, and the conductance of branch ij during period t respectively; N is the number of nodes;

[0151] The demand response compensation cost includes the electric hydrogen demand response compensation cost, the interruptible electric load demand response compensation cost, and the transferable wind and solar power abandonment penalty cost C p As shown below:

[0152]

[0153] In the formula, c p,PV 、c p,WT They represent the penalty costs for unit solar power abandonment and wind power abandonment respectively; They represent the predicted output and actual output of photovoltaic i at time t, They represent the predicted output and actual output of wind turbine i at time t respectively; N PV 、N WT Respectively represent the number of photovoltaic and wind turbines;

[0154] Electric hydrogen demand response compensation cost C DR As shown below:

[0155] C DR =C DR,int +C DR,shif +C HDR ;(twenty one)

[0156] Among them, C DR,int , C DR,shif , C HDR They respectively represent the demand response compensation cost for interruptible electric load, the demand response compensation cost for transferable electric load, and the demand response compensation cost for hydrogen load.

[0157] Interruptible load demand response compensation cost C DR,int As shown below:

[0158]

[0159] in, represents the unit compensation cost of demand response for user i’s interruptable load, represents the interruptible load of user i participating in demand response during period t;

[0160] The compensation cost of shiftable electric load demand response C DR,shif As shown below:

[0161]

[0162] represents the unit compensation cost of user i’s transferable electric load demand response; represents the transferable load of user i participating in demand response during period t;

[0163] Hydrogen load demand response compensation cost C HDR As shown below:

[0164]

[0165] represents the unit compensation cost of hydrogen load demand response for user i, It indicates that user i participates in demand response hydrogen load during period t.

[0166] Step S4, under the operating constraints of the electric-hydrogen coupled distribution system, solving the optimal operation model of the electric-hydrogen coupled distribution system, and optimizing the scheduling of the electric-hydrogen coupled distribution system; the operating constraints of the electric-hydrogen coupled distribution system include network flow constraints, wind and solar power unit output constraints, demand response constraints, and hydrogen energy storage system equipment constraints.

[0167] The network power flow constraint is described by a branch power flow model based on second-order cone relaxation, as follows:

[0168]

[0169] Where v(j) and w(j) represent the first node set and the last node set of the branch connected to node j respectively; P ij,t represents the active power of branch ij at time t, P jk,t represents the active power of branch jk at time t; r ij represents the line resistance of branch ij, represents the square of the current in branch ij at time t; P j,t represents the active power injected into node j during period t; Q ij,t represents the reactive power of branch ij at time t, Q jk,t represents the reactive power of branch jk at time t; x ij represents the line reactance of branch ij, Q j,t represents the reactive power injected into node j during period t; It represents the power consumption of the electrolytic cell during period t, It indicates that the combustion battery j node is connected to generate electric power at time t; represents the square of the voltage at node j during period t, represents the square of the voltage at node i during period t, represents the active power provided by the upper power grid to node j during period t, represents the active power connected by photovoltaic power to node j in period t; represents the active power connected by the wind turbine at node j during period t; represents the active load of node j in period t; represents the reactive power provided by the upper power grid to node j during period t, represents the reactive power connected by the wind turbine to node j during period t; represents the reactive load of node j in period t; They represent the upper and lower limits of the square of the voltage at node i during period t respectively; They represent the upper and lower limits of the square of the current in branch ij at time t. The output constraints of the wind and solar generator set are as follows:

[0170]

[0171] Among them, P i PV,max , P i WT,max They represent the upper limits of active power connected to the i-node by photovoltaic and wind turbines respectively;

[0172] The demand response constraint is as follows:

[0173]

[0174] The equipment constraints of the hydrogen energy storage system are as follows:

[0175]

[0176] Under the constraints of safe operation of the system, the optimal operation model of the electric-hydrogen coupled distribution system considering the comprehensive demand response strategy is solved. The model problem belongs to a mixed integer second-order cone programming problem. The MATLAB platform is used to call the MOSEK commercial solver to solve the optimal operation model of the electric-hydrogen coupled distribution system.

[0177] Step S5, based on the optimization dispatch result of the electric-hydrogen coupled distribution system, establish a system wind-solar unit, hydrogen energy storage system, and upper-level power grid interconnection power output diagram and a load comparison curve before and after demand response in the electric-hydrogen coupled distribution system, so as to judge the operation economy of the electric-hydrogen coupled distribution system and the effectiveness of demand response; the calculation method of the load participation in demand response effect is as follows:

[0178]

[0179] Among them, P t LDR , P t 0 They represent the electric load after participating in demand response and the electric load before demand response in period t respectively; They represent the hydrogen load after participating in demand response and the hydrogen load before demand response in period t respectively; ξ, ξ H They respectively represent the effects of participating in the electric load demand response and participating in the hydrogen load demand response.

[0180] The output distribution of the electric-hydrogen coupled distribution system is as follows: Figure 5 As shown in the figure, the comparison curve of electric hydrogen load before and after demand response is as follows: Figure 6 The effect of electric and hydrogen loads participating in the demand response under the comprehensive demand response strategy is calculated, and the results are shown in Table 1. The peak period of electric load coincides with the peak period of hydrogen load. The excess wind and solar power in the valley period from 13:00 to 17:00 is mainly used to produce hydrogen for storage to meet the hydrogen load demand during the peak period, which limits the transfer of electric load. Therefore, the demand response effect of electric load is small.

[0181] Table 1 Effect of electric and hydrogen load participating in demand response under comprehensive demand response strategy (%)

[0182] ξ 10.01 <![CDATA[ξ H ]]> 18.67

[0183] Step S6, change the demand response strategy of the electric-hydrogen coupled distribution system and the proportion of loads participating in the demand response, and repeat steps S4 and S5 to calculate the economic operation cost and new energy consumption of the electric-hydrogen coupled distribution system under different demand response strategies and proportions of loads participating in the demand response, so as to judge the feasibility and effectiveness of the comprehensive demand response strategy. Specifically, the following steps are included: Step S61, change the demand response strategy and the proportion of electric-hydrogen loads participating in the demand response, and the proportion of loads participating in the demand response is as follows:

[0184]

[0185] Among them, P t DR , P t 0 They represent the electric load participating in demand response and the electric load before demand response in period t respectively; They represent the hydrogen load participating in demand response and the hydrogen load before demand response in period t, respectively; λ, λ H They respectively represent the proportion of participating in electric load demand response and participating in hydrogen load demand response.

[0186] Change λ, λ H Select values ​​to establish the electric and hydrogen loads not participating in demand response, only the electric loads participating in demand response, only the hydrogen loads participating in demand response, electric and hydrogen loads combined demand response, high ratio (λ, λ H ≥30%) participate in the different demand response strategies of the comprehensive demand response of the demand response electric hydrogen load; they are defined as strategy 1, strategy 2, strategy 3, strategy 4, and strategy 5. The proportion of loads participating in demand response under different demand response strategies is shown in Table 2.

[0187] Table 2 Proportion of participants in demand response under different demand response strategies (%)

[0188]

[0189] Step S62, using the optimization operation model of the electric-hydrogen coupled distribution system to calculate the total economic operation cost of the system and the amount of new energy consumed; under different demand response strategies and proportions of loads participating in demand response, the economic operation cost of the system and the amount of new energy consumed are calculated, as shown in Table 3.

[0190] Table 3 System operation indicators under different demand response strategies

[0191] Demand response strategy / system operation indicators Total economic cost of system operation (10,000 yuan) New energy consumption (%) Strategy 1 8.314 82.67 Strategy 2 7.511 87.76 Strategy 3 7.741 86.72 Strategy 4 7.209 92.23 Strategy 5 6.934 96.11

[0192] Step S63, compare the total economic operation cost and new energy consumption of the system under different demand response participation ratios and demand response strategies, and determine the optimization effect of the comprehensive demand response strategy on the economic operation of the system.

[0193] As can be seen from Table 3, by comparing Strategy 1 with Strategy 2, after considering the electricity load demand response, the total cost is reduced by 8,000 yuan, a relative decrease of 9.7%, and the amount of new energy consumption is increased by 5.09%. Figure 7 As shown in the figure, it can be seen that considering the electric load demand response can smooth the load curve and optimize the economic cost; comparing strategy 1 and strategy 3, after considering the hydrogen load demand response, the total cost is reduced by 5,700 yuan, a relative decrease of 6.9%, and the new energy consumption is increased by 4.05%. Combined with the hydrogen load curve under strategy 3, as shown in Figure 8 As shown in the figure, it can be seen that the hydrogen load demand response makes the hydrogen load curve flatter. Compared with the overlap of the hydrogen load peak period and the electric load peak period before the demand response, the hydrogen load demand response makes the hydrogen load in the original peak period shift to the valley period, which promotes the consumption of new energy. On the other hand, due to the transfer of hydrogen load during the peak period, more hydrogen in the hydrogen storage tank can be used for hydrogen fuel cell power generation, further reducing the distribution system's demand for power purchase from the upper power grid.

[0194] Further comparing strategies 4 with 2 and 3, after considering the electric hydrogen demand response, the total cost of strategy 4 is relatively reduced by 4.02% and 6.87%, and the new energy consumption is increased by 4.47% and 5.51%. It can be seen that considering the comprehensive demand response strategy of electric hydrogen can further reduce the economic operation cost of the system and improve the new energy consumption capacity. Further increasing the proportion of loads participating in demand response, comparing strategy 5 with strategy 4, the total cost is relatively reduced by 3.81%, and the new energy consumption is increased by 3.88%. It can be seen that as the proportion of comprehensive demand response of electric hydrogen increases, the distribution system can better match the output of renewable energy and reasonably dispatch the hydrogen energy storage system, making the system more flexible and economical to operate.

[0195] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for operating an electricity-hydrogen coupled distribution system considering comprehensive demand response, characterized in that: The method comprises the following steps: Step S1, based on the electric-hydrogen coupled power distribution system architecture, a three-stage model of production-storage-use of a hydrogen energy storage system is established; the step S1 specifically comprises the following steps: Step S11, establish a hydrogen energy storage system hydrogen production stage equipment model - a proton exchange membrane based electrolyzer hydrogen production model: H P2H,t =P P2H,t a P2H ;(1) Where: H P2H,t , P P2H,t They represent the equivalent hydrogen production power of the electrolyzer at time t and the energy consumption power of the electrolyzer at time t respectively; α P2H It represents the conversion efficiency of electrolyzer; Indicates the maximum operating power of the electrolyzer at time t; Step S12, establishing a hydrogen storage tank hydrogen storage model, a hydrogen storage stage equipment model of a hydrogen energy storage system: The amount of hydrogen stored in the hydrogen storage tank is expressed as follows: In the formula, SOH i,t Indicates the hydrogen storage capacity of hydrogen storage tank i during period t; SOH i,t-1 represents the hydrogen storage capacity of hydrogen storage tank i during period t-1; is a binary variable, indicating the hydrogen filling state of hydrogen storage tank i during period t. When it is equal to 1, it means that hydrogen storage tank i is in the hydrogen filling state during period t; when it is equal to 0, it means that hydrogen storage tank i is not in the hydrogen filling state during period t. de,t represents the hydrogen load demand during period t; H H2P,t represents the equivalent hydrogen consumption of the fuel cell at time t; △t represents the unit time period; The hydrogen storage tank capacity constraints and operation constraints are expressed as follows: in, Respectively represent the upper and lower limits of the capacity of hydrogen storage tank i; It represents the initial hydrogen storage capacity ratio of hydrogen storage tank i in period t; They represent the hydrogen storage capacity of hydrogen storage tank i at the initial period and the end period of time t respectively; Step S13, establishing a hydrogen energy storage system hydrogen consumption stage equipment model - a hydrogen fuel cell hydrogen consumption model: Among them, P H2P,t Indicates the electric power generated by burning the battery at time t; β H2P represents the fuel cell conversion efficiency, Indicates the maximum operating power of the hydrogen fuel cell at time t; Step S2, based on the flexible characteristics of electric and hydrogen loads, establish a comprehensive demand response strategy for the electric and hydrogen coupled distribution system; based on the different characteristics of electric loads, divide the electric loads into rigid electric loads, interruptible electric loads and transferable electric loads according to their ability to participate in demand response, and establish different electric load demand response strategies; based on the transferability of hydrogen loads, establish a hydrogen load demand response strategy; Step S3, considering the comprehensive demand response strategy, based on the three-stage model of hydrogen energy storage system production-storage-use, and aiming at minimizing the system operation cost, establishes an optimization operation model of the electric-hydrogen coupled distribution system; said step S3 comprises the following steps: Step S31, the optimization operation model of the electricity-hydrogen coupled distribution system is as follows: minC tol =C upgrid +C loss +C DR +C p ;(17) Among them, C tol represents the total economic operation cost of the distribution network-hydrogen energy system; C upgrid , C loss , C DR , C p They represent the cost of purchasing and selling electricity from the superior power grid, the cost of distribution network loss, the cost of compensation for hydrogen demand response, and the penalty cost for wind and solar power abandonment; Cost of purchasing and selling electricity to the upper-level power grid C upgrid As shown below: Among them, P grid,t Indicates the amount of electricity traded between the system and the superior power grid during period t. A positive value indicates that the system purchases electricity from the superior power grid, and a negative value indicates that the system sells electricity to the superior power grid. They represent the price of electricity purchased or sold by the system from the upper power grid during period t; the distribution network loss cost C loss As shown below: Among them, c loss Indicates the unit energy loss cost; U i,t , U j,t ,θ ij,t , G ij They represent the voltage of node i, the voltage of node j, the phase angle difference between the voltages of nodes i and j, and the conductance of branch ij during period t respectively; N is the number of nodes; The demand response compensation cost includes the electric hydrogen demand response compensation cost, the interruptible electric load demand response compensation cost, and the transferable wind and solar power abandonment penalty cost C p As shown below: In the formula, c p,PV 、c p,WT They represent the penalty costs for unit solar power abandonment and wind power abandonment respectively; They represent the predicted output and actual output of photovoltaic i at time t, They represent the predicted output and actual output of wind turbine i at time t respectively; N PV 、N WT Respectively represent the number of photovoltaic and wind turbines; Electric hydrogen demand response compensation cost C DR As shown below: C DR =C DR,int +C DR,shif +C HDR ;(21) Among them, C DR,int , C DR,shif , C HDR They represent the demand response compensation cost for interruptible electric load, the demand response compensation cost for transferable electric load, and the demand response compensation cost for hydrogen load respectively; Step S4, solving the optimal operation model of the electric-hydrogen coupled power distribution system under the operating constraints of the electric-hydrogen coupled power distribution system, and optimizing the scheduling of the electric-hydrogen coupled power distribution system; Step S5, according to the optimization dispatch result of the electric-hydrogen coupled distribution system, establish a system wind-solar unit, hydrogen energy storage system, and upper-level power grid interconnection power output diagram and a load comparison curve before and after demand response in the electric-hydrogen coupled distribution system, so as to judge the operation economy of the electric-hydrogen coupled distribution system and the effectiveness of demand response; Step S6, change the demand response strategy of the electric-hydrogen coupled distribution system and the proportion of load participating in demand response, and repeat steps S4 and S5 to calculate the economic operation cost and new energy consumption of the electric-hydrogen coupled distribution system under different demand response strategies and proportions of load participating in demand response, so as to judge the feasibility and effectiveness of the comprehensive demand response strategy.

2. The method for operating an electric-hydrogen coupled distribution system considering comprehensive demand response according to claim 1, characterized in that: The step S2 specifically includes the following steps: Step S21, according to different electric load demand response strategies, the electric loads participating in demand response include interruptible electric loads and transferable electric loads, as follows: in, They represent the electric load of user i participating in demand response, the electric load after demand response, and the electric load before demand response in period t respectively; They represent the interruptible load and transferable load of user i participating in demand response in period t respectively; Step S22, two types of electric load demand response models, namely, interruptible electric load and transferable electric load, are established as follows: in, They represent the proportion of interruptible load and transferable load participating in the response respectively; They represent the interruptible load and transferable load of user i in period t respectively; A positive value indicates an outgoing load, and a negative value indicates an incoming load; T is the total time period of the dispatch cycle; Step S23, according to the hydrogen load demand response strategy, a hydrogen load demand response model is established as follows: in, They represent the hydrogen load of user i participating in demand response, the hydrogen load after demand response, and the hydrogen load before demand response during period t respectively; Positive means outgoing load, negative means incoming load; Indicates the proportion of hydrogen load participating in demand response.

3. The method for operating an electric-hydrogen coupled distribution system considering comprehensive demand response according to claim 1, characterized in that: The interruptible load demand response compensation cost C DR,int As shown below: in, represents the unit compensation cost of demand response for user i’s interruptable load, represents the interruptible load of user i participating in demand response during period t; The compensation cost of shiftable electric load demand response C DR,shif As shown below: represents the unit compensation cost of user i’s transferable electric load demand response; represents the transferable load of user i participating in demand response during period t; Hydrogen load demand response compensation cost C HDR As shown below: represents the unit compensation cost of hydrogen load demand response for user i, It indicates that user i participates in demand response hydrogen load during period t.

4. The method for operating an electric-hydrogen coupled distribution system considering comprehensive demand response according to claim 1, characterized in that: The operating constraints of the electric-hydrogen coupled distribution system in step S4 include network flow constraints, wind and solar power unit output constraints, demand response constraints, and hydrogen energy storage system equipment constraints; The network power flow constraint is described by a branch power flow model based on second-order cone relaxation, as follows: Where v(j) and w(j) represent the first node set and the last node set of the branch connected to node j respectively; P ij,t represents the active power of branch ij at time t, P jk,t represents the active power of branch jk at time t; r ij represents the line resistance of branch ij, represents the square of the current in branch ij at time t; P j,t represents the active power injected into node j during period t; Q ij,t represents the reactive power of branch ij at time t, Q jk,t represents the reactive power of branch jk at time t; x ij represents the line reactance of branch ij, Q j,t represents the reactive power injected into node j during period t; It represents the power consumption of the electrolytic cell during period t, It indicates that the combustion battery j node is connected to generate electric power at time t; represents the square of the voltage at node j during period t, represents the square of the voltage at node i during period t, represents the active power provided by the upper power grid to node j during period t, represents the active power connected by photovoltaic power to node j during period t; represents the active power connected by the wind turbine at node j during period t; represents the active load of node j in period t; represents the reactive power provided by the upper power grid to node j during period t, represents the reactive power connected by the wind turbine to node j during period t; represents the reactive load of node j in period t; They represent the upper and lower limits of the square of the voltage at node i during period t respectively; They represent the upper and lower limits of the square of the current in branch ij at time t respectively; The output constraints of wind and solar generators are as follows: Among them, P i PV,max , P i WT,max They represent the upper limits of active power connected to the i-node by photovoltaic and wind turbines respectively; The demand response constraint is as follows: The equipment constraints of the hydrogen energy storage system are as follows:

5. The method for operating an electric-hydrogen coupled distribution system considering comprehensive demand response according to claim 1, characterized in that: In step S4, the MOSEK commercial solver is called by the MATLAB platform to solve the optimization operation model of the electric-hydrogen coupled distribution system.

6. The method for operating an electric-hydrogen coupled distribution system considering comprehensive demand response according to claim 1, characterized in that: The calculation method of the load participation demand response effect in step S5 is as follows: Among them, P t LDR , P t 0 They represent the electric load after participating in demand response and the electric load before demand response in period t respectively; They represent the hydrogen load after participating in demand response and the hydrogen load before demand response in period t respectively; ξ, ξ H They respectively represent the effects of participating in the electric load demand response and participating in the hydrogen load demand response.

7. The method for operating an electric-hydrogen coupled distribution system considering comprehensive demand response according to claim 1, characterized in that: The step S6 specifically includes the following steps: Step S61, change the demand response strategy and the proportion of electric and hydrogen loads participating in the demand response. The proportion of loads participating in the demand response is as follows: Among them, P t DR , P t 0 They represent the electric load participating in demand response and the electric load before demand response in period t respectively; They represent the hydrogen load participating in demand response and the hydrogen load before demand response in period t, respectively; λ, λ H They represent the proportion of participating in the electric load demand response and participating in the hydrogen load demand response respectively; Change λ, λ H Select values, and establish different demand response strategies: electric and hydrogen loads do not participate in demand response, only electric loads participate in demand response, only hydrogen loads participate in demand response, electric and hydrogen loads participate in demand response, and electric and hydrogen loads participate in demand response in combination; Step S62, using the optimization operation model of the electric-hydrogen coupled power distribution system to calculate the total economic operation cost of the system and the amount of new energy consumption; Step S63, compare the total economic operation cost and new energy consumption of the system under different demand response participation ratios and demand response strategies, and determine the optimization effect of the comprehensive demand response strategy on the economic operation of the system.

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