Method and system for calculating degree of coupling of heterogeneous energy of integrated energy system comprising multi-output coupling units, and related device

Abstract

The present invention relates to the technical field of integrated energy systems, and in particular to a method and system for calculating the degree of coupling of heterogeneous energy of an integrated energy system comprising multi-output coupling units, and a related device. The method comprises the steps of: modeling an integrated energy system to obtain an integrated energy system model, wherein the integrated energy system model comprises a power system model, a hydrogen system model and a thermodynamic system model; modeling coupling units to obtain a coupling unit model, comprising output power and a conversion rate, wherein the coupling units comprise an electric heating boiler, an electrolytic cell and a fuel cell; collecting real-time operation data of the integrated energy system; and calculating the degree of coupling of the integrated energy system on the basis of the real-time data. The method can achieve calculation of the degrees of coupling of existing integrated energy systems comprising multi-output coupling units. Real-time quantitative data of the degrees of coupling of systems is provided for operators of the integrated energy systems, and a quantitative tool for analyzing the degrees of coupling of heterogeneous energy of the integrated energy systems is provided for researchers.

Description

A heterogeneous energy coupling degree calculation method and system for a comprehensive energy system with multiple output coupling units and related equipment TECHNICAL FIELD

[0001] The present application relates to the technical field of comprehensive energy systems, in particular to a heterogeneous energy coupling degree calculation method and system for a comprehensive energy system with multiple output coupling units and related equipment. BACKGROUND

[0002] The coupling between heterogeneous energies is a very prominent feature of comprehensive energy systems that distinguishes them from single energy systems such as power grids, gas networks, and heat networks. Numerous studies on comprehensive energy systems have focused on the impact of coupling between heterogeneous energy subsystems. Lu Zhonglin et al. "Short-term load forecasting of comprehensive energy systems based on coupling characteristics and multi-task learning [J]" uses coupling characteristics to achieve short-term load forecasting of comprehensive energy systems. Lu Quan et al. "Coupling balance analysis model of provincial electric-thermal comprehensive energy system with multiple flexible resources [J]" uses electric-thermal coupling balance to orderly call flexible resources of comprehensive energy systems. Zhao Haipeng et al. "Research on optimization operation strategy of park comprehensive energy system considering cold and heat demand coupling response characteristics [J]" discusses the effect of energy coupling on demand response based on a comprehensive energy system optimization model. However, these studies have not been able to quantitatively measure the coupling degree between heterogeneous energy subsystems when considering energy balance and safety constraints in the coupling link. Wang Weiliang et al. "Steady-state analysis of regional electric-natural gas comprehensive energy system considering natural gas network state [J]" proposes a pressure-load sensitivity in the natural gas system, providing a certain basis for analyzing the energy coupling degree of electric-gas systems. Qin Jiaqian et al. "Probabilistic Pareto maximum load margin and sensitivity analysis of electric-gas coupled systems [J]" proposes a load sensitivity for electric-gas coupled comprehensive energy systems to evaluate the impact of energy coupling on load margins of each energy flow, but only considers two cases of isolated operation and coupled operation of the power network and the natural gas network.

[0003] LV H C, WANG C F, WANG Y, et al. The impact of coupling degree on optimal operation of integrated energy system[C] proposed a concept of system coupling degree for integrated energy system, which firstly quantitatively described the coupling degree of integrated energy system, but there was a certain deficiency in dealing with the key coupling units, which was only divided into two states of complete coupling and no coupling, and failed to distinguish the different coupling degrees of coupling units in real-time running state, thus leading to the inaccuracy of the obtained system coupling degree value. Xiao Jun et al. Energy coupling degree of integrated energy system and its influence on operation domain[J] proposed a coupling degree definition to quantify the heterogeneous energy coupling degree of integrated energy system, but the coupling degree calculation method is only applicable to single-output coupling units such as compressors, gas generators, etc., and is not applicable to multi-output coupling units such as CHP units, fuel cells, electrolytic cells, etc. Therefore, it is limited to integrated energy systems containing only single-output coupling units such as electricity-gas and electricity-hydrogen, and cannot calculate integrated energy systems containing multi-output coupling units such as electricity-gas-heat, electricity-heat-hydrogen, electricity-gas-heat-cold, etc., lacking of universality.

[0004] SUMMARY

[0005] In view of the problems in the prior art, the present application provides a heterogeneous energy coupling degree calculation method, system and related equipment for an integrated energy system containing multi-output coupling units. The existing method can only calculate the coupling degree of an integrated energy system with only single-output coupling units, while the method of the present application can calculate an integrated energy system with multi-output coupling units, and is suitable for the heterogeneous energy coupling degree calculation of all existing integrated energy systems with different energy combinations. The specific technical solutions are as follows:

[0006] A heterogeneous energy coupling degree calculation method for an integrated energy system containing multi-output coupling units, comprising the following steps:

[0007] Modeling the integrated energy system to obtain an integrated energy system model, wherein the integrated energy system model includes an electric power system model, a hydrogen system model and a thermal system model;

[0008] Modeling the coupling units to obtain a coupling unit model, including output power and conversion rate; the coupling units include electric heat boilers, electrolytic cells and fuel cells;

[0009] Collecting real-time running data of the integrated energy system;

[0010] Calculating the coupling degree of the integrated energy system according to the real-time data.

[0011] Preferably, the power system model needs to consider the balance equation when the power grid is running and the safety constraints that the power grid elements need to meet, as follows: the power system alternating current flow constraint is as follows:

[0012] In the formula: i and j are power system nodes; P i and Q i are the active power and reactive power injected at node i, respectively; U i is the voltage amplitude of node i; G ij and B ij are the conductance and susceptance of the line ij between node i and node j; θ ij is the phase difference of the voltage at both ends of the line ij.

[0013] The power balance constraint in the power system is as follows:

[0014] In the formula: P D,i and Q D,i are the active power and reactive power of the load at node i, respectively; P G,i and Q G,i are the active power and reactive power injected into node i by the generator connected to node i; P T,i is the active power injected into node i by the gas generator connected to node i; N E is the number of nodes connected to node i; P L,ij and Q L,ij are the active power and reactive power between node i and node j.

[0015] The voltage constraint of the power system is as follows:

[0016] U N ·b≤U i ;

[0017] In the formula: U N is the rated voltage; b is the lowest percentage of voltage allowed to drop;

[0018] The upper and lower limits of the active and reactive power injected by the node are as follows:

[0019] In the formula: P max,n and P min,n are the upper and lower limits of the active power injected by the power system node; Q max,n and Q min,n are the upper and lower limits of the reactive power injected by the power system node.

[0020] The line capacity constraint is as follows:

[0021] P L,ij2 +Q L,ij 2 =S L,ij 2

[0022] S L,ij ≤C L,ij ;

[0023] wherein S L,ij is the apparent power of line ij; C L,ij is the capacity of line L.

[0024] Preferably, the hydrogen system model needs to consider the balance equation when the pipe network is running and the safety constraints that the pipe network elements need to meet, as follows: the gas system pipeline flow constraint is as follows:

[0025] In the formula: i and j are gas system nodes; f ij is the gas flow of pipeline ij; C ij is the pipeline coefficient in the flow equation; π i and π j are the pressures of nodes i and j, respectively; sign P (π i ,π j ) is a sign function indicating the flow direction; in the gas pipe network, given the pressure π i ,π j of both ends of a pipeline, the size of the pipeline flow f ij is obtained by calculating the arithmetic square root of the absolute value of the square difference of the pressure of both ends of the pipeline multiplied by the pipeline coefficient C ij ; the sign function sign P (π i ,π j ) obtains the flow direction of the pipeline by judging the pressure of both ends of the pipeline, and the flow direction of the pipeline is from the node with higher pressure to the node with lower pressure; if π i ≥π j , sign P (π i ,π j ) is +1, otherwise sign P (π i ,π j ) is -1.

[0026] In the formula: Z G is the gas compression constant; T G is the gas temperature; δ G is the gas density relative to air; D ij and L ij are the inner diameter and length of the pipeline, respectively; χij The friction coefficient of the gas pipeline;

[0027] The node traffic balancing constraints are as follows:

[0028] In the formula: f i Let be the load flow of node i; j∈i represents the connection between node i and node j;

[0029] The pressure balance constraints at the loop nodes are as follows:

[0030] Δπ ij =π j -π i ;

[0031] In the formula: ij∈l n Pipe ij belongs to loop l n ;Δπ ij This represents the decrease in air pressure in pipeline ij.

[0032] The load flow constraints are as follows:

[0033] f min,i ≤f i ≤f max,i ;

[0034] In the formula: f min,i and f max,i These are the minimum and maximum load flows at node i, respectively;

[0035] The nodal pressure constraints are as follows:

[0036] π min,i ≤π i ≤π max,i ;

[0037] Where: π min,i and π max,i These are the minimum and maximum air pressure values ​​at node i, respectively;

[0038] The pipeline flow safety constraints are as follows:

[0039] f ij ≤C ij ;

[0040] In the formula, f ij C represents the airflow rate of pipe ij during operation; ij Let be the capacity of pipe ij.

[0041] Preferably, the thermal system model needs to consider the balance equations during the operation of the heating network and the safety constraints that the heating network components need to satisfy, specifically as follows: The flow continuity equation of the thermal system is as follows:

[0042] A h M = M q ;

[0043] In the formula: A h M is the node-pipeline correlation matrix; M is the pipeline flow vector; Mq is the water flow vector injected into node q;

[0044] The pressure loss equation for a thermodynamic system is shown below:

[0045] h f =KM|M|;

[0046] Where: h f |M| is the pipeline pressure drop vector; K is the pipeline resistance coefficient matrix; |M| is the pipeline flow vector magnitude.

[0047] The heat power balance equation of the thermodynamic system is shown below:

[0048] Φ i =c p m i (T s -T0);

[0049] Where: Φ i c is the heat load power of node i; p T is the specific heat capacity of water. s For water supply temperature; m i T0 represents the flow rate of pipe i; T0 represents the return water temperature at node i.

[0050] The equation for temperature drop in a thermal system pipe is as follows:

[0051] In the formula: T start T represents the starting temperature of the pipeline. end T represents the end temperature of the pipeline. a For ambient temperature; r i Let l be the heat transfer coefficient of pipe i; i Let i be the length of pipe i;

[0052] The equation for the nodal mixing temperature of the thermodynamic system is shown below:

[0053] (∑m out )T out =∑m in T in ;

[0054] Where: m min m out These represent the inflow and outflow of traffic to the node, respectively; T in T out These are the inflow water temperature and outflow water temperature at the nodes, respectively.

[0055] The pipe flow equation in the heat system energy flow calculation is as follows:

[0056] In the formula: m i is the flow of pipe i; Φ i is the heat load power of node i; n i is the heat energy coefficient of node i;

[0057] When n i is calculated, let the heat energy flowing through pipe i be Ψ i , and ignore the heat loss of the pipe network, then Ψ i can be represented by the heat load of each node, and when the flow of the pipe flowing into the load node m i is calculated, since the temperature of the nodes of the water supply network changes little, n k in the formula is calculated as follows:

[0058] The heat load power constraint is as follows:

[0059] Φ min,i ≤ Φ i ≤ Φ max,i ;

[0060] In the formula: Φ min,i and Φ max,i are the minimum and maximum values of the heat load at node i, respectively;

[0061] The node temperature constraint is as follows:

[0062] T min,i ≤ T i ≤ T max,i ;

[0063] In the formula: T min,i and T max,i are the minimum and maximum values of the temperature of node i, respectively.

[0064] Preferably, the electric heat boiler is used as an electric-thermal coupling unit of the integrated energy system, generates heat by consuming electric energy, and the output heat power is as follows:

[0065] In the formula: is the real-time output heat power of the electric heat boiler; is the real-time electric power consumed by the electric heat boiler; η EB is the efficiency of the electric heat boiler;

[0066] The electrolytic cell is a coupling device for coupling electric, hydrogen, and heat energy, and its efficiency is calculated as follows:

[0067] In the formula: ηEL η is the electrolyzer efficiency; a1-a5 are Faraday efficiency coefficients; T EL T is the electrolyzer temperature; I EL I is the electrolyzer direct current; A cell A is the electrolyzer module area;

[0068] The electrolyzer operating temperature is set to a constant value of 70℃, and the electrolyzer electric heating power is related as follows:

[0069] In the formula: P is the real-time input electric power of the electrolyzer; P is the real-time output hydrogen power of the electrolyzer; P is the real-time output heat power of the electrolyzer; η is the electrolyzer electric-to-heat conversion rate; η is the electrolyzer electric-to-hydrogen conversion rate;

[0070] The fuel cell is a coupling device coupling electric, hydrogen, and heat energy, and its efficiency is calculated by the following formula:

[0071] In the formula: η FC η is the electrolyzer efficiency; υ is the fuel utilization rate; HHV H2 HHV is the high heat value of hydrogen; V cell V is the electrolyzer volume;

[0072] The fuel cell electric heating power relationship is as follows:

[0073] In the formula: P is the real-time total power obtained by the fuel cell from the hydrogen storage tank; P is the real-time output electric power of the fuel cell; P is the real-time output heat power of the fuel cell; η is the hydrogen-to-heat conversion rate of the fuel cell; η is the hydrogen-to-electric conversion rate of the fuel cell.

[0074] Preferably, calculating the coupling degree of the comprehensive energy system comprises:

[0075] Calculate the capacity coupling degree: the capacity coupling degree refers to the proportion of the total capacity of the coupling unit in the total capacity of the comprehensive energy system, and is specifically as follows:

[0076] In the formula: D C,S D is the capacity coupling degree; P i,max P is the input capacity of the coupling unit i; n is the number of coupling units; C SDk,m is the total capacity of the integrated energy system. The dual-quality coupling degree of the coupling unit is calculated: the dual-quality coupling degree of the coupling unit refers to the coupling degree of two heterogeneous energies of the coupling unit, and the calculation formula is as shown in the formula:

[0077] In the formula, Dk,m is the total capacity of the integrated energy system. k-m Dk,m is the coupling degree of the coupling unit k to m, wherein k, m represent electric, thermal, and gas heterogeneous energies, and k is not equal to m; Ck,m is the real-time conversion rate of the coupling unit k to m. k-m Ck,m is the rated conversion rate of the coupling unit k to m. k-m Lk,m is the output power of the coupling unit k to m. m Lk,m is the output power of the coupling unit k to m. m,max Pm is the capacity of the output m of the coupling unit. k Pm is the capacity of the output m of the coupling unit. k,max Pm is the capacity of the output m of the coupling unit.

[0078] The total coupling degree of the coupling unit is calculated: the total coupling degree of the coupling unit refers to the coupling degree of all heterogeneous energies of the coupling unit, and the calculation formula is as shown in the formula:

[0079] In the formula, Dk,m is the total capacity of the integrated energy system. u Dk,m is the total coupling degree of the coupling unit; S is the number of output ports of the coupling unit; Ck,m is the real-time conversion rate of the coupling unit. u Ck,m is the rated conversion rate of the coupling unit. u Lk,m is the output power of the coupling unit k to m. i,s Lk,m is the output power of the coupling unit k to m. Lk,m is the total output power of the coupling unit i. i,s,max Lk,m is the output capacity of the coupling unit i. Lk,m is the total output capacity of the coupling unit i.

[0080] The system coupling degree is calculated: the system coupling degree refers to the proportion of the multi-directional energy conversion power between heterogeneous energy subsystems at a certain moment in the real-time total power of the system, and the specific calculation is as follows:

[0081] In the formula, P is the input power of the coupling unit i; n is the number of coupling units; P is the real-time total power of the integrated energy system. i P is the input power of the coupling unit i; n is the number of coupling units; P is the real-time total power of the integrated energy system. S P is the real-time total power of the integrated energy system.

[0082] A heterogeneous energy coupling degree calculation system of a multi-output coupling unit integrated energy system, characterized by being applied to the method, comprising:

[0083] The system modeling module is used for modeling the integrated energy system to obtain an integrated energy system model, and the integrated energy system model includes an electric power system model, a hydrogen system model, and a thermal system model.

[0084] a coupling unit modeling module, configured to model a coupling unit to obtain a coupling unit model, the coupling unit including an electric heating boiler, an electrolytic tank, and a fuel cell, and the coupling unit model including output power and conversion rate;

[0085] a data collection module, configured to collect real-time operation data of the integrated energy system;

[0086] a coupling degree calculation module, configured to calculate the coupling degree of the integrated energy system according to the real-time data.

[0087] A computer readable storage medium, comprising a stored program, wherein the computer readable storage medium controls a device where the computer readable storage medium is located to execute the heterogeneous energy coupling degree calculation method of the integrated energy system with multiple output coupling units when the program is run.

[0088] A processor, configured to run a program, wherein the processor executes the heterogeneous energy coupling degree calculation method of the integrated energy system with multiple output coupling units when the program is run.

[0089] An electronic device, comprising a memory and a processor, the memory being configured to store a computer program, and the processor being configured to run the computer program to make the electronic device execute the heterogeneous energy coupling degree calculation method of the integrated energy system with multiple output coupling units.

[0090] Compared with the prior art, the method can calculate the coupling degree of the existing integrated energy system with multiple output coupling units, and provide real-time quantitative data of the coupling degree of the system for operation personnel of the integrated energy system and a quantitative tool for researchers to analyze the coupling degree of heterogeneous energy of the integrated energy system. BRIEF DESCRIPTION OF DRAWINGS

[0091] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0092] Fig. 1 is a flow chart of the method of the present application.

[0093] Fig. 2 is a schematic diagram of the system of the present application.

[0094] Fig. 3 is a schematic diagram of the topology structure of an electric-thermal-hydrogen coupling example in the embodiment. DETAILED DESCRIPTION

[0095] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described, obviously, the described embodiments are a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0096] It should be understood that the terms "comprising" and "including" as used in the specification and the appended claims indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0097] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0098] It should be further understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0099] Embodiment one:

[0100] As shown in FIG. 1, the present embodiment provides a heterogeneous energy coupling degree calculation method for a comprehensive energy system with multiple output coupling units, including the following steps:

[0101] Modeling the comprehensive energy system to obtain a comprehensive energy system model, the comprehensive energy system model including a power system model, a hydrogen system model, and a thermal system model;

[0102] Modeling the coupling unit to obtain a coupling unit model, including output power and conversion rate; the coupling unit including an electric heating boiler, an electrolytic cell, and a fuel cell;

[0103] Collecting real-time operation data of the comprehensive energy system;

[0104] Calculating the coupling degree of the comprehensive energy system according to the real-time data.

[0105] The power system model needs to consider the balance equation during the operation of the power grid and the safety constraints that the power grid elements need to meet, specifically as follows:

[0106] The power system alternating current flow constraint is as follows:

[0107] where i and j are power system nodes; P i and Q i are active and reactive power injected at node i; U i is the voltage magnitude at node i; G ij and B ij are conductance and susceptance of line ij between node i and node j; θ ij is the phase difference of voltage across line ij;

[0108] The power balance constraints in the power system are as follows:

[0109] where P D,i and Q D,i are active and reactive power of the load at node i; P G,i and Q G,i are active and reactive power injected at node i by generators connected to node i; P T,i is the active power injected at node i by gas generators connected to node i; N E is the number of nodes connected to node i; P L,ij and Q L,ij are active and reactive power between node i and node j;

[0110] The voltage constraints of the power system are as follows:

[0111] U N · b ≤ U i ; (3)

[0112] where U N is the rated voltage; b is the lowest percentage of voltage drop allowed;

[0113] The upper and lower limits of active and reactive power injected at nodes are as follows:

[0114] where P max,n and P min,n are upper and lower limits of active power injected at nodes of the power system; Q max,n and Q min,n are upper and lower limits of reactive power injected at nodes of the power system;

[0115] The line capacity constraints are as follows:

[0116] S L,ij ≤ C L,ij ; (5)

[0117] where S L,ij is the apparent power of line ij, P L,ij 2+Q L,ij 2 = S L,ij 2 ; C L,ij is the capacity of line L.

[0118] The hydrogen system model needs to consider the balance equation when the pipe network is running and the safety constraints that the pipe network elements need to meet, as follows:

[0119] The pipe flow constraint in the gas system is as follows:

[0120] where i and j are nodes of the gas system; f ij is the gas flow of pipe ij; C ij is the pipe coefficient in the flow equation; π i and π j are the pressures of nodes i and j, respectively; sign P (π i ,π j ) is a sign function indicating the flow direction; in the gas pipe network, given the pressures π i ,π j of both ends of a pipe and the pipe coefficient C ij , the flow f ij of the pipe is obtained by calculating the square root of the absolute value of the square difference of the pressures of both ends of the pipe multiplied by the pipe coefficient; the sign function sign P (π i ,π j ) obtains the flow direction of the pipe by judging the pressures of both ends of the pipe, and the flow direction of the pipe is from the node with higher pressure to the node with lower pressure; if π i ≥π j , sign P (π i ,π j ) is +1, otherwise sign P (π i ,π j ) is -1.

[0121] where Z G is the gas compression constant; T G is the gas temperature; δ G is the gas density relative to air; D ij and L ij are the inner diameter and length of the pipe, respectively; χ ij is the friction coefficient of the gas pipe.

[0122] The node flow balance constraint is as follows:

[0123] where: f i is the load flow of node i; j e i is that node i is connected with node j;

[0124] The loop node pressure balance constraint is as follows:

[0125] where: ij e l n is that pipe ij belongs to loop l n ; Δπ ij is the value of the pressure drop of pipe ij, Δπ ij = π j - π i ;

[0126] The load flow constraint is as follows:

[0127] f min,i ≤ f i ≤ f max,i ; (10)

[0128] where: f min,i and f max,i are the minimum and maximum values of the load flow at node i, respectively;

[0129] The node pressure constraint is as follows:

[0130] π min,i ≤ π i ≤ π max,i ; (11)

[0131] where: π min,i and π max,i are the minimum and maximum values of the pressure at node i, respectively;

[0132] The pipe flow safety constraint is as follows:

[0133] f ij ≤ C ij ; (12)

[0134] where: f ij is the gas flow of pipe ij at runtime; C ij is the capacity of pipe ij.

[0135] The heat supply system model needs to consider the balance equation at runtime of the heat supply network and the safety constraints that the heat supply network elements need to satisfy, which are as follows:

[0136] The heat supply system flow continuity equation is as follows:

[0137] A h M = M q ; (13)

[0138] where: A his the node-pipe incidence matrix; M is the pipe flow rate vector; Mq is the water flow rate vector injected at node q;

[0139] The pressure loss equation of the thermal system is shown as follows:

[0140] h f = KM |M|; (14)

[0141] In the formula: h f is the pipe pressure drop vector; K is the pipe resistance coefficient matrix; |M| is the pipe flow rate vector modulus;

[0142] The thermal power balance equation of the thermal system is shown as follows:

[0143] Φ i = cm (T-T0); (15) p i s

[0144] In the formula: Φ i is the thermal load power of node i; c p is the specific heat capacity of water; T s is the water supply temperature; m i is the flow rate of pipe i; T0 is the node return water temperature;

[0145] The pipe temperature drop equation of the thermal system is shown as follows:

[0146] In the formula: T start is the pipe starting temperature; T end is the pipe ending temperature; T a is the ambient temperature; r i is the heat transfer coefficient of pipe i; l i is the length of pipe i;

[0147] The node mixing temperature equation of the thermal system is shown as follows:

[0148] (Σm out )T out = Σm in T in ; (17)

[0149] In the formula: m min , m out are the node inflow and outflow, respectively; T in , T out are the node inflow and outflow water temperature, respectively;

[0150] The pipe flow rate equation in the energy flow calculation of the thermal system is shown as follows:

[0151] ​​​wherein: m i is the flow of pipeline i; Φ i is the thermal load power of node i; n i is the thermal energy coefficient of node i;

[0152] When n i is calculated, let the thermal energy flowing through pipeline i be Ψ i , ignoring the heat loss of the pipe network, then Ψ i can be represented by the thermal load of each node, when calculating the flow m i of the pipeline flowing into the load node, since the temperature of the nodes of the water supply network changes little, n k is calculated by the following formula:

[0153] The thermal load power constraint is as follows:

[0154] Φ min,i ≤ Φ i ≤ Φ max,i ; (20)

[0155] wherein: Φ min,i and Φ max,i are the minimum and maximum values of the thermal load at node i, respectively;

[0156] The node temperature constraint is as follows:

[0157] T min,i ≤ T i ≤ T max,i ; (21)

[0158] wherein: T min,i and T max,i are the minimum and maximum values of the temperature of node i, respectively.

[0159] The electric heat boiler, as an electric-thermal coupling unit of the integrated energy system, generates thermal energy by consuming electric energy, and its output thermal power is as follows:

[0160] wherein: is the real-time output thermal power of the electric heat boiler; is the real-time electric power consumed by the electric heat boiler; η EB is the efficiency of the electric heat boiler;

[0161] The electrolytic cell is a coupling device of electric, hydrogen, and thermal energy coupling, and its efficiency is calculated by the following formula:

[0162] wherein: η EL is the efficiency of the electrolytic cell; a1-a5 are Faraday efficiency coefficients; T EL is the temperature of the electrolytic cell; I ELThe direct current of the electrolytic cell; A cell The area of the electrolytic module;

[0163] The working temperature of the electrolytic cell is set to a constant value of 70℃, and the electric heating power of the electrolytic cell is related as follows:

[0164] In the formula: P is the real-time input electric power of the electrolytic cell; P is the real-time output hydrogen power of the electrolytic cell; P is the real-time output heat power of the electrolytic cell; η is the electric-to-heat conversion rate of the electrolytic cell; η is the electric-to-hydrogen conversion rate of the electrolytic cell;

[0165] The fuel cell is a coupling device coupling electric, hydrogen and heat energy, and its efficiency is calculated by the following formula:

[0166] In the formula: η FC is the efficiency of the electrolytic cell; υ is the fuel utilization rate; HHV H2 is the high heat value of hydrogen; V cell is the volume of the electrolytic cell;

[0167] The electric and heat power relationship of the fuel cell is as follows:

[0168] In the formula: P is the real-time total power obtained by the fuel cell from the hydrogen storage tank; P is the real-time output electric power of the fuel cell; P is the real-time output heat power of the fuel cell; η is the hydrogen-to-heat conversion rate of the fuel cell; η is the hydrogen-to-electric conversion rate of the fuel cell.

[0169] The coupling degree of the comprehensive energy system includes:

[0170] Calculate the capacity coupling degree: the capacity coupling degree refers to the proportion of the total capacity of the coupling unit in the total capacity of the comprehensive energy system, which is as follows:

[0171] In the formula: D C,S is the capacity coupling degree; P i,max is the input capacity of the coupling unit i; n is the number of coupling units; C S is the total capacity of the comprehensive energy system.

[0172] The coupling unit refers to a single energy conversion device in the comprehensive energy system, and the input and output power relationship is as follows:

[0173] L U =CU P U ;(28)

[0174] wherein: C U is the conversion rate of the coupling unit; P U is the input power of the coupling unit; L U is the output power of the coupling unit.

[0175] The conversion rate of the coupling unit is the ratio of the output available energy of the coupling unit to its input energy, that is, the efficiency of the energy conversion device. The conversion rate is a percentage without unit. Under different working conditions, the conversion rate and the output power have a nonlinear relationship, and the efficiency dynamic test data need to be obtained by querying the efficiency characteristic curve of the energy conversion device or through experiments.

[0176] The coupling relationship of the heterogeneous energy subsystems in the integrated energy system is established through the coupling unit, and therefore, the coupling unit is analyzed first to lay a foundation for measuring the coupling degree of the system. The present application proposes two coupling degree definitions applicable to both single-output coupling units and multi-output coupling units: the coupling unit dual-quality coupling degree and the coupling unit total coupling degree.

[0177] The coupling unit dual-quality coupling degree is calculated: the coupling unit dual-quality coupling degree refers to the coupling degree of two kinds of heterogeneous energy of the coupling unit, and it is only used to quantitatively represent the coupling relationship between two different energy flows in the coupling unit. The calculation formula is as shown in the formula:

[0178] wherein: D k-m is the coupling degree of the coupling unit k to m, wherein k and m represent electric, thermal, and gas heterogeneous energy, and k is not equal to m; C k-m is the conversion rate of the coupling unit k to m; η k-m is the rated conversion rate of the coupling unit k to m; L m is the output power of the coupling unit k to m; L m,max is the capacity of the output m of the coupling unit; P k is the input power of the coupling unit k to m; P k,max is the capacity of the input k of the coupling unit;

[0179] The coupling unit total coupling degree is calculated: the coupling unit total coupling degree refers to the coupling degree of all heterogeneous energy of the coupling unit, and it is used to quantitatively represent the coupling relationship between multiple different energy flows in the coupling unit. The calculation formula is as shown in the formula:

[0180] wherein: D u is the coupling unit total coupling degree; S is the number of output ports of the coupling unit; C u is the real-time conversion rate of the coupling unit; η uPci,s is the output power of the s-th port of the coupling unit i; L i,s Pci,s is the output power of the s-th port of the coupling unit i; L Pci is the total output power of the coupling unit i; L i,s,max Pci,s is the output power of the s-th port of the coupling unit i; L Pci is the total output power of the coupling unit i; L

[0181] It is worth noting that for the coupling unit with single output, since only two kinds of heterogeneous energy coupling are involved, the dual-quality coupling degree is equal to the total coupling degree. The system coupling degree refers to the proportion of the multi-directional energy conversion power between the heterogeneous energy subsystems at a certain moment in the real-time total power of the system, and is calculated as follows:

[0182] Pci is the total output power of the coupling unit i; L i Pci is the total output power of the coupling unit i; L S P is the real-time total power of the integrated energy system.

[0183] Embodiment two:

[0184] As shown in FIG. 2, based on the same inventive concept as in embodiment one, the embodiment provides a heterogeneous energy coupling degree calculation system for an integrated energy system with multiple-output coupling units, characterized in that the method is applied, which comprises:

[0185] A system modeling module is configured to model the integrated energy system to obtain an integrated energy system model, wherein the integrated energy system model comprises an electric power system model, a hydrogen system model, and a thermal system model.

[0186] A coupling unit modeling module is configured to model the coupling unit to obtain a coupling unit model, including output power and conversion rate, wherein the coupling unit comprises an electric heat boiler, an electrolytic cell, and a fuel cell.

[0187] A data acquisition module is configured to acquire real-time operation data of the integrated energy system.

[0188] A coupling degree calculation module is configured to calculate the coupling degree of the integrated energy system according to the real-time data.

[0189] Embodiment three:

[0190] Based on the same inventive concept as in embodiment one, the embodiment provides a computer readable storage medium, which comprises a stored program, wherein when the program is running, the device where the computer readable storage medium is located is controlled to execute the heterogeneous energy coupling degree calculation method for an integrated energy system with multiple-output coupling units.

[0191] Embodiment four:

[0192] Based on the same inventive concept as Embodiment One, this embodiment provides a processor for running a program, wherein the program performs the heterogeneous energy coupling degree calculation method for the integrated energy system with multiple output coupling units when running.

[0193] Embodiment Five:

[0194] Based on the same inventive concept as Embodiment One, this embodiment provides an electronic device comprising a memory for storing a computer program and a processor for running the computer program to make the electronic device perform the heterogeneous energy coupling degree calculation method for the integrated energy system with multiple output coupling units.

[0195] Embodiment Six:

[0196] 1. Basic situation of the example

[0197] This embodiment provides an example, and the topology structure of the example is shown in FIG. 1. The system is composed of a 6-node thermal system, a 3-node power system and a 6-node hydrogen system: which contains one single output coupling unit: electric boiler EB and two multiple output coupling units: fuel cell FC, electrolytic cell EC. The power required by the fuel cell is provided by the hydrogen pipeline system node H5, and the power required by the electrolytic cell and the electric boiler is provided by the power system node C. The coupling unit parameter settings are shown in Table 1, and the system node and branch parameter settings are shown in Tables 2-7.

[0198] Table 1: Coupling unit parameters of the example

[0199] Table 2: Pipeline parameters of the thermal system

[0200] Table 3: Node parameters of the thermal system

[0201] Table 4: Node parameters of the power system of the example

[0202] Note: The voltage is in per unit, and the reference value is 220V.

[0203] Table 5: Branch parameters of the power system of the example

[0204] Table 6: Node parameters of the hydrogen system of the example

[0205] Table 7: Pipeline parameters of the hydrogen system of the example

[0206] 2. Calculation steps of the present application

[0207] 2.1 Capacity coupling degree calculation

[0208] Total capacity of the integrated energy system C S＝ 4 MW, capacity coupling degree D calculated from the data in Table 1 and equation (27) C,S = 12.25%.

[0209] 2.2 Real-time coupling degree calculation

[0210] 2.2.1 Coupling unit coupling degree calculation

[0211] (1) Single-output coupling unit coupling degree calculation

[0212] First, the power consumed by the electric heating boiler is calculated by equation (22), then the conversion rate is calculated according to the electric heating boiler efficiency characteristic curve, and finally the coupling degree D of the electric heating boiler under different working conditions is calculated according to equation (29) EB , and the results are shown in Table 8.

[0213] Table 8 Coupling degree of electric heating boiler under different working conditions

[0214] (2) Multi-output coupling unit coupling degree calculation

[0215] a) Electrolytic cell coupling degree calculation

[0216] First, the efficiency of the electrolytic cell under each working condition is calculated by equation (23), then the output hydrogen power and heat power of the electrolytic cell under each working condition are calculated according to equation (24). Then the conversion rate is calculated according to the electrolytic cell efficiency characteristic curve, and finally the electric-to-hydrogen coupling degree D E-Hy , electric-to-heat coupling degree D E-H and total coupling degree D EC of the electrolytic cell under different working conditions are calculated according to equations (29) and (30). The results are shown in Table 9.

[0217] Table 9 Coupling degree of electrolytic cell under different working conditions

[0218] b) Fuel cell coupling degree calculation

[0219] First, the efficiency of the fuel cell under each working condition is calculated by equation (25), then the output electric power and heat power of the fuel cell under each working condition are calculated according to equation (26). Then the conversion rate is calculated according to the fuel cell efficiency characteristic curve, and finally the hydrogen-to-electric coupling degree D Hy-E , hydrogen-to-heat coupling degree D Hy-H and total coupling degree D FC of the fuel cell under different working conditions are calculated according to equations (29) and (30). The results are shown in Table 10.

[0220] Table 10 Coupling degree of fuel cell under different working conditions

[0221] 2.2.2 System coupling degree calculation

[0222] Verification of real-time coupling degree definition in this paper by changing the electric boiler EB coupling degree D EB , the electrolytic cell EC coupling degree D EC and the fuel cell FC coupling degree D FC . The design is as follows:

[0223] 1) Working condition 0 is a non-coupling working condition: D EB = D EC = D FC = 0.

[0224] 2) Working conditions 1-1 to 1-4 are EB operation only working conditions: D EC = D FC = 0, D EB changes.

[0225] 3) Working conditions 2-1 to 2-2 are EB and EC simultaneous operation working conditions: D FC = 0, D EB and D EC change.

[0226] 4) Working conditions 3-1 to 3-4 are EB, EC and FC simultaneous operation working conditions: D EB , D EC , D FC change simultaneously.

[0227] The system coupling degree of different working conditions is calculated by formula (31), and the results are shown in Table 11.

[0228] Table 11 System coupling degree

[0229] Those skilled in the art can realize that the modules of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software or a combination of both, and in order to clearly illustrate the interchangeability of hardware and software, the components of each example have been generally described in the above description. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0230] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and 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 application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A method for calculating the coupling degree of heterogeneous energy in a comprehensive energy system with multiple output coupling units, characterized in that, The method comprises the following steps: modeling the integrated energy system to obtain an integrated energy system model, wherein the integrated energy system model comprises a power system model, a hydrogen system model, and a heat system model; modeling a coupling unit to obtain a coupling unit model, wherein the coupling unit model comprises output power and conversion rate, and the coupling unit comprises an electric heat boiler, an electrolytic cell, and a fuel cell; collecting real-time operation data of the integrated energy system; calculating the coupling degree of the integrated energy system according to the real-time data.

2. The method of claim 1, wherein the method is characterized by: The power system model needs to consider the balance equation during power grid operation and the safety constraints that the power grid elements need to meet, and is specifically as follows: The AC power flow constraints of the power system are as follows: where: i and j are power system nodes; P i and Q i are the active and reactive power injected at node i, respectively; U i is the voltage magnitude at node i; G ij and B ij are the conductance and susceptance of the line ij between node i and node j; θ ij is the phase difference of the voltages at the ends of the line ij. The power balance constraint in the power system is as follows: In the formula: P D,i and Q D,i P represents the active power and reactive power of the load at node i, respectively; G,i and Q G,i P represents the active power and reactive power injected into node i by the generator connected to node i, respectively. T,i N represents the active power injected into node i by the gas generator connected to node i; E P represents the number of nodes connected to node i; L,ij and Q L,ij These represent the active power and reactive power between node i and node j, respectively. The voltage constraint of the power system is as follows: U N • b < U i ; where: U N is the rated voltage; b is the lowest percentage of voltage drop allowed; The node injection active and reactive upper and lower limit constraints are shown as follows: where: P max,i and P min,i are the upper and lower limits of the active power injection at the power system node i, respectively; Q max,i and Q min,i Qi and QL are the upper and lower limits of the reactive power injection at the power system node i, respectively. The line capacity constraint is as follows: P L,ij 2 +Q L,ij 2 =S L,ij 2 S L,ij ≤C L,ij ; where S L,ij is the apparent power of line ij; C L,ij is the capacity of line L.

3. The method of claim 1, wherein the method further comprises: The hydrogen system model needs to consider the balance equation during pipe network operation and the safety constraints that the pipe network elements need to meet, and is specifically as follows: The pipe flow constraint in a gas system is as follows: where: i and j are gas system nodes; f ij is the gas flow of pipe ij; C ij is the pipe coefficient in flow equation; π i and π j are the pressures of nodes i and j respectively; sign P (π i, , π j ) is a sign function indicating the flow direction; in a gas pipe network, given the pressures π i , π j and pipe coefficient C ij , the flow f ij of a pipe is obtained by calculating the square root of the absolute value of the square difference of the pressures of the two ends of the pipe multiplied by the pipe coefficient; the sign function sign P (π i , π j ) obtains the flow direction of the pipe by judging the pressures of the two ends of the pipe, the flow direction of the pipe being from the node with higher pressure to the node with lower pressure; if π i ≥ π j , sign P (π i , π j ) is +1, otherwise sign P (π i , π j ) is -1; where: Z G is the gas compressibility factor; T G is the gas temperature; δ G is the gas density relative to air; D ij and L ij are the internal diameter and length of the pipe, respectively; χ ij is the friction factor for the gas pipe; The node flow balance constraint is as follows: where: f i is the flow of load at node i; j e i is that node i is connected to node j; The loop node pressure balance constraint is as follows: Δπ ij = π j - π i ; where: ij∈l n is the pipe ij belongs to loop l n ; Δπ ij is the value of pressure drop of pipe ij; The load flow constraint is as follows: f min,i ≤f i ≤f max,i ; where: f min,i and f max,i are the minimum and maximum load flow values at node i, respectively. The node gas pressure constraint is as follows: π min,i ≤π i ≤π max,i ； where: π min,i and π max,i are the minimum and maximum values of the air pressure at node i, respectively. The pipe flow safety constraint is as follows: f ij ≤C ij ; where f ij is the gas flow rate of the runtime pipe ij; C ij is the capacity of the pipe ij.

4. The method of claim 1, wherein the method further comprises: The heat system model needs to consider the balance equation during heat network operation and the safety constraints that the heat network elements need to meet, and is specifically as follows: The heat system flow continuity equation is as follows: A h M = M q ; where: A h is the node-pipe incidence matrix; M is the pipe flow vector; and Mq is the water flow vector injected at node q. The heat system pressure loss equation is as follows: h f = KM | M | ; where: h f is the pipe pressure drop vector; K is the pipe resistance coefficient matrix; |M| is the pipe flow vector modulus; The heat system heat power balance equation is as follows: Φ i = c p m i (T s -T0); where: Φ i is the thermal load power of node i; c p is the specific heat capacity of water; T s is the supply water temperature; m i is the flow rate of pipe i; T0is the node return water temperature; The temperature drop equation of the heat supply system pipeline is as follows: where: T start is the temperature at the beginning of the pipe; T end is the temperature at the end of the pipe; T a is the ambient temperature; r i is the heat transfer coefficient of pipe i; l i is the length of pipe i; The heat system node mixed temperature equation is as follows: (∑m out )T out =∑m in T in ; wherein: m in , m out are the node inflow and outflow, respectively; T in , T out are the node inflow and outflow water temperature, respectively; The pipe flow equation in the heat system energy flow calculation is shown as follows: where: m i is the flow rate of pipe i; Φ i is the thermal load power of node i; n i is the thermal energy coefficient of node i; n = number of nodes i Ψ = heat energy flowing through pipe i i Ψ = heat energy flowing through pipe i i Ψ = heat energy flowing through pipe i i Ψ = heat energy flowing through pipe i k Ψ = heat energy flowing through pipe i The heat load power constraint is as follows: Φ min,i ≤ Φ i ≤ Φ max,i ; where: Φ min,i and Φ max,i are the minimum and maximum values of the thermal load at node i, respectively. The node temperature constraint is as follows: T min,i ≤T i ≤T max,i ; where: T min,i and T max,i are the minimum and maximum temperature values of node i, respectively.

5. The method of claim 1, wherein the method further comprises: As an electric heat coupling unit of the integrated energy system, the electric heat boiler generates heat by consuming electric energy, and its output heat power is as follows: In the formulae: To output real-time heat power for an electric heating boiler; η EB η is the efficiency of the electrically heated boiler. The electrolytic cell is a coupling device of electricity, hydrogen and heat, and its efficiency is calculated by the following formula: wherein: η EL is the electrolyser efficiency; a1-a5 are Faraday efficiency coefficients; T EL is the electrolyser temperature; I EL is the electrolyser direct current; A cell is the electrolyser module area; If the electrolyzer operating temperature is set to a constant value of 70°C, the electrolyzer electric heating power is related as shown in the following equation: In the formulae: to input electric power to the electrolytic cell in real time; to output real-time hydrogen power for electrolytic cell; to output real-time heat power for electrolytic cell; Electrolytic cell electric conversion heat conversion rate The conversion rate of the electrolytic cell from electricity to hydrogen; The fuel cell is a coupling device coupling three kinds of energy of electricity, hydrogen and heat, and its efficiency is calculated by the following formula: where: η FC is the cell efficiency; υ is the fuel utilization; HHV H2 is the high heating value of hydrogen; V cell is the cell volume; The fuel cell electric heating power relationship is shown in the following equation: In the formulae: to obtain real-time total power from the hydrogen storage tank for the fuel cell; to output electric power in real time to a fuel cell; to output real-time thermal power for a fuel cell; conversion of hydrogen to heat for fuel cells; The conversion rate of the fuel cell from hydrogen to electricity.

6. The method of claim 1, wherein the method further comprises: The calculation of the coupling degree of the integrated energy system comprises: The calculation of the capacity coupling degree: the capacity coupling degree refers to the proportion of the total capacity of the coupling unit in the total capacity of the integrated energy system, and is specifically as follows: In the formula: D C,S is the capacity coupling degree; P i,max is the input capacity of the coupling unit i; n is the number of coupling units; C S is the total capacity of the integrated energy system. The coupling degree of the dual-nature coupling unit is the coupling degree of the two different energies of the coupling unit, and the calculation formula is as shown in the formula: wherein: D k-m is the coupling degree of the coupling unit k to m, wherein k, m represent electric, thermal, gas heterogeneous energy sources, k is not equal to m; C k-m is the conversion rate of the coupling unit k to m; η k-m is the rated conversion rate of the coupling unit k to m; L m is the output power of the coupling unit k to m; L m,max is the capacity of the output m of the coupling unit; P k is the input power of the coupling unit k to m; P k,max is the capacity of the input k of the coupling unit; Total coupling degree of coupling unit: the total coupling degree of coupling unit refers to the coupling degree of all heterogeneous energy of the coupling unit, and the calculation formula is as shown in the formula: where D u is the total coupling of the coupling unit; S is the number of output ports of the coupling unit; C u is the real-time conversion rate of the coupling unit; η u is the rated conversion rate of the coupling unit; L i,s denotes the output power of the s-th port of the coupling unit i, to couple the total output power of the coupling unit i; L i,s,max denotes the output capacitance of the s-th port of the coupling unit i, The total output capacity of the coupling unit i; System coupling degree: the system coupling degree refers to the proportion of the power of multi-directional energy conversion between the heterogeneous energy subsystems at a certain moment in the real-time total power of the system, and is specifically as follows: In the formula, P i is the input power of the coupling unit i; n is the number of coupling units; P S is the real-time total power of the integrated energy system.

7. A heterogeneous energy coupling degree calculation system of a comprehensive energy system containing multiple output coupling units, characterized in that, The method according to any one of claims 1 to 6 comprises: a system modeling module, configured to model the integrated energy system to obtain an integrated energy system model, wherein the integrated energy system model comprises a power system model, a hydrogen system model, and a heat system model; a coupling unit modeling module, configured to model a coupling unit to obtain a coupling unit model, wherein the coupling unit model comprises output power and conversion rate, and the coupling unit comprises an electric heat boiler, an electrolytic cell, and a fuel cell; a data collection module, configured to collect real-time operation data of the integrated energy system; a coupling degree calculation module, configured to calculate the coupling degree of the integrated energy system according to the real-time data.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium comprises a stored program, wherein the program controls the device where the computer readable storage medium is located to execute the heterogeneous energy coupling degree calculation method for the integrated energy system with multiple output coupling units according to any one of claims 1 to 6 when the program is running.

9. A processor, comprising: The processor is configured to run a program, wherein the program executes the heterogeneous energy coupling degree calculation method for the integrated energy system with multiple output coupling units according to any one of claims 1 to 6 when the program is running.

10. An electronic device, comprising: The electronic device comprises a memory and a processor, wherein the memory is configured to store a computer program, and the processor is configured to run the computer program to make the electronic device execute the heterogeneous energy coupling degree calculation method for the integrated energy system with multiple output coupling units.

Images