Consider the cogeneration unit of integrated energy system system reliability calculation method

Abstract

The present application relates to a kind of integrated energy system system reliability calculation method considering cogeneration unit, consider the multi-state characteristics of integrated energy system and each component in actual operation exists, propose the multi-state performance model of integrated energy system formed by cogeneration unit and gas distribution network, define the energy supply capacity and probability of heat, electricity, gas in each state, and introduce energy conversion path and efficiency coefficient, the influence of coupling relationship on system reliability is quantified.The present application aggregates device-level multi-state model into system-level performance model, reduces the complexity of traditional state space, improves calculation accuracy.The present application supports the joint modeling of multi-state system with topology structure, can adapt to various conditions such as unit aging failure, energy fluctuation in actual system, and is suitable for real-time scheduling decision of complex energy system.The present application is suitable for any energy system with multi-state and coupling relationship, and makes up for the shortcomings of traditional system reliability analysis method.

Description

Technical Field

[0001] This invention belongs to the field of power system reliability calculation, and in particular to a method for calculating the reliability of integrated energy systems considering combined heat and power units. Background Technology

[0002] With the continuous growth of modern energy demand, integrated energy systems have become an important means to improve energy utilization efficiency. Integrated energy systems encompass the aggregation and dispatch of multiple energy sources, including electricity, heat, and natural gas. Combined heat and power (CHP) units and gas distribution network aggregation are common forms. CHP units are widely used in integrated energy systems, capable of simultaneously providing electricity and heat, offering significant economic and environmental benefits. However, traditional system analysis methods often overlook the complex coupling relationships between various energy forms such as electricity, heat, and natural gas, leading to insufficient reliability assessment. To address this challenge, an analytical method is needed that can comprehensively consider the synergistic effects of CHP units and other energy equipment, thereby improving the accuracy of reliability analysis and assessment of integrated energy systems. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a reliability calculation method for integrated energy systems considering combined heat and power (CHP) units. This method is designed for integrated energy systems consisting of CHP units, gas distribution networks, and transmission units. It fully considers the multi-state degradation characteristics of system equipment during actual operation, the heat-electric coupling output characteristics of CHP units, the capacity constraints of transmission units, and the multi-directional energy conversion relationships between heat, electricity, and gas. It constructs a system reliability calculation model for multi-energy coupling scenarios, enabling accurate assessment of the energy supply reliability of integrated energy systems.

[0004] The technical problem solved by this invention is achieved through the following technical solution: The method for calculating the reliability of a combined heat and power (CHP) unit's integrated energy system includes the following steps: Step 1: Analyze the coupling relationship between thermal energy, electrical energy and gas in the integrated energy system, and establish a conversion model between different energy sources; Step 2: Based on the conversion models between different energy sources, use extended general generating functions to perform multi-state probabilistic modeling of cogeneration units, gas distribution networks and transmission units, and establish a performance evaluation model for a multi-state integrated energy system with energy coupling. Step 3: Based on the performance evaluation model, calculate the reliability probability and expected energy deficit of the integrated energy system under specific needs.

[0005] Furthermore, step 1 includes the following steps: Step 1.1: Select the state characteristic parameters of the cogeneration unit, gas distribution network, and transmission unit; Step 1.2: Based on the state characteristic parameters selected in Step 1.1, and considering the coupling relationship between electrical and thermal performance and electrical and gas performance, define the multi-energy conversion efficiency, conversion ratio upper limit, and conversion restriction conditions. Step 1.3: Establish a conversion model between different energies, and calculate the remaining energy, energy deficit, and effective energy supply status of the system after conversion based on the conversion model.

[0006] Furthermore, the state characteristic parameters of the cogeneration unit in step 1.1 include the number of units, the number of states of the unit, the thermal and electrical energy capacity and thermoelectric coefficient of each state, and the probability of each state; the state characteristic parameters of the gas distribution network include the number of gas distribution networks, the number of states, the gas supply capacity of each state, and the probability of each state; the state characteristic parameters of the transmission unit include the number of transmission units, the number of states, the upper limit of thermal energy transmission, the upper limit of electrical energy transmission, and the probability of each state.

[0007] Furthermore, the specific implementation method of step 1.2 is as follows: Establish the coupling relationship between electrical energy and thermal energy, and between electrical energy and gas, using energy performance conversion to represent: Users have multiple energy needs, when one type of energy... a When supply is insufficient to meet demand, excess energy b It can be converted into energy to a certain extent. a To meet user needs, energy a Supply shortage F a With energy b superfluous S b They are represented as follows: , In the formula, Represents energy a The supply is insufficient. Represents energy b The excess amount that meets the demand. Indicates the unit i or gas distribution network k In state j i or j k The energy below a Production volume Indicates the unit i or gas distribution network k In state j i or j k The energy below b Production volume D aand D b They represent the energy a Demand and energy b The demand, N Indicates the number of generating units.

[0008] From energy b Convert into energy a The performance conversion efficiency can be expressed as ,energy b Convert into energy a The value of energy has an upper limit. b Used to meet energy needs a The upper limit value is: In the formula, It is a performance conversion coefficient between 0 and 1; The performance conversion quantity from energy b to energy a Q b,a Represented as: .

[0009] Furthermore, the specific implementation method of step 1.3 is as follows: The conversion model between different energies can be summarized as a multi-energy conversion efficiency matrix and a conversion ratio upper limit matrix, which are used to describe the convertible paths, conversion efficiencies, and conversion capacity limits between different energies.

[0010] Based on the previous step, the multi-energy conversion efficiency matrix can be constructed as follows: in, Indicates energy Convert into energy The conversion efficiency, the energy collection is ,in H, E, G Let these represent thermal energy, electrical energy, and natural gas, respectively; when there is no convertible path between two types of energy, let .

[0011] Simultaneously, the upper limit matrix of the conversion ratio can be constructed as follows: After conversion, energy a The update requirement is The remaining performance of energy b can be expressed as: ;energy a The updated energy supply deficit is: When a system has both multiple energy surpluses and multiple energy shortages, a multi-energy deficit compensation optimization model is introduced to minimize the overall energy deficit after conversion and determine the conversion amount between different energy sources. Q b,a Represents energy b To energy a Given the conversion amount, the multi-energy deficit compensation optimization model is as follows: In the formula, Indicates the renewed energy after conversion a Energy shortage; Indicates energy a The deficit weight. When the three demands for heat, electricity, and gas are all met after the conversion, the system's reliability can be described as: In the formula, R Indicates the reliability of the system. This indicates the energy deficiency value after the conversion is updated. Pr This indicates a probability calculation.

[0012] Furthermore, the specific implementation method of step 2 is as follows: Step 2.1: Apply the extended general function method to construct performance evaluation models for cogeneration units constrained by transmission units and gas distribution networks, respectively. Step 2.2: Consider the connection method between the cogeneration system and the gas distribution network system, and establish a performance evaluation model for the entire multi-state integrated energy system.

[0013] Furthermore, the specific implementation method of step 2.1 is as follows: By applying extended general function methods, performance evaluation models for cogeneration units constrained by transmission units and gas distribution networks are constructed respectively: Single cogeneration unit i The performance is: In the formula, Indicates a single unit i Energy supply performance This represents the heat generation and power generation performance values ​​under the above conditions; Indicates the unit i In state j i The probability, n i Indicates the unit i The number of existing states.

[0014] Therefore, by NA combined heat and power system consisting of multiple combined heat and power units s The performance is: In the formula, Indicates a combined heat and power system s Performance, Indicates a combined heat and power system s In system state x The feasible domain of heat generation and power generation values ​​under the limitation of the transmission unit, and , X Represents the total number of states in the system. Representation system s In state x The probability of; This represents a combination operator for all unit states and probabilities.

[0015] Single gas distribution network k The performance is: In the formula, Indicates a single gas distribution network k Performance, This indicates the amount of gas supplied by the gas distribution network under the above conditions; Indicates when the gas distribution network k In state j k The probability of that time. n k Indicates gas distribution network k The number of existing states.

[0016] Depend on K Gas supply system of individual gas distribution networks s' The energy supply performance can be expressed as: In the formula, Indicates the gas distribution network system s Energy supply performance Representation system s' In system state x′ The feasible range of gas supply values ​​is as follows, and , X' This represents the total number of states in the gas distribution network system. Representation system s' In state x The probability of.

[0017] Furthermore, the specific implementation method of step 2.2 is as follows: Cogeneration systems and gas distribution networks are typically connected in parallel to supply energy to users. Two parallel-connected cogeneration systems (s) and gas distribution networks (s) The performance is In the formula, This represents the total energy supply performance of the two systems s and s' connected in parallel. This indicates that the multipliers are connected in parallel.

[0018] The advantages and positive effects of this invention are: This invention proposes a system reliability analysis method for integrated energy systems containing combined heat and power (CHP) units. By performing multi-state analysis on each component of the system, defining the energy supply capacity and corresponding probability of each state, considering the coupling relationship between different energies, constructing an energy conversion efficiency function, and correcting and updating the converted energy status, a dynamic balance of multiple energy supply is achieved. The method performs probabilistic modeling and evaluation of the energy supply performance of each component and the integrated energy system, thereby realizing the reliability analysis of the system. Attached Figure Description

[0019] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the overall energy system according to an embodiment of the present invention. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings.

[0021] Considering the integrated energy system reliability calculation method of combined heat and power units, such as... Figure 1 As shown, it includes the following steps: Step 1: Analyze the coupling relationship between thermal energy, electrical energy and gas in the integrated energy system, and establish a conversion model between different energy sources.

[0022] The specific steps of step 1 include: Step 1.1: Select the state characteristic parameters of the combined heat and power unit, gas distribution network, and transmission unit; such as... Figure 2 As shown, the combined heat and power (CHP) system contains three units. Units i1, i2, and i3 are configured as back-pressure CHP units, where their thermal power is directly proportional to their electrical power, and the relationship between heat generation and power generation is positively linear. These units are configured with three states: 0, 1, and 2, each with different thermal and electrical capacities and coefficients of performance.

[0023] The system has a total of N For a given cogeneration unit, i， It has n iThere are several states, each with different thermal and electrical energy production performance. When a combined heat and power unit... i The state of being j i At that time, its heat energy and electrical energy can be expressed as follows: , And this state j i The probability of its existence is .

[0024] For combined heat and power units i In state j i In this case, the combined heat and electricity power supply performance is no longer represented by a single capacity, but is constructed as a two-dimensional performance vector constrained by the thermoelectric coupling relationship. Let the unit... i In state The maximum heating capacity and maximum power generation capacity are respectively and Thermoelectric coefficient is Then the feasible energy supply set in this state can be represented as: In the formula, Indicates a combined heat and power unit i In state j i The feasible domain for combined thermoelectric output. and These represent the unit's maximum heating capacity and maximum power supply capacity under this condition, respectively. This feasible region can simultaneously characterize the impact of unit condition degradation, capacity reduction, and thermoelectric output coupling constraints on system reliability.

[0025] In this embodiment, the parameters of the combined heat and power unit are as follows: For unit i1, the thermoelectric capacities in states 2, 1, and 0 are 75MW, 45MW, and 0MW, respectively. The thermoelectric coefficients (ratio of thermal power to electrical power) in states 2 and 1 are 1.25 and 1.5, respectively. Its maximum power generation and heating performance vectors are as follows: In state 2, (This indicates that unit i1 in state 2 has a maximum heat output of 75MW and a maximum power output of 60MW, and so on); in state 1, In state 0, .

[0026] For unit i2, the thermoelectric capacities in states 2, 1, and 0 are 40MW, 25MW, and 0MW, respectively. The thermoelectric coefficients between states 2 and 1 are 1.33 and 1.5625, respectively. The maximum performance vector is as follows: In state 2, In state 1, In state 0, .

[0027] For unit i3, the thermoelectric capacities in states 2, 1, and 0 are 45MW, 30MW, and 0MW, respectively. The thermoelectric coefficients in states 2 and 1 are 1.3235 and 1.67, respectively. The maximum performance vector is as follows: In state 2, In state 1, In state 0, .

[0028] In this embodiment, the probabilities of each state for each unit are as follows: For units i1, i2, and i3: p i1,2 =0.9, p i1,1 =0.05, p i1,0 =0.05 (meaning that the probabilities of unit i1 being in state 2, 1, and 0 are 0.9, 0.05, and 0.05 respectively, and so on). p i2,2 =0.8, p i2,1 =0.1, p i2,0 =0.1; p i3,2 =0.8, p i3,1 =0.15, p i3,0 =0.05.

[0029] The system has a total of K For a certain gas distribution network, k It also has There are several states, each with a different gas supply, when the gas distribution network... k In state j k At that time, its gas supply can be expressed as And the probability of this state existing is Furthermore, for combined heat and power (CHP) units and gas distribution networks, the constraints on their energy supply capacity under various conditions are expressed as follows: .

[0030] In this embodiment, there are two gas distribution networks supplying energy to users. k1 and k2 They have exactly the same performance. The gas distribution network has three states; in state 2, = =50 (indicates gas distribution network) k1 andk2 In state 2, 50 units of gas can be supplied, and so on; in state 1, = =25; In state 0, = =0.

[0031] The state probabilities of the gas distribution network are as follows: p k1,2 = p k2,2 =0.8, p k1,1 = p k2,1 =0.15, p k1,0 = p k2,0 =0.05 (Gas Distribution Network) k1 and k2 The probability of being in state 2 is 0.8, the probability of being in state 1 is 0.15, and the probability of being in state 0 is 0.05.

[0032] Then the gas distribution network k1 and k2 After the combination, there are 5 states, each corresponding to a different gas supply performance, as shown in Table 1: Table 1 Summary of Gas Distribution Network Energy Supply

[0033] When a combined heat and power (CHP) unit supplies energy to the demand side, the energy transfer must pass through a transmission unit, which is limited and constrained by the transmission capacity of the transmission unit, as shown below. For the transmission unit T k Let its state set be Each state corresponds to a heat transfer limit. and the upper limit of power transmission .

[0034] In this embodiment, the parameters of the transmission unit are as follows: Transmission unit T1: The transmission capacity in states 3, 2, 1, and 0 is as follows: In state 3, (This indicates that transmission unit T1 can transmit a maximum of 60MW of thermal energy and 40MW of electrical energy in state 3, and so on); in state 2 In state 1, In state 0, .

[0035] Transmission unit T2: The transmission capacity in states 3, 2, 1, and 0 is as follows: In state 3, In state 2, In state 1, In state 0, .

[0036] In state 3, the transmission unit can transmit both heat and electrical energy simultaneously. In state 2, it can only transmit electrical energy. In state 1, it can only transmit heat energy. In state 0, it is completely inoperable and cannot transmit any energy.

[0037] In this embodiment, the probabilities of each state of the transmission unit are as follows: In transmission units T1 and T2, , .

[0038] in, This indicates that the transmission unit is capable of transmitting electrical energy. This indicates that the transmission unit can transmit heat energy. This indicates that the transmission unit cannot transmit electrical energy. This indicates that the transmission unit cannot transmit heat energy.

[0039] Step 1.2: Based on the state characteristic parameters selected in Step 1.1, and considering the coupling relationship between electrical and thermal performance and electrical and gas performance, define the multi-energy conversion efficiency, conversion ratio upper limit, and conversion restriction conditions. The definition establishes a coupling relationship between electrical energy and thermal energy, and between electrical energy and gas; different energies can be converted into each other to a certain extent. Energy performance conversion indicates that a user has multiple energy needs, and when one type of energy... a When supply is insufficient to meet demand, excess energy b It can be converted into energy to a certain extent. a To meet user needs. Energy a Supply shortage F a With energy b superfluous S b They can be represented as: , .

[0040] In the formula, Represents energy a The supply is insufficient. Represents energy b The excess amount that meets the demand. Indicates the unit i or gas distribution network k In state j i or jk The energy below a Production volume Indicates the unit i or gas distribution network k In state j i or j k The energy below b Production volume.

[0041] From energy b Convert into energy a The performance conversion efficiency can be expressed as In addition, energy b Convert into energy a The value of energy has an upper limit. b It can be used to meet energy needs a The upper limit value is: .

[0042] In the formula, It is the maximum value of energy b that can be converted into energy a. It is a performance conversion coefficient between 0 and 1.

[0043] Therefore, the performance conversion quantity from energy b to energy a Q b,a It can be represented as: .

[0044] Step 1.3: Establish a conversion model between different energies, and calculate the remaining energy, energy deficit, and effective energy supply status of the system after conversion based on the conversion model.

[0045] The multi-directional conversion relationships between thermal energy, electrical energy, and gas can be summarized, and a multi-energy conversion efficiency matrix can be constructed as follows: In the formula, the energy set is ,in H, E, G Let these represent thermal energy, electrical energy, and natural gas, respectively; when there is no convertible path between two types of energy, let .

[0046] Simultaneously, construct the upper limit matrix of the conversion ratio: By using a multi-energy conversion efficiency matrix and a conversion ratio upper limit matrix, the impact of electricity-heat, electricity-gas, and other scalable energy conversion paths on system reliability can be uniformly characterized.

[0047] After conversion, energy a The update requirement can be expressed as The remaining performance of energy b can be expressed as: ;energy a The insufficient update performance can be described as .

[0048] When a system simultaneously experiences both surpluses and shortages of multiple energy sources, a multi-energy deficit compensation optimization model is introduced. This model aims to minimize the overall energy deficit after conversion and determines the optimal conversion amounts between different energy sources. The model is expressed as: In the formula, Indicates the renewed energy after conversion a Energy shortage; Indicates energy a The missing weight.

[0049] In this embodiment, considering the coupling relationship between electricity and heat, up to 50% of the heat energy demand can be converted into electrical energy demand. Each unit of electrical energy demand is equivalent to 0.8 units of heat energy demand, meaning that a certain amount of electrical energy can be used to compensate for the insufficient heat energy supply. For example, when the user's heat energy demand is 56 units, a maximum of 56 × 50% = 28 units of heat energy demand can be met by electrical energy. To compensate for the remaining 28 units of heat energy demand, an additional 28 / 0.8 = 35 units of electrical energy are needed.

[0050] Considering the coupling relationship between electricity and gas, at most 50% of the gas demand can be converted into electricity demand. Each unit of electricity demand is equivalent to 0.6 units of heat energy demand, meaning that a certain amount of electricity can be used to compensate for insufficient gas supply. For example, when a user's gas demand is 30 units, electricity can meet a maximum of 30 × 50% = 15 units of gas demand. To compensate for the remaining 15 units of heat energy demand, an additional 15 / 0.6 = 25 units of electricity are needed.

[0051] Step 2: Based on the conversion models between different energy sources, use extended general generating functions to perform multi-state probabilistic modeling of cogeneration units, gas distribution networks and transmission units, and establish a performance evaluation model for a multi-state integrated energy system with energy coupling. Step 2 specifically includes: Step 2.1: Apply the extended general generating function method to construct the performance evaluation model of the cogeneration unit and the gas distribution network constrained by the transmission unit, respectively.

[0052] For a single cogeneration unit i The performance of this, using the extended general generator method, can be described as follows: In the formula, Indicates a single uniti Energy supply performance This indicates the heat generation and power generation performance values ​​under the above conditions.

[0053] Therefore, by N A combined heat and power system consisting of multiple combined heat and power units s The performance can be expressed as: .

[0054] In the formula Indicates a combined heat and power system s Performance, Indicates a combined heat and power system s In system state x The feasible domain of heat generation and power generation values ​​under the limitation of the transmission unit, and , X Represents the total number of states in the system. Representation system s In state x The probability of.

[0055] Similarly, for a single gas distribution network k The performance can be described as follows: .

[0056] In the formula, Indicates a single gas distribution network k Performance, This indicates the amount of gas supplied by the gas distribution network under the above conditions.

[0057] Depend on K Gas supply system of individual gas distribution networks s' The energy supply performance can be expressed as: .

[0058] In the formula, Indicates the gas distribution network system s Energy supply performance Representation system s' In system state x′ The feasible range of gas supply values ​​is as follows, and , X' This represents the total number of states in the gas distribution network system. Representation system s' In state x The probability of.

[0059] Step 2.2: Consider the connection method between the cogeneration system and the gas distribution network system, and establish a performance evaluation model for the entire multi-state integrated energy system.

[0060] The combined heat and power (CHP) system and the gas distribution network system both supply energy to users, and can be considered as being connected in parallel. The two parallel-connected CHP system s and gas distribution network system s The performance can be described as follows: In the formula, This represents the total energy supply performance of the two systems s and s' connected in parallel. This indicates that the multipliers are connected in parallel.

[0061] Step 3: Based on the performance evaluation model, calculate the reliability probability and expected energy deficit of the integrated energy system under specific needs.

[0062] Step 3 specifically includes: The system's performance requirements can be expressed as follows: ,in D H , D E , D G These represent the demand for heat energy, the demand for electricity, and the demand for fuel gas, respectively. The combined heat and power (CHP) system is then derived from these values. s With gas distribution network system s After determining the energy supply performance and the probability distribution of each state, the entire integrated energy system can be obtained. S The parameters can then be calculated in the demand vector. The probability of reliability and expected energy shortage value of the integrated energy system under the given conditions. The system reliability probability can be simply summarized as the cumulative probability of each state of the system under the condition of meeting demand, which can be expressed as: .

[0063] In the formula, This indicates that the demand has been met. D The reliability probability of the integrated energy system It indicates the energy supply of the integrated energy system.

[0064] Specifically, when the system can meet the user's energy needs for heat, electricity, and natural gas under a certain state, the reliability probability of the integrated energy system after considering multi-energy coupling and conversion can be expressed as: .

[0065] In the formula, R represents the reliability of the system.

[0066] In this embodiment, for example, in demand Wei D When 1=(56,40,30), the reliability probability is calculated as follows: The specific calculation results are shown in the table below: Table 2 System reliability values ​​under different requirements

[0067] In addition to reliability probability, the expected energy deficit can also be used to evaluate the system, which can be expressed as: In the formula, EIPD To address the expected energy supply shortfall, D C represents the demand vector consisting of heat energy, electrical energy, and gas; C represents the performance vector of the system in a certain state, indicating the system's energy supply capacity in that state, including heat generation, power generation, and gas supply. p ( D, C) This represents the joint probability distribution of the demand vector and the system performance vector, which indicates the probability of each combination of demand vector and performance vector occurring.

[0068] In this embodiment, the expected energy supply deficit values ​​of the system under different demands are shown in the table below: Table 3 System EIPD values ​​under different requirements

[0069] In various demand scenarios, considering the coupling relationships between energy sources can improve the system's reliability probability and reduce the expected energy deficit, especially for medium-demand systems. D 2 The improvement to the system after considering energy coupling is significant.

[0070] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A method for calculating the reliability of a combined heat and power (CHP) unit's integrated energy system, characterized by: Includes the following steps: Step 1: Analyze the coupling relationship between thermal energy, electrical energy and gas in the integrated energy system, and establish a conversion model between different energy sources; Step 2: Based on the conversion models between different energy sources, use extended general generating functions to perform multi-state probabilistic modeling of cogeneration units, gas distribution networks and transmission units, and establish a performance evaluation model for a multi-state integrated energy system with energy coupling. Step 3: Based on the performance evaluation model, calculate the reliability probability and expected energy deficit of the integrated energy system under specific needs.

2. The method for calculating the reliability of a comprehensive energy system considering a combined heat and power unit as described in claim 1, characterized in that: Step 1 includes the following steps: Step 1.1: Select the state characteristic parameters of the cogeneration unit, gas distribution network, and transmission unit; Step 1.2: Based on the state characteristic parameters selected in Step 1.1, and considering the coupling relationship between electrical and thermal performance and electrical and gas performance, define the multi-energy conversion efficiency, conversion ratio upper limit, and conversion restriction conditions. Step 1.3: Establish a conversion model between different energies, and calculate the remaining energy, energy deficit, and effective energy supply status of the system after conversion based on the conversion model.

3. The method for calculating the reliability of a comprehensive energy system considering a combined heat and power unit as described in claim 2, characterized in that: In step 1.1, the state characteristic parameters of the cogeneration unit include the number of units, the number of states of the unit, the thermal and electrical energy capacity and thermoelectric coefficient of each state, and the probability of each state; the state characteristic parameters of the gas distribution network include the number of gas distribution networks, the number of states, the gas supply capacity of each state, and the probability of each state; the state characteristic parameters of the transmission unit include the number of transmission units, the number of states, the upper limit of thermal energy transmission, the upper limit of electrical energy transmission, and the probability of each state.

4. The method for calculating the reliability of a comprehensive energy system considering a combined heat and power unit as described in claim 2, characterized in that: The specific implementation method of step 1.2 is as follows: Establish the coupling relationships between electrical energy and heat energy, and between electrical energy and gas energy, and represent them using energy performance conversion: Users have multiple energy needs, and when one type of energy... a When supply is insufficient to meet demand, excess energy b It can be converted into energy to a certain extent. a To meet user needs, energy a Supply shortage F a With energy b superfluous S b They are represented as follows: ， In the formula, Represents energy a The supply is insufficient. Represents energy b The excess amount that meets the demand. Indicates the unit i or gas distribution network k In state j i or j k The energy below a Production volume Indicates the unit i or gas distribution network k In state j i or j k The energy below b Production volume D a and D b They represent the energy a Demand and energy b The demand, N Indicates the number of generating units; From energy b Convert into energy a The performance conversion efficiency can be expressed as ,energy b Convert into energy a The value of energy has an upper limit. b Used to meet energy needs a The upper limit value is: In the formula, It is a performance conversion coefficient between 0 and 1; The performance conversion quantity from energy b to energy a Q b,a Represented as: 。 5. The method for calculating the reliability of a comprehensive energy system considering a combined heat and power unit as described in claim 2, characterized in that: The specific implementation method of step 1.3 is as follows: The multi-energy conversion efficiency matrix is ​​as follows: in, Indicates energy Convert into energy The conversion efficiency, the energy collection is ,in H, E, G Let these represent thermal energy, electrical energy, and natural gas, respectively; when there is no convertible path between two types of energy, let ; Simultaneously, the upper limit matrix of the conversion ratio can be constructed as follows: After conversion, energy a The update requirement is The remaining performance of energy b can be expressed as: ;energy a The updated energy supply deficit is: When there are multiple energy surpluses and multiple energy shortages in the system at the same time, a multi-energy deficit compensation optimization model is introduced to determine the conversion amount between different energy sources with the goal of minimizing the overall energy supply deficit after conversion. Q b,a Represents energy b To energy a Given the conversion amount, the multi-energy deficit compensation optimization model is as follows: In the formula, Indicates the renewed energy after conversion a Energy shortage; Indicates energy a The deficit weight; when the three demands of heat, electricity, and gas are all met after conversion, the reliability of the system can be described as: In the formula, R Indicates the reliability of the system. This indicates the energy deficiency value after the conversion is updated. Pr This indicates a probability calculation.

6. The method for calculating the reliability of an integrated energy system considering a combined heat and power unit as described in claim 1, characterized in that: The specific implementation method of step 2 is as follows: Step 2.1: Apply the extended general function method to construct performance evaluation models for cogeneration units constrained by transmission units and gas distribution networks, respectively. Step 2.2: Consider the connection method between the cogeneration system and the gas distribution network system, and establish a performance evaluation model for the entire multi-state integrated energy system.

7. The method for calculating the reliability of an integrated energy system considering a combined heat and power unit as described in claim 6, characterized in that: The specific implementation method of step 2.1 is as follows: Using an extended general function method, performance evaluation models for cogeneration units constrained by transmission units and gas distribution networks are constructed respectively. Single cogeneration unit i The performance is: In the formula, Indicates a single unit i Energy supply performance This represents the heat generation and power generation performance values ​​under the above conditions; Indicates the unit i In state j i The probability, n i Indicates the unit i The number of existing states; Single gas distribution network k The performance is: In the formula, Indicates a single gas distribution network k Performance, This indicates the amount of gas supplied by the gas distribution network under the above conditions; Indicates when the gas distribution network k In state j k The probability of that time. n k Indicates gas distribution network k The number of existing states.

8. The method for calculating the reliability of an integrated energy system considering a combined heat and power unit as described in claim 7, characterized in that: The constructed models of a single cogeneration unit and a single gas distribution network are used to construct system-level evaluation models, respectively. Depend on N A combined heat and power system consisting of multiple combined heat and power units s The performance is: In the formula, Indicates a combined heat and power system s Performance, Indicates a combined heat and power system s In system state x The feasible domain of heat generation and power generation values ​​under the limitation of the transmission unit, and , X Represents the total number of states in the system. Representation system s In state x The probability of; This represents a combination operator for all unit states and probabilities; Depend on K Gas supply system of individual gas distribution networks s' The energy supply performance can be expressed as: In the formula, Indicates the gas distribution network system s Energy supply performance Representation system s' In system state x′ The feasible range of gas supply values ​​is as follows, and , X' This represents the total number of states in the gas distribution network system. Representation system s' In state x The probability of.

9. The method for calculating the reliability of an integrated energy system considering a combined heat and power unit as described in claim 6, characterized in that: The specific implementation method of step 2.2 is as follows: the cogeneration system and the gas distribution network system are usually connected in parallel to supply energy to users. Two parallel cogeneration systems s and gas distribution network systems s The performance is In the formula, This represents the total energy supply performance of the two systems s and s' connected in parallel. This indicates that the multipliers are connected in parallel.

10. The method for calculating the reliability of a comprehensive energy system considering a combined heat and power unit as described in claim 1, characterized in that, In step 3, the method for calculating the reliability probability of the integrated energy system is as follows: The user's energy demand vector can be defined as the system's demand for different performance characteristics, which can be expressed as follows: ,in , , These represent the demand for energy a, energy b, and energy c, respectively. The system reliability probability is the cumulative probability of all system states that meet the energy supply requirements, expressed as: In the formula, This indicates that the demand has been met. D The reliability probability of the integrated energy system Indicates the energy supply of the integrated energy system; In step 3, the formula for calculating the expected energy supply deficit of the integrated energy system is as follows: In the formula, EIPD To address the expected energy supply shortfall, D Demand vector representing the composition of thermal energy, electrical energy, and gas; C The performance vector represents the system's performance in a certain state, indicating the system's energy supply capacity in that state, including heat generation, power generation, and gas supply. p(D, C) This represents the joint probability distribution of the demand vector and the system performance vector, which indicates the probability of each combination of demand vector and performance vector occurring.

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