Reliability assessment method for multi-state integrated energy system with multi-energy demand response

Abstract

The application discloses a kind of comprehensive energy system reliability evaluation methods considering dynamic multi-energy demand response.A comprehensive flexible resource is divided into four kinds of multi-state comprehensive flexible resources, a multi-state model of comprehensive flexible resource considering time sequence characteristics is constructed, a multi-state model of comprehensive flexible resource reduction, transfer, alternative response considering time sequence characteristics is respectively established, a multi-state model of total demand response is established by fusing three kinds of multi-state models, a multi-state supply-side operation standby capacity model of supply-side equipment is established, a multi-state optimal scheduling model is comprehensively constructed, the amount of load shedding is obtained by processing, and the reliability of comprehensive energy system is evaluated by using time sequence Monte Carlo method to obtain the reliability parameters of comprehensive energy system.The application can more accurately represent the dynamic characteristics of comprehensive flexible resource and comprehensive energy system by using multi-state model, which helps to accurately obtain the system reliability considering demand response.

Description

Technical Field

[0001] The present invention relates to a reliability assessment method in the field of energy systems, and in particular to a reliability assessment method for a multi-state integrated energy system taking into account multi-energy demand responses. Background Art

[0002] The increasing depletion of traditional fossil energy and its high environmental pollution have led to the rapid development of integrated energy systems. However, with the large-scale integration of intermittent renewable energy, integrated energy systems require a large amount of operational reserve to maintain safe and reliable system operation. Traditional operational reserve is typically provided by energy production equipment, that is, on the power generation side. However, providing operational reserve on the power generation side may lead to increased operating and maintenance costs. Demand-side response, as an important way for demand-side loads to participate in flexible power interaction, can, to a certain extent, maintain stable system operation, promote the consumption of renewable energy, reduce peak and valley load differences, and reduce system operating costs. With the development of integrated energy systems and the deepening of the coupling between different energy sources, demand response is no longer limited to the reduction or transfer of electricity load, but also includes the complementary demand substitution between multiple energy types. The concept of comprehensive demand response considering multiple energy sources has been proposed.

[0003] Comprehensive demand response refers to the diverse, large, and widely distributed presence of comprehensive flexible resources on the demand side. Through flexible control and regulation, it can provide demand-side operating reserve capacity for the integrated energy system, achieving the goal of two-way collaborative interaction between the main grid and the distribution network. Comprehensive flexible resources refer to multi-energy load devices, including electric vehicles, air conditioners, heat pumps, and energy storage, whose multi-energy load demand can be shifted between different time periods or varied within a certain range through certain control and regulation methods. Changes in the multi-energy load demand of comprehensive flexible resources can effectively provide demand-side operating reserve capacity for these devices to the power grid.

[0004] Various equipment in integrated energy systems, including load shedding equipment (e.g., combined heat and power units, natural gas units, and combined cooling, heating, and power units), multi-energy transmission equipment (e.g., urban integrated management systems), primary equipment such as circuit breakers, and their associated secondary equipment, are subject to various types of failures, impacting the normal operation of the integrated energy system and the supply of energy to users. Failures in integrated energy systems can cause varying degrees of economic losses to energy companies, users, and certain sectors of the national economy. Therefore, integrated energy systems must possess high reliability. Furthermore, with the advancement of intelligent power grids, the high proportion of intermittent energy sources (e.g., wind and solar) is leading to increasing peak-to-valley load variations in the grid. Integrated energy systems urgently require a reliability assessment method that considers both supply-side output and supply- and demand-side operating reserve for optimal scheduling. Therefore, a reliability assessment method that considers optimal scheduling of both supply and demand sides of integrated energy systems is crucial.

[0005] The current reliability analysis method mainly focuses on power system reliability analysis, but with the introduction of multiple coupled energies, only the power system reliability analysis that can evaluate the power energy is not applicable to the comprehensive energy system reliability analysis containing multiple energy coupling. The gas, heat, cold, electricity and other multiple energies need to be reflected in the reliability at the same time.

[0006] In the traditional reliability evaluation model considering the comprehensive demand response of flexible resources, the upper limit of the comprehensive demand response of the comprehensive flexible resources is often represented by the same scalar at any time or only represented by a 0-1 parameter. However, the comprehensive demand response process of multi-energy load equipment will be affected by the time sequence characteristics and operation characteristics and has different upper limits. A single fixed comprehensive demand response upper limit cannot accurately represent the time sequence dispatchable potential of multi-energy load equipment, and cannot accurately model and represent the demand side operation reserve capacity provided by the multi-energy load equipment. Therefore, the present application proposes a new demand response model of comprehensive flexible resources, which can be used to quantify the demand side operation reserve capacity provided by the comprehensive flexible resources considering dynamic multi-energy demand response, and consider the multiple intermediate states generated by the dynamic time sequence characteristics of multi-energy load equipment in the supply and demand bilateral optimization scheduling.

[0007] The current optimization scheduling and reliability evaluation method mainly focuses on two-state optimization scheduling analysis, but the complexity of the time sequence characteristics of the system, only the two-state optimization scheduling and reliability analysis cannot be applied to the optimization scheduling and reliability analysis of the comprehensive energy system containing multiple states. The multi-state characteristics of the power and reserve provided by the gas, heat, cold, electricity and other multiple energies need to be reflected in the scheduling and evaluation model at the same time. Therefore, the present application proposes a new optimization scheduling and reliability evaluation method, which can be used to calculate the reliability of the comprehensive energy considering the supply and demand bilateral multi-state optimization scheduling.

[0008] The disadvantages of the prior art are summarized as follows:

[0009] Disadvantage 1 of the prior art: The traditional reliability evaluation method mainly focuses on power system reliability evaluation, but with the introduction of multiple coupled energies, only the power system reliability analysis that can evaluate the power energy is not applicable to the comprehensive energy system reliability analysis containing multiple energy conversion.

[0010] Disadvantage 2 of existing technology: Existing optimization scheduling technology regards the comprehensive demand response process of comprehensive flexible resources as two states, namely complete failure or perfect operation. The upper limit of demand response is often represented by the same scalar or only by 0-1 parameters at any time, and does not consider the dynamic timing characteristics of the comprehensive demand response process. Therefore, due to insufficient modeling of comprehensive flexible resources, the obtained demand response model cannot accurately reflect the dynamic demand response timing characteristics of comprehensive flexible resources, and the reliability assessment calculation based on optimized scheduling cannot reflect the impact of the timing characteristics of comprehensive flexible resources on reliability.

[0011] Existing technology disadvantage 3: Existing optimization scheduling technology and reliability analysis calculations regard the system operation process as two states, namely complete failure or perfect operation, and do not consider the dynamic timing characteristics of the system operation. As a result, the modeling of the interaction between supply and demand is insufficient, making the resulting scheduling and reliability assessment models unable to accurately reflect the multi-state characteristics of the system. Summary of the Invention

[0012] In response to the shortcomings of the existing technology, the present invention proposes a multi-state integrated energy system reliability assessment method considering multi-energy demand response, which is applied to reliability applications that provide backup by considering multi-state interaction on both the supply and demand sides of the integrated energy system.

[0013] like Figure 1 As shown, the technical solution of the present invention is as follows:

[0014] Step 1: Classify the integrated flexible resources into four types of multi-state integrated flexible resources, and construct a multi-state model of integrated flexible resources that considers time series characteristics to obtain the multi-energy load demand of each integrated flexible resource in different states;

[0015] Step 2: Establish a multi-state model of the curtailment response of integrated flexible resources considering the time series characteristics, which is used to obtain the load amount that the integrated flexible resources can participate in the curtailment response in each state and the multi-energy load demand of the integrated flexible resources after the curtailment response ends;

[0016] Step 3: Establish a multi-state model of the integrated flexible resource transfer response that takes into account the timing characteristics, in order to obtain the load that the integrated flexible resource can participate in the transfer response in each state and the multi-energy load demand of the integrated flexible resource after the transfer response is completed;

[0017] Step 4: Establish a multi-state model of the substitution response of integrated flexible resources considering the time series characteristics, which is used to obtain the load amount that the integrated flexible resources can participate in the substitution response in each state and the multi-energy load demand of the integrated flexible resources after the substitution response ends;

[0018] Step 5: Integrate the three multi-state models of the integrated flexible resource response to establish a multi-state model of the total demand response of the integrated flexible resource, which is used to obtain the demand-side operating reserve provided by the integrated flexible resource in multiple states;

[0019] Step 6: Establish a multi-state supply-side operating reserve capacity model for the supply-side equipment of the integrated energy system, and solve it to obtain the output and supply-side operating reserve capacity provided by the supply-side equipment of the integrated energy system;

[0020] Step 7: Integrate the multi-state model of the total demand response of the integrated flexible resources and the multi-state supply-side operating reserve model of the supply-side equipment of the integrated energy system to build a multi-state optimal scheduling model for the interactive provision of reserve by the supply and demand sides of the integrated energy system. Process and obtain scheduling parameters such as the demand-side operating reserve, supply-side output, supply-side operating reserve, and load shedding provided by the integrated flexible resources.

[0021] Step 8: Based on the load shedding of the integrated flexible resources, the reliability of the integrated energy system is evaluated using the time series Monte Carlo method to obtain the reliability parameters of the integrated energy system.

[0022] The integrated flexible resource exhibits multiple multi-energy load demands, each of which represents a multi-state state. By accounting for multiple energy sources, the multi-energy load demands and the output of multi-energy conversion equipment from integrated flexible resources have expanded from a single dimension to a multi-dimensional state.

[0023] The present invention takes into account energy forms such as electricity, natural gas, and thermal energy. The multi-energy loads of comprehensive flexible resources are expanded from one-dimensional loads to multi-dimensional multi-energy loads, so that multiple energy sources can be universally represented by one load form.

[0024] The energy forms of the integrated energy system include electricity, natural gas, thermal energy, etc.

[0025] An integrated energy system is divided into a supply side and a demand side. The supply side generates and transmits energy to the demand side, which in turn provides the required multi-energy load. An integrated energy system has many nodes, each of which contains multiple supply-side devices and multiple integrated flexible resources on the demand side.

[0026] The equipment on the supply side of the integrated energy system is multi-energy conversion equipment (the most common multi-energy conversion equipment is various types of multi-energy conversion units, such as cogeneration units, natural gas units, combined heat and power units, etc.).

[0027] On the demand side of the integrated energy system, multi-energy load equipment such as air conditioners and heat pumps can actively participate in the two-way interaction of the power grid as integrated flexible resources. Integrated flexible resources provide demand-side operating reserve to the system in the form of demand-side response through aggregation.

[0028] The present invention takes into account the different operating characteristics of different types of loads, and provides demand-side operating reserve through three main demand response strategies of integrated flexible resources: integrated flexible resource reduction response, integrated flexible resource transfer response and integrated flexible resource substitution response: Integrated flexible resource reduction response refers to changing the size of integrated flexible resources to provide system reserve; integrated flexible resource transfer response refers to changing the energy consumption time of integrated flexible resources to provide system reserve; integrated flexible resource substitution response refers to changing the energy carrier of integrated flexible resources to provide equivalent system reserve, for example, the heat load can be provided by a cogeneration unit, or a gas boiler, or a heat pump.

[0029] In the first step, the integrated flexible resources are divided into four types of multi-state integrated flexible resources, namely, fixed integrated flexible resources, transferable integrated flexible resources, curtailable integrated flexible resources, and replaceable integrated flexible resources, according to the multi-energy load demand of the integrated flexible resources;

[0030] The fixed comprehensive flexible resources refer to comprehensive flexible resources that cannot be changed, such as industrial loads; the transferable comprehensive flexible resources refer to comprehensive flexible resources whose usage time can be changed, such as the gas load required for gas kitchen appliances; the reducible comprehensive flexible resources refer to comprehensive flexible resources whose energy consumption can be changed, such as the electrical load required for air conditioning; the replaceable comprehensive flexible resources refer to comprehensive flexible resources whose energy source can be changed, such as water heaters require electrical loads. However, if the comprehensive energy system is equipped with a natural gas unit, the electrical load required for the water heater can be equivalently replaced by a gas load.

[0031] The relationship between the loads of different multi-state integrated flexible resources is:

[0032] F=FS+FC+FT+FR

[0033] Where F represents the multi-energy load demand of integrated flexible resources, FS represents the load of fixed integrated flexible resources, FC represents the load of curtailable integrated flexible resources, FT represents the load of transferable integrated flexible resources, and FR represents the load of replaceable integrated flexible resources.

[0034] The load, demand and reserve mentioned in the present invention are all power quantities.

[0035] Fixed integrated flexible resources, transferable integrated flexible resources, curtailable integrated flexible resources and replaceable integrated flexible resources have different load demands due to their dynamic timing characteristics. Within the required period, the four types of integrated flexible resources have M states, that is, the four types of integrated flexible resources all have M multi-energy load demands, and thus the demand-side operating reserve that can be provided by the four types of integrated flexible resources also has M states.

[0036] Comprehensive flexible resources include V types of energy. Comprehensive flexible resources i can be represented by a V-dimensional energy vector. Comprehensive flexible resources may have different multi-energy load demands. The following comprehensive flexible resource multi-state model considering the timing characteristics is established:

[0037] F i =(F i 1 ,F i 2 ,...,F i M )

[0038]

[0039]

[0040]

[0041] Among them, F i represents the multi-energy load demand set of comprehensive flexible resource i, i represents the type number of comprehensive flexible resource, represents the multi-energy load demand of the integrated flexible resource i in state j, j∈(1,2,...,M), M represents the total number of states of the integrated flexible resource; represents the multi-energy load demand of the comprehensive flexible resource i when considering energy form v in state j, v∈(1,2,...,V), V represents the total sequence number of the energy form; represents the fixed integrated flexible resource load of integrated flexible resource i at state j, represents the load of the fixed comprehensive flexible resource i when considering energy form v in state j, v∈(1,2,...,V), V represents the total sequence number of the energy form; represents the amount of load that can be reduced for the comprehensive flexible resource i at state j, represents the load of comprehensive flexible resources that can be reduced by comprehensive flexible resources i when considering energy form v in state j; represents the load of the transferable comprehensive flexible resource of comprehensive flexible resource i at state j, represents the load of the transferable comprehensive flexible resource i when considering energy form v in state j; represents the load of the alternative comprehensive flexible resource i at state j, represents the load of the alternative comprehensive flexible resource i when considering energy form v in state j; T represents the matrix transpose.

[0042] in, and Known in advance.

[0043] The multi-energy load demand of each comprehensive flexible resource i in state j is obtained according to the multi-state model of comprehensive flexible resources.

[0044] The second step is specifically as follows:

[0045] Based on the comprehensive flexible resource multi-state model, the following comprehensive flexible resource reduction response multi-state model is established:

[0046]

[0047]

[0048] in, represents the multi-energy load demand of the comprehensive flexible resource i after curtailment response at state j, represents the load of the integrated flexible resource i in response to the reduction in state j, represents the load reduction response of the integrated flexible resource i in state j and considering energy form v;

[0049] At the same time, in state j, the maximum load that can be reduced by the integrated flexible resource i is less than or equal to its integrated demand response upper limit, that is, the total load that can be reduced contained in the integrated flexible resource i in state j The constraints for the integrated flexible resource reduction response of the following model are established:

[0050]

[0051] The load of the comprehensive flexible resource i in each state related to the reduction response Calculated by the optimization scheduling model in step 7, combined with the previously known and The multi-state model processing input to the comprehensive flexible resource reduction response can obtain the multi-energy load demand of the comprehensive flexible resource after the reduction response in each state.

[0052] The third step is specifically as follows:

[0053] Based on the multi-state model of integrated flexible resources, integrated flexible resources can be transferred out of state j or transferred in from other states. The following multi-state model of integrated flexible resource transfer response is established:

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] wherein, represents the multi-energy load demand of the integrated flexible resource i after the transfer response at state j; represents the load amount of the integrated flexible resource i that is completely transferred out at state j, represents the load amount of the integrated flexible resource i that has the integrated demand response about the transfer from state j to state j’ at state j, represents the load amount of the integrated flexible resource i from state j to state j’ considering the energy form v, l e (1, 2, …, M); represents the load amount of the integrated flexible resource i that is completely transferred in at state j, represents the load amount of the integrated flexible resource i that has the integrated demand response about the transfer from state j’ back to state j, represents the load amount of the integrated flexible resource i from state j’ back to state j considering the energy form v;

[0060] At the same time, the maximum transferable integrated flexible resource of the integrated flexible resource i at state j is less than or equal to the upper limit of the integrated demand response, that is, the total transferable load of the integrated flexible resource i at state j satisfies the energy conservation principle, and the transfer load amount of the integrated flexible resource at the jth state is equal to the sum of the transfer load amounts to other states, the following model is established to constrain the transfer response of the integrated flexible resource:

[0061]

[0062]

[0063] wherein, D j represents the load duration of the integrated flexible resource at state j, D j' represents the load duration of the integrated flexible resource at state j’.

[0064] The load amount of the integrated flexible resource i at each state about the transfer response and are calculated from the optimization scheduling model of step seven, so as to combine the previously known and to obtain the multi-energy load demand of the integrated flexible resource after the transfer response at each state

[0065] The fourth step is specifically as follows:

[0066] Based on the comprehensive flexible resource multi-state model, the following comprehensive flexible resource substitution response multi-state model is established:

[0067]

[0068]

[0069]

[0070] in, represents the multi-energy load demand of comprehensive flexible resource i after alternative response at state j; represents the load of the comprehensive flexible resource i participating in the alternative response, It represents the load of flexible resource i participating in the alternative response in state j and considering energy form v; represents the load obtained by the comprehensive flexible resource i after alternative response, It represents the load obtained by the comprehensive flexible resource i after the alternative response in state j and considering the energy form v. Represents the multi-performance conversion matrix of the multi-energy conversion device s connected to the integrated flexible resource i at state j; the alternative response needs to be completed through the multi-energy conversion device.

[0071] At the same time, in state j, the initial comprehensive flexible resource of the most participating in the substitution response process of comprehensive flexible resource i is less than or equal to its comprehensive demand response upper limit, that is, all the substitutable loads contained in comprehensive flexible resource i in state j. The constraint conditions of the comprehensive flexible resource substitution response of the following model are established:

[0072]

[0073] The load of the comprehensive flexible resource i in each state on the alternative response and the loadings obtained after surrogate responses Calculated by the optimization scheduling model in step 7, combined with the previously known and The multi-state model processing input to the comprehensive flexible resource reduction response can obtain the multi-energy load demand of the comprehensive flexible resource after the alternative response in each state.

[0074] The fifth step is specifically as follows:

[0075] Based on the multi-state model of comprehensive flexible resource reduction response, transfer response and alternative response, a multi-state model of comprehensive flexible resource demand response is constructed, and the demand side operation reserve capacity that the comprehensive flexible resource demand response can provide in each state is obtained.

[0076] Considering the reduction, transfer and alternative response processes of comprehensive flexible resources, the demand side operation reserve capacity provided by comprehensive flexible resource i presents a multi-state trend due to the difference in the state of comprehensive flexible resources. The following multi-state model of comprehensive flexible resource total demand response is established:

[0077]

[0078]

[0079]

[0080] Where, DRR i represents the set of demand side operation reserve capacity provided by comprehensive flexible resources participating in demand response in M states, represents the demand side operation reserve capacity provided by comprehensive flexible resource i in state j after three types of demand response, represents the demand side operation reserve capacity provided by comprehensive flexible resource i considering the energy form v; represents the multi-energy load demand of comprehensive flexible resource i after three types of demand response in state j;

[0081] According to the F i j and the multi-energy load demand after reduction, transfer and alternative response input into the multi-state model of comprehensive flexible resource total demand response to obtain the multi-energy load demand of comprehensive flexible resource i after three types of demand response, and then combine the multi-energy load demand F i j of comprehensive flexible resource to obtain the demand side operation reserve capacity provided by comprehensive flexible resource i

[0082] The sixth step is specifically:

[0083] In addition to providing output, the multi-energy conversion device in the operating state will also reserve a part as the supply side operation reserve capacity provided in the accident state.

[0084] The following multi-state supply side operation reserve capacity model of multi-energy conversion device s is established and represented as:

[0085] GR s =(GR s,1 ,GR s,2 ,...,GRs,M ) T

[0086]

[0087] w s =(w s,1 ,w i,2 ,...,w s,M ) T

[0088]

[0089] Where GR s represents the supply-side operating reserve of the multi-energy conversion equipment s, GR s,j represents the supply side operating reserve of the multi-energy conversion device s in state j, represents the supply-side operating reserve of the multi-energy conversion device s in operating state j considering the energy form v, It represents the proportion of the reserve power of multi-energy conversion equipment in the overall output under state j, represents the proportion of the reserve power of multi-energy conversion equipment in the overall output under state j, w s Indicates the multi-state and multi-energy output of the multi-energy conversion device s. The multi-energy conversion device s has M states, w s,j represents the multi-energy output of the multi-energy conversion device s in state j, It represents the output of multi-energy conversion device s at state j when considering energy form v;

[0090] The multi-energy conversion device s can provide at most The reserve and The downward reserve, that is, the supply-side operating reserve provided by the multi-energy conversion equipment s meets the constraint:

[0091]

[0092] Supply-side operating reserve capacity GR of multi-energy conversion equipment s s and multi-power output s Obtained according to the optimized scheduling calculation in step seven.

[0093] The seventh step is specifically as follows:

[0094] Based on the multi-state model for the total demand response of integrated flexible resources and the multi-state supply-side operating reserve model for supply-side equipment constructed above, the multi-energy load demand of integrated flexible resources, the fixed load of integrated flexible resources, the load that can be curtailed, the upper limit of the load that can be curtailed, and the upper limit of the load that can be shifted are obtained for each state. Combined with the known upper limits for the multi-energy output and load shedding of multi-energy conversion equipment, these are substituted into the integrated energy system optimal scheduling model to calculate the multi-energy output of the multi-energy conversion equipment, the supply-side operating reserve of the multi-energy conversion equipment, and the demand-side operating reserve of the integrated flexible resources.

[0095] The required time period is T, during which the multi-energy conversion equipment and integrated flexible resources have M states, and the duration of each state is D j ,Right now The states of the supply and demand sides of the integrated energy system are represented by V-dimensional vectors, and the costs involved in the objective function are also V-dimensional vectors.

[0096] The following multi-state optimization scheduling model is established:

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] Where C represents the operating cost of the comprehensive energy system, C v represents the operating cost of the integrated energy system considering the energy form v, is the multi-energy output of the s-th multi-energy conversion device on the integrated energy system node l when it is in state j, represents the output of the multi-energy conversion device s at state j when considering the energy form v; The supply side operating reserve provided when the s-th multi-energy conversion device on the integrated energy system node l is in state j, It represents the supply-side operating reserve of the multi-energy conversion equipment s in operating state j considering the energy form v; The demand-side operating reserve provided by the i-th integrated flexible resource on the integrated energy system node l when it is in state j, It represents the demand-side operating reserve of the i-th integrated flexible resource in state j considering energy form v; is the load shedding amount when the i-th integrated flexible resource on the integrated energy system node l is in state j, denotes the amount of shed load of the i-th integrated flexible resource in state j considering the energy form v; V denotes the state dimension of the supply side and demand side of the integrated energy system;

[0103] M, N, ns, nsr, ndr, nc are the number of partitioning, the number of nodes, the number of multi-energy conversion devices on node l, the number of multi-energy conversion devices providing backup on node l, the number of integrated flexible resources providing backup on node l, the number of integrated flexible resources of shed load on node l, respectively, are the supply side energy output cost, the supply side cost of providing operational backup, the demand side cost of providing operational backup and the shed load cost of the s-th multi-energy conversion device or the i-th integrated flexible resource on node l in state j, respectively;

[0104] The integrated energy system contains electricity, gas and heat, and the constraint condition for establishing optimal scheduling is:

[0105] (1) Power balance constraint:

[0106] (1.1) Electric power balance:

[0107]

[0108] In the formula, denotes the electric energy output of the ns multi-energy conversion devices on node l in state j, denotes the electric energy backup provided by the nsr multi-energy conversion devices providing operational backup on node l in state j, denotes the electric energy load demand of the ndr integrated flexible resources after demand side response on node l in state j, denotes the electric energy shed load of the nc integrated flexible resources needing to be shed on node l in state j; this constraint indicates that the electric energy needs to maintain balance between generation and consumption during system operation.

[0109] (1.2) Gas power balance:

[0110]

[0111] In the formula, denotes the natural gas output of the ns multi-energy conversion devices on node l in state j, denotes the natural gas backup provided by the nsr multi-energy conversion devices providing operational backup on node l in state j, denotes the natural gas load demand of the ndr integrated flexible resources after demand side response on node l in state j, represents the natural gas load shedding capacity of nc comprehensive flexible resources that need to be shelved at node l in state j. This constraint indicates that natural gas production and consumption must be balanced during system operation.

[0112] 3) Thermal balance power:

[0113]

[0114] Where, represents the thermal energy output generated by ns multi-energy conversion devices at node l and state j, represents the thermal energy reserve provided by nsr multi-energy conversion devices providing operation backup at node l in state j, represents the heat load demand of ndr integrated flexible resources at node l and state j after the demand side response, represents the thermal energy load shedding amount of nc comprehensive flexible resources that need to be shed at node l and state j; this constraint indicates that when the system is running, the thermal energy generation and consumption need to be balanced.

[0115] (2) Equipment output constraints:

[0116]

[0117] v=(gas,elec,heat)

[0118] Where, represents the output of the multi-energy conversion device s regarding energy form v at node l and state j, and The upper and lower limits of its output are shown in Figure 2. This constraint indicates that when the system is running, each energy source needs to meet the upper and lower limits of the equipment's output.

[0119] (3) Supply-side operating reserve constraints:

[0120]

[0121] v=(gas,elec,heat)

[0122] Where, It represents the supply-side operating reserve of the multi-energy conversion equipment s in energy form v at node l and state j, is the maximum adjustable reserve ratio of multi-energy conversion equipment s in state j, is the maximum adjustable lower reserve ratio of the multi-energy conversion equipment s in state j; this constraint indicates that when the system is running, each energy source needs to meet the upper and lower limits of the maximum reserve that can be provided by the equipment.

[0123] (4) Demand-side response constraints:

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] wherein, denotes the demand of the multi-energy load of the integrated flexible resource i after considering the demand response at node l, state j, is the fixed integrated flexible resource amount of the integrated flexible resource i at node l, state j, denotes the upper limit of the demand of the multi-energy load of the integrated flexible resource i at node l, state j; denotes the maximum reducible integrated flexible resource load amount contained in the integrated flexible resource i at node l, state j, denotes the maximum transferable integrated flexible resource load amount contained in the integrated flexible resource i at node l, state j, denotes the maximum replaceable integrated flexible resource load amount contained in the integrated flexible resource i at node l, state j; denotes the load amount reduced after the integrated flexible resource i at node l, state j participates in the reduction response, denotes the load amount transferred out after the integrated flexible resource i at node l, state j participates in the transfer response, denotes the load amount replaced after the integrated flexible resource i at node l, state j participates in the replacement response, denotes the load amount of the integrated flexible resource i at node l transferred from state j to state j', D j denotes the duration of state j, D j' denotes the duration of state j'; this constraint indicates that the demand response of each energy needs to meet the upper and lower limit constraints of the maximum amount of demand response that can be participated in during the integrated flexible resource demand response.

[0130] (5) Load shedding constraint:

[0131]

[0132] v = (gas, elec, heat)

[0133] wherein, denotes the load shedding amount of the i-th integrated flexible resource with respect to the energy form v at node l, state j, represents the upper limit of the cut load amount of the i th integrated flexible resource with respect to the energy form v at the node l in the state j; the constraint indicates that each energy needs to meet the maximum cut load upper and lower limit constraint when the system is running.

[0134] For the multi-state optimization scheduling model, a discrete linear programming method is used to solve the output of the multi-energy conversion equipment on the supply side Supply side operation reserve Demand side operation reserve provided by integrated flexible resources And the cut load amount of the integrated flexible resource

[0135] The application constructs an integrated energy system optimization scheduling mode considering expected dynamic multi-energy demand response, which can more accurately and effectively perform distribution and operation reserve for the integrated energy system.

[0136] In the application, the bold letters represent vectors.

[0137] The eighth step specifically includes:

[0138] According to the cut load amount of the integrated flexible resource The reliability parameters of the integrated energy system are calculated:

[0139]

[0140]

[0141] In the formula, represents the cut load amount of the integrated flexible resource i considering the energy form v at the node l in the state j; delta A () represents a cut load amount size judgment function; when , Otherwise EENS v represents the energy deficiency expectation parameter considering the energy form v; LOLP v represents the energy deficiency probability parameter considering the energy form v; MCSN is the total sampling number of the time sequence Monte Carlo; N is the total number of nodes in the integrated energy system, and nc is the integrated flexible resource of the cut load at the node l;

[0142] The energy deficiency expectation parameter EENS v and the energy deficiency probability parameter LOLP v constitute the reliability parameters of the integrated energy system.

[0143] Further, the energy deficiency expectation parameter and the energy deficiency probability parameter can be used for structure optimization, reserve optimization and system maintenance of the integrated energy system considering the reliability constraint.

[0144] The present invention first proposes a multi-state model of comprehensive flexible resource reduction response considering time series characteristics, a multi-state multi-energy load demand model of comprehensive flexible resource transfer response and a multi-state model of comprehensive flexible resource substitution response, and then establishes a multi-state model of comprehensive flexible resources to evaluate the demand-side operating reserve that comprehensive flexible resources can provide in multiple states. Secondly, a multi-state multi-energy output and a multi-state supply-side operating reserve model of the supply side of the comprehensive energy system are constructed, and then a multi-state optimization scheduling model for the interactive provision of reserve by the supply side and the demand side is constructed. Finally, a time series Monte Carlo method is used to evaluate the system reliability after demand response.

[0145] The multi-state model adopted in the present invention can more accurately characterize the dynamic characteristics of integrated flexible resources and integrated energy systems, help to build a multi-state model of interaction between supply and demand, and accurately obtain the system reliability considering demand response.

[0146] The present invention constructs a multi-state integrated energy system reliability assessment model that takes into account expected multi-energy demand responses, providing a basis for the reliable operation of the integrated energy system.

[0147] The beneficial effects of the present invention are as follows:

[0148] With the introduction of multi-energy coupling, the peak-to-valley difference in integrated energy systems has gradually increased, and the problem of balancing supply and demand has become more prominent. Integrated energy systems urgently need a multi-energy reliability assessment method that can optimize the scheduling of supply-side output and supply- and demand-side operating reserve capacity. The method proposed in this paper can accurately and effectively schedule multi-state supply-side output and allocate multi-state operating reserve capacity on both sides while ensuring supply and demand balance, and evaluate system reliability.

[0149] Compared to traditional reliability assessment methods, this method considers the dynamic timing characteristics of the integrated demand response process and evaluates the multi-state demand-side operating reserve capacity provided by different types of integrated flexible resources. This more accurately represents the demand-side operating reserve capacity provided by integrated flexible resources, which has a positive impact on reducing the operating reserve and environmental pollution caused by traditional units. Furthermore, this method can construct a multi-state model of supply-side output and reserve, achieving multi-state operating reserve optimization on both the supply and demand sides, providing a more accurate and detailed parameter basis for system reliability assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0150] Figure 1 It is a flow chart of the present invention.

[0151] Figure 2 Schematic diagram of load variation in the embodiment.

[0152] Figure 3 and Figure 4Schematic diagram of reliability evaluation of the embodiment. DETAILED DESCRIPTION

[0153] The present invention will be further described below with reference to the accompanying drawings and examples.

[0154] like Figure 1 As shown, the embodiment and implementation process of the present invention are as follows:

[0155] The present invention uses the IEEE 30-node system and the Belgian 20-node natural gas system and their corresponding parameters to form a test system. The time period is 24 hours, and the local time period is 1 hour. The load demand changes of any power and natural gas node at each moment are as follows: Figure 2 As shown in Figure 1, based on the actual electricity and natural gas load demand at each node, the electricity and natural gas load demand for each node in each time period is proportionally scaled. Based on the electricity and natural gas load demand at each moment, the integrated flexible resource is constructed into 24 states. The supply-side equipment of the integrated energy system all adopts a three-state model, and the transition rates between each state are shown in Table 1. Using the Markov process, the 24 multi-state output sequences of the supply-side equipment within a time period can also be calculated.

[0156] Table 1 State transition rate of each device

[0157] Transfer rate / h 100% output cap 50% output cap 0 100% output cap -0.004 0.002 0.002 50% output cap 0.012 -0.022 0.012 0 0.018 0.018 -0.036

[0158] The reserve cost for electricity and natural gas units is 10% of their energy output cost. Supply-side reserve capacity, both upward and downward, is capped at 20% of the current period's output. Load shedding is capped at the system's load, meaning all load can be removed in an emergency. Demand response capacity for electricity, natural gas load shifting, curtailment, and substitution is capped at 10%, 20%, and 10% of the current period's load, respectively. Load is assumed to be shifted only to the next three localized periods. During the initial system operation phase, all equipment is assumed to be operating perfectly.

[0159] Without considering the demand response process of comprehensive flexible resources, when the supply side output changes, the demand side can only ensure the balance between supply and demand by shedding load. Taking electricity as an example, the reliability parameters with and without comprehensive demand response are as follows: Figure 3 and Figure 4 As shown. Figure 3 It can be seen that considering comprehensive demand response can greatly improve system reliability.

[0160] It can be seen from the above examples that the method of the present invention can accurately and effectively evaluate system reliability while ensuring the balance between supply and demand.

Claims

1. A method for evaluating the reliability of an integrated energy system with dynamic multi-energy demand response, characterized by: Step 1: Classify the integrated flexible resources into four types of multi-state integrated flexible resources, and construct a multi-state model of integrated flexible resources that considers the timing characteristics to obtain the multi-energy load demand of each integrated flexible resource; Step 2: Establish a multi-state model of comprehensive flexible resource curtailment response considering the time series characteristics, so as to obtain the multi-energy load demand of comprehensive flexible resources after the curtailment response ends in each state; Step 3: Establish a multi-state model of the integrated flexible resource transfer response considering the timing characteristics, so as to obtain the multi-energy load demand of the integrated flexible resource after the transfer response is completed in each state; Step 4: Establish a multi-state model of the substitution response of comprehensive flexible resources considering the time series characteristics, so as to obtain the multi-energy load demand of comprehensive flexible resources after the substitution response ends in each state; Step 5: Integrate the three multi-state models of the integrated flexible resource response to establish a multi-state model of the total demand response of the integrated flexible resource, which is used to obtain the demand-side operating reserve provided by the integrated flexible resource in multiple states; Step 6: Establish a multi-state supply-side operating reserve capacity model for the supply-side equipment of the integrated energy system, and solve it to obtain the output and supply-side operating reserve capacity provided by the supply-side equipment of the integrated energy system; Step 7: Integrate the multi-state model of the total demand response of integrated flexible resources and the multi-state supply-side operating reserve model of the supply-side equipment of the integrated energy system to build a multi-state optimal scheduling model for the interactive provision of reserve by the supply and demand sides of the integrated energy system, and process the demand-side operating reserve, supply-side output, supply-side operating reserve, and load shedding capacity provided by the integrated flexible resources. Step 8: Based on the load shedding of the integrated flexible resources, the reliability of the integrated energy system is evaluated using the time series Monte Carlo method to obtain the reliability parameters of the integrated energy system; In the first step, the integrated flexible resources are divided into four types of multi-state integrated flexible resources, namely, fixed integrated flexible resources, transferable integrated flexible resources, curtailable integrated flexible resources, and replaceable integrated flexible resources, according to the multi-energy load demand of the integrated flexible resources; Comprehensive flexible resources include V types of energy forms. The following comprehensive flexible resource multi-state model considering the timing characteristics is established: F i =(F i 1 ,F i 2 ,...,F i M ) Among them, F i represents the multi-energy load demand set of comprehensive flexible resource i, i represents the type number of comprehensive flexible resource, F i j represents the multi-energy load demand of the integrated flexible resource i in state j, j∈(1,2,...,M), M represents the total number of states of the integrated flexible resource; represents the fixed integrated flexible resource load of integrated flexible resource i at state j, represents the load of the fixed integrated flexible resource i when considering energy form v in state j; represents the load that can be reduced for the comprehensive flexible resource i at state j, represents the load that can be reduced by the comprehensive flexible resource i when considering energy form v in state j; FT i j represents the load of the transferable comprehensive flexible resource of comprehensive flexible resource i at state j, represents the load of the transferable comprehensive flexible resource i when considering energy form v in state j; represents the load of the alternative comprehensive flexible resource of comprehensive flexible resource i at state j, represents the load of the alternative comprehensive flexible resource i when considering energy form v in state j; T represents the matrix transpose; The third step is specifically as follows: The following multi-state model of comprehensive and flexible resource transfer response is established: in, represents the multi-energy load demand of the integrated flexible resource i after the transfer response at state j; ΔFT i j represents the load that is transferred out of the comprehensive flexible resource i in state j, ΔFT i j→j' In state j, the integrated flexible resource i undergoes a comprehensive demand response related to the transfer, and the load is transferred from state j to state j'. represents the load of the integrated flexible resource i transferred from state j to state j' when considering energy form v, l∈(1,2,...,M); Δ'FT i j represents the total load transferred from the integrated flexible resource i in state j, ΔFT i j'→j Indicates the load amount of the integrated flexible resource i that has undergone the integrated demand response about the transfer from state j' back to state j, represents the load amount of the integrated flexible resource i when state j' is transferred back to state j when energy form v is considered; At the same time, the constraints of the comprehensive flexible resource transfer response of the following models are established: ΔFT i j ≤FT i j Among them, D j represents the load duration of the integrated flexible resource in state j, D j' represents the load duration of the integrated flexible resource in state j'; The fourth step is specifically as follows: The following multi-state model of comprehensive flexible resource substitution response is established: in, represents the multi-energy load demand of comprehensive flexible resource i after alternative response at state j; represents the load of the comprehensive flexible resource i participating in the alternative response, It represents the load of flexible resource i participating in the alternative response in state j and considering energy form v; represents the load obtained by the comprehensive flexible resource i after alternative response, It represents the load obtained after the replacement response of the comprehensive flexible resource i in state j and considering the energy form v; represents the multi-performance conversion matrix of the multi-energy conversion device s connected to the integrated flexible resource i at state j; At the same time, the constraints of the comprehensive flexible resource substitution response of the following models are established: The fifth step is specifically as follows: The following multi-state model of aggregate demand response for integrated flexible resources is established: Among them, DRR i represents the set of demand-side operating reserves provided by the comprehensive flexible resources participating in demand response in M ​​states, represents the demand-side operating reserve provided by comprehensive flexible resource i in state j after three types of demand response, represents the demand-side operating reserve provided by the integrated flexible resource i under the consideration of energy form v; represents the multi-energy load demand of the integrated flexible resource i after the three types of demand response at state j; According to the optimized scheduling calculation in step 7, F i j and the multi-energy load demand after reduction, transfer, and substitution response Input into the multi-state model of the total demand response of the integrated flexible resource to obtain the multi-energy load demand of the integrated flexible resource i after the three types of demand response, and then combine it with the multi-energy load demand F of the integrated flexible resource i j Obtain demand-side operating reserve capacity provided by comprehensive flexible resources i The sixth step is specifically as follows: The following multi-state supply-side operation reserve model of multiple energy conversion equipment s is established and expressed as: GR s =(GR s,1 ,GR s,2 ,...,GR s,M ) T In s =(in s,1 ,In i,2 ,...,In s,M ) T Where GR s represents the supply-side operating reserve of the multi-energy conversion equipment s, GR s,j represents the supply side operating reserve of the multi-energy conversion device s in state j, represents the supply-side operating reserve of the multi-energy conversion device s in operating state j considering the energy form v, Indicates the proportion of the maximum reserve of multi-energy conversion equipment to the overall output in state j, represents the proportion of the maximum reserve of multi-energy conversion equipment to the overall output in state j, w s Indicates the multi-state and multi-energy output of the multi-energy conversion device s, w s,j represents the multi-energy output of the multi-energy conversion device s in state j, It represents the output of multi-energy conversion device s at state j when considering energy form v; The multi-energy conversion device s can provide at most The reserve and The downward reserve, that is, the supply-side operating reserve provided by the multi-energy conversion equipment s meets the constraint: Supply-side operating reserve capacity GR of multi-energy conversion equipment s s and multi-power output s Obtained according to the optimized scheduling calculation in step seven.

2. The method for evaluating the reliability of an integrated energy system with dynamic multi-energy demand response according to claim 1, characterized in that: The second step is specifically as follows: Develop the following multi-state model for comprehensive and flexible resource reduction responses: in, represents the multi-energy load demand of the comprehensive flexible resource i after curtailment response at state j, represents the load of the integrated flexible resource i in response to the reduction in state j, represents the load reduction response of the integrated flexible resource i in state j and considering energy form v; At the same time, the constraints of the comprehensive flexible resource reduction response of the following models are established:

3. The method for evaluating the reliability of an integrated energy system with dynamic multi-energy demand response according to claim 1, characterized in that: The seventh step is specifically as follows: The following multi-state optimization scheduling model is established: Where C represents the operating cost of the comprehensive energy system, C v represents the operating cost of the integrated energy system considering the energy form v, is the multi-energy output of the s-th multi-energy conversion device on the integrated energy system node l when it is in state j, represents the output of the multi-energy conversion device s at state j when considering the energy form v; The supply side operating reserve provided when the s-th multi-energy conversion device on the integrated energy system node l is in state j, It represents the supply-side operating reserve of the multi-energy conversion equipment s in operating state j considering the energy form v; The demand-side operating reserve provided by the i-th integrated flexible resource on the integrated energy system node l when it is in state j, It represents the demand-side operating reserve of the i-th integrated flexible resource in state j considering energy form v; is the load shedding amount when the i-th integrated flexible resource on the integrated energy system node l is in state j, represents the load shedding of the i-th integrated flexible resource in state j considering energy form v; V represents the state dimension of the supply side and demand side of the integrated energy system; M, N, ns, nsr, ndr, and nc are the number of time periods, the number of nodes, the number of multi-energy conversion devices on node l, the number of multi-energy conversion devices providing backup on node l, the number of comprehensive flexible resources providing backup on node l, and the number of comprehensive flexible resources for load shedding on node l, respectively. are the supply-side energy output cost, the cost of providing operating reserve on the supply side, the cost of providing operating reserve on the demand side, and the load shedding cost when the s-th multi-energy conversion device or the i-th integrated flexible resource on node l is in state j; The integrated energy system includes three energy forms: electricity, gas, and heat. The constraints for establishing optimal scheduling are: (1) Power balance constraints: (1.1) Electric balance power: Where, represents the power output generated by ns multi-energy conversion devices at node l and state j, represents the amount of power reserve provided by nsr multi-energy conversion devices that provide backup operation at node l in state j, represents the electric energy load demand of ndr integrated flexible resources at node l and state j after the demand side response, represents the electric energy load shedding amount of nc comprehensive flexible resources that need to shed load at node l in state j; (1.2) Gas balance power: Where, represents the natural gas output generated by ns multi-energy conversion devices at node l and state j, represents the natural gas reserve provided by nsr multi-energy conversion devices providing operation backup at node l in state j, represents the natural gas load demand of ndr integrated flexible resources at node l and state j after demand-side response, represents the natural gas load shedding amount of nc comprehensive flexible resources that need to be shelved at node l in state j; 3) Thermal balance power: Where, represents the thermal energy output generated by ns multi-energy conversion devices at node l and state j, represents the thermal energy reserve provided by nsr multi-energy conversion devices providing operation backup at node l in state j, represents the heat load demand of ndr integrated flexible resources at node l and state j after the demand side response, represents the thermal energy load shedding amount of nc comprehensive flexible resources that need to be shedded at node l in state j; (2) Equipment output constraints: v=(gas,elec,heat) Where, represents the output of the multi-energy conversion device s regarding energy form v at node l and state j, and The upper and lower limits of its output; (3) Supply-side operating reserve constraints: v=(gas,elec,heat) Where, It represents the supply-side operating reserve of the multi-energy conversion equipment s in energy form v at node l and state j, is the maximum adjustable reserve ratio of multi-energy conversion equipment s in state j, is the maximum reserve ratio that can be adjusted downward for the multi-energy conversion equipment s in state j; (4) Demand-side response constraints: Where, represents the multi-energy load demand of comprehensive flexible resource i after considering demand response at node l and state j, is the fixed comprehensive flexible resource amount of comprehensive flexible resource i at node l and state j, represents the upper limit of the multi-energy load demand of the comprehensive flexible resource i at node l and state j; represents the maximum reducible comprehensive flexible resource load contained in comprehensive flexible resource i at node l and state j, represents the maximum transferable comprehensive flexible resource load contained in comprehensive flexible resource i at node l and state j, represents the maximum replaceable comprehensive flexible resource load contained in comprehensive flexible resource i at node l and state j; represents the load reduction after the comprehensive flexible resource i participates in the reduction response at node l and state j, represents the load transferred out after the comprehensive flexible resource i participates in the transfer response at node l and state j, represents the load replaced by the comprehensive flexible resource i at node l and state j after participating in the replacement response, represents the load of the integrated flexible resource i at node l transferred from state j to state j', D j represents the duration of state j, D j' represents the duration of state j'; (5) Load shedding constraints: v=(gas,elec,heat) Where, represents the load shedding of the i-th integrated flexible resource in energy form v at node l and state j, represents the upper limit of the load shedding capacity of the i-th integrated flexible resource with respect to energy type v at node l and state j; For the multi-state optimization scheduling model, the discrete linear programming method is used to solve the output of multiple energy conversion equipment on the supply side. Supply-side operating reserve Demand-side operating reserve provided by comprehensive flexible resources and load shedding capacity of integrated flexible resources 4. The method for evaluating the reliability of an integrated energy system with dynamic multi-energy demand response according to claim 1, characterized in that: The eighth step is specifically as follows: Load shedding based on comprehensive flexible resources Calculate the reliability parameters of the integrated energy system: Where, represents the load shedding of the integrated flexible resource i in the energy form v when the integrated energy system node l is in state j; δ A () represents the load shedding size judgment function; EENS v represents the expected energy deficit parameter considering energy form v; LOLP v represents the energy shortage probability parameter considering energy form v; MCSN is the total number of sampling times of the time series Monte Carlo; N is the total number of nodes in the integrated energy system, and nc is the comprehensive flexible resource for load shedding at node l; Energy deficiency expectation parameter EENS v and energy shortage probability parameter LOLP v It constitutes the reliability parameters of the integrated energy system.

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