A multi-cycle natural gas pipeline network transmission capacity improvement design method and device

Abstract

The present application discloses a multi-cycle natural gas pipeline network transmission capacity improvement design method and device, the method includes: obtaining basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters and supply and demand data; based on the obtained basic parameters, generating constraints of the multi-cycle natural gas pipeline network MILP model to be established; based on the generated constraints and the preset cost objective function, establishing the MILP model; solving the MILP model by a MILP solver based on the branch and bound algorithm, and obtaining the multi-cycle natural gas pipeline network transmission capacity improvement design result. In this way, the natural gas pipeline transmission capacity improvement design is made under the multi-cycle perspective, and the multi-cycle natural gas pipeline network MILP model is solved by the branch and bound algorithm to obtain the global optimal solution as a whole, which provides effective support and guidance for the improvement of the gas transmission capacity of the natural gas pipeline network and reduces the total cost.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas pipeline networks, and in particular to a multi-cycle natural gas pipeline network transmission capacity improvement design method and device. Background Art

[0002] With the continuous increase in natural gas demand, higher requirements are placed on the transmission capacity of the natural gas pipeline network. With the gradual formation of "one network across the country", new gas storage facilities or new users will be connected to the existing natural gas pipeline network. The natural gas pipeline network is large in scale, with a complex topological structure and complex network-wide analysis. It is difficult to decide on the optimal design plan to improve the natural gas pipeline network's transmission capacity by manpower.

[0003] The design of natural gas pipeline network transmission capacity improvement is a multi-cycle, long-term and complex problem. In order to obtain a natural gas pipeline network transmission capacity improvement plan with the lowest possible cost, a systematic, scientific and reasonable design is required, taking into account many factors, including upstream and downstream supply and demand, infrastructure capacity in the pipeline network system, flow distribution of pipelines, etc. Therefore, the infrastructure and topology of the pipeline network need to be adjusted to meet the basic gas supply needs at different times.

[0004] At present, some scholars have considered the rising demand for natural gas in the literature, but they often adopt a modeling method based on an annual scale, ignoring the actual role of gas storage facilities, which often results in serious discrepancies between the planned pipeline network and the actual situation. Since there is a large difference in demand for natural gas in different periods of the same year, and as the demand continues to rise, the difference between the off-season and the peak season will be more significant. In the peak season, the gas storage serves as a "gas source", and the natural gas pipeline network undertakes a greater transportation task at this time. However, only using an annual scale cannot accurately and effectively analyze the actual natural gas pipeline network blockages, which affects the timing of pipeline construction and produces large errors in the improvement of the gas transmission capacity of the natural gas pipeline network. In addition, for model solutions, although intelligent algorithms and heuristic methods are commonly used, it is still difficult to ensure that the results are globally optimal. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a multi-cycle natural gas pipeline network transmission capacity improvement design method and device, which can provide effective support and guidance for the improvement of the natural gas pipeline network transmission capacity and reduce the total cost. The specific scheme is as follows:

[0006] A multi-cycle natural gas pipeline network transmission capacity improvement design method, comprising:

[0007] Obtaining basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters, and supply and demand data;

[0008] Generating constraint conditions of a multi-period natural gas pipeline network MILP model to be established according to the basic parameters obtained;

[0009] Establishing the MILP model according to the generated constraint conditions and the preset cost objective function;

[0010] The MILP model is solved by a MILP solver based on a branch and bound algorithm to obtain a multi-period natural gas pipeline network transmission capacity improvement design result.

[0011] Preferably, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, before establishing the MILP model, it also includes:

[0012] Calculate the costs of transporting natural gas, the costs of building new or expanded pipelines, and the costs associated with gas storage;

[0013] According to the cost of natural gas transportation, the cost of new or expanded pipelines and the cost related to the gas storage, the cash flows in different periods are obtained;

[0014] According to the cash flows in different periods, the minimum total cost net present value is obtained, and the minimum total cost net present value is used as the cost objective function.

[0015] Preferably, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, the cost required for natural gas transmission, the cost of building or expanding pipelines, and the costs related to gas storage are calculated, including:

[0016] The transportation cost of a single pipeline is calculated based on the product of pipeline transportation cost, transportation distance and pipeline transportation flow rate; the sum of the transportation costs of all pipelines is taken as the cost required for transporting natural gas;

[0017] Calculate the cost of building or expanding pipelines based on the unit length cost of the pipeline and the distance of the pipeline;

[0018] Calculate the gas storage related expenses based on the total cost of gas injection, gas production and gas storage in the gas storage.

[0019] Preferably, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, the constraint conditions of the multi-period natural gas pipeline network MILP model to be established are generated, including:

[0020] For each node, node upload flow, node download flow, pipeline inflow flow and pipeline outflow flow are defined to characterize the flow relationship of the pipeline network;

[0021] A flow balance constraint condition is generated according to the flow relationship of the pipeline network, the size relationship between the node upload flow and the local natural gas production, and the size relationship between the node download flow and the local minimum demand for natural gas.

[0022] Preferably, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, the constraint conditions for generating the multi-period natural gas pipeline network MILP model to be established also include:

[0023] Based on the condition that a pipeline is only constructed once between two nodes where new or expanded pipelines may be constructed, the pipeline network structure constraints are generated.

[0024] Preferably, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, the constraint conditions for generating the multi-period natural gas pipeline network MILP model to be established also include:

[0025] The transport capacity of the existing pipeline that is not to be expanded is set as a fixed value, and the pipeline transport capacity constraint condition is generated according to the relationship between the transport capacity of the newly built or expanded pipeline and the current maximum transport capacity;

[0026] Based on the conditions that there is only one flow direction in the pipeline at the same time and the flow direction is consistent with the flow direction, the pipeline transportation direction constraint conditions are generated.

[0027] Preferably, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, the constraint conditions for generating the multi-period natural gas pipeline network MILP model to be established also include:

[0028] The gas storage reservoir constraints are generated according to the gas storage capacity constraints, gas injection capacity constraints, gas production capacity constraints and the relationship between the gas production capacity and the gas storage inventory.

[0029] Preferably, in the above-mentioned multi-cycle natural gas pipeline network transmission capacity improvement design method provided in an embodiment of the present invention, the multi-cycle natural gas pipeline network transmission capacity improvement design results include the time, location, and designed transmission volume of pipeline construction, the required pipeline transportation, pipeline construction, and gas storage operation costs, the flow rate of each pipeline in each cycle, the pipeline utilization rate, and the working conditions of the gas storage in the pipeline network in each cycle.

[0030] The embodiment of the present invention also provides a multi-cycle natural gas pipeline network transmission capacity improvement design device, comprising:

[0031] A parameter acquisition module is used to acquire basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters, and supply and demand data;

[0032] A constraint condition generation module, used to generate constraint conditions of a multi-period natural gas pipeline network MILP model to be established according to the acquired basic parameters;

[0033] A model building module, used to build the MILP model according to the generated constraint conditions and a preset cost objective function;

[0034] The model solving module is used to solve the MILP model by using a MILP solver based on a branch and bound algorithm to obtain a multi-cycle natural gas pipeline network transmission capacity improvement design result.

[0035] Preferably, in the above-mentioned multi-cycle natural gas pipeline network transmission capacity improvement design device provided in the embodiment of the present invention, it also includes:

[0036] The objective function acquisition module is used to calculate the cost required for natural gas transportation, the cost of building a new or expanded pipeline, and the cost related to the gas storage; based on the cost required for natural gas transportation, the cost of building a new or expanded pipeline, and the cost related to the gas storage, the cash flow of different periods is obtained; based on the cash flow of different periods, the minimum total cost net present value is obtained, and the minimum total cost net present value is used as the cost objective function.

[0037] It can be seen from the above technical scheme that a multi-cycle natural gas pipeline network transmission capacity improvement design method provided by the present invention includes: obtaining basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters and supply and demand data; based on the acquired basic parameters, generating constraints of the multi-cycle natural gas pipeline network MILP model to be established; establishing the MILP model based on the generated constraints and a preset cost objective function; solving the MILP model by a MILP solver based on a branch and bound algorithm to obtain a multi-cycle natural gas pipeline network transmission capacity improvement design result.

[0038] The above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided by the present invention takes pipelines, pipes, and gas storage as important considerations, makes a natural gas pipeline transmission capacity improvement design under a multi-period perspective, and solves the multi-period natural gas pipeline network MILP model through a branch and bound algorithm to obtain a global optimal solution as a whole. The model can reflect the actual situation of the actual natural gas pipeline network system, and obtains the optimal natural gas pipeline construction plan through basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters and supply and demand data, which provides effective support and guidance for improving the gas transmission capacity of the natural gas pipeline network and reduces the total cost.

[0039] In addition, the present invention also provides a corresponding device for the multi-cycle natural gas pipeline network transmission capacity improvement design method, which further makes the above method more practical, and the device has corresponding advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0041] Figure 1 A flow chart of a multi-cycle natural gas pipeline network transmission capacity improvement design method provided in an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of the structure of a multi-cycle natural gas pipeline network transmission capacity improvement design device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The natural gas pipeline network system usually includes gas sources, pipelines, gas compressor stations, gas storage facilities and users. The gas source is one of the starting points of the pipeline network. Natural gas enters the pipeline from the gas source station, is pressurized by the gas compressor station, and is finally transported to the user; the gas storage facility injects gas when there is excess gas supply and extracts gas when there is insufficient gas supply; the user is the download point of natural gas. The design difficulties of improving the gas transmission capacity of the natural gas pipeline network mainly include the following parts. First, the output of gas fields is fluctuating, and the demand of each user is uncertain, especially the demand in off-season and peak season is obviously different, so it is necessary to use gas storage facilities to reasonably allocate the flow; second, in the long run, the demand for natural gas is rising steadily, and the existing natural gas pipeline transportation capacity is gradually unable to cope with the rapidly growing demand for natural gas, and it is necessary to consider the change of pipeline scale; third, the structure of natural gas pipeline network is becoming increasingly complex. For a given natural gas supply and demand forecast, the natural gas pipeline network has different pipeline planning and flow scheduling schemes. The pipeline transportation cost, pipeline construction cost and gas storage cost of different schemes are different, and the cost of natural gas pipeline is expensive. The cost difference between different pipeline construction schemes is large, and the choice of scheme directly affects the total investment cost of natural gas pipeline network. Fourth, the construction cost calculation of natural gas pipeline involves quite a lot of factors, including the location, length, terrain, whether to cross, construction period, investment contract, etc. of pipeline construction. Considering the above factors at the same time will make the model closer to reality, but it will make the design of pipeline construction to improve the gas transmission capacity of natural gas pipeline network more difficult. Fifth, the design of pipeline construction to improve the gas transmission capacity of natural gas pipeline network is a nonlinear problem, and the complex topological structure will make it difficult for the model to obtain the optimal solution in a short time. Based on this, the present invention proposes a multi-cycle natural gas pipeline network gas transmission capacity improvement design method that coordinates pipeline network operation and overall planning to reduce gas supply costs.

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The present invention provides a multi-cycle natural gas pipeline network transmission capacity improvement design method, such as Figure 1 As shown, the following steps are included:

[0046] S101. Obtain basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters, and supply and demand data;

[0047] Specifically, basic management parameters may include pipeline length, pipe diameter, and pipeline transportation capacity; basic pipe material parameters may include pipe diameter and pipeline transportation capacity; basic gas storage parameters may include initial gas volume of gas storage, maximum inventory, maximum gas injection capacity, minimum gas injection capacity, maximum gas production capacity, minimum gas production capacity, gas production leakage rate, gas storage leakage rate, gas injection leakage rate, unit gas production cost, unit gas storage cost, and unit gas injection cost; technical and economic parameters may include unit pipeline transportation cost and unit pipeline construction cost; supply and demand data may include the demand of natural gas users and planned output of gas fields in a certain period of time in the future.

[0048] S102, generating constraint conditions of a multi-period natural gas pipeline network MILP model to be established according to the acquired basic parameters;

[0049] Specifically, the multi-period natural gas pipeline network MILP model contains many constraints, including nodes and pipelines, pipeline flow, pipeline pressure, obstacles and overall construction. Combined with specific actual data and piecewise linearization method, the model can be transformed into a MILP mathematical model, in which all constraints and objective functions are linear.

[0050] S103, establishing a MILP model according to the generated constraint conditions and the preset cost objective function;

[0051] Preferably, the present invention establishes a multi-period natural gas pipeline network MILP model based on a half-year scale, which takes into account the actual role of gas storage facilities, can effectively analyze the actual natural gas pipeline network blockages, and reduce the error caused by improving the gas transmission capacity of the natural gas pipeline network.

[0052] S104. Solve the MILP model using a MILP solver based on a branch and bound algorithm to obtain a multi-period natural gas pipeline network transmission capacity improvement design result.

[0053] In the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, pipelines, pipes, and gas storage are taken as important considerations, and the peak and off-peak seasons and supply and demand fluctuations are taken into consideration. The natural gas pipeline transmission capacity improvement design is made under the multi-period perspective, and the multi-period natural gas pipeline network MILP model is solved by the branch and bound algorithm to obtain the overall global optimal solution. The model can reflect the actual situation of the actual natural gas pipeline network system, and the optimal natural gas pipeline construction plan is obtained through the basic parameters of the pipeline, the basic parameters of the pipe, the basic parameters of the gas storage, the technical and economic parameters and the supply and demand data, which provides effective support and guidance for the improvement of the gas transmission capacity of the natural gas pipeline network and reduces the total cost.

[0054] It should be noted that the purpose of the multi-cycle natural gas pipeline network gas transmission capacity improvement pipeline construction design method is to establish a mathematical programming model, under given basic economic parameters and process parameters, to develop a pipeline network construction plan with the lowest total cost. As mentioned above, the optimization design is not only economically optimal, but also the needs of natural gas users should be taken into consideration. Therefore, in view of the problems of previous studies that only flow optimization was used, supply and demand fluctuations in the off-season and peak seasons and multi-cycle gas transmission capacity improvement were ignored, the present invention takes gas storage as an important factor, and proposes a multi-cycle natural gas pipeline network gas transmission capacity improvement design method that considers off-seasons and peak seasons and supply and demand fluctuations. It is used to plan the pipeline construction of the natural gas pipeline network. Specifically, the parameter data is first obtained, and then the data is combined into the MILP model for modeling, and the most advanced MILP solver GUROBI is used to solve the model, and finally the optimal natural gas pipeline network construction plan is obtained.

[0055] In practical applications, under the premise of establishing the MILP model, the present invention can assume that: the marginal cost is not considered in the gas transmission cost, and the unit gas transmission cost of the same pipeline takes a fixed value; the water and heat characteristics of the pipeline network are not considered; it can only be built once between two nodes; the injection and production capacity of the gas storage reservoir is changed to the total capacity during half a year (the injection and production capacity in half a year is equal to the daily injection and production capacity multiplied by 182); the gas source supply is stable, the gas supply ratio in the off-season and peak season is 1:1, the user demand is unbalanced, and the demand ratio in the off-season and peak season is 0.45:0.55; the construction cost of the natural gas pipeline is only related to the pipe diameter and the length of the pipeline.

[0056] Furthermore, in a specific implementation, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in an embodiment of the present invention, before executing step S103 to establish the MILP model, it can also include: first, calculating the cost required for natural gas transportation, the cost of new or expanded pipelines, and the costs related to gas storage; then, according to the cost required for natural gas transportation, the cost of new or expanded pipelines, and the costs related to gas storage, obtaining cash flows in different periods; finally, according to the cash flows in different periods, obtaining the minimum total cost net present value, and taking the minimum total cost net present value as the cost objective function.

[0057] It is understandable that the focus of improving gas transmission capacity is to solve macro problems such as natural gas pipeline construction and flow distribution. Focusing on the relationship between pipeline operation, construction and total cost, the objective function and constraints are abstracted by simplifying the processes of pipeline water and heat, pipeline construction and operation costs, and gas storage operation. The present invention takes the minimum total cost net present value as the objective function, considers the pipeline transmission capacity limit in each time period and the gas storage gas injection and production and storage capacity limit, and establishes a MILP model, so that the model can be solved by a MILP solver based on the branch and bound algorithm to obtain a global optimal solution.

[0058] Specifically, the calculation formula of the cost objective function is:

[0059] NPV=∑ t∈T C t (1+r) -t (1)

[0060] Among them, NPV represents the net present value of the objective function within the decision cycle, C t represents the cash flow in period t, t∈T represents the set of time nodes, and r represents the discount rate.

[0061] Cash flow C in period t t It includes three parts: the cost of transporting qualified natural gas, the cost of building or expanding pipelines, and the cost of gas storage facilities:

[0062]

[0063] Among them, Ctran t represents the cost of natural gas transportation during period t, Cpipe t Indicates the cost of building or expanding pipelines during period t, Cstorage t represents the gas storage related costs in period t.

[0064] In specific implementation, the above steps to calculate the cost of natural gas transportation, the cost of new or expanded pipelines and the cost of gas storage facilities may include:

[0065] The transportation cost of a single pipeline is calculated based on the product of pipeline transportation cost, transportation distance and pipeline transportation flow rate; the sum of the transportation costs of all pipelines is taken as the cost required for transporting natural gas;

[0066] Calculate the cost of building or expanding pipelines based on the unit length cost of the pipeline and the distance of the pipeline;

[0067] Calculate the gas storage related expenses based on the total cost of gas injection, gas production and gas storage in the gas storage.

[0068] Specifically, the transportation cost Ctran during period t is t It is equal to the sum of the transportation costs of all pipelines. The transportation cost of a single pipeline is equal to the pipeline transportation cost multiplied by the transportation distance and then multiplied by the pipeline transportation flow rate:

[0069]

[0070] Among them, p tran i,j,t represents the pipeline transportation cost between node i and node j in period t, l i,j represents the distance between two nodes, Q pipe i,j,t represents the pipeline natural gas flow from node i to node j in period t; i,j∈N aRepresents the collection of all points in the pipeline network topology, including gas source points, demand points, gas storage points and common nodes.

[0071] Cost of new / expanded pipelines during period t Cpipe t Equal to the cost per unit length of the pipeline multiplied by the pipeline distance l i,j :

[0072]

[0073] Among them, cpc d represents the unit length construction cost of type d pipeline; if a type d pipeline is newly built or expanded between node i and node j in period t, then BB t,i,j,d =1, otherwise BB t,i,j,d =0; d∈D represents the set of pipe diameter specifications.

[0074] Gas storage related costs during period t Cstorage t It is equal to the sum of the costs of gas injection, gas extraction and gas storage in the gas storage facility:

[0075]

[0076] Among them, Csto t represents the gas storage cost of the gas storage facility during period t, Cdo t represents the gas injection cost of the gas storage in period t, Cup t It represents the gas production cost of the gas storage in period t.

[0077] In period t, the gas storage cost Csto t It is equal to the gas storage capacity of the gas storage facility multiplied by the unit gas storage cost:

[0078]

[0079]

[0080] Among them, cv start i Indicates the initial gas storage inventory, CV i,t Indicates the gas storage capacity of the node, csto i,t Indicates the unit gas storage cost; N q ∈N a Represents a collection of gas storage nodes in the pipeline network topology.

[0081] Gas injection cost of gas storage in period t Cdo t It is equal to the amount of gas injected from the pipeline network to the gas storage multiplied by the unit gas injection cost:

[0082]

[0083] in, Indicates the gas injection volume from the pipeline network to the gas storage (i.e., node download flow), Indicates the unit gas injection cost.

[0084] Gas storage gas production cost Cup in period t t It is equal to the actual gas volume extracted from the gas storage by the pipeline network multiplied by the unit gas extraction cost:

[0085]

[0086] in, Indicates the actual gas volume extracted from the gas storage by the pipeline network, leakage up i represents the gas leakage rate of the gas storage node, Indicates the unit gas production cost.

[0087] In specific implementation, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in an embodiment of the present invention, step S102 generates constraint conditions of the multi-period natural gas pipeline network MILP model to be established, including: defining node upload flow, node download flow, pipeline inflow flow and pipeline outflow flow for each node to characterize the flow relationship of the pipeline network; generating flow balance constraint conditions according to the flow relationship of the pipeline network, the size relationship between the node upload flow and the local natural gas production, and the size relationship between the node download flow and the local minimum natural gas demand.

[0088] Specifically, the following four flows are defined for each node to characterize the flow relationship of the network, including: node upload flow Qup i,t 、Node download traffic Qdo i,t , Pipeline inflow flow Q pipe j,i,t and the pipe outflow rate Q pipe i,j,t .

[0089] Node upload amount Qup i,t Less than or equal to local production capacity:

[0090]

[0091] Among them, qp i,t represents the natural gas production at node i in period t, and the gas source point qp i,t >0, the remaining nodes qp i,t =0.

[0092] Demand node download volume Qdo i,t Greater than or equal to the local minimum demand:

[0093]

[0094] Among them, qdi,t represents the natural gas demand at node i in period t, and the demand point qd i,t >0, the remaining nodes qd i,t = 0. N d ∈N a Represents a collection of demand points in a pipe network topology.

[0095] Other node downloads Qdo i,t is 0:

[0096]

[0097] All node traffic is conserved, (upload + inflow) equals (download + outflow):

[0098]

[0099] Pipeline traffic only exists between different nodes:

[0100]

[0101] In specific implementation, in the above-mentioned multi-cycle natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, step S102 generates the constraint conditions of the multi-cycle natural gas pipeline network MILP model to be established, and also includes: generating the pipeline network structure constraint conditions according to the condition that only one pipeline is built between two nodes where new or expanded pipelines may be built.

[0102] Specifically, the initial topology of the pipeline is assigned:

[0103]

[0104] If there is a pipeline between node i and node j at time t, then BE t,i,j =1, otherwise BE t,i,j = 0. b i,j Indicates whether there is a pipeline between node i and node j in the initial state; t0 represents the initial time.

[0105] A pipeline is only built once between two nodes where a new pipeline may be built or expanded:

[0106]

[0107]

[0108] Where (i,j)∈E a Represents a collection of pipes in the pipe network topology; E e ∈E a Represents the set of pipeline candidates for network topology expansion; E n ∈E aRepresents a collection of alternative routes for newly created pipelines in the pipe network topology.

[0109] After the pipeline is newly built or expanded, the pipeline exists:

[0110]

[0111] The pipeline comes from existing or newly built / expanded:

[0112]

[0113] Once the pipeline exists, it can play a role in subsequent periods:

[0114]

[0115] In specific implementation, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, step S102 generates the constraint conditions of the multi-period natural gas pipeline network MILP model to be established, and also includes: setting the transmission capacity of the existing pipeline that is not expanded to a constant value, and generating the pipeline transmission capacity constraint conditions according to the relationship between the transmission capacity of the newly built or expanded pipeline and the current maximum transmission capacity; generating the pipeline transmission direction constraint conditions according to the conditions that there is only one flow direction in the pipeline at the same time, and the flow direction is consistent with the flow direction.

[0116] Specifically, the pipeline transportation capacity constraints include: the transportation capacity of the existing pipelines that are not to be expanded is always set to a fixed value:

[0117]

[0118] Among them, CP i,j,t represents the pipeline transport capacity from node i to node j in period t, cp i,j Represents the pipeline transportation capacity between the initial states ij.

[0119] Initial status of the transport capacity of the alternative expansion pipeline:

[0120]

[0121] The initial state of the transport capacity of the new alternative pipeline is 0:

[0122]

[0123] The pipeline transportation capacity will increase after the new construction / expansion. The increased capacity is related to the selected pipeline type:

[0124]

[0125] Among them, cpd dIndicates the transport capacity of type d pipeline (the fine approach should be determined by hydrothermal dynamics, and the macro approach can be taken as a given value).

[0126] The flow rate cannot exceed the current maximum transmission capacity:

[0127]

[0128] Taking into account the elastic margin of pipeline transportation, the pipeline transportation capacity is set at 95% of the upper limit.

[0129] The constraints on pipeline transportation direction include: Decision variable BP restricts flow direction:

[0130]

[0131] If the flow rate flows from node i to node j during period t, then BP t,i,j =1, otherwise BP t,i,j =0.

[0132] The flow direction of a one-way pipe is known:

[0133]

[0134]

[0135] Among them, E s ∈E a Represents a collection of one-way pipes in the pipe network topology; E p ∈E a Represents a collection of existing pipes in the pipe network topology.

[0136] There is only one flow direction in the pipeline at the same time:

[0137]

[0138] Flow direction is consistent with flow direction:

[0139]

[0140] Where M represents a sufficiently large number, and the value in the program is the sum of all demands.

[0141] In specific implementation, in the above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, step S102 generates the constraint conditions of the multi-period natural gas pipeline network MILP model to be established, and also includes: generating the gas storage reservoir constraint conditions according to the gas storage capacity constraint conditions of the gas storage reservoir, the gas injection capacity constraint conditions of the gas storage reservoir, the gas production capacity constraint conditions of the gas storage reservoir, and the size relationship between the gas production capacity of the gas storage reservoir and the gas storage inventory.

[0142] Specifically, the initial value of gas storage capacity:

[0143]

[0144] Among them, leak do i,t represents the gas injection leakage rate of the gas storage node during period t, i,t It represents the gas leakage rate of the gas storage in period t.

[0145] Gas storage capacity in subsequent cycles:

[0146]

[0147] Constraints on gas storage capacity:

[0148]

[0149] in, Indicates the minimum value of gas storage inventory, Indicates the maximum value of gas storage inventory.

[0150] Constraints on gas injection capacity of gas storage:

[0151]

[0152] in, Indicates the minimum gas injection volume of the gas storage reservoir, Indicates the maximum gas injection volume of the gas storage.

[0153] Constraints on gas storage capacity:

[0154]

[0155] in, represents the minimum gas extraction volume of the gas storage, Indicates the maximum gas production of the gas storage facility.

[0156] The gas storage capacity is less than the inventory:

[0157]

[0158] Q upi,t ≤CV i,t-1 ,i∈Nq,t∈T and t≠0 (36)

[0159] In specific implementation, in the above-mentioned multi-cycle natural gas pipeline network transmission capacity improvement design method provided in the embodiment of the present invention, the multi-cycle natural gas pipeline network transmission capacity improvement design results may include the time, location, and designed transmission volume of pipeline construction, the required pipeline transportation, pipeline construction and gas storage operation costs, the flow rate of each pipeline in each cycle, the pipeline utilization rate, and the working conditions of the gas storage in the pipeline network in each cycle.

[0160] It should be pointed out that the present invention takes into account multiple cycles in the design process of improving the natural gas pipeline network's transmission capacity, and also takes into account the changes in pipeline transmission capacity and the injection and production storage capacity of the gas storage reservoir. By establishing a MILP model, overall optimization is performed to obtain a global optimal solution.

[0161] In practical applications, the present invention can automatically quantify the results of natural gas demand forecasts, first taking half a year as a scale, taking into account the peak-shaving effect of gas storage, and performing macro-optimization scheduling of the natural gas pipeline network. After a plurality of alternative construction route plans are given, the model can automatically calculate and compare the advantages and disadvantages of each plan, as well as the changes in pipeline deployment and gas storage operation after the completion of each construction plan, and finally determine the most economical natural gas pipeline network transmission capacity improvement design plan.

[0162] Based on the same inventive concept, an embodiment of the present invention also provides a multi-cycle natural gas pipeline network transmission capacity improvement design device. Since the principle of solving the problem by the device is similar to the aforementioned multi-cycle natural gas pipeline network transmission capacity improvement design method, the implementation of the device can refer to the implementation of the multi-cycle natural gas pipeline network transmission capacity improvement design method, and the repeated parts will not be repeated.

[0163] In specific implementation, the multi-cycle natural gas pipeline network transmission capacity improvement design device provided by the embodiment of the present invention is as follows: Figure 2 As shown, specifically including:

[0164] The parameter acquisition module 11 is used to acquire basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters, and supply and demand data;

[0165] The constraint condition generating module 12 is used to generate the constraint conditions of the multi-period natural gas pipeline network MILP model to be established according to the acquired basic parameters;

[0166] A model building module 13 is used to build a MILP model according to the generated constraint conditions and a preset cost objective function;

[0167] The model solving module 14 is used to solve the MILP model by using a MILP solver based on a branch and bound algorithm to obtain a multi-period natural gas pipeline network transmission capacity improvement design result.

[0168] In the above-mentioned multi-cycle natural gas pipeline network transmission capacity improvement design device provided in the embodiment of the present invention, the optimal natural gas pipeline construction plan can be obtained through the interaction of the above-mentioned four modules, which provides effective support and guidance for improving the gas transmission capacity of the natural gas pipeline network and reduces the total cost.

[0169] Furthermore, in a specific implementation, the multi-cycle natural gas pipeline network transmission capacity improvement design device provided in the embodiment of the present invention may further include:

[0170] The objective function acquisition module is used to calculate the cost required for natural gas transportation, the cost of building or expanding pipelines, and the costs related to gas storage; based on the cost required for natural gas transportation, the cost of building or expanding pipelines, and the costs related to gas storage, the cash flow in different periods is obtained; based on the cash flow in different periods, the minimum total cost net present value is obtained, and the minimum total cost net present value is used as the cost objective function.

[0171] For more specific working processes of the above modules, please refer to the corresponding contents disclosed in the above embodiments, which will not be repeated here.

[0172] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0173] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0174] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0175] In summary, a multi-period natural gas pipeline network transmission capacity improvement design method provided by an embodiment of the present invention includes: obtaining basic parameters related to the natural gas pipeline network; the basic parameters include basic parameters of pipelines, basic parameters of pipes, basic parameters of gas storage, technical and economic parameters and supply and demand data; generating constraints of the multi-period natural gas pipeline network MILP model to be established according to the acquired basic parameters; establishing the MILP model according to the generated constraints and the preset cost objective function; solving the MILP model by a MILP solver based on a branch and bound algorithm to obtain a multi-period natural gas pipeline network transmission capacity improvement design result. The above-mentioned multi-period natural gas pipeline network transmission capacity improvement design method takes pipelines, pipes and gas storage as important considerations, makes a natural gas pipeline transmission capacity improvement design under a multi-period perspective, solves the multi-period natural gas pipeline network MILP model by a branch and bound algorithm, and obtains a global optimal solution as a whole. The model can reflect the actual situation of the actual natural gas pipeline network system, and obtains the optimal natural gas pipeline construction plan by using basic parameters of pipelines, basic parameters of pipes, basic parameters of gas storage, technical and economic parameters and supply and demand data, which provides effective support and guidance for improving the gas transmission capacity of the natural gas pipeline network and reduces the total cost. In addition, the present invention also provides a corresponding device for the multi-cycle natural gas pipeline network transmission capacity improvement design method, which further makes the above method more practical, and the device has corresponding advantages.

[0176] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0177] The above is a detailed introduction to the multi-cycle natural gas pipeline network transmission capacity improvement design method and device provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A multi-cycle natural gas pipeline network transmission capacity improvement design method, characterized in that: include: Obtaining basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters, and supply and demand data; Generating constraint conditions of a multi-period natural gas pipeline network MILP model to be established according to the basic parameters obtained; Establishing the MILP model according to the generated constraint conditions and the preset cost objective function; The MILP model is solved by a MILP solver based on a branch and bound algorithm to obtain a multi-period natural gas pipeline network transmission capacity improvement design result.

2. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 1 is characterized in that: Before establishing the MILP model, it also includes: Calculate the costs of transporting natural gas, the costs of building new or expanded pipelines, and the costs associated with gas storage; According to the cost of natural gas transportation, the cost of new or expanded pipelines and the cost related to the gas storage, the cash flows in different periods are obtained; According to the cash flows in different periods, the minimum total cost net present value is obtained, and the minimum total cost net present value is used as the cost objective function.

3. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 2 is characterized in that: Calculate the costs of transporting natural gas, the costs of building new or expanded pipelines, and the costs associated with gas storage, including: The transportation cost of a single pipeline is calculated based on the product of pipeline transportation cost, transportation distance and pipeline transportation flow rate; the sum of the transportation costs of all pipelines is taken as the cost required for transporting natural gas; Calculate the cost of building or expanding pipelines based on the unit length cost of the pipeline and the distance of the pipeline; Calculate the gas storage related expenses based on the total cost of gas injection, gas production and gas storage in the gas storage.

4. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 1 is characterized in that: Generate constraints for the multi-period natural gas pipeline network MILP model to be established, including: For each node, node upload flow, node download flow, pipeline inflow flow and pipeline outflow flow are defined to characterize the flow relationship of the pipeline network; A flow balance constraint condition is generated according to the flow relationship of the pipeline network, the size relationship between the node upload flow and the local natural gas production, and the size relationship between the node download flow and the local minimum demand for natural gas.

5. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 4 is characterized in that: The constraints for generating the multi-period natural gas pipeline network MILP model to be established also include: Based on the condition that a pipeline is only constructed once between two nodes where new or expanded pipelines may be constructed, the pipeline network structure constraints are generated.

6. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 5 is characterized in that: The constraints for generating the multi-period natural gas pipeline network MILP model to be established also include: The transport capacity of the existing pipeline that is not to be expanded is set as a fixed value, and the pipeline transport capacity constraint condition is generated according to the relationship between the transport capacity of the newly built or expanded pipeline and the current maximum transport capacity; Based on the conditions that there is only one flow direction in the pipeline at the same time and the flow direction is consistent with the flow direction, the pipeline transportation direction constraint conditions are generated.

7. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 6 is characterized in that: The constraints for generating the multi-period natural gas pipeline network MILP model to be established also include: The gas storage reservoir constraints are generated according to the gas storage capacity constraints, gas injection capacity constraints, gas production capacity constraints and the relationship between the gas production capacity and the gas storage inventory.

8. The multi-cycle natural gas pipeline network transmission capacity improvement design method according to claim 1 is characterized in that: The multi-cycle natural gas pipeline network transmission capacity improvement design results include the time, location, and designed transmission capacity of pipeline construction, the required pipeline transportation, pipeline construction, and gas storage operation costs, the flow rate of each pipeline in each cycle, pipeline utilization, and the working conditions of the gas storage in the pipeline network in each cycle.

9. A multi-cycle natural gas pipeline network transmission capacity improvement design device, characterized in that: include: A parameter acquisition module is used to acquire basic parameters related to the natural gas pipeline network; the basic parameters include basic pipeline parameters, basic pipe material parameters, basic gas storage parameters, technical and economic parameters, and supply and demand data; A constraint condition generation module, used for generating the constraint conditions of the multi-period natural gas pipeline network MILP model to be established according to the acquired basic parameters; A model building module, used to build the MILP model according to the generated constraint conditions and a preset cost objective function; The model solving module is used to solve the MILP model by using a MILP solver based on a branch and bound algorithm to obtain a multi-cycle natural gas pipeline network transmission capacity improvement design result.

10. The multi-cycle natural gas pipeline network transmission capacity improvement design device according to claim 9, characterized in that: Also includes: The objective function acquisition module is used to calculate the cost of transporting natural gas, the cost of building or expanding pipelines, and the costs associated with gas storage facilities; The cash flows at different periods are obtained based on the costs required for transporting the natural gas, the costs for building or expanding the pipeline, and the costs related to the gas storage. The minimum net present value of the total cost is obtained based on the cash flows at different periods, and the minimum net present value of the total cost is used as the cost objective function.

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