A coordinated optimization method for power supply restoration of an integrated electricity-gas energy system

Abstract

The present invention discloses a coordinated optimization method for the energy supply restoration of an electric-gas integrated energy system. The steps include: identifying the system state, and analyzing the states of the loads to be restored, energy supply resources, branches, and switching devices in the system; making an optimization decision on the gas-to-electricity flow for the paths with normal states, and determining the optimal gas supply systems, gas acquisition paths, and gas acquisition flows of each gas turbine; based on the results of the gas-to-electricity flow optimization decision, performing parallel partition division on the distribution system and the gas distribution system to determine the loads to be restored in each partition; based on the partition results of the distribution system and the gas distribution system, respectively formulating independent restoration optimization plans for each partition; inputting the independent restoration optimization plans of each partition into a pre-established energy supply restoration optimization model of the electric-gas integrated energy system to determine the optimal restoration plan for each partition.

Description

Technical Field

[0001] The present invention relates to a coordinated optimization method for energy supply restoration of an electric-gas integrated energy system, belonging to the technical field of restoration control of the energy Internet. Background Art

[0002] The electric-gas integrated energy system realizes the bidirectional flow of energy between the power system and the natural gas system through gas turbines and power-to-gas equipment, and is an important component of the integrated energy system. Due to the high equipment investment and operating costs, and the current electricity price being higher than the natural gas price, the proportion of power-to-gas equipment is not large, and the electric-gas integrated energy system considering gas-to-power is more common. In recent years, large-scale energy outage events caused by natural disasters, operation errors, and malicious attacks have occurred frequently. The coupling characteristics between the power system and the natural gas system in the electric-gas integrated energy system make any system failure affect the energy supply of the other system, so coordinated decision-making is required for post-disaster energy supply restoration. Currently, there is little research on coordinated decision-making for energy supply restoration of electric-gas integrated energy systems.

[0003] As a complete energy system, the electric-gas integrated energy system should optimize energy supply resources globally during the restoration process after an energy supply interruption. Currently, the delay characteristics of the energy supply system are often ignored during the restoration of the electric-gas integrated energy system, and the structural integrity of the natural gas system, the gas load restoration requirements, and the gas source restoration capabilities are rarely considered. Summary of the Invention

[0004] The purpose of the present invention is to provide a coordinated optimization method for energy supply restoration of an electric-gas integrated energy system to solve the defects of the prior art.

[0005] A coordinated optimization method for energy supply restoration of an electric-gas integrated energy system, the steps of which include:

[0006] Identify the system state, analyze the system's load to be restored, energy supply resources, branch and switch equipment states, and determine the normal restoration paths that can be achieved;

[0007] Make an optimized decision on the gas-to-power flow for the normal restoration paths that can be achieved, and determine the optimal gas supply system, gas acquisition path, and gas acquisition flow rate for each gas turbine;

[0008] According to the optimal gas supply system, gas acquisition path, and gas acquisition flow rate for each gas turbine, perform parallel partition division of the power distribution system and the gas distribution system, and determine the load to be restored within each partition of the power distribution system and the gas distribution system;

[0009] According to the load to be restored within each partition of the power distribution system and the gas distribution system, respectively perform independent restoration optimization schemes for each partition of the power distribution system and the gas distribution system;

[0010] Input the independent restoration optimization plans for each partition of the power distribution system and the gas distribution system into the pre-established power-gas integrated energy system energy supply restoration optimization model to determine the optimal restoration plan for each partition.

[0011] Further, the identification of the system state includes:

[0012] The part of the system with stable energy supply is called the energy supply system, and the source in the power-off state but with self-starting ability is called the quasi-energy supply system, corresponding to the power supply system and the quasi-power supply system in the power distribution system, and the gas supply system and the quasi-gas supply system in the gas distribution system respectively;

[0013] Identify the isolated power-off areas and non-isolated power-off areas according to the topological structure of the system and the fault conditions of the equipment;

[0014] Analyze the available energy of each energy supply system or quasi-energy supply system, corresponding to the available power and available electricity in the power distribution system, and the available flow and available gas volume in the gas distribution system;

[0015] Determine the power supply range of the power supply system or quasi-power supply system according to the available power and the voltage level on the power transmission path; determine the gas supply range of the gas supply system or quasi-gas supply system according to the available flow and the gas pressure level factors on the gas transmission path.

[0016] Further, the gas-to-electricity flow optimization decision includes: Let the objective function of the gas-to-electricity flow optimization be:

[0017]

[0018] Where is F GT The maximum net income obtained in the power distribution system And F GT The maximum net income obtained in the gas distribution system The difference.

[0019] Further, the gas-to-electricity flow optimization method includes:

[0020] Step 1: Generate the set of nodes to be partitioned in the power distribution system Partition the power supply system and the quasi-power supply system except the gas turbine in the power distribution system, where m is The serial number of the node to be partitioned in the power distribution system in is The total number of nodes to be partitioned in the power distribution system in is The mth node to be partitioned in the power distribution system in

[0021] Step 2: Simulate and deduce the restoration plan for each partition, and update If If it is an empty set, end the update;

[0022] Step 3: In response to being non-empty, let the set of all unstarted gas turbines be Ω GT ={GT i | i = 1 , 2,..., N GT}, let the set of all gas supply systems or quasi-gas supply systems be Ω S ={S j | j = 1 , 2,..., N S}, partition the gas supply systems and quasi-gas supply systems in the gas distribution system. If the lower limit of the operating flow rate of a certain gas turbine in Ω GT is greater than the maximum available flow rate obtained from all the partitioned gas supply systems or quasi-gas supply systems it belongs to, then exclude this gas turbine from Ω GT , update Ω GT to obtain the set of gas supply systems or quasi-gas supply systems that can supply gas to all the gas turbines in Ω GT , where i is the serial number of the gas turbine in Ω GT ; N GT is the total number of gas turbines in Ω GT ; GT i is the i-th gas turbine in Ω GT ; j is the serial number of the gas supply system or quasi-gas supply system in Ω S ; N S is the total number of gas supply systems or quasi-gas supply systems in Ω S ; S j is the j-th gas supply system or quasi-gas supply system in Ω S ;

[0023] Step 4: Take the available power of the gas turbines in Ω GT as their rated power, partition them in the power distribution system to obtain the gas turbine GT u with the largest total demand power of the load to be restored, and its set of gas supply systems or quasi-gas supply systems that can supply gas is Otherwise, if the largest total demand power of the load to be restored is 0, then end;

[0024] Step 5: When the largest total demand power of the load to be restored is not equal to 0, exclude the gas supply systems or quasi-gas supply systems that are planned to supply gas to the gas turbines in , update Determine from the gas supply system or quasi-gas supply system with the shortest gas acquisition delay for GT u Then the path with the shortest gas acquisition delay is The maximum available flow rate Among them, ​For the available flow rate is the rated flow rate of GT u ;

[0025] Step 6: Plan to supply gas to GT u and divide the relevant nodes of the path into sub - regions, update and Ω S and update the available flow rate of the sub - regions, and re - divide the nodes in into the sub - regions that can supply gas to them and have the shortest gas - supply delay time.

[0026] Furthermore, the parallel sub - region division of the power distribution system and the gas distribution system includes:

[0027] According to the optimization of the gas - to - electricity flow rate, determine whether there is a gas - receiving flow rate for the gas turbine;

[0028] If there is no gas - receiving flow rate for all gas turbines, in the power distribution system, determine the sub - regions of the power supply system and the quasi - power supply system except the gas turbine;

[0029] According to the optimization of the gas - to - electricity flow rate, in the gas distribution system, divide the sub - regions for the gas supply system and the quasi - gas supply system. For the case where a node can be divided into multiple sub - regions, divide the node to be sub - regioned into the sub - region with the highest air pressure level on the gas - supply path;

[0030] If there is a gas turbine with a gas - receiving flow rate, in the power distribution system, determine the sub - regions of the power supply system and the quasi - power supply system except the gas turbine, and uniquely divide the remaining nodes to be sub - regioned into the sub - region of the gas turbine that can supply electricity to them, is the closest, and has a gas - receiving flow rate;

[0031] In the gas distribution system, for the gas supply system and the quasi - gas supply system that plan to supply gas to the gas turbine, divide the nodes related to the gas - receiving path of the gas turbine into its sub - region; uniquely divide the remaining nodes to be sub - regioned into the sub - region of the gas supply system or the quasi - gas supply system that can supply gas to them and has the shortest gas - supply delay time.

[0032] Furthermore, the independent restoration optimization scheme of the power distribution system and the gas distribution system includes:

[0033] According to the sub - region results of the power distribution system and the gas distribution system, each sub - region optimizes its restoration scheme tree in parallel. Each node in the tree represents a certain power - outage scenario, and each directed branch represents a step in the restoration process. The multi - step restoration process starting from the power - outage scenario corresponding to the root node and gradually restoring to the scenario corresponding to the leaf node of the tree is recorded as a multi - step restoration scheme;

[0034] ​Breadth deduction starts from the same energy outage scenario, and optimizes the restoration plans for different restoration objectives respectively. There are multiple restoration plans for the same restoration objective, and the deduction continues until the number of steps reaches the set depth.

[0035] Furthermore, the steps for optimization within the parallel partition of the power distribution system and the gas distribution system are as follows:

[0036] Step 1: According to the energy outage scenario, screen the partition restoration objectives, and sort them in descending order according to the restoration benefits of the restoration objectives to generate a sequence Ω of the partition restoration objectives to be restored TG ={TG r |r = 1 , 2,..., N TG}, where r is the serial number of the restoration objective to be restored in Ω TG ; N TG is the total number of restoration objectives to be restored in Ω TG ; TG r is the r-th restoration objective to be restored in Ω TG ; Let r = 1;

[0037] Step 2: Select the r-th restoration objective TG TG from Ω r ;

[0038] Step 3: Optimize the restoration plan of TG r ;

[0039] Step 4: If the breadth deduction is completed in the current scenario or r > N TG , then continue; otherwise, go to Step 2 to generate a restoration plan for the next restoration objective in the current scenario;

[0040] Step 5: If the deduction depth of the plan tree has not reached the set value, switch to the simulation of the next energy outage scenario and go to Step 1;

[0041] Step 6: Calculate the net restoration benefit per unit capacity of all multi-step restoration plans in the current partition, and determine the restoration plan with the largest net restoration benefit per unit capacity as the optimal restoration plan.

[0042] Furthermore, the energy supply restoration optimization model of the electric-gas integrated energy system is:

[0043]

[0044] Among them, k P is the step number in the PDS restoration plan; k G is the step number in the GDS restoration plan. A one-step plan is a series of operations taken to restore a certain load; is the total number of steps in the PDS restoration plan within the decision-making period of the same restoration plan; is the total number of steps of the GDS recovery plan within the decision-making period of the same recovery plan; is the k P step's electrical load recovery benefit; is the k P step's electrical load recovery cost; is the k G step's gas load recovery benefit; is the k G step's gas load recovery cost;

[0045] Solve the energy supply recovery optimization model of the electric-gas integrated energy system:

[0046]

[0047] where t e is the preset evaluation end time of G2PIES, set as the larger value after the estimated execution completion times of the PDS and GDS recovery plans; is the k P step's electrical load recovery time; is the k G step's gas load recovery time; is the k P step's unit recovery benefit of the electrical load recovered at time t; is the k G step's unit recovery benefit of the gas load recovered at time t; is the k P step's active power of the electrical load recovered at time t; is the k G step's flow rate of the gas load recovered at time t; is the k P step's unit electricity cost of the electrical load recovered at time t; is the k G step's unit gas cost of the gas load recovered at time t.

[0048] Furthermore, the constraint conditions of the energy supply recovery optimization model of the electric-gas integrated energy system are:

[0049] (1) Distribution system constraints;

[0050] Steady-state constraints:

[0051]

[0052] U i,min ≤U i,t ≤U i,max

[0053] I ij,min ≤Iij,t ≤ I ij,max

[0054] S Pij,t ≤ S Pij,max

[0055] Wherein, N is the total number of PDS electrical load nodes; P i,t is the active power injection of the external network connection line of node i at time t; Q i,t is the reactive power injection of the external network connection line of node i at time t; P DGi,t is the active power of the distributed power source connected to node i at time t; Q DGi,t is the reactive power of the distributed power source connected to node i at time t; P di,t is the active power of the electrical load at node i at time t; Q di,t is the reactive power of the electrical load at node i at time t; U i,t is the voltage value of node i at time t; U j,t is the voltage value of node j at time t; G ij is the real part of the admittance of line ij; B ij is the imaginary part of the admittance of line ij; θ ij,t is the phase angle between nodes i and j at time t; U i,max is the upper limit of the allowable voltage of node i; U i,min is the lower limit of the allowable voltage of node i; I ij,t is the current value of branch ij at time t; I ij,max is the upper limit of the allowable current of branch ij; I ij,min is the lower limit of the allowable current of branch ij; S Pij,t is the actual capacity of branch ij at time t; S Pij,max is the maximum capacity of branch ij;

[0056] Transient constraint:

[0057] To avoid misoperation of protection caused by transient impact caused by the connection of electrical loads, a maximum single-step restored electrical load constraint is set;

[0058] ΔP k,step ≤ ζP kN

[0059] Wherein, ΔP k,step is the active power capacity of the single-step restored electrical load in the k-th step; ζ is the proportionality coefficient of the allowable single-step restored electrical load capacity; P kN is the rated capacity within the live area at the initial moment of the k-th step;

[0060] Topological structure constraint:

[0061] g ∈ G

[0062] Among them, g is the network topology structure after PDS reconstruction; G is the set of all radial network topologies of PDS.

[0063] (2) Gas distribution system constraints

[0064] Steady-state constraints:

[0065]

[0066] Π i,min ≤Π i,t ≤Π i,max

[0067] F ij,min ≤F ij,t ≤F ij,max

[0068] Among them, is the gas injection flow rate at node i at time t; is the upper limit of the gas injection flow rate at node i; is the lower limit of the gas injection flow rate at node i; Π i,t is the pressure value of node i at time t; Π i,max is the upper limit of the allowable pressure of node i; Π i,min is the lower limit of the allowable pressure of node i; F ij,t is the pipe segment flow rate from node i to node j at time t; F ij,max is the upper limit of the pipe segment ij flow rate; F ij,min is the lower limit of the pipe segment ij flow rate;

[0069] Transient constraints:

[0070] The pressure and flow rate of natural gas injected by the gas turbine should be within the regulation range of the regulating valve of the gas regulation system;

[0071] Π GT,min ≤Π GT,t ≤Π GT,max

[0072] F GT,min ≤F GT,t ≤F GT,max

[0073] Among them, Π GT,t is the pressure of natural gas injected by the gas turbine at time t; F GT,t is the flow rate of natural gas injected by the gas turbine at time t; Π GT,max is the upper limit of the pressure of natural gas injected by the gas turbine; Π GT,min is the lower limit of the pressure of natural gas injected by the gas turbine; F GT,max is the upper limit of the flow rate of natural gas injected by the gas turbine; F GT,min is the lower limit of the flow rate of natural gas injected by the gas turbine.

[0074] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention comprehensively considers the recovery benefits and costs, and establishes an optimization model for the energy supply recovery of the integrated electricity-gas energy system; identifies the system state, analyzes the equipment states such as the load to be restored, energy supply resources, branches, and switches in the system; makes an optimization decision on the gas-to-electricity flow rate, and determines the optimal gas supply system (quasi-gas supply system), gas acquisition path, and gas acquisition flow rate for each gas turbine; based on the results of the gas-to-electricity flow rate optimization decision, conducts parallel partition division of the distribution system and the gas distribution system, and determines the load to be restored within each partition; based on the partition results of the distribution system and the gas distribution system, respectively optimizes the recovery plans for each partition, and determines the optimal recovery plan for each partition. In summary, a method for coordinated optimization decision-making of energy supply recovery in an integrated electricity-gas energy system provided by the present invention is significantly helpful for effectively improving the utilization rate of energy supply resources, enhancing the recovery efficiency, and obtaining a large net recovery benefit. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 is a flowchart of the coordinated optimization decision-making for energy supply recovery in the integrated electricity-gas energy system provided by the embodiment of the present invention;

[0076] Figure 2 is a flowchart of the optimization decision-making for the gas-to-electricity flow rate provided by the embodiment of the present invention;

[0077] Figure 3 is a recovery plan tree within the parallel partitions of the distribution system and the gas distribution system provided by the embodiment of the present invention;

[0078] Figure 4 is a flowchart of the optimization of the recovery plan within the parallel partitions of the distribution system and the gas distribution system provided by the embodiment of the present invention;

[0079] Figure 5 is a framework diagram of the coordinated optimization decision-making for energy supply recovery in the integrated electricity-gas energy system provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0080] In order to make the technical means, creative features, achieved purposes, and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0081] As Figures 1 - 5 shown, a method for coordinated optimization of energy supply recovery in an integrated electricity-gas energy system is disclosed, and the method includes the steps of:

[0082] Identify the system state, analyze the equipment states such as the load to be restored, energy supply resources, branches, and switches in the system, and determine the normal recovery path;

[0083] Make an optimization decision on the gas-to-electricity flow rate for the normal recovery path, and determine the optimal gas supply system, gas acquisition path, and gas acquisition flow rate for each gas turbine;

[0084] According to the optimal gas supply system, gas acquisition path and gas acquisition flow rate of each gas turbine, parallel zoning is carried out for the power distribution system and the gas distribution system to determine the loads to be restored within the zones of each power distribution system and gas distribution system;

[0085] According to the loads to be restored within the zones of each power distribution system and gas distribution system, independent restoration optimization plans are respectively carried out for the zones of each power distribution system and gas distribution system;

[0086] Input the independent restoration optimization plans of the zones of each power distribution system and gas distribution system into the pre-established energy supply restoration optimization model of the electric-gas integrated energy system to determine the optimal restoration plan for each zone;

[0087] This embodiment further specifically illustrates the above method:

[0088] In order to maximize the net income of the overall restoration plan of the electric-gas integrated energy system, the energy supply restoration optimization model of the electric-gas integrated energy system is:

[0089]

[0090] Among them, k P is the step number in the PDS restoration plan; k G is the step number in the GDS restoration plan, and one-step plan is a series of operations taken to restore a certain load; is the total number of steps in the PDS restoration plan within the decision-making period of the same restoration plan; is the total number of steps in the GDS restoration plan within the decision-making period of the same restoration plan; is the power load restoration income at the k P th step; is the power load restoration cost at the k P th step; is the gas load restoration income at the k G th step; is the gas load restoration cost at the k G th step.

[0091]

[0092] Among them, t e is the preset evaluation end time of G2PIES, set as the larger value after the estimated execution completion time of the PDS and GDS restoration plans; is the power load restoration time at the k P th step; is the gas load restoration time at the k G th step; is at the kP The unit recovery benefit of the electrical load restored at the k-th step at time t; For the k-th G The unit recovery benefit of the gas load restored at the k-th step at time t; For the k-th P The active power of the electrical load restored at the k-th step at time t; For the k-th G The flow rate of the gas load restored at the k-th step at time t; For the k-th P The unit electricity cost of the electrical load restored at the k-th step at time t; For the k-th G The unit gas cost of the gas load restored at the k-th step at time t.

[0093] The constraint conditions of the power supply recovery optimization model for the integrated electricity-gas energy system are as follows:

[0094] (3) Distribution system constraints

[0095] 1) Steady-state constraints

[0096]

[0097] U i,min ≤U i,t ≤U i,max

[0098] I ij,min ≤I ij,t ≤I ij,max

[0099] S Pij,t ≤S Pij,max

[0100] Among them, N is the total number of electrical load nodes in the PDS; P i,t is the active power injection of the external network connection line at node i at time t; Q i,t is the reactive power injection of the external network connection line at node i at time t; P DGi,t is the active power of the distributed power source connected to node i at time t; Q DGi,t is the reactive power of the distributed power source connected to node i at time t; P di,t is the active power of the electrical load at node i at time t; Q di,t is the reactive power of the electrical load at node i at time t; U i,t is the voltage value of node i at time t; U j,t is the voltage value of node j at time t; G ij is the real part of the admittance of line ij; B ij is the imaginary part of the admittance of line ij; θ ij,t is the phase angle between nodes i and j at time t; U i,maxis the upper limit of the allowable voltage for node i; U i,min is the lower limit of the allowable voltage for node i; I ij,t is the current value of branch ij at time t; I ij,max is the upper limit of the allowable current for branch ij; I ij,min is the lower limit of the allowable current for branch ij; S Pij,t is the actual capacity of branch ij at time t; S Pij,max is the maximum capacity of branch ij.

[0101] 2) Transient constraints

[0102] To avoid misoperation of protection caused by transient impact caused by the connection of electrical loads, a maximum single-step restored electrical load constraint is set.

[0103] ΔP k,step ≤ζP kN

[0104] where, ΔP k,step is the active power capacity of the single-step restored electrical load at the k-th step; ζ is the proportionality coefficient of the allowable single-step restored electrical load capacity; P kN is the rated capacity within the energized area at the initial moment of the k-th step.

[0105] 3) Topological structure constraints

[0106] g ∈ G

[0107] where, g is the network topological structure after PDS reconstruction; G is the set of all radial network topologies of PDS.

[0108] (4) Gas distribution system constraints

[0109] 1) Steady-state constraints

[0110]

[0111] Π i,min ≤Π i,t ≤Π i,max

[0112] F ij,min ≤F ij,t ≤F ij,max

[0113] where, is the gas injection flow rate at node i at time t; is the upper limit of the gas injection flow rate at node i; is the lower limit of the gas injection flow rate at node i; Π i,t is the pressure value of node i at time t; Π i,max is the upper limit of the allowable pressure for node i; Π i,min is the lower limit of the allowable pressure for node i; Fij,t The pipe segment flow rate from node i to node j at time t; F ij,max The upper limit of the pipe segment ij flow rate; F ij,min The lower limit of the pipe segment ij flow rate.

[0114] 2) Transient constraints

[0115] The pressure and flow rate of natural gas injected by the gas turbine should be within the regulation range of the regulating valve of the gas regulation system.

[0116] Π GT,min ≤Π GT,t ≤Π GT,max

[0117] F GT,min ≤F GT,t ≤F GT,max

[0118] Among them, Π GT,t is the pressure of natural gas injected by the gas turbine at time t; F GT,t is the flow rate of natural gas injected by the gas turbine at time t; Π GT,max is the upper limit of the pressure of natural gas injected by the gas turbine; Π GT,min is the lower limit of the pressure of natural gas injected by the gas turbine; F GT,max is the upper limit of the flow rate of natural gas injected by the gas turbine; F GT,min is the lower limit of the flow rate of natural gas injected by the gas turbine.

[0119] As Figure 1 shown, the process of coordinated optimization decision-making for the energy supply restoration of the integrated electricity-gas energy system includes: system state identification, optimization decision-making of the gas-to-electricity flow rate, parallel partition division of the distribution system and the gas distribution system, and optimization decision-making within the parallel partitions of the distribution system and the gas distribution system.

[0120] S2. Identify the system state, and analyze the equipment states such as the load to be restored, energy supply resources, branches, and switches in the system.

[0121] According to the topological structure of the system and the fault conditions of the equipment, identify the isolated power outage areas and non-isolated power outage areas. Among them, the isolated power outage area refers to the power outage area that has no recoverable path to all energy supply systems or quasi-energy supply systems. The isolated power outage area can be changed into a non-isolated power outage area through the deployment and connection of mobile energy supply equipment or equipment repair, and then restored.

[0122] Analyze the available energy of each energy supply system or quasi-energy supply system, which respectively correspond to the available power and available electricity in the distribution system, and the available flow rate and available gas volume in the gas distribution system. Among them, the available power in the distribution system is the standby power of the power supply system or the predicted maximum output of the quasi-power supply system; the available flow rate in the gas distribution system is the standby flow rate of the gas supply system or the rated flow rate of the quasi-gas supply system.

[0123] Determine the power supply range of the power supply system or quasi-power supply system according to the available power and the voltage level on the power transmission path; determine the gas supply range of the gas supply system or quasi-gas supply system according to factors such as the available flow rate and the gas pressure level on the gas transmission path.

[0124] S3. As Figure 2 shown, perform the optimization decision of the gas-to-electricity flow rate to determine the optimal gas supply system (quasi-gas supply system), gas acquisition path and gas acquisition flow rate of each gas turbine.

[0125] The objective function of the gas-to-electricity flow rate optimization is:

[0126]

[0127] Wherein, is the maximum net profit obtained by F GT in the power distribution system and the difference between F GT and the maximum net profit obtained in the gas distribution system .

[0128] The steps of the gas-to-electricity flow rate optimization are as follows:

[0129] Step 1: Set the initial partition of the power distribution system as the power supply system with available power and the quasi-power supply system itself. Add the nodes to be restored in the non-isolated power outage area of the power distribution system to the set of nodes to be partitioned in the power distribution system Wherein, m is the serial number of the node to be partitioned in the power distribution system; is the total number of nodes to be partitioned in the power distribution system; is the mth node to be partitioned in the power distribution system. Partition the power supply system and the quasi-power supply system except the gas turbine in the power distribution system. Based on the power supply range of the initial partition of the power distribution system, the nodes in are partitioned into the nearest partition that can supply power to them. For the case where a node can be partitioned into multiple partitions, if the node to be partitioned is a power source node, it is partitioned into the partition with the largest active power deficit; if the node to be partitioned is a load node, it is partitioned into the partition with the smallest active power deficit. Among them, the active power deficit is the difference between the power demand of the load to be restored in the partition and the available power.

[0130] Step 2: Generate a restoration plan for the available power of each partition of the power distribution system, simulate and deduce the restoration plan of each partition, and update If is an empty set, end this process; otherwise, set the set of all unstarted gas turbines as Ω GT ={GT i |i = 1 ,2,...,N GT}, where i is the serial number of the gas turbine in Ω GT ; N GT is the total number of gas turbines in Ω GT ; GT i is the i-th gas turbine in Ω GT . Go to step 3.

[0131] Step 3: Let the set of all gas supply systems or quasi-gas supply systems be Ω S ={S j |j = 1 , 2,...,N S}, where j is the serial number of the gas supply system or quasi-gas supply system in Ω S ; N S is the total number of gas supply systems or quasi-gas supply systems in Ω S ; S j is the j-th gas supply system or quasi-gas supply system in Ω S . Add the nodes to be restored in the non-isolated energy cut-off area of the gas distribution system to the set of nodes to be partitioned in the gas distribution system where n is the serial number of the nodes to be partitioned in the gas distribution system; is the total number of nodes to be partitioned in the gas distribution system; is the n-th node to be partitioned in the gas distribution system. Let the initial partition of the gas distribution system be the gas supply systems with available flow and the quasi-gas supply systems themselves.

[0132] Based on the gas supply scope of the initial partition of the gas distribution system, partition the nodes into the partition that can supply gas to them with the shortest gas supply delay. If the lower limit of the operating flow of a certain gas turbine in Ω GT is greater than the maximum available flow that it can obtain from all the partitions of its affiliated gas supply systems or quasi-gas supply systems, then exclude this gas turbine from Ω GT (if a gas turbine is not partitioned into any partition of a gas supply system or quasi-gas supply system, the maximum available flow that this gas supply system or quasi-gas supply system can provide to it is 0), update Ω GT . If Ω GT is an empty set, end this process; otherwise, obtain the set of gas supply systems or quasi-gas supply systems available to all gas turbines in Ω GT , where the set of gas supply systems or quasi-gas supply systems available to the i-th gas turbine GT i is where k is the serial number of the gas supply system or quasi-gas supply system in , is is For the k-th gas supply system or quasi-gas supply system in , go to step 4.

[0133] Among them, the calculation method of natural gas supply delay is as follows:

[0134] When the flow state of the pipe section changes, during the transition process between two steady states, assuming that the flow rate change is linear, the average flow rate of the pipe section is the average of the sum of the initial and final flow rates. The flow rate of pipe section ij changes from to The required time τ ij is

[0135]

[0136] Among them, L ij is the length of pipe section ij, in m; D ij is the inner diameter of pipe section ij, in m; σ mi is the set of pipe sections with node i as the end of the pipe section in the gas distribution system; τ' mi is the delay value corresponding to the pipe section where the natural gas flow direction is into i, in h. If there are multiple pipe sections meeting the above conditions, then τ' mi takes its average value.

[0137] Step 4: Take the available power of the gas turbine in Ω GT as its rated power, determine the initial partition of each gas turbine in Ω GT and its power supply range in the power distribution system, and uniquely divide the nodes in into the gas turbine partition that can supply power to it and is the closest. Calculate the total required power of the loads to be restored in each gas turbine partition, and obtain the gas turbine GT u with the largest total required power of the loads to be restored. Its gas supply system or quasi-gas supply system set is If the largest total required power of the loads to be restored is 0, end this process; otherwise, go to step 5.

[0138] Step 5: Exclude the gas supply system or quasi-gas supply system that plans to supply gas to the gas turbine in , and update If is an empty set, go to step 7; otherwise, determine the gas supply system or quasi-gas supply system with the shortest gas acquisition delay for GT from u . Then the path with the shortest gas acquisition delay is The maximum available flow rate Among them, is 's available flow rate, is GT u 's rated flow rate.

[0139] Step 6: Set GT u Obtain the net benefit that can be obtained by the gas flow rate within the partition of its power distribution system as The net benefit that can be obtained by this gas flow rate within the partition of its gas distribution system is Optimize to obtain GT that makes the gas - electricity conversion optimization objective function of the gas turbine hold u The optimal gas acquisition flow rate If then go to Step 7; otherwise,[[]] Plan to supply gas to GT u Supply gas Generate a recovery plan for the available power of GT in the power distribution system, simulate and deduce the GT u partition recovery plan of the power distribution system, and exclude the nodes related to the recovery path of this partition from u Update Exclude the relevant nodes of the path from and divide the relevant nodes into partition, and exclude it from Update and Ω S , and update the available flow rate of the partition. Re - divide the nodes in into the partition that can supply gas to it with the shortest gas supply delay according to the gas distribution system partition method described in Step 3.

[0140] Step 7: Exclude GT u from Ω GT and update Ω GT . If Ω GT is an empty set, then end this process; otherwise, go to Step 4.

[0141] S4. Based on the results of the gas - to - electricity flow rate optimization decision, divide the power distribution system and the gas distribution system into partitions respectively, and determine the loads to be restored within each partition.

[0142] According to the above gas - to - electricity flow rate optimization process, determine whether there is a gas acquisition flow rate for the gas turbine.

[0143] If there is no gas acquisition flow rate for all gas turbines, then in the power distribution system, determine the partitions of the power supply system and the quasi - power supply system except the gas turbine according to the result of Step 1 of the above gas - to - electricity flow rate optimization process; in the gas distribution system, divide the partitions for the gas supply system and the quasi - gas supply system according to the method of Step 3 of the above gas - to - electricity flow rate optimization process. For the case where a node can be divided into multiple partitions, divide the node to be partitioned into the partition with the highest air pressure level on the gas supply path.

[0144] If there is a gas turbine with gas intake flow, in the power distribution system, according to the result of Step 1 of the above gas-to-electricity flow optimization process, determine the partition of the power supply system and the quasi-power supply system except the gas turbine, and uniquely divide the remaining nodes to be partitioned into the gas turbine partition that can supply power to it, is the closest in distance, and has gas intake flow; in the gas distribution system, for the gas supply system and the quasi-gas supply system that are planned to supply gas to the gas turbine, divide the nodes related to the gas intake path of the gas turbine into its partition. Uniquely divide the remaining nodes to be partitioned into the gas supply system or the quasi-gas supply system partition that can supply gas to it and has the shortest gas supply delay.

[0145] S5. As Figure 3 and Figure 4 shown, based on the partition results of the power distribution system and the gas distribution system, optimize the restoration plans for each partition independently to determine the optimal restoration plan for each partition.

[0146] According to the partition results of the power distribution system and the gas distribution system, each partition optimizes its restoration plan tree in parallel. Each node in the tree represents a certain power outage scenario, and each directed branch represents a step in the restoration process. The multi-step restoration process from the power outage scenario corresponding to the root node to the scenario corresponding to the leaf node of the tree is recorded as a multi-step restoration plan.

[0147] Breadth deduction means starting from the same power outage scenario, optimizing the restoration plans for different restoration objectives respectively. There may be multiple restoration plans for the same restoration objective. Keep deducing until the number of steps reaches the set depth.

[0148] The steps for optimizing within the parallel partitions of the power distribution system and the gas distribution system are as follows:

[0149] Step 1: According to the power outage scenario, screen the restoration objectives of the partition and sort them in descending order according to the restoration benefits of the restoration objectives to generate a sequence Ω TG ={TG r |r = 1 , 2,..., N TG}, where r is the serial number of the restoration objective to be restored in Ω TG ; N TG is the total number of restoration objectives to be restored in Ω TG ; TG r is the r-th restoration objective to be restored in Ω TG . Among them, when screening the restoration objectives of the power distribution system partition, factors such as transient frequency constraint and transient voltage constraint need to be considered; when screening the restoration objectives of the gas distribution system partition, factors such as gas supply flow constraint of the gas supply system or the quasi-gas supply system and transient gas pressure constraint need to be considered. Let r = 1.

[0150]

[0151]

[0152] Among them, I P is the recovery benefit of electrical load and power source in the power distribution system; I G is the recovery benefit of gas load in the gas distribution system; is the recovery demand satisfaction rate of the entire power distribution system, are the recovery demand satisfaction rates of the sub - regions to which the power distribution system belongs, that is, the ratio of the available power of the power supply system or quasi - power supply system to the power demand of the electrical load to be restored; is the recovery demand satisfaction rate of the entire gas distribution system, are the recovery demand satisfaction rates of the sub - regions to which the gas distribution system belongs, that is, the ratio of the available flow rate of the gas supply system or quasi - gas supply system to the gas demand flow rate of the gas load to be restored; is the conversion coefficient of the recovery benefit of the electrical load to be restored; is the conversion coefficient of the recovery benefit of the gas load to be restored; is the estimated value of the recovery benefit of the electrical load to be restored; is the estimated value of the recovery benefit of the gas load to be restored; is the cost of restoring the electrical load; is the cost of restoring the gas load.

[0153] Step 2: Select the r - th recovery target TG TG from Ω r .

[0154] Step 3: Optimize the recovery plan of TG r .

[0155] Step 3.1: Search for several shorter recovery paths of TG r (where the shorter recovery path refers to the recovery path with a shorter distance in the power distribution system and the recovery path with a shorter gas delivery delay in the gas distribution system), and generate the recovery path set r of TG Among them, h is the serial number of the recovery path of TG r in; is the total number of recovery paths of TG r in; H TGr,h is the h - th recovery path of TG r in. The recovery paths of TG r in are backup to each other. Let h = 1.

[0156] Step 3.2: Evaluate the recovery benefit and recovery cost of the recovery path H TGr,h , and simulate and deduce a new power outage scenario according to H TGr,h .

[0157] Step 3.3: Let h = h + 1. If then go to Step 3.2; otherwise, let r = r + 1 and go to Step 4.

[0158] Step 4: Since the scenario tree is deduced branch by branch in breadth - first manner, if the breadth - first deduction is completed in the current scenario or r > N TG , then go to Step 5; otherwise go to Step 2 to generate a recovery plan for the next recovery target in the current scenario.

[0159] Step 5: If the deduction depth of the scenario tree has not reached the set value, then switch to the simulation stop - energy scenario of the next step and go to Step 1; otherwise go to Step 6.

[0160] Step 6: Calculate the net recovery benefit per unit capacity of all multi - step recovery plans in the current partition, and determine the recovery plan with the largest net recovery benefit per unit capacity as the optimal recovery plan. Herein, the ratio of the net recovery benefit of a recovery plan to its recovery capacity is defined as its net recovery benefit per unit capacity.

[0161] The above - mentioned is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A coordinated optimization method for energy supply restoration of an integrated electrical-gas energy system, characterized in that The steps include: Identifying the system state, analyzing the system's load to be restored, energy supply resources, branch and switch equipment states, and determining the normal restoration paths that can be achieved; Making an optimal decision on the gas-to-electricity flow rate for the normal restoration paths, and determining the optimal gas supply systems, gas acquisition paths, and gas acquisition flow rates for each gas turbine; Based on the optimal gas supply systems, gas acquisition paths, and gas acquisition flow rates for each gas turbine, conducting parallel partitionings of the power distribution system and the gas distribution system, and determining the loads to be restored within each partition of the power distribution system and the gas distribution system; According to the loads to be restored within each partition of the power distribution system and the gas distribution system, respectively formulating independent restoration optimization plans for each partition of the power distribution system and the gas distribution system; Inputting the independent restoration optimization plans for each partition of the power distribution system and the gas distribution system into a pre-established energy supply restoration optimization model for the integrated electricity-gas energy system to determine the optimal restoration plan for each partition; The optimal decision on the gas-to-electricity flow rate includes: setting the objective function for the optimal gas-to-electricity flow rate as: Among them, is F GT The maximum net benefit obtained in the power distribution system and F GT The maximum net benefit obtained in the gas distribution system The difference; The methods for optimizing the gas-to-electricity flow rate include: Step 1: Generate the set of nodes to be partitioned in the distribution system Partition the power supply system and the quasi-power supply system except the gas turbine in the distribution system, where m is the serial number of the node to be partitioned in the distribution system in ; the total number of nodes to be partitioned in the distribution system in ; the m-th node to be partitioned in the distribution system in Step 2: Simulate and deduce the recovery plan for each partition and update If is an empty set, end the update; Step 3: In response to being non-empty, let the set of all unstarted gas turbines be Ω GT ={GT i | i = 1 , 2,..., N GT}, and let the set of all gas supply systems or quasi-gas supply systems be Ω S ={S j | j = 1 , 2,..., N S}. Divide the gas supply systems and quasi-gas supply systems in the gas distribution system into zones. If the lower limit of the operating flow rate of a certain gas turbine in Ω GT is greater than the maximum available flow rate it obtains from all the gas supply systems or quasi-gas supply system zones it belongs to, then exclude this gas turbine from Ω GT , update Ω GT to obtain the set of gas supply systems or quasi-gas supply systems that can supply gas to all the gas turbines in Ω GT , where i is the serial number of the gas turbine in Ω GT ; N GT is the total number of gas turbines in Ω GT ; GT i is the i-th gas turbine in Ω GT ; j is the serial number of the gas supply system or quasi-gas supply system in Ω S ; N S is the total number of gas supply systems or quasi-gas supply systems in Ω S ; S j is the j-th gas supply system or quasi-gas supply system in Ω S ; Step 4: Take Ω GT The available power of the gas turbine in GT is its rated power. In the distribution system, divide it into partitions to obtain the gas turbine GT with the largest total demand power of the load to be restored u , and the gas supply system or the set of quasi-gas supply systems that it can supply is Otherwise, if the maximum total demand power of the load to be restored is 0, then end; Step 5: When the total demand power of the maximum load to be restored is not equal to 0, exclude the gas supply system or quasi-gas supply system that plans to supply gas to the gas turbine in , and update Determine from the gas supply system or quasi-gas supply system with the shortest gas acquisition delay for GT u , then the path with the shortest gas acquisition delay is The maximum available flow rate where is the available flow rate of , and is the rated flow rate of GT u ;​ Step 6: Plan to GT u Gas supply The path The relevant nodes are divided into Partition, Update and Ω S , and update Partition available traffic and re- The mid-node is divided into partitions to which air can be supplied with the shortest air supply delay.

2. The power supply restoration coordination optimization method for the electrical-gas integrated energy system according to claim 1, wherein The identification of the system state includes: Regarding the part of the system with stable energy supply as the energy supply system, and the sources in the power-off state but with self-starting capabilities as the quasi-energy supply systems, corresponding to the power supply system and the quasi-power supply system in the power distribution system, and the gas supply system and the quasi-gas supply system in the gas distribution system respectively; Identifying the isolated power-off areas and non-isolated power-off areas according to the topological structure of the system and the fault conditions of the equipment; Analyzing the available energy of each energy supply system or quasi-energy supply system, corresponding to the available power and available electricity in the power distribution system, and the available flow rate and available gas volume in the gas distribution system; Determining the power supply range of the power supply system or the quasi-power supply system according to the available power and the voltage level on the power transmission path; determining the gas supply range of the gas supply system or the quasi-gas supply system according to the available flow rate and the gas pressure level factors on the gas transmission path.

3. The power supply restoration coordination optimization method for the electric-gas integrated energy system according to claim 1, characterized in that The parallel partitioning of the power distribution system and the gas distribution system includes: Judging whether there is a gas acquisition flow rate for the gas turbines according to the optimization of the gas-to-electricity flow rate; If there is no gas acquisition flow rate for all gas turbines, in the power distribution system, determining the partitions of the power supply system and the quasi-power supply systems other than the gas turbines; According to the optimization of the gas-to-electricity flow rate, in the gas distribution system, partitioning the gas supply system and the quasi-gas supply systems. For the case where a node can be partitioned into multiple partitions, dividing the node to be partitioned into the partition with the highest gas pressure level on the gas transmission path; If there are gas turbines with gas acquisition flow rates, in the power distribution system, determining the partitions of the power supply system and the quasi-power supply systems other than the gas turbines, and uniquely dividing the remaining nodes to be partitioned into the partition of the gas turbine that can supply power to it, is the closest, and has a gas acquisition flow rate; In the gas distribution system, for the gas supply system and the quasi-gas supply systems planned to supply gas to the gas turbines, dividing the nodes related to the gas acquisition paths of the gas turbines into their partitions; uniquely dividing the remaining nodes to be partitioned into the partition of the gas supply system or the quasi-gas supply system that can supply gas to it and has the shortest gas supply delay.

4. The power supply restoration coordination optimization method for the electrical-gas integrated energy system according to claim 1, wherein The independent restoration optimization plans for the power distribution system and the gas distribution system include: According to the zoning results of the power distribution system and the gas distribution system, each zone optimizes its restoration plan tree in parallel. Each node in the tree represents a certain power outage scenario, and each directed branch represents a step in the restoration process. Starting from the power outage scenario corresponding to the root node, the multi-step restoration process of gradually restoring to the scenario corresponding to the leaf node of the tree is recorded as a multi-step restoration plan; Breadth deduction means starting from the same power outage scenario, optimizing the restoration plans for different restoration objectives respectively. There are multiple restoration plans for the same restoration objective, and the deduction continues until the number of steps reaches the set depth.

5. The power supply restoration coordination optimization method for the electrical-gas integrated energy system according to claim 1, wherein The steps for optimizing within the parallel zones of the power distribution system and the gas distribution system include: Step 1: According to the power outage scenario, screen the partition restoration targets, and sort them in descending order according to the restoration benefits of the restoration targets to generate a sequence Ω of the partition targets to be restored TG ={TG r |r = 1 , 2,..., N TG}, where r is the serial number of the target to be restored in Ω TG ; N TG is the total number of targets to be restored in Ω TG ; TG r is the r-th target to be restored in Ω TG ; Let r = 1; Step 2. Select the r-th recovery target TG from Ω TG ; r Select the r-th recovery target TG Step 3: Optimize TG r Recovery solution; Step 4. If the breadth deduction is completed in the current scenario or r > N TG , then continue; otherwise, go to Step 2 to generate a recovery plan for the next recovery target in the current scenario. Step 5: If the deduction depth of the plan tree has not reached the set value, switch to the simulation of the next power outage scenario and go to Step 1; Step 6: Calculate the net restoration benefit per unit capacity of all multi-step restoration plans in the current zone, and determine the restoration plan with the maximum net restoration benefit per unit capacity as the optimal restoration plan.

6. The power supply restoration coordination optimization method for the electric-gas integrated energy system according to claim 1, wherein The power-gas integrated energy system supply restoration optimization model is: Among them, k P is the step number in the PDS recovery plan; k G is the step number in the GDS recovery plan. A one-step plan is a series of operations taken to restore a certain load; is the total number of steps in the PDS recovery plan within the decision-making period of the same recovery plan; is the total number of steps in the GDS recovery plan within the decision-making period of the same recovery plan; is the electrical load recovery benefit of the k P th step; is the electrical load recovery cost of the k P th step; is the gas load recovery benefit of the k G th step; is the gas load recovery cost of the k G th step; Solve the power-gas integrated energy system supply restoration optimization model: Among them, t e is the preset evaluation end time of G2PIES, which is set as the larger value after the estimated execution completion time of the PDS and GDS recovery plans; is the electrical load recovery time at the k P th step; is the gas load recovery time at the k G th step; is the unit recovery benefit of the electrical load recovered at the k P th step at time t; is the unit recovery benefit of the gas load recovered at the k G th step at time t; is the active power of the electrical load recovered at the k P th step at time t; is the flow rate of the gas load recovered at the k G th step at time t; is the unit electricity cost of the electrical load recovered at the k P th step at time t; is the unit gas cost of the gas load recovered at the k G th step at time t.

7. The power supply restoration coordination optimization method for the electrical-gas integrated energy system according to claim 1, wherein The constraint conditions of the power-gas integrated energy system supply restoration optimization model are: (1) Power distribution system constraints Steady-state constraints: U i,min ≤U i,t ≤U i,max I ij,min ≤I ij,t ≤I ij,max S Pij,t ≤ S Pij,max where N is the total number of PDS electrical load nodes; P i,t is the active power injection of the external network connection line of node i at time t; Q i,t is the reactive power injection of the external network connection line of node i at time t; P DGi,t is the active power of the distributed power source connected to node i at time t; Q DGi,t is the reactive power of the distributed power source connected to node i at time t; P di,t is the active power of the electrical load at node i at time t; Q di,t is the reactive power of the electrical load at node i at time t; U i,t is the voltage value of node i at time t; U j,t is the voltage value of node j at time t; G ij is the real part of the admittance of line ij; B ij is the imaginary part of the admittance of line ij; θ ij,t is the phase angle between nodes i and j at time t; U i,max is the upper limit of the allowable voltage of node i; U i,min is the lower limit of the allowable voltage of node i; I ij,t is the current value of branch ij at time t; I ij,max is the upper limit of the allowable current of branch ij; I ij,min is the lower limit of the allowable current of branch ij; S Pij,t is the actual capacity of branch ij at time t; S Pij,max is the maximum capacity of branch ij; Transient constraints: To avoid misoperation of protection caused by the transient impact caused by the connection of electrical loads, a maximum single-time restored electrical load constraint is set; ΔP k,step ≤ζP kN where, ΔP k,step is the active power capacity for a single-step restoration of the electrical load at the k-th step; ζ is the proportionality coefficient for allowing the capacity of a single-step restoration of the electrical load; P kN is the rated capacity within the energized area at the initial moment of the k-th step; Topological structure constraints: g ∈ G where g is the network topological structure after the reconstruction of the PDS; G is the set of all radial network topologies of the PDS; (2) Gas distribution system constraints Steady-state constraints: Π i,min ≤ Π i,t ≤ Π i,max F ij,min ≤ F ij,t ≤ F ij,max Among them, is the gas source injection flow rate at node i at time t; is the upper limit of the gas source injection flow rate at node i; is the lower limit of the gas source injection flow rate at node i; Π i,t is the pressure value of node i at time t; Π i,max is the upper limit of the allowable pressure of node i; Π i,min is the lower limit of the allowable pressure of node i; F ij,t is the pipe segment flow rate flowing from node i to node j at time t; F ij,max is the upper limit of the pipe segment ij flow rate; F ij,min is the lower limit of the pipe segment ij flow rate; Transient constraints: The pressure and flow rate of natural gas injected by the gas turbine should be within the regulation range of the regulating valve of the gas regulation system; Π GT,min ≤ Π GT,t ≤ Π GT,max F GT,min ≤F GT,t ≤F GT,max Among them, Π GT,t is the pressure of natural gas injected into the gas turbine at time t; F GT,t is the flow rate of natural gas injected into the gas turbine at time t; Π GT,max is the upper limit of the pressure of natural gas injected into the gas turbine; Π GT,min is the lower limit of the pressure of natural gas injected into the gas turbine; F GT,max is the upper limit of the flow rate of natural gas injected into the gas turbine; F GT,min is the lower limit of the flow rate of natural gas injected into the gas turbine.

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