CN112670976A - Multi-energy flow calculation and analysis of electric-gas coupling system under attack of controllable load - Google Patents

Abstract

The invention belongs to the technical field of multi-energy flow calculation of an electric-gas coupling system, and particularly relates to multi-energy flow calculation and analysis of the electric-gas coupling system under the attack of a controllable load. The system comprises a load attack module and a multi-energy flow calculation analysis module. The invention considers the scene of maliciously attacking the controllable load from multiple aspects, constructs a controllable load multi-target state attack model, describes the multi-state load after being attacked, adopts an improved k-means cluster analysis method to process the attack state, analyzes a power system and a natural gas network in an electric-gas coupling system, adopts different working modes for different load attack types, and provides the electric-gas coupling system multi-energy flow calculation method suitable for all load attack scenes.

Description

Multi-energy flow calculation and analysis of electric-gas coupling system under attack of controllable load

Technical Field

The invention belongs to the technical field of calculation of multi-energy flow of an electric-gas coupling system, and particularly relates to a method for calculating and analyzing the multi-energy flow of the electric-gas coupling system under the attack of a controllable load.

Background

With structural reformation of an energy supply side, the application of natural gas is increasingly wide, the coupling degree of an electric power system and a natural gas system is continuously increased due to continuous development of an electric gas conversion technology and a gas turbine, an electric-gas interconnection system can become a new carrier for energy transmission in the future, and interconnection of two energy networks also puts new requirements on the safety of the whole system, particularly the safety of the existing controllable load is relatively weak, and the safety protection measures on the load side are weak or lacked, so that the controllable load is easily and maliciously controlled by an attacker to achieve the purpose of influencing the safe and stable operation of a power distribution network. If a large amount of loads are controlled maliciously, the system load will fluctuate abnormally, and the reliable operation of the electric-gas coupling system is threatened. The interconnection of the energy network increases the regulation difficulty and the safety risk of the whole system, and after a fault occurs in one subsystem, if the fault is not repaired and controlled in time, other subsystems can be influenced, so that a larger range of faults are caused.

At present, the multi-energy-flow analysis research of the electric-gas coupling system considering that the controllable load is maliciously attacked is less, a set of complete models are not provided for describing the attacked scene of the controllable load, and meanwhile, the multi-energy-flow analysis technology of the electric-gas interconnection system considering the attacked scene of the controllable load is not mature.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a multi-energy flow calculation and analysis method for an electric-gas coupling system under the condition of controllable load attack. The invention aims to realize the purposes of low calculated amount, high calculation efficiency, widening the range of energy flow calculation scenes, timely and effectively detecting and controlling various complex load attack scenes and ensuring the stable operation of a power grid and a gas grid.

The technical scheme adopted by the invention for realizing the purpose is as follows:

the electric-gas coupling system under the attack of the controllable load can calculate and analyze the multi-energy flow, and comprises a load attack module and a multi-energy flow calculation and analysis module;

the load attack module is used for simulating various complex controllable load attacked scenes and constructing a load attack scene forecast set by arranging and combining the load attack success rate, the load attack types, the load attack quantity and the state of the attacked load;

the multi-energy flow calculation and analysis module is used for providing an electric-gas coupling system multi-energy flow calculation method suitable for all load attack scenes, aiming at different types of load attacks, adopting different working modes to calculate multi-energy flow distribution so as to detect whether the system has an out-of-limit condition or not and whether the system recovers a normal running state or not, and once a fault caused by the attack is found to be unrecoverable, carrying out next-step load recovery scheduling.

The load attack module includes:

establishing a controllable load multi-target state attack model, arranging and combining attack success probability, attack load type, quantity and the state after the load is attacked, constructing a load attack scene preconceived set, and simulating the attacked scene of the system:

the controllable load is directly reflected as the change of the load states of the electric power subsystem and the natural gas subsystem by the malicious attack in the coupling system, and a load multi-target state attack matrix is constructed as follows:

P_i(t)＝{ΔL(t),T}

the attack with load as object is recorded as Z, the attack control command is recorded as P, the command sending time is recorded as t, the attacked load transaction can be expressed as the matrix, wherein xi represents attack success probability coefficients of different attack types, and P represents attack success probability coefficients of different attack types_i(t) representsThe load is subjected to the abnormal change after being maliciously attacked, the delta L (T) represents the abnormal change of the size of the attacked load, and the T is the holding time of an attack command;

the attack model of the whole electric-gas coupling system is expressed as a block matrix P:

wherein Z is_e、Z_eg、Z_geAnd Z_gRepresenting malicious attacks on the power system, the P2G unit, the gas turbine, and the natural gas system, respectively.

The multi-energy flow calculation analysis module comprises: the system comprises a load attack analysis module, a decoupling module, an electric subsystem energy flow calculation module, a natural gas subsystem energy flow calculation module and an output module;

wherein:

the load attack analysis module is used for classifying the forecast sets of the complex load attack scenes and classifying the load attack sets into different categories based on historical data and corresponding evaluation factors;

the decoupling module is used for realizing decoupling of the electric-gas coupling system and adapting to attacks of different load types through conversion of working modes of the coupling elements;

the power subsystem energy flow calculation module is used for calculating the decoupled power system energy flow;

the natural gas subsystem energy flow calculation module is used for calculating the energy flow of the decoupled natural gas subsystem;

and the output module outputs a multi-energy flow calculation result.

The load attack analysis module comprises the following steps:

step 4.1: taking the historical load attack type and the corresponding evaluation factor as an input data set theta ═ { x ═ x₁,x₂,x₃,…x_nN is the number of sample data in the input data set;

step 4.2: calculating the distance of every two data in the data set and summing, i.e.

Where v is the two samples x in the set_pAnd x_qIs associated with the coefficient, | x_p-x_q| is sample data x in the input data set_pAnd sample data x_qThe Euclidean distance between;

step 4.3: s is subjected to mean value processing to obtain W, namely

Step 4.4: for data sample x in the set_pIf S is_iIf the sample number is more than W, separating the original data from the original data set, and processing the original sample to obtain a new data set theta ', wherein the total number of samples of the new set is n ', and the data separated from the original set is used as an alternative set and is marked as theta ';

step 4.5: setting the new set theta' ═ x₁,x₂,x₃,…x_n'Divide it into k classes, i.e. { B }₁,B₂,……B_n'And setting the total number of k-th clustered data samples to be n'_kCalculate each cluster B_iAverage value of (d):

where ε is the data x_qIn cluster set B_iWeight coefficient of (1):

setting b as a clustering center;

step 4.6: setting an objective function

Performing multiple iterations to obtain k clustering results which enable the target function to be minimum;

step 4.7: setting a dynamic distance threshold tau of each type after clustering, and calculating each type c in the new set_pIf the Euclidean distance between the center and each clustering center in the clustering center set is less than a set distance threshold value tau, executing the step 4.8, otherwise, returning toStep 4.2;

step 4.8: let cluster center c'_q＝c_pC 'to cluster center'_qClassifying into an attack data set;

step 4.9: and (3) executing steps 4.5-4.8 on the alternative set until the sample classification is completed, outputting all attack mode sets, and outputting all attack type sets if the sample classification is divided into m categories, wherein the attack type sets are recorded as: p ═ A₁,A₂,A₃,……,A_mThe evaluation factor coefficient is recorded as: γ ═ γ₁，γ₂，γ₃，……γ_m}。

The decoupling module comprises the following components:

(1) when the air load is attacked: the P2G unit is a balance node of a natural gas system, namely a pressure constant node, a gas turbine access node is set as a PV or PQ node, and the power change delta P of P2G_P2GThe power change Delta P of the gas turbine is determined by a node balance equation after convergence of the multi-energy flow_GIs zero;

(2) when the electric load is attacked: the P2G unit access node is used as a natural gas system flow constant node, the gas turbine unit is a power system balance node, the power system is in an island mode, and the power change delta P of P2G_P2GZero, gas turbine power change Δ P_GThe node balance equation after the convergence of the multi-energy flow is determined;

(3) when the electric and gas loads are simultaneously attacked: the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine access node is set as a PV or PQ node.

The power subsystem power flow calculation module comprises the following components:

(1) assuming that a system has N nodes, wherein M PQ nodes, N-M-1 PV nodes and 1 balance node, constructing a power system power balance equation:

in the above formula,. DELTA.P_kRepresents the difference, Δ Q, between the injected active power and the outgoing active power at node k_kRepresenting the difference between the injected reactive power and the outgoing reactive power at node k; p_skAnd Q_skIs the net active power and net reactive power injected into node k, i.e. the generated power injected into the node minus the load power; v_kIs the voltage modulus of node k, V_lIs the voltage modulus of node l; delta_klIs the phase difference of the voltages of the nodes k and l; g_kl、B_klRespectively the conductance and susceptance of elements corresponding to nodes k and l in the node admittance matrix, wherein N is the number of system nodes;

the above equation is written in the form:

wherein: Δ P ═ Δ P₁，ΔP₂，…，ΔP_N-1]^T，ΔQ＝[ΔQ₁，ΔQ₂，…，ΔQ_M]^T，δ＝[δ₁，δ₂，…，δ_N-1]^T，V＝[V₁，V₂，…，V_M]^T(ii) a Δ P is the active power matrix, Δ P₁、ΔP₂、…ΔP_N-1N-1 active power balance equations; Δ Q is a reactive power matrix, Δ Q₁、ΔQ₂、…ΔQ_MM reactive power balance equations; delta is a phase difference matrix, delta₁、δ₂、…δ_N-1Is the phase difference between the nodes; v is a matrix of voltage modulus values, V₁、V₂、…V_MThe voltage modulus is the node voltage modulus;

(2) introducing a correction equation:

in the formula, Δ δ₁…Δδ_N-1The node phase difference correction value is obtained; Δ V₁…ΔV_MThe node voltage modulus value is a modified value;

the matrix is divided into two parts, namely:

the elements of the blocking matrix are respectively represented as follows:

in the above formula, δ_kjIs the phase difference of the voltages of nodes k and j; g_kk、B_kkRespectively, conductance and susceptance of the node k; g_kj、B_kjRespectively the conductance and susceptance of the elements corresponding to the nodes k and j in the node admittance matrix;V_jis the voltage modulus of node j; n, H, M, L are all in matrix form, N_kkFor a block matrix N diagonal elements, N_kjIs the element of the k row and j column of the matrix; h_kkIs a diagonal element of the matrix H, H_kjIs the element of the k row and j column of the matrix; m_kkIs a matrix M diagonal elements, M_kjIs the element of the k row and j column of the matrix; l is_kkIs a matrix L diagonal element, L_kjIs the element in the kth row and jth column of the matrix.

The natural gas subsystem energy flow calculation module comprises the following components:

(1) the method comprises the following steps of constructing a natural gas system multi-time scale pipeline flow sectional equation:

in the formula (I), the compound is shown in the specification,

the flow sectional equation of the natural gas pipeline is expressed,

the flow of the natural gas pipeline containing the compressor is represented, and delta t represents a time step; Δ x represents the length of the gas pipeline segment, and the specific value is L/N through Δ x_pSolving, where L represents the natural gas pipeline length, N_pRepresenting the number of segments per natural gas pipeline, N_TThe number of the time segments is shown,

representing the pressure value of the x-th section of the pipeline at the time t,

representing the pressure value of the x +1 th segment of the pipeline at the time t,

representing the pressure value of the x-th section of the pipeline at time t-1,

representing the pressure value of the x-1 th section of the pipeline at the time t,

representing the flow vector value of the xth segment of the pipeline at time t,

denotes the absolute value of the flow rate of the x-th section of the pipeline at the time T, D denotes the diameter of the pipeline, R denotes the gas constant in the pipeline, T denotes the natural gas temperature in the pipeline, Z denotes the compression factor, ρ₀Denotes natural gas density, F denotes friction factor, Ng denotes number of natural gas system nodes, Nc denotes number of natural gas system compressors, F denotes number of natural gas system compressors^k-sourceRepresenting the natural gas source flow, f, connected to node k^k-loadRepresenting the air load flow of node k, f_cWhich is indicative of the flow rate through the compressor,

representing the pipe end flow connecting nodes i, k,

represents the flow at the beginning of the pipeline connecting nodes i, k, S_cThe flow direction of the compressor is shown, the inflow node k is 1, otherwise, the inflow node k is-1;

(2) obtaining an equation set matrix form expression of node load and pipeline flow according to a Kirchhoff first law and a node flow balance equation, and introducing a load attack evaluation factor gamma:

wherein: l is_dNon-electric gas demand vector, L_eIs the electric power gas demand vector, L_gIs P2G yields a natural gas vector, L is the gas load vector in the natural gas pipeline; a. the₁Is a correlation matrix; f is the pipeline flow vector;

substituting pi for square vector of node pressure, i.e. pi equals p²The matrix of the relationship between the pressure drop of the sectional pipeline and the node pressure is expressed as follows:

ΔП＝-A^TП

natural gas flow formula:

f＝Φ′(ΔП)

the node load and pressure relationship matrix is then as follows:

wherein A is^TA transposed matrix representing the correlation matrix, A_1d、A_1e、A_1gRespectively represent L_d、L_e、L_gL is a gas load vector in the natural gas pipeline;

the entire set of error matrices is:

wherein: σ is a function of the node error;

and correcting the node pressure through continuous iteration until the error is smaller than the set value, and solving the load and pressure relation matrix to obtain an energy flow distribution result of the natural gas subsystem.

The multi-energy flow calculation method of the electric-gas coupling system suitable for all load attack scenes comprises the following steps:

step 1: generating a load attack data set according to the load attack multi-target state model;

step 2: dividing an attack state data set into m classes by adopting an improved k-means cluster analysis method, and outputting an evaluation factor set gamma-gamma ═ gamma { (gamma)₁，γ₂，γ₃，……γ_mIn which γ₁，γ₂，γ₃，……γ_mAn evaluation factor coefficient for each type of attack;

and step 3: acquiring basic parameters of circuit elements and natural gas network elements in the electric-gas coupling system;

and 4, step 4: determining the load attack type according to the basic parameters, and determining the working mode and the evaluation factor coefficient of a system coupling link;

and 5: and calculating the distribution condition of the system multipotent flow under the determined system working mode.

The basic parameters include: the system comprises a set in the power system, an electric load and branch parameters, an air source in a natural gas network, a pipeline, a compressor, an air load parameter and a load attack parameter;

the determining the load attack type according to the basic parameters and the working mode and the evaluation factor coefficient of the system coupling link comprise:

when the gas load is attacked, the P2G unit is a balance node of a natural gas system, and a gas turbine access node is set as a PV or PQ node; when the electric load is attacked, the access node of the P2G unit is used as a natural gas system flow constant node, and the gas turbine unit is used as a power system balance node;

when electric and gas loads are simultaneously attacked, the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine access node is set as a PV or PQ node;

the natural gas system adopts a Newton node method, and comprises the following steps:

step (1): setting an initial value, setting the initial value of the voltage of the PQ node as the rated voltage of the point, and setting the phase angle to be 0; the voltage amplitude at the PV node is known and the phase angle is set to 0;

step (2): to findActive and reactive power increment delta P of PQ output node^(k)、ΔQ^(k)And increasing the active power and the voltage amplitude of the PV node and solving a Jacobian matrix J^(k)；

And (3): solving a correction equation to obtain the correction quantity delta V of the voltage amplitude and the phase angle^(k)And delta^(k)Correcting the set initial voltage value according to the correction value;

and (4): judging whether the error meets the requirement, namely | | | delta^(k)||＜ε₁、||ΔV^(k)||＜ε₂(ii) a If the requirements are met, outputting the result; and (4) if the requirement is not met, continuing the iteration in the step (2).

A computer storage medium having a computer program stored thereon, wherein the computer program when executed by a processor implements the steps of calculating and analyzing the multi-power flow of the electro-pneumatic coupling system under attack of the controllable load.

The invention has the following beneficial effects and advantages:

the invention provides a multi-energy-flow decoupling calculation and analysis method of an electric-gas bidirectional coupling system based on a gas turbine and P2G, and the method is used for considering an emergent scene that a controllable load is maliciously attacked. And (3) considering the scene of the malicious attack of the controllable load from multiple aspects, constructing a controllable load multi-target state attack model, and describing the attacked multi-state load. The invention adopts an improved k-means cluster analysis method to process attack states, respectively analyzes a power system and a natural gas network in an electric-gas coupling system, adopts different working modes for different load attack types, and provides an electric-gas coupling system multi-energy flow calculation method suitable for all load attack scenes.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart of the calculation of the multi-energy flow of the electro-pneumatic coupling system in consideration of malicious load attacks according to the embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating a power system power flow calculation process in the multi-energy flow calculation according to an embodiment of the present invention;

FIG. 3 is a flowchart of the classification of attacks based on improved clustering load according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a 14-20 node electro-pneumatic coupling system in which an embodiment of the present invention is used;

FIG. 5 is a schematic illustration of the natural gas pipeline flow distribution for the different attack types of FIG. 3;

FIG. 6 is a schematic diagram of node pressures for the power system of FIG. 3 for different attack types.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

The solution of some embodiments of the invention is described below with reference to fig. 1-6.

Example 1

The invention relates to a multi-energy flow calculation and analysis method for an electric-gas coupling system under the attack of a controllable load, which specifically comprises a load attack module and a multi-energy flow calculation and analysis module.

The load attack module is used for simulating various complex controllable load attacked scenes and constructing a load attack scene forecast set by arranging and combining the load attack success rate, the load attack types, the load attack quantity and the state of the attacked load.

Further, the load attack module includes:

establishing a controllable load multi-target state attack model, arranging and combining attack success probability, attack load type, quantity and the state after the load is attacked, constructing a load attack scene preconceived set, and simulating the attacked scene of the system:

the controllable load is directly reflected as the change of the load states of the electric power subsystem and the natural gas subsystem by the malicious attack in the coupling system, and a load multi-target state attack matrix is constructed as follows:

P_i(t)＝{ΔL(t),T}

the attack with load as object is recorded as Z, the attack control command is recorded as P, the command sending time is recorded as t, the attacked load transaction can be expressed as the matrix, wherein xi represents attack success probability coefficients of different attack types, and P represents attack success probability coefficients of different attack types_i(T) represents the variation of the load after being maliciously attacked, Δ l (T) represents the variation of the load size after being attacked, and T is the attack command holding time.

The attack model of the whole electric-gas coupling system is expressed as a block matrix P:

wherein Z is_e、Z_eg、Z_geAnd Z_gRepresenting malicious attacks on the power system, the P2G unit, the gas turbine, and the natural gas system, respectively.

The multi-energy flow calculation and analysis module is used for providing an electric-gas coupling system multi-energy flow calculation method suitable for all load attack scenes, aiming at different types of load attacks, adopting different working modes to calculate multi-energy flow distribution so as to detect whether the system has an out-of-limit condition or not and whether the system recovers a normal running state or not, and once a fault caused by the attack is found to be unrecoverable, carrying out next-step load recovery scheduling.

Furthermore, the multi-energy flow calculation analysis module comprises a load attack analysis module, a decoupling module, an electric power subsystem energy flow calculation module, a natural gas subsystem energy flow calculation module and an output module. The method comprises the following specific steps:

(1) the load attack analysis module is used for classifying the complicated load attack scene preconceived sets and classifying the load attack sets into different categories based on historical data and corresponding evaluation factors;

(2) the decoupling module is used for realizing decoupling of the electric-gas coupling system and adapting to attacks of different load types through conversion of working modes of the coupling elements;

(3) the power subsystem energy flow calculation module is used for calculating the decoupled power system energy flow;

(4) the natural gas subsystem energy flow calculation module is used for calculating the energy flow of the decoupled natural gas subsystem;

(5) and the output module outputs the multi-energy flow calculation result.

Further, the load attack analysis module introduces a dynamic distance threshold on the basis of a traditional k-means clustering analysis method for a complex dynamic load attack scene, and classifies the established load attack forecast set through historical data and set evaluation factors, and the specific steps are as follows:

step 4.1: taking the historical load attack type and the corresponding evaluation factor as an input data set theta ═ { x ═ x₁,x₂,x₃,…x_nN is the number of sample data in the input data set;

step 4.2: calculating the distance of every two data in the data set and summing, i.e.

Where v is the two samples x in the set_pAnd x_qIs associated with the coefficient, | x_p-x_q| is sample data x in the input data set_pAnd sample data x_qThe Euclidean distance between;

step 4.3: s is subjected to mean value processing to obtain W, namely

Step 4.4: for data sample x in the set_pIf S is_iIf the sample number is more than W, separating the original data from the original data set, and processing the original sample to obtain a new data set theta ', wherein the total number of samples of the new set is n ', and the data separated from the original set is used as an alternative set and is marked as theta ';

step 4.5: setting the new set theta' ═ x₁,x₂,x₃,…x_n'Divide it into k classes, i.e. { B }₁,B₂,……B_n'And setting the total number of k-th clustered data samples to be n'_kCalculate each cluster B_iAverage value of (d):

where ε is the data x_qIn cluster set B_iWeight coefficient of (1):

setting b as a clustering center;

step 4.6: setting an objective function

Performing multiple iterations to obtain k clustering results which enable the target function to be minimum;

step 4.7: setting a dynamic distance threshold tau of each type after clustering, and calculating each type c in the new set_pIf the Euclidean distance between the center and each clustering center in the clustering center set is smaller than a set distance threshold value tau, executing the step 4.8, otherwise, returning to the step 4.2;

step 4.8: let cluster center c'_q＝c_pC 'to cluster center'_qClassifying into an attack data set;

step 4.9: and (3) executing steps 4.5-4.8 on the alternative set until the sample classification is completed, outputting all attack mode sets, and outputting all attack type sets if the sample classification is divided into m categories, wherein the attack type sets are recorded as: p ═ A₁,A₂,A₃,……,A_mThe evaluation factor coefficient is recorded as: γ ═ γ₁，γ₂，γ₃，……γ_m}。

Further, the decoupling module uses the coupling element gas turbine and the P2G unit to achieve decoupling of the power system and the natural gas system, considers different load attack modes, and adapts to different load type attacks by switching the working modes of the coupling element, which specifically includes the following steps:

(1) when the air load is attacked: the P2G unit is a balance node of a natural gas system, namely a pressure constant node, and a gas turbine access node is set as a PV or PQ node. P2G Power Change Δ P_P2GThe power change Delta P of the gas turbine is determined by a node balance equation after convergence of the multi-energy flow_GIs zero;

(2) when the electric load is attacked: the P2G unit access node is used as a natural gas system flow constant node, the gas turbine unit is a power system balance node, the power system is in an island mode, and the power change delta P of P2G_P2GZero, gas turbine power change Δ P_GThe node balance equation after the convergence of the multi-energy flow is determined.

(3) When the electric and gas loads are simultaneously attacked: the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine access node is set as a PV or PQ node.

Further, the power subsystem power flow calculation module specifically includes the following:

(1) assuming that a system has N nodes, wherein M PQ nodes, N-M-1 PV nodes and 1 balance node, constructing a power system power balance equation:

in the above formula,. DELTA.P_kRepresents the difference, Δ Q, between the injected active power and the outgoing active power at node k_kRepresenting the difference between the injected reactive power and the outgoing reactive power at node k; p_skAnd Q_skIs net active power and net reactive power injected into node k, i.e. injectionSubtracting the load power from the generated work power to the node; v_kIs the voltage modulus of node k, V_lIs the voltage modulus of node l; delta_klIs the phase difference of the voltages of the nodes k and l; g_kl、B_klRespectively the conductance and susceptance of the corresponding elements of the nodes k and l in the node admittance matrix, and N is the number of the system nodes.

The above equation is written in the form:

wherein: Δ P ═ Δ P₁，ΔP₂，…，ΔP_N-1]^T，ΔQ＝[ΔQ₁，ΔQ₂，…，ΔQ_M]^T，δ＝[δ₁，δ₂，…，δ_N-1]^T，V＝[V₁，V₂，…，V_M]^T. Δ P is the active power matrix, Δ P₁、ΔP₂、…ΔP_N-1N-1 active power balance equations; Δ Q is a reactive power matrix, Δ Q₁、ΔQ₂、…ΔQ_MM reactive power balance equations; delta is a phase difference matrix, delta₁、δ₂、…δ_N-1Is the phase difference between the nodes; v is a matrix of voltage modulus values, V₁、V₂、…V_MThe voltage modulus is the node voltage modulus.

(2) Introducing a correction equation:

in the formula, Δ δ₁…Δδ_N-1The node phase difference correction value is obtained; Δ V₁…ΔV_MThe node voltage modulus value is a modified value.

The matrix is divided into two parts, namely:

the elements of the blocking matrix are respectively represented as follows:

in the above formula, δ_kjIs the phase difference of the voltages of nodes k and j; g_kk、B_kkRespectively, conductance and susceptance of the node k; g_kj、B_kjRespectively the conductance and susceptance of the elements corresponding to the nodes k and j in the node admittance matrix; v_jIs the voltage modulus of node j; n, H, M, L are all in matrix form, N_kkFor a block matrix N diagonal elements, N_kjIs an element of the k row and j column of the matrixA peptide; h_kkIs a diagonal element of the matrix H, H_kjIs the element of the k row and j column of the matrix; m_kkIs a matrix M diagonal elements, M_kjIs the element of the k row and j column of the matrix; l is_kkIs a matrix L diagonal element, L_kjIs the element in the kth row and jth column of the matrix.

Further, the natural gas subsystem energy flow calculation module provides a natural gas multi-time scale pipeline flow segmentation equation, which specifically includes the following steps:

(1) the method comprises the following steps of constructing a natural gas system multi-time scale pipeline flow sectional equation:

in the formula (I), the compound is shown in the specification,

the flow sectional equation of the natural gas pipeline is expressed,

the flow of the natural gas pipeline containing the compressor is represented, and delta t represents a time step; Δ x represents the length of the gas pipeline segment, and the specific value is L/N through Δ x_pSolving, where L represents the natural gas pipeline length, N_pRepresenting the number of segments per natural gas pipeline, N_TThe number of the time segments is shown,

representing the pressure value of the x-th section of the pipeline at the time t,

representing the pressure value of the x +1 th segment of the pipeline at the time t,

representing the pressure value of the x-th section of the pipeline at time t-1,

representing the pressure value of the x-1 th section of the pipeline at the time t,

representing the flow vector value of the xth segment of the pipeline at time t,

denotes the absolute value of the flow rate of the x-th section of the pipeline at the time T, D denotes the diameter of the pipeline, R denotes the gas constant in the pipeline, T denotes the natural gas temperature in the pipeline, Z denotes the compression factor, ρ₀Denotes natural gas density, F denotes friction factor, Ng denotes number of natural gas system nodes, Nc denotes number of natural gas system compressors, F denotes number of natural gas system compressors^k-sourceRepresenting the natural gas source flow, f, connected to node k^k-loadRepresenting the air load flow of node k, f_cWhich is indicative of the flow rate through the compressor,

representing the pipe end flow connecting nodes i, k,

represents the flow at the beginning of the pipeline connecting nodes i, k, S_cIndicating the compressor flow direction, the inflow node k is 1, otherwise it is-1.

(2) Obtaining an equation set matrix form expression of node load and pipeline flow according to a Kirchhoff first law and a node flow balance equation, and introducing a load attack evaluation factor gamma:

wherein: l is_dNon-electric gas demand vector, L_eIs the electric power gas demand vector, L_gIs P2G yields a natural gas vector, L is the gas load vector in the natural gas pipeline; a. the₁Is a correlation matrix; f is the pipe flow vector.

Substituting pi for square vector of node pressure, i.e. pi ═ p²The matrix of the relationship between the pressure drop of the sectional pipeline and the node pressure is expressed as follows:

ΔП＝-A^TП

natural gas flow formula:

f＝Φ′(ΔП)

the node load and pressure relationship matrix is then as follows:

wherein A is^TA transposed matrix representing the correlation matrix, A_1d、A_1e、A_1gRespectively represent L_d、L_e、L_gL is the gas load vector in the natural gas pipeline.

The entire set of error matrices is:

wherein: σ is a function of the node error.

And correcting the node pressure through continuous iteration until the error is smaller than the set value, and solving the load and pressure relation matrix to obtain an energy flow distribution result of the natural gas subsystem.

Example 2

The invention also provides an embodiment, which is an electro-pneumatic coupling system multi-energy flow calculation and analysis under the attack of a controllable load, wherein the electro-pneumatic coupling system multi-energy flow calculation method suitable for all load attack scenes specifically comprises the following steps:

step 1: generating a load attack data set according to the load attack multi-target state model;

step 2: dividing an attack state data set into m classes by adopting an improved k-means cluster analysis method, and outputting an evaluation factor set gamma-gamma ═ gamma { (gamma)₁，γ₂，γ₃，……γ_mIn which γ₁，γ₂，γ₃，……γ_mAn evaluation factor coefficient for each type of attack;

and step 3: and acquiring basic parameters of circuit elements and natural gas network elements in the electric-gas coupling system.

The basic parameters include: the system comprises a set in the power system, an electric load and branch parameters, an air source in a natural gas network, a pipeline, a compressor, an air load parameter and a load attack parameter;

and 4, step 4: and determining the load attack type according to the basic parameters, and determining the working mode and the evaluation factor coefficient of the system coupling link.

When the gas load is attacked, the P2G unit is a balance node of the natural gas system, and the gas turbine access node is set as a PV or PQ node. When the electric load is attacked, the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine unit is a power system balance node.

When electric and gas loads are simultaneously attacked, the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine access node is set as a PV or PQ node;

and 5: and calculating the distribution condition of the system multipotent flow under the determined system working mode.

Further, the natural gas system adopts a newton node method, as shown in fig. 1 and fig. 2, fig. 1 is a flow chart of computing the energy flow of the electric-gas coupling system under consideration of malicious load attack according to the embodiment of the present invention, and fig. 2 is a flow chart of computing the energy flow of the power system in computing the energy flow according to the embodiment of the present invention. The method specifically comprises the following steps:

step (1): setting an initial value, setting the initial value of the voltage of the PQ node as the rated voltage of the point, and setting the phase angle to be 0; the voltage magnitude at the PV node is known and the phase angle is set to 0.

Step (2): determining the active and reactive power increment delta P of PQ node^(k)、ΔQ^(k)And increasing the active power and the voltage amplitude of the PV node and solving a Jacobian matrix J^(k)。

And (3): solving a correction equation to obtain the correction quantity delta V of the voltage amplitude and the phase angle^(k)And delta^(k)And correcting the set initial voltage value according to the correction value.

And (4): judging whether the error meets the requirement, namely | | | delta^(k)||＜ε₁、||ΔV^(k)||＜ε₂. If the requirements are met, outputting the result; and (4) if the requirement is not met, continuing the iteration in the step (2).

Taking a 14-node power system coupled with a 20-node natural gas grid as an example of an electric-electric coupling system, the coupling system is shown in fig. 4, and fig. 4 is a schematic diagram of a 14-20-node electric-electric coupling system applied in an embodiment of the present invention. Having one gas turbine GT and two P2G units P2G₁、P2G₂And the nodes 11, 6, 1, 3 and 14, 8 are respectively connected with a natural gas network and a power grid. The calculation results of the system multipotency flow distribution when the system is not attacked are calculated by adopting the multipotency flow calculation method provided by the invention, and the calculation results of the natural gas system node pressure and the relevant parameters of the power system are shown in the table 1-2:

TABLE 1

TABLE 2

Node numbering	Voltage (pu)	Phase angle	Work (pu)	Reactive power (pu)
					1	1.0600	0	3.3103	0.2070i
2	1.0450	-0.4349	0.1830	0.3634i
					3	1.0100	-0.9391	-0.7444	0.2744i
4	1.0052	-0.9317	-0.4780	0.0390i
					5	0.9960	-0.8184	-0.0760	-0.0160
6	1.0700	-1.6572	0.0056	-0.0750i
					7	1.0613	-1.3206	0	0
8	1.0900	-1.3206	0	0.5092
					9	1.0659	-1.5176	-0.4200	0
10	1.0596	-1.5595	-0.0900	-0.0580i
					11	1.0618	-1.6152	-0.0350	0.0180i
12	1.0381	-1.7996	-0.0610	0.0160i
					13	0.9986	-1.9683	-1.1350	-0.0580i
14	1.0168	-1.7716	-0.1490	-0.0500i

The multi-energy-flow calculation method under the controlled load attacked scene provided by the invention is adopted to obtain the multi-energy-flow calculation results under the normal condition and under the condition that two loads are attacked, the natural gas pipeline flow and the electric power system node pressure calculation results are shown in fig. 5 and 6, fig. 5 is a natural gas pipeline flow distribution schematic diagram under different attack types in fig. 3, and fig. 6 is a power system node pressure schematic diagram under different attack types in fig. 3. The results show that when the controllable load is attacked to different degrees, the system energy flow fluctuates to different degrees, and in some cases, when the system is attacked, the system can still normally operate within an allowable range due to the scheduling of the coupling link of the gas turbine and the P2G unit, however, when the attack degree is large, the node pressure, the flow and the like in the system can exceed the allowable range, and the safety constraint of the system is not satisfied, so that the system cannot normally operate.

Example 3

Based on the same inventive concept, an embodiment of the present invention further provides a computer storage medium, where a computer program is stored on the computer storage medium, and when the computer program is executed by a processor, the steps of calculating and analyzing the multi-power flow of the electro-pneumatic coupling system under the attack of the controllable load described in embodiment 1 or 2 are implemented.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (10)

1. The multi-energy flow calculation and analysis method of the electric-gas coupling system under the attack of the controllable load is characterized by comprising the following steps: the system comprises a load attack module and a multi-energy flow calculation analysis module;

the load attack module is used for simulating various complex controllable load attacked scenes and constructing a load attack scene forecast set by arranging and combining the load attack success rate, the load attack types, the load attack quantity and the state of the attacked load;

the multi-energy flow calculation and analysis module is used for providing an electric-gas coupling system multi-energy flow calculation method suitable for all load attack scenes, aiming at different types of load attacks, adopting different working modes to calculate multi-energy flow distribution so as to detect whether the system has an out-of-limit condition or not and whether the system recovers a normal running state or not, and once a fault caused by the attack is found to be unrecoverable, carrying out next-step load recovery scheduling.

2. The calculation and analysis of the multipotency flows of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 1, wherein: the load attack module includes:

establishing a controllable load multi-target state attack model, arranging and combining attack success probability, attack load type, quantity and the state after the load is attacked, constructing a load attack scene preconceived set, and simulating the attacked scene of the system:

the controllable load is directly reflected as the change of the load states of the electric power subsystem and the natural gas subsystem by the malicious attack in the coupling system, and a load multi-target state attack matrix is constructed as follows:

P_i(t)＝{ΔL(t),T}

the attack with load as object is recorded as Z, the attack control command is recorded as P, the command sending time is recorded as t, the attacked load transaction can be expressed as the matrix, wherein xi represents attack success probability coefficients of different attack types, and P represents attack success probability coefficients of different attack types_i(T) represents the abnormal change of the load after being maliciously attacked, Δ l (T) represents the abnormal change of the load after being attacked, and T is the holding time of the attack command;

the attack model of the whole electric-gas coupling system is expressed as a block matrix P:

wherein Z is_e、Z_eg、Z_geAnd Z_gRepresenting malicious attacks on the power system, the P2G unit, the gas turbine, and the natural gas system, respectively.

3. The calculation and analysis of the multipotency flows of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 1, wherein: the multi-energy flow calculation analysis module comprises: the system comprises a load attack analysis module, a decoupling module, an electric subsystem energy flow calculation module, a natural gas subsystem energy flow calculation module and an output module;

wherein:

the load attack analysis module is used for classifying the forecast sets of the complex load attack scenes and classifying the load attack sets into different categories based on historical data and corresponding evaluation factors;

the decoupling module is used for realizing decoupling of the electric-gas coupling system and adapting to attacks of different load types through conversion of working modes of the coupling elements;

the power subsystem energy flow calculation module is used for calculating the decoupled power system energy flow;

the natural gas subsystem energy flow calculation module is used for calculating the energy flow of the decoupled natural gas subsystem;

and the output module outputs a multi-energy flow calculation result.

4. The calculation and analysis of the multi-power flow of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 3, wherein: the load attack analysis module comprises the following steps:

step 4.1: taking the historical load attack type and the corresponding evaluation factor as an input data set theta ═ { x ═ x₁,x₂,x₃,…x_nN is the number of sample data in the input data set;

step 4.2: calculating the distance of every two data in the data set and summing, i.e.

Where v is the two samples x in the set_pAnd x_qIs associated with the coefficient, | x_p-x_q| is sample data x in the input data set_pAnd sample data x_qThe Euclidean distance between;

step 4.3: s is subjected to mean value processing to obtain W, namely

Step 4.4: for data sample x in the set_pIf S is_iIf the sample number is more than W, separating the original data set from the original data set, and processing the original data set to obtain a new data set theta ', wherein the total number of samples of the new set is n',taking the data separated from the original set as an alternative set, and marking the data as theta;

step 4.5: setting the new set theta' ═ x₁,x₂,x₃,…x_n'Divide it into k classes, i.e. { B }₁,B₂,……B_n'And setting the total number of k-th clustered data samples to be n'_kCalculate each cluster B_iAverage value of (d):

where ε is the data x_qIn cluster set B_iWeight coefficient of (1):

setting b as a clustering center;

step 4.6: setting an objective function

Performing multiple iterations to obtain k clustering results which enable the target function to be minimum;

step 4.7: setting a dynamic distance threshold tau of each type after clustering, and calculating each type c in the new set_pIf the Euclidean distance between the center and each clustering center in the clustering center set is smaller than a set distance threshold value tau, executing the step 4.8, otherwise, returning to the step 4.2;

step 4.8: let cluster center c'_q＝c_pC 'to cluster center'_qClassifying into an attack data set;

step 4.9: and (3) executing steps 4.5-4.8 on the alternative set until the sample classification is completed, outputting all attack mode sets, and outputting all attack type sets if the sample classification is divided into m categories, wherein the attack type sets are recorded as: p ═ A₁,A₂,A₃,……,A_mThe evaluation factor coefficient is recorded as: γ ═ γ₁，γ₂，γ₃，……γ_m}。

5. The calculation and analysis of the multi-power flow of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 3, wherein: the decoupling module comprises the following components:

(1) when the air load is attacked: the P2G unit is a balance node of a natural gas system, namely a pressure constant node, a gas turbine access node is set as a PV or PQ node, and the power change delta P of P2G_P2GThe power change Delta P of the gas turbine is determined by a node balance equation after convergence of the multi-energy flow_GIs zero;

(2) when the electric load is attacked: the P2G unit access node is used as a natural gas system flow constant node, the gas turbine unit is a power system balance node, the power system is in an island mode, and the power change delta P of P2G_P2GZero, gas turbine power change Δ P_GThe node balance equation after the convergence of the multi-energy flow is determined;

(3) when the electric and gas loads are simultaneously attacked: the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine access node is set as a PV or PQ node.

6. The calculation and analysis of the multi-power flow of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 3, wherein: the power subsystem power flow calculation module comprises the following components:

(1) assuming that a system has N nodes, wherein M PQ nodes, N-M-1 PV nodes and 1 balance node, constructing a power system power balance equation:

in the above formula,. DELTA.P_kRepresents the difference, Δ Q, between the injected active power and the outgoing active power at node k_kRepresenting the difference between the injected reactive power and the outgoing reactive power at node k; p_skAnd Q_skIs the net active power and net reactive power injected into node k, i.e. the generated power injected into the node minus the load power; v_kIs the voltage modulus of node k, V_lIs the voltage modulus of node l; delta_klIs the phase difference of the voltages of the nodes k and l; g_kl、B_klAre respectively node guideConductance and susceptance of elements corresponding to nodes k and l in the nano matrix, wherein N is the number of system nodes;

the above equation is written in the form:

wherein: Δ P ═ Δ P₁，ΔP₂，...，ΔP_N-1]^T，ΔQ＝[ΔQ₁，ΔQ₂，…，ΔQ_M]^T，δ＝[δ₁，δ₂，...，δ_N-1]^T，V＝[V₁，V₂，...，V_M]^T(ii) a Δ P is the active power matrix, Δ P₁、ΔP₂、...ΔP_N-1N-1 active power balance equations; Δ Q is a reactive power matrix, Δ Q₁、ΔQ₂、...ΔQ_MM reactive power balance equations; delta is a phase difference matrix, delta₁、δ₂、...δ_N-1Is the phase difference between the nodes; v is a matrix of voltage modulus values, V₁、V₂、...V_MThe voltage modulus is the node voltage modulus;

(2) introducing a correction equation:

in the formula, Δ δ₁...Δδ_N-1The node phase difference correction value is obtained; Δ V₁...ΔV_MThe node voltage modulus value is a modified value;

the matrix is divided into two parts, namely:

the elements of the blocking matrix are respectively represented as follows:

in the above formula, δ_kjIs the phase difference of the voltages of nodes k and j; g_kk、B_kkRespectively, conductance and susceptance of the node k; g_kj、B_kjRespectively the conductance and susceptance of the elements corresponding to the nodes k and j in the node admittance matrix; v_jIs the voltage modulus of node j; n, H, M, L are all in matrix form, N_kkFor a block matrix N diagonal elements, N_kjIs the element of the k row and j column of the matrix; h_kkIs a diagonal element of the matrix H, H_kjIs the element of the k row and j column of the matrix; m_kkIs a matrix M diagonal elements, M_kjIs the element of the k row and j column of the matrix; l is_kkIs a matrix L diagonal element, L_kjIs the element in the kth row and jth column of the matrix.

7. The calculation and analysis of the multipotency flows of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 1, wherein: the natural gas subsystem energy flow calculation module comprises the following components:

(1) the method comprises the following steps of constructing a natural gas system multi-time scale pipeline flow sectional equation:

in the formula (I), the compound is shown in the specification,

the flow sectional equation of the natural gas pipeline is expressed,

the flow of the natural gas pipeline containing the compressor is represented, and delta t represents a time step; Δ x represents the length of the gas pipeline segment, and the specific value is L/N through Δ x_pSolving, where L represents the natural gas pipeline length, N_pRepresenting the number of segments per natural gas pipeline, N_TThe number of the time segments is shown,

representing the pressure value of the x-th section of the pipeline at the time t,

representing the pressure value of the x +1 th segment of the pipeline at the time t,

representing the pressure value of the x-th section of the pipeline at time t-1,

representing the pressure value of the x-1 th section of the pipeline at the time t,

representing the flow vector value of the xth segment of the pipeline at time t,

denotes the absolute value of the flow rate of the x-th section of the pipeline at the time T, D denotes the diameter of the pipeline, R denotes the gas constant in the pipeline, T denotes the natural gas temperature in the pipeline, Z denotes the compression factor, ρ₀Denotes natural gas density, F denotes friction factor, Ng denotes number of natural gas system nodes, Nc denotes number of natural gas system compressors, F denotes number of natural gas system compressors^k-sourceRepresenting the natural gas source flow, f, connected to node k^k-loadRepresenting the air load flow of node k, f_cWhich is indicative of the flow rate through the compressor,

representing the pipe end flow connecting nodes i, k,

represents the flow at the beginning of the pipeline connecting nodes i, k, S_cIndicating the compressor flow direction, the inflow node k is 1, otherwiseIs-1;

(2) obtaining an equation set matrix form expression of node load and pipeline flow according to a Kirchhoff first law and a node flow balance equation, and introducing a load attack evaluation factor gamma:

wherein: l is_dNon-electric gas demand vector, L_eIs the electric power gas demand vector, L_gIs P2G yields a natural gas vector, L is the gas load vector in the natural gas pipeline; a. the₁Is a correlation matrix; f is the pipeline flow vector;

substituting pi for square vector of node pressure, i.e. pi ═ p²The matrix of the relationship between the pressure drop of the sectional pipeline and the node pressure is expressed as follows:

ΔП＝-A^TП

natural gas flow formula:

f＝Φ′(ΔП)

the node load and pressure relationship matrix is then as follows:

wherein A is^TA transposed matrix representing the correlation matrix, A_1d、A_1e、A_1gRespectively represent L_d、L_e、L_gL is a gas load vector in the natural gas pipeline;

the entire set of error matrices is:

wherein: σ is a function of the node error;

and correcting the node pressure through continuous iteration until the error is smaller than the set value, and solving the load and pressure relation matrix to obtain an energy flow distribution result of the natural gas subsystem.

8. The calculation and analysis of the multipotency flows of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 1, wherein: the multi-energy flow calculation method of the electric-gas coupling system suitable for all load attack scenes comprises the following steps:

step 1: generating a load attack data set according to the load attack multi-target state model;

step 2: dividing an attack state data set into m classes by adopting an improved k-means cluster analysis method, and outputting an evaluation factor set gamma-gamma ═ gamma { (gamma)₁，γ₂，γ₃，……γ_mIn which γ₁，γ₂，γ₃，……γ_mAn evaluation factor coefficient for each type of attack;

and step 3: acquiring basic parameters of circuit elements and natural gas network elements in the electric-gas coupling system;

and 4, step 4: determining the load attack type according to the basic parameters, and determining the working mode and the evaluation factor coefficient of a system coupling link;

and 5: and calculating the distribution condition of the system multipotent flow under the determined system working mode.

9. The calculation and analysis of the multi-power flow of the electro-pneumatic coupling system under the attack of the controllable load as claimed in claim 8, wherein: the basic parameters include: the system comprises a set in the power system, an electric load and branch parameters, an air source in a natural gas network, a pipeline, a compressor, an air load parameter and a load attack parameter;

the determining the load attack type according to the basic parameters and the working mode and the evaluation factor coefficient of the system coupling link comprise:

when the gas load is attacked, the P2G unit is a balance node of a natural gas system, and a gas turbine access node is set as a PV or PQ node; when the electric load is attacked, the access node of the P2G unit is used as a natural gas system flow constant node, and the gas turbine unit is used as a power system balance node;

when electric and gas loads are simultaneously attacked, the P2G unit access node is used as a natural gas system flow constant node, and the gas turbine access node is set as a PV or PQ node;

the natural gas system adopts a Newton node method, and comprises the following steps:

step (1): setting an initial value, setting the initial value of the voltage of the PQ node as the rated voltage of the point, and setting the phase angle to be 0; the voltage amplitude at the PV node is known and the phase angle is set to 0;

step (2): determining the active and reactive power increment delta P of PQ node^(k)、ΔQ^(k)And increasing the active power and the voltage amplitude of the PV node and solving a Jacobian matrix J^(k)；

And (3): solving a correction equation to obtain the correction quantity delta V of the voltage amplitude and the phase angle^(k)And delta^(k)Correcting the set initial voltage value according to the correction value;

and (4): judging whether the error meets the requirement, namely | | | delta^(k)||＜ε₁、||ΔV^(k)||＜ε₂(ii) a If the requirements are met, outputting the result; and (4) if the requirement is not met, continuing the iteration in the step (2).

10. A computer storage medium, characterized by: the computer storage medium has stored thereon a computer program which, when executed by a processor, performs the steps of calculating and analyzing the multi-power flow of the electro-pneumatic coupling system under attack of a controllable load as claimed in claims 1 to 9.

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