A method and system for fast power flow calculation of an electro-mechanical coupled system considering thermal characteristics of power transmission elements

Abstract

The application relates to a power-gas coupling system constant coefficient fast power flow calculation method and system considering the thermal characteristics of power transmission elements, and belongs to the technical field of power system engineering. A partial differential equation describing a natural gas network dynamic model is subjected to spatial integral processing, is converted into a common differential equation, and a lumped parameter model of the natural gas pipe network is constructed, and the mathematical conversion eliminates the mathematical form obstacle of simultaneous solution of the partial differential equation and the algebraic equation. On the basis, the lumped parameter model of the natural gas pipe network, the power balance equation of the power network and the dynamic thermal balance equation of the overhead conductor are included into a unified calculation framework, and a unified power flow calculation model is constructed; the model realizes synchronous solution of the above equations by using the Newton method, effectively overcomes the convergence difficulty of alternating iteration caused by the mismatch of time constants, and provides an accurate mathematical model for global analysis of the system.

Description

Technical Field

[0001] This invention relates to a method and system for calculating fast power flow with constant coefficients in an electro-pneumatic coupling system that takes into account the thermal characteristics of transmission components, and belongs to the field of power system engineering technology. Background Technology

[0002] With the continuous increase in the proportion of large-scale renewable energy grid connection, natural gas, with its rapid ramp-up and flexible adjustment capabilities, has become a key flexible resource for smoothing the fluctuations in new energy output and supporting system absorption. However, the increasingly strong cross-system coupling relationship within the electric-gas coupling system has brought new operational risks under extreme weather conditions. Recent operational accidents have shown that the safe and stable operation of the electric-gas coupling system increasingly depends on the interaction between the natural gas supply capacity and the transmission limit of overhead lines based on the Dynamic Thermal Rating (DTR). The dynamic process of the natural gas network and the characteristics of its linepack changes directly affect the definition of the system's actual operating boundary.

[0003] Conversely, under extreme high-temperature and drought conditions, the power system needs to deploy gas turbines on a large scale for power compensation due to limited hydropower output and a surge in air conditioning load. At this time, the natural gas network faces the risk of rapid depletion of local pipeline reserves and pressure drops at nodes due to increased gas consumption by gas turbines. Simultaneously, rising ambient temperatures reduce the allowable current carrying capacity of overhead conductors, making the maximum allowable conductor temperature a core physical constraint on power transmission capacity. Therefore, during high-load periods, both natural gas supply capacity and transmission channel temperature constraints become key factors determining the system's operating boundaries.

[0004] Accurately calculating the true operating boundary of the system during peak load requires a comprehensive consideration of the coupling relationship between the dynamic processes of the natural gas pipeline network and the thermal dynamic characteristics of the power transmission components. On the natural gas pipeline side, the inherent gas storage buffer characteristics of the pipeline can absorb fluctuations in the gas consumption of the gas turbine and affect the power consumption of the electric compressor during load ramping. On the power transmission side, the thermal inertia of overhead lines causes a 10–20 minute lag in the response of conductor temperature rise to current changes. Existing studies have introduced the Dynamic Thermal Rating (DTR) model to characterize the dynamic current-carrying capacity of conductors. However, to quantitatively analyze the combined impact of the pipeline dynamic processes and conductor thermal inertia on the system operating boundary, a unified power flow model that integrates the equations of all physical systems must be established.

[0005] In the field of natural gas network simulation, the mainstream implicit finite difference method (FDM), while not subject to the strict limitations of explicit stability conditions on the step size, requires iteratively solving a large-scale nonlinear equation system at each time step. This involves frequent updates and decompositions of high-dimensional Jacobian matrices, and the computational cost increases rapidly with the system size. The method of characteristics (MOC), while capable of describing the pressure wave propagation process within pipelines, is constrained by the Courant-Friedrichs-Lewy (CFL) stability condition. Its simulation step size depends on the physical dimensions of the shortest pipeline in the network, making it difficult to efficiently perform long-term operational analyses of large-scale systems.

[0006] Furthermore, during the unified solution process, the conductor temperature and power flow are bidirectionally coupled through the temperature resistance effect and Joule heating, which further increases the number and dimension of off-diagonal sub-blocks in the Jacobian matrix. Although the implicit solver has numerical stability, the Jacobian matrix is ​​prone to ill-conditioned characteristics when dealing with strongly rigid equation systems. Frequent matrix updates and inversion operations restrict the computational efficiency and online analysis applicability of this type of model in large-scale systems.

[0007] Therefore, how to construct a unified power flow calculation method that can eliminate the obstacle of solving simultaneous partial differential equations, alleviate numerical rigidity, and take into account the computational efficiency of large-scale networks has become an urgent technical problem to be solved in the field of safety assessment of electro-electric coupling systems. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method and system for calculating fast power flow with constant coefficients in an electro-pneumatic coupling system that takes into account the thermal characteristics of transmission components.

[0009] The technical solution of the present invention is as follows: A method for calculating fast power flow with constant coefficients in an electro-electric coupling system that takes into account the thermal characteristics of transmission components, comprising the following steps: S1. Construct a unified power flow calculation model consisting of the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor, and integrate the cross-system coupled correlation equation consisting of the fuel consumption of the gas turbine and the power consumption of the electric compressor. S2: The partial differential equation of pipeline momentum balance in the dynamic mass conservation equation of natural gas nodes is spatially integrated along the pipeline axis to transform it into a lumped parameter ordinary differential equation describing the change of pipeline mass flow rate; the second-order implicit trapezoidal method is used to discretize the dynamic mass conservation equation of natural gas nodes, the lumped parameter ordinary differential equation, and the dynamic thermal balance equation of overhead conductors in time, and a set of algebraic equations containing known quantities of the operating state at the previous simulation time are constructed. S3: At each time step, extract the current operating state variables and physical parameters of the electric-gas coupling system, and use the analytical expression of the off-diagonal partial derivatives of the Jacobian matrix between the power network, natural gas network and overhead conductor thermal characteristic models to calculate the values ​​of the elements in each cross-system coupling sub-block; S4: Based on the connection relationship of the gas turbine, electric compressor and overhead line, the operation control mode and the element values ​​calculated in step S3, determine the reserved state of the electric-thermal, thermal-electric, electric-gas and gas-electric coupling sub-blocks in the global Jacobian matrix and construct a global constant coefficient Jacobian matrix with an asymmetric structure. S5: Iteratively solve using the global constant coefficient Jacobian matrix to update the power flow distribution of the entire system.

[0010] Preferably, in step S1, the mathematical modeling process for gas turbine fuel consumption is as follows: Construct a system to describe the fuel consumption L of a gas turbine. D，j Its power generation P G The quadratic polynomial equation relating the functions between them:

[0011] Among them, a g b g c g The coefficients characterizing the fuel consumption properties of the gas turbine are obtained through quadratic polynomial fitting based on the heat rate curves, historical operating data, or rated operating condition test data provided by the gas turbine equipment manufacturer. After determining the coefficients, the analytical expression for the incremental rate of fuel consumption is extracted based on the above equation:

[0012] It is used as the basic physical parameter for calculating the cross-system interaction sensitivity index between the gas network and the power grid.

[0013] Preferably, in step S1, the mathematical modeling process for the power consumption of the electric compressor is as follows: Construct a system to describe the active power P consumed by an electric compressor. L，comp,i Nonlinear equations:

[0014] Among them, the power consumption coefficient B c The parsing expression is:

[0015] Gas compressibility factor z at compressor outlet conditions c The parsing expression is:

[0016] In the formula, The mass flow rate through the electrically driven compressor. and These are the absolute pressures at the compressor inlet and outlet, respectively. For the efficiency of the drive motor, For variable efficiency, Z is the adiabatic index of the gas. a Z is the gas compressibility factor under inlet operating conditions. c T is the gas compressibility factor under outlet operating conditions. in，c T represents the inlet gas temperature. n The outlet gas temperature, The gas density under standard conditions is used as the fundamental parameter for calculating the sensitivity of the power grid to the gas grid cross-system interaction. The gas turbine fuel consumption equation and the electric compressor power consumption equation are incorporated into the unified power flow calculation model as associated constraints for electro-gas coupling equipment. Specifically, for a gas turbine connecting an electric node and a natural gas node, its power generation P... G Fuel consumption is taken into account in the power balance equation of the power network. The gas load term for the corresponding natural gas node is included, and the relationship between the active power output of the gas turbine and the gas consumption of the natural gas node is established through the fuel consumption equation; for electrically driven compressors powered by power nodes and connected to the first and last nodes of the natural gas pipeline, their active power consumption is... The active load of the corresponding power node is included, and its inlet pressure, outlet pressure, and mass flow rate through the compressor are incorporated into the natural gas network operating variables. The relationship between gas network pressure, mass flow rate, and power load is established through the compressor power consumption equation. Thus, the coupling constraints of the gas turbine and electric compressor are incorporated into the power network power balance equation and the natural gas node dynamic mass conservation equation, forming a unified power flow calculation model. Preferably, in step S1, the construction process of the natural gas node dynamic mass conservation equation is as follows:

[0017] For any non-constant pressure node in the natural gas network Based on the balance between the change in gas mass within the node control volume and the net mass inflow into the node, a dynamic mass conservation equation for the natural gas node is constructed:

[0018] Among them, natural gas nodes Net mass inflow Represented as:

[0019] In the formula, For natural gas nodes At simulation time Absolute pressure below; For natural gas nodes The equivalent storage coefficient; and Each is based on natural gas nodes A collection of ordinary pipes with end nodes and beginning nodes; and Each is based on natural gas nodes This is the set of electrically driven compressor branches for the exit and inlet nodes; For ordinary natural gas pipelines mass flow rate; For flow through the electric compressor mass flow rate; To connect to natural gas nodes The mass flow rate of the gas source injection; For natural gas nodes The conventional natural gas load mass flow rate; To connect to natural gas nodes Gas turbine fuel consumption mass flow rate; Since electric compressors are driven by electric motors, ignoring internal gas leakage and internal gas storage capacity, electric compressors... The inlet mass flow rate is equal to the outlet mass flow rate, that is:

[0020] Therefore, the mass flow rate of the electric compressor It is recorded as an outflow in the net mass inflow at its inlet natural gas node and as an inflow in the net mass inflow at its outlet natural gas node. When natural gas nodes When multiple gas turbines are connected, This represents the sum of the mass flow rates of fuel consumption from all gas turbines connected to this node; Natural gas node Equivalent storage coefficient Represented as:

[0021] In the formula, For allocation to natural gas nodes The equivalent control volume, The velocity of sound of the gas inside the pipe.

[0022] When the node control volume is determined by averaging the geometric volumes of adjacent pipelines, the natural gas node... equivalent control volume Represented as:

[0023] In the formula, For natural gas nodes The collection of all connected ordinary pipes; and They are ordinary natural gas pipelines The cross-sectional area and length of the electric compressor branch are not included in the equivalent control volume of the node; For a natural gas source node with a given absolute pressure, its absolute pressure is used as a known boundary condition and is not used as a power flow iteration variable; the dynamic mass conservation relationship of the node is still retained and used to determine the gas source injection mass flow rate of the node.

[0024] Preferably, in step S1, the specific process of constructing the dynamic thermal balance equation for the overhead conductor is as follows: For any overhead conductor in a power network, considering the asynchrony and thermal inertia between conductor current changes and conductor temperature changes, the following dynamic thermal balance equation is constructed:

[0025] in, Mass per unit length of conductor The specific heat capacity of the wire, Let I be the real-time temperature of the conductor, and I be the amplitude of the current flowing through the conductor. The AC resistance varies with temperature, and its functional expression is as follows:

[0026] In the formula, R0 is the DC resistance at the reference temperature T0. The temperature coefficient of resistance is given; the endothermic and dissipative terms respectively include the heat absorption power q under illumination. s Convection heat dissipation power q c and radiative heat dissipation power q r ; Describing the real-time temperature of the conductor using dynamic heat balance equations The amplitude of the current flowing through the conductor The dynamic response process of changes in environmental meteorological conditions and conductor physical parameters is studied, and the maximum allowable temperature T of the conductor is introduced. max As a criterion for the thermal safety operation of transmission lines, when the real-time temperature of the conductor meets the requirements... When the transmission line is in a thermally safe operating state, the dynamic thermal balance equation is used as a constraint on the thermal characteristics of the transmission element and is incorporated into the unified power flow calculation model described in step S1. Together with the power balance equation of the power network and the dynamic mass conservation equation of the natural gas node, it participates in the subsequent discretization processing and unified iterative solution, thereby taking into account the change in conductor temperature rise and its impact on line parameters in the power flow calculation process, and realizing the characterization of the dynamic current carrying capacity of the transmission element.

[0027] Preferably, in step S2, the second-order implicit trapezoidal rule is used to discretize the lumped-parameter ordinary differential equation in time, transforming the dynamic differential process into the equivalent algebraic equation shown below:

[0028] In the formula, The pipeline mass flow rate at the current simulation time t. The equivalent adjoint admittance coefficient of the pipeline, obtained by discretization using the second-order implicit trapezoidal method, is used to characterize the linear effect of the absolute pressure difference between the first and last nodes of the pipeline on the current mass flow rate of the pipeline. and These represent the absolute pressures at the beginning and end nodes of the pipeline at the current simulation time t, respectively. For the previous simulation moment The known constants for determining the pipeline pressure and mass flow rate are expressed analytically as follows;

[0029] In the formula, The pipeline mass flow rate at the current simulation time t; To ensure a uniform step size in the simulation; L is the pipe length; A is the pipe cross-sectional area; f is the pipe friction coefficient; a is the sound velocity of the gas inside the pipe; D is the pipe inner diameter; This represents the average pipeline pressure at the previous simulation time. The expression is .

[0030] Furthermore, the second-order implicit trapezoidal rule is used to discretize the dynamic mass conservation equation of the natural gas node in time, thus obtaining the natural gas node... Pressure calculation residuals:

[0031] When the power flow calculation results at the current simulation moment satisfy the dynamic mass conservation relationship of natural gas nodes, we have:

[0032] In the formula, For natural gas nodes At the current simulation moment Pressure calculation residuals; and These are the current simulation times. and the previous simulation time Next natural gas node Net mass inflow; and All of these are known quantities determined by the running state at the previous simulation moment; To unify the step size in simulation; For natural gas pipelines The equivalent algebraic equation for the pipeline mass flow rate, obtained after spatial integration and time discretization, is written in residual form:

[0033] When the power flow calculation results at the current simulation moment satisfy the momentum balance relationship of the natural gas pipeline, we have:

[0034] In the formula, For natural gas pipelines At the current simulation moment The residual for calculating the mass flow rate; For natural gas pipelines mass flow rate; For natural gas pipelines The equivalent adjoint admittance coefficient; and Natural gas pipelines The first and last nodes at the current simulation time Absolute pressure; This refers to known historical data determined based on the pipe pressure and mass flow rate status at the previous simulation point.

[0035] Preferably, in step S3, the operating state variables include the phase angle of the grid node voltage, the voltage amplitude of the PQ node, the absolute pressure of the natural gas node, the pipeline mass flow rate, and the conductor temperature of the overhead conductor. Physical parameters include transmission line resistance, reactance, temperature coefficient of resistance, fuel consumption characteristic coefficient of gas turbine, efficiency of electric compressor, gas velocity, pipe length, pipe inner diameter, pipe cross-sectional area, and coefficient of friction.

[0036] Preferably, in step S4, a global Jacobian matrix is ​​established. The non-diagonal coupled sub-block retention determination method determines the global Jacobian matrix at each time step of the power flow calculation based on the connection relationships of the gas turbine, electric compressor, and overhead conductors in step S1, as well as the corresponding equipment's operating control mode in the current time period. The retention states of the electric-thermal, thermal-electric, electric-gas, and gas-electric coupling sub-blocks are as follows: for off-diagonal coupling sub-block elements that have no physical association or do not participate in iterative coupling under the current operating mode, the values ​​are set to zero; for off-diagonal coupling sub-block elements that need to be retained, the values ​​are taken according to the partial derivative analytical expression in step S3; at the same time, the diagonal sub-blocks corresponding to their own variables in the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor are constantized. First, a global Jacobian matrix is ​​constructed, incorporating the partial derivative relationships between the power balance equation of the power network, the dynamic mass conservation equation of natural gas nodes, and the dynamic heat balance equation of overhead conductors. The global Jacobian matrix is ​​presented as follows: The block structure, its complete representation matrix is:

[0037] In the formula, This is the global Jacobian matrix; The voltage phase angle vector of the power network nodes; For power grid Node voltage magnitude vector; This represents the temperature vector of the overhead conductor. This represents the absolute pressure vector of the natural gas node. This represents the mass flow rate vector of the natural gas pipeline. This refers to the active power imbalance in the power grid. This refers to the reactive power imbalance in the power network. This refers to the unbalance quantity corresponding to the dynamic thermal balance equation of overhead conductors. This represents the unbalance quantity corresponding to the natural gas node pressure equation; The unbalance quantity corresponds to the mass flow rate equation of the natural gas pipeline; each element in the matrix represents the partial derivative of the corresponding unbalance quantity with respect to the corresponding state variable. Define the full-dimensional state vector as Define the unbalance vector for the entire system as follows: ; In the formula, To unify the full-dimensional state variable vector of the power flow calculation model, Let T be the vector of unbalanced quantities in the entire system, which is composed of the power balance equation of the power network, the dynamic heat balance equation of the overhead conductor, and the dynamic mass conservation equation of the natural gas node. T represents the vector transpose.

[0038] Preferably, in step S4, based on the determination of retaining off-diagonal coupled sub-blocks according to the cross-system coupled sub-block elements calculated in step S3, the global Jacobian matrix is ​​subjected to constant coefficient processing. Constant coefficient processing includes zeroing off-diagonal coupled sub-blocks that satisfy the zero-structure determination condition, and parameter solidification processing of the diagonal sub-blocks corresponding to their own variables in the power network power balance equation, the natural gas node dynamic mass conservation equation, and the overhead conductor dynamic heat balance equation; wherein, the pipeline equivalent adjoint admittance coefficient in the equivalent algebraic equation of step S2... These are discretization coefficients belonging to the natural gas network pipeline equations themselves, used to construct relevant diagonal sub-blocks of the natural gas network, and are not cross-system coupling sub-block elements as described in step S3; Specifically, the nominal pipeline mass flow rate is extracted based on the initial steady-state power flow solution. Average pressure of nominal pipeline The equivalent admittance coefficient of the pipeline in step S2 is... Curing to a constant coefficient:

[0039] In the formula, The equivalent admittance coefficient of the pipeline obtained by solidification at the nominal operating point, where A is the cross-sectional area of ​​the pipeline. To ensure a uniform simulation step size, L represents the pipe length, f represents the pipe friction coefficient, a represents the sound velocity of the gas inside the pipe, and D represents the pipe inner diameter. The nominal pipeline mass flow rate, The nominal average pipeline pressure is used as the basis for subsequent power flow iterations. Replace the time-varying coefficients in the equivalent algebraic equation in step S2 It participates in solving the natural gas network equations, thereby reducing the repeated updates of Jacobian matrix elements related to the natural gas network.

[0040] Preferably, the global Jacobian matrix includes cross-system coupling sub-blocks reflecting the thermal characteristic models of the power system, natural gas system, and overhead conductors, specifically: via electrothermal coupling sub-block and Describe the impact of the resistance-temperature effect on the admittance parameters of the power network; through thermoelectric coupling sub-blocks. and Describe the effect of Joule heating generated by the current on the calculation of the unbalance in the conductor temperature; through the electrical coupling sub-block. and This describes the impact of changes in natural gas pressure and flow rate on the power consumption fluctuations of the electric compressor, and consequently on the active power imbalance in the power system; this is illustrated through a gas-electric coupling sub-block. Describe the impact of generator output adjustment on the pressure distribution of gas grid nodes via gas turbine fuel consumption.

[0041] Preferably, in step S4, the decoupling determination process is as follows: at each time step of the power flow calculation, firstly, based on the connection relationship of the gas turbine, electric compressor, and overhead conductor in step S1, the off-diagonal coupled sub-blocks in the global Jacobian matrix are structurally screened; for power nodes, natural gas nodes, or transmission lines that do not have physical connections, their corresponding off-diagonal partial derivative elements are set to zero; for off-diagonal coupled sub-blocks that have physical connections, their retention status is further determined based on the operating status of the coupled equipment and the element values ​​calculated in step S3. For the electro-thermal coupled sub-block, when the temperature change of the corresponding transmission line does not affect the power network admittance parameter, let , When the temperature change of the corresponding transmission line affects the power network admittance parameter through the resistance-temperature effect, the calculation is based on the line resistance-temperature relationship. , And retain; For the thermo-electric coupling sub-block, when the voltage state of the corresponding power node does not affect the transmission line current, let , When the voltage state of the corresponding power node affects the Joule heating of the conductor through the line current, the dynamic heat balance equation of the overhead conductor discretized by the second-order implicit trapezoidal rule is used to calculate... , And retain; For the electro-pneumatic coupling sub-block, when the corresponding power node is not connected to the electric drive compressor, or when the electric drive compressor is running at a given active power during the current time period, let , When the power consumption of the electric compressor changes with the compressor inlet pressure, outlet pressure, or mass flow rate, it is calculated according to the power consumption equation of the electric compressor. , And retain; For the gas-electric coupling sub-block, when the corresponding natural gas node is not connected to the gas turbine, or the gas turbine has active power output... When the variable is not adjusted according to the current power flow iteration, let When the gas turbine acts as a balancing unit or participates in active power regulation, it is based on the incremental rate of fuel consumption. With the active power-phase angle sensitivity of the power system calculate And retain; Therefore, the cross-system coupling sub-block elements calculated in step S3 specifically correspond to the elements in the global Jacobian matrix. , , , , , as well as When constructing the global constant coefficient Jacobian matrix, the off-diagonal coupled sub-block elements that satisfy the above zero structure condition are simplified to zero values, while the off-diagonal coupled sub-block elements that have an effect on the current power flow iteration are retained, thus forming a global constant coefficient Jacobian matrix with an asymmetric structure.

[0042] Preferably, in step S4, at each time step, the off-diagonal partial derivatives of the natural gas node pressure imbalance with respect to the power system node voltage phase angle are calculated according to the following formula:

[0043] In the formula, For natural gas nodes The off-diagonal partial derivatives of pressure imbalance with respect to the phase angle of power system node voltages; For natural gas nodes Pressure imbalance; The phase angle of the voltage at the power system node; To unify the step size in simulation; To include natural gas nodes; Gas turbine fuel consumption; For the active power output of the gas turbine; This represents the rate of increase in gas turbine fuel consumption relative to active power output. These are the active-phase angle sensitivity elements in the power balance equation of the power network; For natural gas nodes The equivalent storage coefficient, its analytical expression is:

[0044] In the formula, For natural gas nodes The associated equivalent geometric volume of the pipeline, The velocity of sound of the gas inside the pipe.

[0045] During the power flow iteration process, based on the off-diagonal coupled sub-block retention determination method in step S4, the global Jacobian matrix is... The electric-thermal, thermal-electric, electric-gas, and gas-electric coupling sub-blocks are classified and processed. Specifically, for the gas-electric coupling sub-block, when the corresponding natural gas node is not connected to the gas turbine, or the gas turbine has active power output... When the variable is not adjusted according to the current power flow iteration, let When the gas turbine is used as a balancing unit or participates in active power regulation, the fuel consumption increment rate is considered. With active phase angle sensitivity Calculate and retain Therefore, in constructing the global constant coefficient Jacobian matrix... At that time, the effective off-diagonal partial derivatives in the gas-electric coupling sub-block are retained in one direction, thus forming an asymmetric matrix structure.

[0046] According to a preferred embodiment of the present invention, in step S5, during the power flow iteration process, the unbalance vector F of the entire system is calculated based on the current iteration point, and the pre-constructed global constant coefficient Jacobian matrix at that time step is invoked. The state variable correction is obtained by solving the following system of linear correction equations:

[0047] Update the state variables based on the state correction amount:

[0048] In the formula, This represents the number of times the current trend has iterated. For the first The state variable vector of the next iteration. For the first The state variable correction amount obtained in the next iteration The updated state variable vector; the global constant coefficient Jacobian matrix It remains unchanged during the power flow iteration at the same time step and reuses its matrix decomposition results.

[0049] A constant-coefficient fast power flow calculation system for an electro-electric coupling system that takes into account the thermal characteristics of transmission components, comprising: The model building module constructs a unified power flow calculation model consisting of the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor, and integrates the cross-system coupled correlation equation consisting of the fuel consumption of the gas turbine and the power consumption of the electric compressor. The discretization module is used to spatially integrate the partial differential equation of pipeline momentum balance in the dynamic mass conservation equation of natural gas nodes along the pipeline axis, transforming it into a lumped parameter ordinary differential equation describing the change of pipeline mass flow rate. The module also performs time discretization processing on the dynamic mass conservation equation of natural gas nodes, the lumped parameter ordinary differential equation, and the dynamic thermal balance equation of overhead conductors, constructing a set of algebraic equations containing known quantities of the operating state at the previous simulation moment. The global constant coefficient Jacobian matrix construction module is used to extract the operating state variables and physical parameters of the current electro-gas coupling system at each time step. It uses the analytical expression of the off-diagonal partial derivatives of the Jacobian matrix between the power network, natural gas network and overhead conductor thermal characteristic models to calculate the values ​​of elements in each cross-system coupling sub-block. Based on the connection relationship, operation control mode and element values ​​of the gas turbine, electric compressor and overhead conductor, it determines the reserved state of the electro-thermal, thermal-electric, electro-gas and gas-electric coupling sub-blocks in the global Jacobian matrix and constructs a global constant coefficient Jacobian matrix with an asymmetric structure. The update module uses a global constant coefficient Jacobian matrix for iterative solution to update the power flow distribution of the entire system.

[0050] The beneficial effects of this invention are as follows: Traditional power flow calculations for electro-gas coupled systems, which consider the thermal characteristics of transmission components, often face challenges when dealing with dynamic models of natural gas networks. This is because the partial differential equations describing the natural gas pipeline network and the algebraic equations describing conventional steady-state power flow in power systems are mathematically incompatible, making direct simultaneous solution difficult. Furthermore, using alternating iterative methods for separate solutions leads to slow convergence or even divergence due to time constant differences in the thermal dynamic processes of the power network, natural gas network, and transmission components. This invention addresses this by spatially integrating the partial differential equations describing the dynamic model of the natural gas network, transforming them into ordinary differential equations, and thus constructing a lumped parameter model of the natural gas pipeline network. This mathematical transformation eliminates the mathematical formality barrier of simultaneously solving partial differential equations and algebraic equations. Based on this, this invention integrates the lumped parameter model of the natural gas pipeline network, the power balance equations of the power network, and the dynamic thermal balance equations of overhead conductors into a unified computational framework, constructing a unified power flow calculation model. This model utilizes Newton's method to achieve simultaneous solution of the above equations, effectively overcoming the convergence problem of alternating iterations caused by time constant mismatch, and providing an accurate mathematical model for the global analysis of the system.

[0051] Based on the aforementioned unified power flow calculation model, this invention further improves the iterative solution process of the Jacobian matrix. By performing constant coefficient processing on the diagonal sub-blocks of the Jacobian matrix and introducing an asymmetric matrix structure based on decoupling conditions, this invention reduces the update frequency and inversion computation of the Jacobian matrix elements during the Newton-Raphson method iteration process, while ensuring accurate characterization of the pressure and mass flow velocity distribution characteristics of natural gas pipeline network nodes. This solution scheme, which combines lumped parameterized modeling and asymmetric matrix structure, breaks through the efficiency bottleneck of solving complex power flow models containing dynamic temperature constraints of transmission components, accelerates the update speed of the power flow distribution of the entire system, and provides decision support that balances accuracy and timeliness for system safety assessment and operation scheduling. Attached Figure Description

[0052] Figure 1This is a schematic diagram of the method flow of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the unified power flow calculation model structure in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of spatial integration and lumped parameter processing for the dynamic model of a natural gas network in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the global constant coefficient Jacobian matrix block structure and off-diagonal coupled sub-block processing in Embodiment 1 of the present invention; Figure 5 The conductor temperature, actual current carrying capacity, and dynamic thermal setpoint variation curves of the critical line L14 provided in Embodiment 2 of the present invention; Figure 6 This is a dynamic pressure distribution diagram of natural gas network nodes provided in Embodiment 2 of the present invention; Figure 7 This is a graph showing the change in mass flow rate of a key pipeline as provided in Embodiment 2 of the present invention. Figure 8 This is a comparison chart of the total simulation time of the fully coupled Newton method and the constant coefficient fast power flow method for systems of different scales provided in Embodiment 2 of the present invention. Detailed Implementation

[0053] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0054] Example 1: like Figure 1 As shown in the figure, this embodiment provides a method for calculating the fast power flow of an electro-electric coupling system with constant coefficients, taking into account the thermal characteristics of transmission components. The steps are as follows: S1: Construct a unified power flow calculation model consisting of the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node (or the dynamic equation of the natural gas network), and the dynamic heat balance equation of the overhead conductor, and integrate the cross-system coupled correlation equation consisting of the fuel consumption of the gas turbine and the power consumption of the electric compressor. S2: The pipeline momentum balance partial differential equation in the natural gas node dynamic mass conservation equation is spatially integrated along the pipeline axis to transform it into a lumped parameter ordinary differential equation describing the change in pipeline mass flow rate; the second-order implicit trapezoidal method is used to discretize the natural gas node dynamic mass conservation equation, the lumped parameter ordinary differential equation, and the overhead conductor dynamic thermal balance equation in time, and construct a set of algebraic equations containing known quantities of the operating state at the previous simulation time; Natural gas node dynamic mass conservation equation S3: At each time step, the operating state variables and physical parameters of the current electro-gas coupling system are extracted, and the values ​​of the elements in each cross-system coupling sub-block are calculated using the analytical expression of the off-diagonal partial derivatives of the Jacobian matrix between the power network, the natural gas network, and the thermal characteristic model of the overhead conductor; S4: Based on the connection relationship of the gas turbine, electric compressor, and overhead conductor, the operation control mode, and the off-diagonal partial derivative elements of the Jacobian matrix calculated in step S3, determine the retention status of the electric-thermal, thermal-electric, electric-gas, and gas-electric coupling sub-blocks in the global Jacobian matrix; set the off-diagonal coupling sub-block elements that have no physical association or do not participate in iterative coupling under the current operation mode to zero, and take the values ​​of the off-diagonal coupling sub-blocks that need to be retained according to the corresponding partial derivative analytical expressions; at the same time, perform constant coefficient processing on the diagonal sub-blocks corresponding to their own variables in the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor, and construct a global constant coefficient Jacobian matrix with an asymmetric structure; S5: Iteratively solve the global constant coefficient Jacobian matrix to update the power flow distribution of the entire system.

[0055] 1. Construction of a unified electro-pneumatic power flow model considering the thermal characteristics of transmission components 1.1 Spatial Integral Processing of Partial Differential Equations for Natural Gas Networks Applying the partial differential equation for the momentum balance of a natural gas pipeline along the pipeline axial distance Spatial integral over the interval:

[0056] When performing full-path integration, the spatial integration of the inertia term is equivalently replaced by the average flow rate change rate of the entire pipeline, and the spatial integration of the pressure gradient term is equivalently replaced by the pressure difference between the first and last nodes of the pipeline. Simultaneously, the average pressure of the pipeline is introduced. By replacing the local pressure in the friction term, the partial differential form is transformed into a lumped-parameter ordinary differential equation describing the time variation of the flow rate, as shown below:

[0057] In the formula, For the length of the pipe, The cross-sectional area of ​​the pipe. The coefficient of friction of the pipeline. The inner diameter of the pipe. For the speed of sound in gas, For pipeline mass flow rate, This refers to the absolute pressure distributed along the axial direction of the pipeline. and These are the absolute pressures at the beginning and end nodes of the pipeline, respectively. The average pressure in the pipeline, and After spatial integration of the partial differential equations of the natural gas network dynamic model, the dynamic process distributed along the pipeline axis is transformed into a process expressed in terms of pipeline mass flow rate. It is a lumped parameter ordinary differential equation for state variables, which eliminates the inconsistency in mathematical expression between it and the algebraic equation of power network and the ordinary differential equation of dynamic thermal balance of overhead conductors, thus achieving adaptation with the unified solution framework of Newton's method.

[0058] 1.2 Construction of Dynamic Mass Conservation Equations for Natural Gas Nodes For any non-constant pressure node in the natural gas network Based on the balance between the change in gas mass within the equivalent control volume of the node and the net mass inflow into the node, a dynamic mass conservation equation for the natural gas node is constructed:

[0059] Among them, natural gas nodes Net mass inflow Represented as:

[0060] In the formula, For natural gas nodes At simulation time Absolute pressure below; For natural gas nodes The equivalent storage coefficient; and Each is based on natural gas nodes A collection of ordinary pipes with end nodes and beginning nodes; and Each is based on natural gas nodes This is the set of electrically driven compressor branches for the exit and inlet nodes; For ordinary natural gas pipelines mass flow rate; For flow through the electric compressor mass flow rate; To connect to natural gas nodes The mass flow rate of the gas source injection; For natural gas nodes The conventional natural gas load mass flow rate; To connect to natural gas nodes The mass flow rate of fuel consumption in the gas turbine. Since the electric compressor uses an electric motor to provide compression power and does not consume natural gas as driving fuel, neglecting internal gas leakage and internal gas storage capacity, the electric compressor... The inlet mass flow rate is equal to the outlet mass flow rate, that is: Therefore, the mass flow rate of the electric compressor It is recorded as an outflow in the net mass inflow at its inlet natural gas node and as an inflow in the net mass inflow at its outlet natural gas node. Natural Gas Node Equivalent storage coefficient Represented as:

[0061]

[0062] In the formula, For allocation to natural gas nodes The equivalent control volume, Let be the velocity of sound of the gas inside the pipeline. When determining the equivalent control volume of a node using the method of averaging the geometric volumes of adjacent ordinary pipelines, the natural gas node... equivalent control volume Represented as:

[0063]

[0064] In the formula, For natural gas nodes The collection of all connected conventional natural gas pipelines; and They are ordinary natural gas pipelines The cross-sectional area and length. For a natural gas source node with a given absolute pressure, its absolute pressure is used as a known boundary condition, but not as a power flow iteration variable; the dynamic mass conservation relationship of the node is still retained and used to determine the gas source injection mass flow rate of the node.

[0065] 1.3 Construction of Dynamic Thermal Equilibrium Equations for Overhead Conductors Taking into account the asynchronous nature and thermal inertia of the changes in conductor current and conductor temperature, a dynamic thermal equilibrium differential equation is constructed:

[0066] In the formula, Mass per unit length of conductor The specific heat capacity of the wire, Real-time temperature of the conductor. The magnitude of the current flowing through the conductor. Let be the AC resistance that varies with temperature, and its functional expression is: ,in Reference temperature DC resistance below, The temperature coefficient of resistance. The heat absorption and heat dissipation terms respectively include the heat absorption power from illumination. Convection heat dissipation power and radiative heat dissipation power Maximum permissible temperature of the introduced conductor. As a basis for determining the thermal safety of transmission lines.

[0067] 1.4 Analytical Modeling of Gas Turbine and Electric Compressor Construct a description of gas turbine fuel consumption Its power generation The quadratic polynomial equation relating the functions between them:

[0068] In the formula, The heat loss coefficient characterizes the fuel consumption characteristics of a gas turbine. The analytical expression for the incremental rate of fuel consumption is extracted as follows: Construct a description of the active power consumed by the electric compressor. Nonlinear equations:

[0069]

[0070] In the formula, The mass flow rate through the electrically driven compressor. and These are the absolute pressures at the compressor inlet and outlet, respectively. This refers to the efficiency of the drive motor.

[0071] 2. Model time discretization and algebraic processing The ordinary differential equation is discretized in time using the second-order implicit trapezoidal rule, transforming the dynamic differentiation process into the equivalent algebraic equation shown below:

[0072] Among them, the constant term is known. The parsing expression is:

[0073] In the formula, For the current simulation moment The mass flow rate of the pipeline below, The equivalent adjoint admittance coefficient of the pipeline is obtained by discretization using the second-order implicit trapezoidal method. For the previous simulation moment The known constants determined by the pipe pressure and mass flow rate state. To ensure a uniform step size in the simulation, and These are the current simulation times. The absolute pressure at the beginning and end nodes of the lower pipeline. The average pipeline pressure at the previous simulation time is given, and .

[0074] Furthermore, the dynamic mass conservation equations for natural gas nodes are discretized over time using the second-order implicit trapezoidal rule, yielding:

[0075] Rearranging the above equation into a natural gas node Pressure calculation residuals:

[0076] When the calculation results at the current simulation moment satisfy the dynamic mass conservation relationship of natural gas nodes, we have:

[0077] In the formula, For natural gas nodes At the current simulation moment Calculate the residual under the pressure; For natural gas nodes In the previous simulation time Absolute pressure below; and Natural gas nodes At the current simulation moment and the previous simulation time Net mass inflow; and All of these are known quantities determined by the running state at the previous simulation moment.

[0078] For natural gas pipelines The equivalent algebraic equation for the pipeline mass flow rate, obtained after spatial integration and time discretization, is rearranged into the residual for mass flow rate calculation:

[0079] When the calculation results at the current simulation moment satisfy the momentum balance relationship of the natural gas pipeline, we have:

[0080] In the formula, For natural gas pipelines At the current simulation moment The residuals for calculating the mass flow rate are as follows; For natural gas pipelines mass flow rate; For natural gas pipelines The equivalent adjoint admittance coefficient; and Natural gas pipelines The first and last nodes at the current simulation time Absolute pressure below; This refers to known historical data determined based on the pipe pressure and mass flow rate status at the previous simulation point.

[0081] Through the above time discretization and residual processing, the dynamic mass conservation equation of natural gas nodes, the lumped parameter equation of mass flow rate of natural gas pipelines, and the dynamic heat balance equation of overhead conductors are uniformly transformed into algebraic equations suitable for iterative solution using the Newton method.

[0082] 3. Construction and decoupling determination of the global asymmetric constant coefficient Jacobian matrix 3.1 Constant coefficient transformation of the Jacobian matrix Based on nominal flow reference value Compared with nominal pressure reference value For equivalent conductance Perform constant factorization:

[0083] In the formula, and The network stiffness matrix is ​​obtained by extracting the initial steady-state power flow solution. Using the analytical expression, the time-varying network stiffness matrix is ​​transformed into a constant coefficient matrix, and the matrix is ​​directly reused during the iteration process. Decomposition results.

[0084] 3.2 Decision-making for retaining off-diagonal coupled sub-blocks and construction of asymmetric matrices Define the system's integrated state vector as follows:

[0085] Define the discretized imbalance vector of the system as:

[0086] In the formula, Let V be the voltage phase angle vector of the power network nodes. For power grid Node voltage magnitude vector For the overhead conductor temperature vector, This represents the absolute pressure vector of the natural gas node. This represents the mass flow rate vector of the natural gas pipeline. This refers to the imbalance of active power. This refers to the reactive power imbalance. This refers to the thermal imbalance of the conductor. This refers to the pressure imbalance at natural gas nodes. This refers to the unbalanced mass flow rate in the pipeline. This represents the transpose of a vector.

[0087] During the power flow iteration process, the global Jacobian matrix is ​​adjusted based on the connection relationships between the gas turbine, electric compressor, and overhead power lines. The off-diagonal coupled sub-blocks in the process are structurally screened; for power nodes, natural gas nodes or transmission lines that do not have physical connections, their corresponding off-diagonal partial derivative elements are set to zero; for off-diagonal coupled sub-blocks that have physical connections, their retention status is further determined based on the operating status of the coupled equipment and the partial derivative elements calculated in the current iteration step.

[0088] The cross-system coupling sub-block elements calculated in step S3 specifically correspond to the global Jacobian matrix. In , , , , , as well as When constructing the global constant coefficient Jacobian matrix, off-diagonal coupled sub-block elements that satisfy the zero structure criterion are set to zero, while off-diagonal coupled sub-block elements that have an effect on the current power flow iteration are retained.

[0089] Specifically, for the electro-thermal coupling sub-block, when the temperature change of the corresponding transmission line does not affect the power network admittance parameter, let , When the temperature change of the corresponding transmission line affects the power network admittance parameter through the resistance-temperature effect, the calculation is based on the line resistance-temperature relationship. , And retain.

[0090] For the thermo-electric coupling sub-block, when the voltage state of the corresponding power node does not affect the transmission line current, let , When the voltage state of the corresponding power node affects the Joule heating of the conductor through the line current, the dynamic heat balance equation of the overhead conductor discretized by the implicit trapezoidal rule is used to calculate... , And retain.

[0091] For the electro-pneumatic coupling sub-block, when the corresponding power node is not connected to the electric drive compressor, or when the electric drive compressor is running at a given active power during the current time period, let , When the power consumption of the electric compressor changes with the compressor inlet pressure, outlet pressure, or mass flow rate, it is calculated according to the power consumption equation of the electric compressor. , And retain.

[0092] For the gas-electric coupled sub-block, the off-diagonal partial derivatives of the natural gas node pressure imbalance with respect to the power system node voltage phase angle are calculated according to the following formula:

[0093] In the formula, For natural gas nodes The off-diagonal partial derivatives of pressure imbalance with respect to the phase angle of power system node voltages; For natural gas nodes Pressure imbalance; To unify the step size in simulation; To include natural gas nodes Gas turbine fuel consumption; For the active power output of the gas turbine; This represents the rate of increase in gas turbine fuel consumption relative to active power output. These are the active-phase sensitivity elements in the Jacobian matrix of the power system. For natural gas nodes The equivalent storage coefficient, its analytical expression is:

[0094] In the formula, For natural gas nodes The associated equivalent geometric volume of the pipeline, The velocity of sound of the gas inside the pipe.

[0095] When the corresponding natural gas node is not connected to the gas turbine, or the gas turbine has active power output When the variable is not adjusted according to the current power flow iteration, let When the gas turbine is used as a balancing unit or participates in active power regulation, the fuel consumption increment rate is considered. With active phase angle sensitivity Calculate and retain Therefore, in constructing a global constant coefficient Jacobian matrix... At that time, the effective off-diagonal partial derivatives in the gas-electric coupling sub-block are retained in one direction, thus forming an asymmetric matrix structure.

[0096] 4. Unified power flow iterative solution Iterative solutions are obtained using a constructed global asymmetric constant-coefficient Jacobian matrix, through a system of equations. Determine the correction values ​​for each state variable and update the power flow distribution of the entire system. These variables include the voltage amplitude and phase angle at grid nodes, the pressure at gas grid nodes, the mass flow velocity in pipelines, and the conductor temperature of overhead lines.

[0097] Figure 4 This is a schematic diagram of the global constant coefficient Jacobian matrix block structure and off-diagonal coupled sub-block processing in Embodiment 1 of the present invention, showing that after the off-diagonal coupled sub-block is set to zero, the gas-electric off-diagonal partial derivative terms are... After unidirectional retention and constant coefficient processing of diagonal sub-blocks, the global Jacobian matrix is ​​transformed from a fully coupled structure into a global constant coefficient Jacobian matrix with an asymmetric structure, thereby reducing the computational cost of repeated updates and decompositions of the Jacobian matrix during power flow iteration.

[0098] Example 2: A constant-coefficient fast power flow calculation method for an electro-gas coupled system considering the thermal characteristics of transmission components is presented in this embodiment. Using a coupled system consisting of a 39-node power network and a 20-node Belgian natural gas network as an example, the effectiveness of the constant-coefficient fast power flow calculation method is verified. The baseline capacity of the power system is set to 100 MVA, the maximum allowable operating temperature of overhead conductors is set to 70 ℃, the total simulation period is 0–24 h, and the distance step length is Δt = 300 s (i.e., 5 min). The environmental parameters required for the test system are shown in Table 1, and the basic physical constraints and parameters of the power and natural gas networks are shown in Tables 2-1 and 2-2.

[0099] Table 1: Typical meteorological and environmental data within 0-24 hours

[0100] Table 2-1: Structural Parameters of Natural Gas Network Pipelines

[0101] Table 2-2: Power Output Characteristic Parameters of Power Grid Units

[0102] 1) Dynamic thermal characteristics and electrothermal coupling analysis of power transmission components; Under the parameters of the above example, a safety analysis was performed on this scenario. The actual current carrying capacity, conductor temperature, and dynamic thermal setpoint of line L14 were extracted over 24 hours. The resulting curves are shown below. Figure 5 As shown.

[0103] Table 3: Critical Line Status Quantities During Peak Load Periods

[0104] From Table 3 and Figure 5 Calculation data from the peak load period from 4 PM to 9 PM shows that the power transmission components exhibit obvious thermal characteristics. Figure 5The data shows that the current carrying capacity of line L14 reached 1723.10 A at 16:20, exceeding the dynamic thermal setpoint of 1605.19 A determined based on real-time meteorological conditions. At 19:40, the current carrying capacity rose to 2277.29 A, which, although higher than the dynamic thermal setpoint of 1861.86 A, the conductor temperature at that time was 69.16 ℃, not reaching the maximum allowable operating temperature limit of 70 ℃. By 20:20, the calculated current carrying capacity was 1786.99 A, exceeding the dynamic thermal setpoint of 1412.88 A, while the conductor temperature was only 68.39 ℃. The calculation results indicate that using temperature as an operating constraint can improve the utilization efficiency of transmission components and tap into the current carrying capacity of line L14.

[0105] like Figure 5 As shown, the peak current-carrying capacity occurred at 19:40, while the conductor temperature reached a peak of 69.30 ℃ 10 minutes later (19:50). The temperature rise lag effect caused by the thermal inertia of the conductor meant that the short-term overload current-carrying condition did not cause drastic temperature fluctuations. The above calculation results fully demonstrate that using temperature as an operational constraint, rather than the traditional dynamic thermal setpoint, can effectively alleviate the operational pressure on transmission sections during peak periods, thereby tapping into the transmission margin of the line and improving the utilization efficiency of transmission components.

[0106] 2) Dynamic response analysis of natural gas network pressure and flow; Under the parameters described in the above example, a safety analysis is performed on this scenario. This invention extracts the pressure and mass flow rate calculation results of the natural gas network over 24 hours, and the resulting curves are shown below. Figure 6 and Figure 7 As shown, the values ​​at typical moments are shown in Table 4.

[0107] Table 4: Natural Gas Network Operating Parameters

[0108] From Table 4, Figure 6 and Figure 7 It can be seen that the pressure and flow rate of the natural gas network fluctuate over time. From 04:00 to 08:00, the electric compressor operates at a higher pressure ratio, and the natural gas network enters the pipeline storage phase. Figure 2 The pressure at node 15 increased from 7.70 MPa to the upper limit of 9.40 MPa, and the corresponding mass flow rate of pipeline 12 in Table 4 increased from 187.79 kg / s to 304.22 kg / s during this period. During this phase, the gas supply exceeded the terminal consumption, and energy was stored inside the pipeline in the form of compressed gas.

[0109] During the peak load period from 4 PM to 9 PM, the natural gas network releases stored gas by reducing pressure to supplement the fuel consumption required by the gas turbine to increase output. Table 4 shows that at 5 PM, the mass flow rates of pipelines 16 and 17 became negative, at -21.23 kg / s and -28.21 kg / s, respectively. Figure 3 The results show that because the gas consumption rate of the gas turbine exceeds the gas supply rate, the high-pressure gas stored in the pipe expands as the pressure decreases and flows towards the gas consumption node, causing the gas flow direction to reverse in a local section of the pipe. By 8 PM, the pressure at downstream node 13 had dropped from 7.41 MPa before the peak to 3.66 MPa. Under the premise of meeting the lower pressure limit constraint, the natural gas network alleviated the energy supply pressure during the peak period by utilizing the pipe storage release characteristics.

[0110] Comparison Figure 2 and Figure 3 The distribution of physical quantities at different times reveals that the pressure and flow response of the natural gas network exhibits a time delay relative to fluctuations in electrical load. This invention, through a unified solution of the equations for the entire system, reflects the dynamic balance between the system's active power and gas flow. While ensuring that the pressure of the natural gas network does not exceed limits, this method utilizes the flow characteristics of gas within the pipes to meet the energy demand during peak load periods, thus ensuring the safe operation of the electro-gas coupling system.

[0111] 3) Verification of fast power flow calculation time with constant coefficients; This embodiment verifies the computation time of the proposed constant-coefficient fast power flow calculation method based on the aforementioned unified power flow calculation model. This embodiment uses an electro-gas coupled system consisting of an IEEE 39-node power network and a Belgian 20-node natural gas network as the basic example, and retains the overhead conductor heat balance equation, gas turbine gas consumption equation, and electric compressor power consumption equation to form a unified power flow calculation model. To examine the computation time characteristics of this method under different scale conditions, this embodiment constructs an extended system by replicating subnets and connecting them with interconnecting lines and pipelines. The total simulation time period is taken as... , far from taking a long walk This embodiment solves the unified power flow equations using both the fully coupled Newton method and the constant-coefficient fast power flow method under the same simulation conditions. For example... Figure 8As shown in Table 5, the structural parameters of the system at different scales are given. Table 5 shows that when the scale factor increases from 2 to 8, the number of power buses increases from 78 to 312, the number of power lines increases from 96 to 398, the number of natural gas nodes increases from 40 to 160, the number of natural gas pipelines increases from 51 to 214, and the total number of variables increases from 309 to 1260. Since the unified power flow equation includes state variables such as grid node voltage amplitude, node phase angle, natural gas node pressure, natural gas pipeline mass flow rate, and conductor temperature, the dimension of the Jacobian matrix corresponding to the unified power flow equation and the solution scale of the equation increase synchronously as the system scale increases. To reduce the impact of fluctuations in the program's operating environment on the timing results, this embodiment repeats the two methods at each scale three times, and takes the average value as the statistical results shown in Table 6. Table 6 gives the statistical results of the computation time of the two methods at different scales. The total simulation time in Table 6 is denoted as . The average matrix construction time per step is denoted as The average time to solve the equation per step is denoted as . In this embodiment, both methods completed dynamic simulations of all time steps at various scales. Therefore, the statistical results in Table 6 can be directly used to compare the time characteristics of the two methods under different scale conditions.

[0112] Table 5: Structural Parameters of Systems of Different Sizes

[0113] Table 6: Statistical results of computation time for the two methods at different scales

[0114] Table 6 shows the total simulation time of the constant coefficient fast power flow method at various scales. All are lower than the fully coupled Newton's method. When the scale factors are 2, 4, 6, and 8, the fully coupled Newton's method... They are respectively , , and Constant coefficient fast power flow method They are respectively , , and If the difference in total simulation time between the two methods is denoted as:

[0115]

[0116] in, This represents the total simulation time of the fully coupled Newton's method. Let represent the total simulation time of the constant coefficient fast power flow method. Then, when the scale factor increases from 2 to 8, They are respectively , , and The above results show that as the system size increases, the total computation time saved by the constant-coefficient fast power flow method compared to the fully coupled Newton method continuously increases. Let the ratio of the total simulation time of the two methods be denoted as:

[0117]

[0118] From Table 6, we can see that when the scale multiples are 2, 4, 6, and 8, Approximately , , and The results show that the time advantage of the constant-coefficient fast power flow method over the fully coupled Newton method further increases with the scale of the system. In other words, the larger the system scale, the greater the reduction in total computation time by the method of this invention, and the more significant its acceleration effect. Table 6 further shows the average matrix construction time per step of the constant-coefficient fast power flow method at various scales. and average time to solve the equation per step All are lower than the fully coupled Newton's method. When the scale factor increases from 2 to 8, the fully coupled Newton's method... Depend on Increase to Constant coefficient fast power flow method Depend on Increase to Fully Coupled Newton's Method Depend on Increase to Constant coefficient fast power flow method Depend on Increase to The above results demonstrate that the constant-coefficient fast power flow method has lower time overhead in both matrix construction and equation solving, and the gap in equation solving time widens further with increasing scale. The constant-coefficient fast power flow method proposed in this embodiment reduces computation time due to its unified mathematical processing in the solution process. First, it performs spatial integration on the partial differential equations of the natural gas network dynamic model, transforming them into a lumped-parameter model capable of participating in unified discrete solutions. This allows the dynamic mass conservation equations of natural gas nodes to be incorporated into the same Newton's method solution framework as the algebraic equations of the power network and the ordinary differential equations of conductor thermal balance. Subsequently, within each time step, based on decoupling conditions, the off-diagonal coupled sub-blocks in the Jacobian matrix that meet the requirements are simplified to zero, and the diagonal sub-blocks are constantized. These processes reduce the number of matrix updates and the burden of equation solving. For larger systems, this approach mitigates the impact of numerical rigidity caused by differences in the time constants of various physical systems on computation time, resulting in lower total simulation time, lower average matrix construction time per step, and lower average equation solving time per step, as shown in Table 6. In summary, the results shown in Tables 5 and 6 demonstrate that, compared to the fully coupled Newton's method, the constant-coefficient fast power flow method proposed in this invention can reduce the total simulation time, average matrix construction time per step, and average equation solution time per step in unified power flow calculations for electro-gas coupled systems of different scales. Furthermore, the total computation time saved by this method increases further as the system scale expands. These results indicate that by spatially integrating the dynamic model of the natural gas network and constructing a lumped parameter model, combined with decoupling conditions and constant-coefficient diagonal sub-block processing, it can be used for dynamic power flow calculations of electro-gas coupled systems of different scales.

[0119] Figure 6 This is a dynamic distribution diagram of natural gas network node pressure provided in Embodiment 2 of the present invention. The horizontal axis represents the simulation time in hours, and the vertical axis represents the absolute pressure of the node in megapascals. Different curves represent the pressure change process of different natural gas nodes. This shows that the pressure of natural gas network nodes changes dynamically with the pressurization of electric compressors, gas consumption of gas turbines, and release of pipeline storage. It also verifies that the unified power flow calculation model can describe the time-series response of the pressure state of the natural gas network. Figure 7 The key pipeline mass flow rate variation curve provided in Embodiment 2 of the present invention shows that the mass flow rate of the natural gas network pipeline changes with the gas consumption demand of the gas turbine and the pipeline storage release process, and can reflect the local pipeline gas flow reversal phenomenon, thereby verifying the ability of the unified power flow calculation model to characterize the dynamic flow distribution of the natural gas network. Example 3: A constant-coefficient fast power flow calculation system for an electro-electric coupling system that takes into account the thermal characteristics of transmission components, comprising: The model building module constructs a unified power flow calculation model consisting of the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor, and integrates the cross-system coupled correlation equation consisting of the fuel consumption of the gas turbine and the power consumption of the electric compressor. The discretization module is used to spatially integrate the pipeline momentum balance partial differential equation in the dynamic mass conservation equation of the natural gas node along the pipeline axis, transforming it into a lumped parameter ordinary differential equation describing the change in pipeline mass flow rate. A second-order implicit trapezoidal method is used to discretize the dynamic mass conservation equation of the natural gas node, the lumped parameter ordinary differential equation, and the dynamic thermal balance equation of the overhead conductor, constructing a set of algebraic equations containing known quantities of the operating state at the previous simulation time. The global constant coefficient Jacobian matrix construction module is used to extract the operating state variables and physical parameters of the current electro-gas coupling system at each time step. Using the analytical expression of the off-diagonal partial derivatives of the Jacobian matrix between the power network, natural gas network, and overhead conductor thermal characteristic models, the module calculates the values ​​of elements in each cross-system coupling sub-block. Based on the connection relationship, operation control mode, and element values ​​of the gas turbine, electric compressor, and overhead conductor, the module determines the retained states of the electro-thermal, thermal-electric, electro-gas, and gas-electric coupling sub-blocks in the global Jacobian matrix, constructing a global constant coefficient Jacobian matrix with an asymmetric structure. The update module uses a global constant coefficient Jacobian matrix for iterative solution to update the power flow distribution of the entire system.

[0120] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for calculating fast power flow with constant coefficients in an electro-electric coupling system considering the thermal characteristics of transmission components, characterized in that, The steps are as follows: S1. Construct a unified power flow calculation model consisting of the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor, and integrate the cross-system coupled correlation equation consisting of the fuel consumption of the gas turbine and the power consumption of the electric compressor. S2: Spatially integrate the pipeline momentum balance partial differential equation in the natural gas node dynamic mass conservation equation along the pipeline axis to transform it into a lumped parameter ordinary differential equation describing the change in pipeline mass flow rate; use the second-order implicit trapezoidal method to discretize the natural gas node dynamic mass conservation equation, the lumped parameter ordinary differential equation, and the overhead conductor dynamic thermal balance equation in time, and construct a set of algebraic equations containing known quantities of the operating state at the previous simulation time; Natural gas node dynamic mass conservation equation S3: At each time step, extract the operating state variables and physical parameters of the current electro-gas coupling system, and use the analytical expression of the off-diagonal partial derivatives of the Jacobian matrix between the power network, the natural gas network, and the thermal characteristic model of the overhead conductor to calculate the values ​​of the elements in each cross-system coupling sub-block; S4: Based on the connection relationship of the gas turbine, electric compressor and overhead line, the operation control mode and the element values ​​calculated in step S3, determine the reserved state of the electric-thermal, thermal-electric, electric-gas and gas-electric coupling sub-blocks in the global Jacobian matrix and construct a global constant coefficient Jacobian matrix with an asymmetric structure. Based on the determination of retaining off-diagonal coupled sub-blocks according to the cross-system coupled sub-block elements calculated in step S3, the global Jacobian matrix is ​​subjected to constant coefficient processing. This constant coefficient processing includes zeroing off-diagonal coupled sub-blocks that satisfy the zero-structure determination condition, and parameter solidification processing of the diagonal sub-blocks corresponding to their own variables in the power network power balance equation, the natural gas node dynamic mass conservation equation, and the overhead conductor dynamic heat balance equation. Specifically, the pipeline equivalent adjoint admittance coefficient in the equivalent algebraic equation of step S2... These are discretization coefficients belonging to the natural gas network pipeline equations themselves, used to construct relevant diagonal sub-blocks of the natural gas network, and are not cross-system coupling sub-block elements as described in step S3; Nominal pipeline mass flow rate extracted based on initial steady-state power flow solution. Average pressure of nominal pipeline The equivalent admittance coefficient of the pipeline in step S2 is... Curing to a constant coefficient: ； In the formula, The equivalent admittance coefficient of the pipeline obtained by solidification at the nominal operating point, where A is the cross-sectional area of ​​the pipeline. To ensure a uniform simulation step size, L represents the pipe length, f represents the pipe friction coefficient, a represents the sound velocity of the gas inside the pipe, and D represents the pipe inner diameter. The nominal pipeline mass flow rate, The nominal average pipeline pressure; The global Jacobian matrix contains cross-system coupling sub-blocks reflecting the thermal characteristic models of the power system, natural gas system, and overhead conductors, specifically: via electrothermal coupling sub-block and Describe the impact of the resistance-temperature effect on the admittance parameters of the power network; through thermoelectric coupling sub-blocks. and Describe the effect of Joule heating generated by the current on the calculation of the unbalance in the conductor temperature; through the electrical coupling sub-block. and This describes the impact of changes in natural gas pressure and flow rate on the power consumption fluctuations of the electric compressor, and consequently on the active power imbalance in the power system; this is illustrated through a gas-electric coupling sub-block. Describe the impact of generator output adjustment on the pressure distribution of gas grid nodes via gas turbine fuel consumption; The specific process of decoupling determination is as follows: For the electro-thermal coupled sub-block, when the temperature change of the corresponding transmission line does not affect the power network admittance parameter, let , When the temperature change of the corresponding transmission line affects the power network admittance parameter through the resistance-temperature effect, the calculation is based on the line resistance-temperature relationship. , And retain; For the thermo-electric coupling sub-block, when the voltage state of the corresponding power node does not affect the transmission line current, let , When the voltage state of the corresponding power node affects the Joule heating of the conductor through the line current, the dynamic heat balance equation of the overhead conductor discretized by the second-order implicit trapezoidal rule is used to calculate... , And retain; For the electro-pneumatic coupling sub-block, when the corresponding power node is not connected to the electric drive compressor, or when the electric drive compressor is running at a given active power during the current time period, let , When the power consumption of the electric compressor changes with the compressor inlet pressure, outlet pressure, or mass flow rate, it is calculated according to the power consumption equation of the electric compressor. , And retain; For the gas-electric coupling sub-block, when the corresponding natural gas node is not connected to the gas turbine, or the gas turbine has active power output... When the variable is not adjusted according to the current power flow iteration, let When the gas turbine acts as a balancing unit or participates in active power regulation, it is based on the incremental rate of fuel consumption. With the active power-phase angle sensitivity of the power system calculate And retain; Therefore, the cross-system coupling sub-block elements calculated in step S3 specifically correspond to the elements in the global Jacobian matrix. , , , , , as well as When constructing the global constant coefficient Jacobian matrix, the off-diagonal coupled sub-block elements that satisfy the above zero structure condition are simplified to zero values, while the off-diagonal coupled sub-block elements that have an effect on the current power flow iteration are retained. S5: Iteratively solve using the global constant coefficient Jacobian matrix to update the power flow distribution of the entire system.

2. The method for calculating the constant-coefficient fast power flow of an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 1, characterized in that, In step S1, the mathematical modeling process for gas turbine fuel consumption is as follows: Construct a system to describe the fuel consumption L of a gas turbine. D，j Its power generation P G，j The quadratic polynomial equation relating the functions between them: ； Among them, a g b g c g To characterize the fuel consumption characteristics of a gas turbine, an analytical expression for the incremental rate of fuel consumption is extracted based on the above equation: ； And use it as the basic physical parameter for calculating the cross-system interaction sensitivity index between the gas grid and the power grid; The mathematical modeling process for the power consumption of an electrically driven compressor is as follows: Construct a system to describe the active power P consumed by an electric compressor. L，comp,i Nonlinear equations: ； Among them, the power consumption coefficient B c The parsing expression is: ； Gas compressibility factor z at compressor outlet conditions c The parsing expression is: ； In the formula, The mass flow rate through the electrically driven compressor. and These are the absolute pressures at the compressor inlet and outlet, respectively. For the efficiency of the drive motor, For variable efficiency, Z is the adiabatic index of the gas. a Z is the gas compressibility factor under inlet operating conditions. c T is the gas compressibility factor under outlet operating conditions. in，c T represents the inlet gas temperature. n The outlet gas temperature, This refers to the gas density under standard conditions. The gas turbine fuel consumption equation and the electric drive compressor power consumption equation are incorporated into the unified power flow calculation model as associated constraints of the electro-gas coupling equipment. The specific process of constructing the dynamic thermal balance equation for overhead conductors is as follows: For any overhead conductor in a power network, considering the asynchrony and thermal inertia between conductor current changes and conductor temperature changes, the following dynamic thermal balance equation is constructed: ； in, Mass per unit length of conductor The specific heat capacity of the wire, Let I be the real-time temperature of the conductor, and I be the amplitude of the current flowing through the conductor. The AC resistance varies with temperature, and its functional expression is as follows: ； In the formula, R0 is the DC resistance at the reference temperature T0. The temperature coefficient of resistance is given; the endothermic and dissipative terms respectively include the heat absorption power q from illumination. s Convection heat dissipation power q c and radiative heat dissipation power q r ; Describing the real-time temperature of the conductor using dynamic thermal balance equations The amplitude of the current flowing through the conductor The dynamic response process of changes in environmental meteorological conditions and conductor physical parameters is studied, and the maximum allowable temperature T of the conductor is introduced. max As a criterion for the thermal safety operation of transmission lines, when the real-time temperature of the conductor meets the requirements... At that time, it was determined that the transmission line was in a thermally safe operating state; The process of constructing the dynamic mass conservation equations for natural gas nodes is as follows: For any non-constant pressure node in the natural gas network Construct the dynamic mass conservation equation for natural gas nodes: ； Among them, natural gas nodes Net mass inflow Represented as: ； In the formula, For natural gas nodes At the current simulation moment Absolute pressure below; For natural gas nodes The equivalent storage coefficient; and Each is based on natural gas nodes A collection of pipes consisting of end nodes and beginning nodes; and Each is based on natural gas nodes This is the set of electrically driven compressor branches for the exit and inlet nodes; For natural gas pipelines At the current simulation moment The mass flow rate is below; For flow through the electric compressor mass flow rate; To connect to natural gas nodes The mass flow rate of the gas source injection; For natural gas nodes The conventional natural gas load mass flow rate; To connect to natural gas nodes Gas turbine fuel consumption mass flow rate; Since the compressor is driven by an electric motor, ignoring internal gas leakage and internal gas storage capacity, the electric compressor... The inlet mass flow rate is equal to the outlet mass flow rate, that is: ； Therefore, the mass flow rate of the electric compressor It is recorded as an outflow item in the net mass inflow at its inlet node and as an inflow item in the net mass inflow at its outlet node. When natural gas nodes When multiple gas turbines are connected, This represents the sum of the mass flow rates of fuel consumption from all gas turbines connected to this node; natural gas node. Equivalent storage coefficient Represented as: ； In the formula, For allocation to natural gas nodes The equivalent control volume, The velocity of sound of the gas inside the pipe.

3. The method for calculating the constant-coefficient fast power flow of an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 2, characterized in that, In step S2, the second-order implicit trapezoidal method is used to discretize the dynamic mass conservation equation and lumped parameter ordinary differential equation of the natural gas node in time, and transform the dynamic differential process of the natural gas network into a set of algebraic equations containing known state variables at the previous simulation time. The dynamic mass conservation equations for natural gas nodes are discretized over time using the second-order implicit trapezoidal method, yielding: ； The discrete equations are rearranged into natural gas nodes. Pressure calculation residuals: ； When the dynamic mass conservation relationship at the natural gas node is satisfied, we have: ； In the formula, For natural gas nodes At the current simulation moment Calculate the residual under the pressure; To unify the step size in simulation; For natural gas nodes In the previous simulation time Absolute pressure below; and These are the current simulation times. and the previous simulation time Next natural gas node Net mass inflow; and All of these are known quantities determined by the running state at the previous simulation moment; For any natural gas pipeline The second-order implicit trapezoidal rule is used to discretize the lumped parameter ordinary differential equation over time, transforming the dynamic differential process of pipeline mass flow rate into the following equivalent algebraic equation: ； In the formula, For natural gas pipelines At the current simulation moment The mass flow rate is below; The equivalent adjoint admittance coefficients of the pipeline, obtained by discretization using the second-order implicit trapezoidal method, are used to characterize natural gas pipelines. The impact of the absolute pressure difference between the first and last nodes on the current pipeline mass flow rate; and Natural gas pipelines The first and last nodes at the current simulation time Absolute pressure below; These are known historical terms determined by the pipe pressure and mass flow rate states at the previous simulation time. Known historical items The parsing expression is: ； Among them, natural gas pipelines In the previous simulation time Average pressure Represented as: ； In the formula, For natural gas pipelines In the previous simulation time The mass flow rate is below; For natural gas pipelines Length; For natural gas pipelines The cross-sectional area; For natural gas pipelines The coefficient of friction; For natural gas pipelines The inner diameter; The velocity of sound of the gas inside the pipe; and Natural gas pipelines The first and last nodes at the previous simulation time Absolute pressure below; The equivalent algebraic equation for the mass flow rate of a natural gas pipeline is rearranged to represent the natural gas pipeline. Mass flow rate calculation residuals: ； When the momentum balance relationship of the natural gas pipeline is satisfied, we have: ； In the formula, For natural gas pipelines At the current simulation moment The residuals for calculating the mass flow rate are as follows; For natural gas pipelines mass flow rate; For natural gas pipelines The equivalent adjoint admittance coefficient; and Natural gas pipelines The first and last nodes at the current simulation time Absolute pressure; This refers to known historical terms determined based on the pipe pressure and mass flow rate status at the previous simulation point; The pressure calculation residual vector of natural gas nodes is composed of the pressure calculation residuals of each non-constant pressure natural gas node: ； The mass flow rate calculation residual vector of natural gas pipelines is composed of the mass flow rate calculation residuals of each natural gas pipeline: ； In the formula, The number of non-constant pressure natural gas nodes participating in the pressure iteration calculation; The number of pipelines in the natural gas network; This represents the transpose of a vector.

4. The method for calculating the constant coefficient fast power flow of an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 3, characterized in that, In step S3, the operating state variables include the phase angle of the grid node voltage, the voltage amplitude of the PQ node, the absolute pressure of the natural gas node, the pipeline mass flow rate, and the conductor temperature of the overhead conductor. Physical parameters include transmission line resistance, reactance, temperature coefficient of resistance, fuel consumption characteristic coefficient of gas turbine, efficiency of electric compressor, gas velocity, pipe length, pipe inner diameter, pipe cross-sectional area, and coefficient of friction.

5. The method for calculating the constant-coefficient fast power flow of an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 4, characterized in that, In step S4, a global Jacobian matrix is ​​established. The non-diagonal coupled sub-block retention determination method determines the global Jacobian matrix at each time step of the power flow calculation based on the connection relationships of the gas turbine, electric compressor, and overhead conductors in step S1, as well as the corresponding equipment's operating control mode in the current time period. The retention state of the electric-thermal, thermal-electric, electric-gas, and gas-electric coupling sub-blocks is set to zero for off-diagonal coupling sub-block elements that have no physical association or do not participate in iterative coupling under the current operating mode. For off-diagonal coupling sub-block elements that need to be retained, the value is determined according to the analytical expression of the partial derivative. First, a global Jacobian matrix is ​​constructed, incorporating the partial derivative relationships between the power balance equation of the power grid, the dynamic mass conservation equation of natural gas nodes, and the dynamic heat balance equation of overhead conductors. The global Jacobian matrix is ​​presented as follows: The block structure, its complete representation matrix is: ； In the formula, This is the global Jacobian matrix; The voltage phase angle vector of the power network nodes; For power grid Node voltage magnitude vector; This represents the temperature vector of the overhead conductor. This represents the absolute pressure vector of the natural gas node. This represents the mass flow rate vector of the natural gas pipeline. This refers to the active power imbalance in the power grid. This refers to the reactive power imbalance in the power network. This represents the unbalance quantity corresponding to the dynamic thermal balance equation of overhead conductors. This represents the unbalance quantity corresponding to the natural gas node pressure equation; The unbalance quantity corresponds to the mass flow rate equation of the natural gas pipeline; each element in the matrix represents the partial derivative of the corresponding unbalance quantity with respect to the corresponding state variable. Define the full-dimensional state vector as Define the unbalance vector for the entire system as follows: ; In the formula, To unify the full-dimensional state variable vector of the power flow calculation model, Let T be the vector of unbalanced quantities in the entire system, which is composed of the power balance equation of the power network, the dynamic heat balance equation of the overhead conductor, and the dynamic mass conservation equation of the natural gas node. T represents the vector transpose.

6. The method for calculating the constant coefficient fast power flow of an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 5, characterized in that, In step S4, at each time step, the off-diagonal partial derivatives of the natural gas node pressure imbalance with respect to the power system node voltage phase angle are calculated according to the following formula: ； In the formula, For natural gas nodes The off-diagonal partial derivatives of pressure imbalance with respect to the phase angle of power system node voltages; For natural gas nodes Pressure imbalance; The phase angle of the voltage at the power system node; To unify the step size in simulation; To include natural gas nodes; Gas turbine fuel consumption; For the active power output of the gas turbine; This represents the rate of increase in gas turbine fuel consumption relative to active power output. These are the active-phase angle sensitivity elements in the power balance equation of the power network; For natural gas nodes The equivalent storage coefficient, its analytical expression is: ； In the formula, For natural gas nodes The associated equivalent geometric volume of the pipeline, The velocity of sound of the gas inside the pipe; During the power flow iteration process, based on the off-diagonal coupled sub-block retention determination method in step S4, the global Jacobian matrix is... The electric-thermal, thermal-electric, electric-gas, and gas-electric coupling sub-blocks are classified and processed. For the gas-electric coupling sub-block, when the corresponding natural gas node is not connected to the gas turbine, or the gas turbine has active power output... When the variable is not adjusted according to the current power flow iteration, let When the gas turbine is used as a balancing unit or participates in active power regulation, the fuel consumption increment rate is used as a reference. With active phase angle sensitivity Calculate and retain ; Therefore, in constructing the global constant coefficient Jacobian matrix At that time, the effective off-diagonal partial derivatives in the gas-electric coupling sub-block are retained in one direction.

7. The method for calculating the constant coefficient fast power flow of an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 6, characterized in that, In step S5, during the power flow iteration process, the unbalance vector F of the entire system and the global Jacobian matrix are calculated based on the current iteration point, and the linear correction equations are solved: ； Update the state variable correction value based on the obtained state correction value: ； In the formula, k is the current power flow iteration number, X k Let ΔX be the state variable vector for the k-th iteration. k Let X be the state variable correction amount obtained in the k-th iteration. k+1 The updated state variable vector; the global constant coefficient Jacobian matrix remains unchanged during the power flow iteration at the same time step, and its matrix decomposition result is reused.

8. A constant-coefficient fast power flow calculation system for an electro-electric coupling system considering the thermal characteristics of transmission components, applied to the constant-coefficient fast power flow calculation method for an electro-electric coupling system considering the thermal characteristics of transmission components as described in claim 1, characterized in that, include: The model building module constructs a unified power flow calculation model consisting of the power balance equation of the power network, the dynamic mass conservation equation of the natural gas node, and the dynamic heat balance equation of the overhead conductor, and integrates the cross-system coupled correlation equation consisting of the fuel consumption of the gas turbine and the power consumption of the electric compressor. The discretization module is used to spatially integrate the pipeline momentum balance partial differential equation in the dynamic mass conservation equation of the natural gas node along the pipeline axis, transforming it into a lumped parameter ordinary differential equation describing the change in pipeline mass flow rate. The second-order implicit trapezoidal method is used to discretize the dynamic mass conservation equation of the natural gas node, the lumped parameter ordinary differential equation, and the dynamic thermal balance equation of the overhead conductor in time, constructing a set of algebraic equations containing known quantities of the operating state at the previous simulation time. The global constant coefficient Jacobian matrix construction module is used to extract the operating state variables and physical parameters of the current electro-gas coupling system at each time step. It uses the analytical expression of the off-diagonal partial derivatives of the Jacobian matrix between the power network, natural gas network and overhead conductor thermal characteristic models to calculate the values ​​of elements in each cross-system coupling sub-block. Based on the connection relationship, operation control mode and element values ​​of the gas turbine, electric compressor and overhead conductor, it determines the reserved state of the electro-thermal, thermal-electric, electro-gas and gas-electric coupling sub-blocks in the global Jacobian matrix and constructs a global constant coefficient Jacobian matrix with an asymmetric structure. The update module uses a global constant coefficient Jacobian matrix for iterative solution to update the power flow distribution of the entire system.

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