Simulation modeling and online measurement fusion-based enclosed busbar state early warning method

Abstract

The invention discloses an enclosed busbar state early warning method based on simulation modeling and on-line measurement fusion. The method comprises the following steps: performing mesh generation according to a specified rule for a geometric model of an enclosed busbar of each unit; the subdivided model is segmented to obtain a plurality of sub-segments, and each sub-segment comprises a connection part composed of a generator circuit breaker in one or more isolated-phase enclosed buses; carrying out physical field modeling on each segment, optimizing a model obtained by modeling, coupling at least one physical field model during modeling, and optimizing the coupled physical field model based on actually measured data to obtain a simulation model of the enclosed bus; obtaining a to-be-predicted measurement parameter, and simulating the to-be-predicted measurement parameter through the simulation model to obtain a simulation result; and determining the state of the enclosed bus through the simulation result. Simulation prediction can be objectively carried out on the enclosed bus through multi-physics field coupling so that early warning can be timely carried out on the operation state of the enclosed bus.

Description

Technical Field

[0001] The present invention relates to the field of information processing technology, and in particular to a closed busbar state early warning method based on simulation modeling and online measurement fusion. Background Art

[0002] The development of the power industry has placed higher demands on the safe and stable operation of power equipment. This is especially true in hydropower stations, where long-distance enclosed busbars, crucial transmission lines connecting generators and transformers, have a direct impact on the safety of the entire power station and even the power grid.

[0003] This embodiment targets vertical, long-distance enclosed busbars, which are routed from the generator mezzanine in an underground powerhouse (over a hundred meters in elevation) through busbar tunnels, busbar shafts, and busbar corridors (over a hundred meters in elevation) to the surface substation and connected to the main transformer. The vertical height difference of the enclosed busbars can reach hundreds of meters, with the height difference between different units typically exceeding hundreds of meters. There are no engineering applications for high-current enclosed busbars with such a high vertical arrangement exceeding 100 meters.

[0004] Once the enclosed busbar is operational, maintenance is minimal. The casing, conductors, and expansion joints require minimal maintenance, primarily replacing the insulators. For this purpose, access holes are provided on the casing where the insulators are mounted. To protect the insulation between the busbar and the casing, the operating status of the enclosed busbar, such as its temperature, must be monitored during both operational and shutdown periods.

[0005] In the related art, there is no solution for how to provide status warning for vertical long-distance closed busbars. Summary of the Invention

[0006] The main purpose of the present invention is to provide a closed busbar status early warning method based on simulation modeling and online measurement fusion to solve the deficiencies existing in the related art.

[0007] In order to achieve the above-mentioned purpose, according to a first aspect of the present invention, a closed busbar status early warning method based on the fusion of simulation modeling and online measurement is provided, comprising meshing the geometric model of the closed busbar of each unit according to specified rules; segmenting the segmented model to obtain multiple sub-segments, wherein the sub-segments include one or more connecting parts composed of generator circuit breakers in the isolated closed busbar; performing physical field modeling on each segment and optimizing the model obtained by modeling, wherein at least one physical field model is coupled during modeling, and the coupled physical field model is optimized based on measured data to obtain a simulation model of the closed busbar; obtaining measurement parameters to be predicted, simulating the measurement parameters to be predicted by the simulation model to obtain simulation results; and determining the status of the closed busbar by the simulation results.

[0008] Optionally, the physical field includes an electromagnetic field model, and the control equation of the electromagnetic field model is: Where A is the magnetic vector, μ is the magnetic permeability, σ is the electrical conductivity, and J ext (t) is the time-varying current density, and t is the time.

[0009] Optionally, the physical field model includes a temperature field model, which is established for the interior of the closed busbar housing. The temperature distribution of each segmented closed busbar is determined based on the temperature field model, and the control equation of the temperature field model is: Where ρ is the conductor material density of the closed busbar, c p is the specific heat capacity, k is the thermal conductivity, T is the temperature field, is the rate of change of temperature over time, used to represent transient characteristics; is the heat conduction term, which indicates the process of heat conduction through the material; Q joule is the Joule heat source, Q joule =σ|J(t)| 2 , J(t) is the current density, the change of the current density is determined based on the change of conductivity, and the change of conductivity is determined based on the change of temperature, Q external For external heat sources, including additional cooling or heating power.

[0010] Optionally, before meshing, air flow conditions are set for the geometric model of the closed busbar; when performing physical field modeling on each segment, the method includes: calculating the convection heat dissipation coefficient, wherein the convection heat dissipation coefficient is Nusselt number, k f Fluid thermal conductivity, D h is the conductor diameter of the closed busbar; the control equation of the temperature field model is determined based on the convection heat dissipation coefficient:

[0011] Optionally, the method further includes: establishing a temperature load at each segment connection for the temperature field model, so as to apply the temperature load to the interface between adjacent sub-segments: Determine the governing equations of the temperature field model based on the temperature load: Where k is the thermal conductivity of the interface material, A contact is the release area of ​​the contact material, L contact is the release length of the contact material, T in is the segment inlet temperature, T out The outlet temperature of the segment is used as the inlet temperature of the next adjacent segment.

[0012] Optionally, the physical field model includes a stress field model, determines the temperature distribution based on the temperature field model, and determines the temperature difference ΔT between the closed busbar and the environment at a specified distribution point based on the temperature distribution; determines the thermal stress based on the temperature difference; determines the total strain force based on the stress field model, and solves the displacement field u(x, y, z) based on the total strain force.

[0013] Optionally, the stress field model includes: σ total =σ mech +σ thermal And the governing equations as physical constraints, namely the dynamic equilibrium equations: Among them, σ mech is the mechanical stress, σ thermal is thermal stress, σ total is the total stress; σ mech =C:ε mech , C is the elastic stiffness tensor, ε mech is the mechanical strain; σ thermal =αEΔT·I, where α is the coefficient of thermal expansion, E is the elastic modulus, and ΔT is the temperature difference between the closed busbar and the environment at the specified distribution point; is the inertial force, is the damping force, f ext (t) is the external body force, which is the sum of the electromagnetic body force density and the vibration body force density. The electromagnetic body force density is the force f generated by the electromagnetic field. em =J(t)×B(t), where J(t) is the current density, B(t) is the magnetic field, the vibration volume force density is the force generated by external excitation, i.e., the fan vibration, and ρ is the material density of the closed busbar.

[0014] Optionally, optimizing the coupled physical field model based on the measured data to obtain a closed busbar simulation model includes: obtaining historical measured data, dividing the historical measured data of different working conditions into historical measured data to be simulated and verification data in chronological order, wherein the different working conditions include steady-state working conditions and startup working conditions; simulating the historical measured data to be simulated by the model obtained by simulation to obtain simulation data; optimizing the simulation model based on the verification data and the simulation data, wherein, based on the objective function Optimize, where T sim (t i ) is the temperature distribution of the simulation output at the i-th time step, T meas (t i ), is the measured temperature distribution at the i-th time step.

[0015] Optionally, determining the state of the closed busbar through the simulation result includes: determining whether the simulation result meets an early warning condition; and determining whether to issue an alarm for the closed busbar based on the judgment result.

[0016] According to a second aspect of the present invention, a closed busbar status early warning device based on the fusion of simulation modeling and online measurement is provided, comprising a preprocessing unit for performing meshing on the geometric model of the closed busbar of each unit according to specified rules; segmenting the segmented model to obtain a plurality of sub-segments, wherein the sub-segments include a connection portion composed of a generator circuit breaker in one or more phase-isolated closed buses; a modeling unit for performing physical field modeling on each segment, wherein at least one physical field model is coupled, and the coupled physical field model is optimized based on measured data to obtain a simulation model of the closed busbar; an early warning unit for obtaining measurement parameters to be predicted, simulating the measurement parameters to be predicted by the simulation model to obtain simulation results; and determining the status of the closed busbar by means of the simulation results.

[0017] This embodiment is based on a closed busbar status warning method that integrates simulation modeling and online measurement, including meshing the geometric model of each unit's closed busbar according to specified rules; segmenting the segmented model to obtain multiple sub-segments, wherein the sub-segments include one or more connecting parts of the isolated closed busbar composed of generator circuit breakers; performing physical field modeling on each segment and optimizing the model obtained by modeling, wherein at least one physical field model is coupled during modeling, and the coupled physical field model is optimized based on measured data to obtain a simulation model of the closed busbar; obtaining the measurement parameters to be predicted, simulating the measurement parameters to be predicted using the simulation model to obtain simulation results; and determining the status of the closed busbar using the simulation results. Through multi-physical field coupling, the closed busbar can be objectively simulated and predicted, and thus the operating status of the closed busbar can be timely warned. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a flow chart of a closed busbar status early warning method based on simulation modeling and online measurement fusion according to an embodiment of the present invention; Figure 2 Schematic diagram of the application of a closed busbar status early warning method based on the fusion of simulation modeling and online measurement according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a first alarm standard of a closed busbar status early warning method based on the fusion of simulation modeling and online measurement according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the second alarm standard of the closed busbar status early warning method based on the fusion of simulation modeling and online measurement in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0022] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] According to an embodiment of the present invention, a closed busbar status early warning method based on simulation modeling and online measurement fusion is provided. Figure 1 As shown, it includes the following steps 101 to 103: Step 101: Meshing the geometric model of the enclosed busbar of each unit according to a specified rule; segmenting the meshed model to obtain a plurality of sub-segments, wherein the sub-segments include a connection portion formed by a generator circuit breaker in one or more isolated phase enclosed busbars.

[0024] In this step, in order to obtain accurate busbar temperature distribution, an overall model of the closed busbar system is established. In the geometric model of the closed busbar, the conductor material is set to copper and the shell material is set to aluminum. The overall model is divided into a grid to obtain the number of nodes and units of the finite element model. Since the overall busbar model is large, it is difficult to perform simulation analysis directly on it, so the overall model is divided into sub-segments. For the finite element model of the isolated closed busbar, it is necessary to make a reasonable division according to the structure, such as the first, second, third, and fourth sections from left to right, and perform simulation analysis separately.

[0025] For example, full-scale modeling is performed on the closed busbar structure of n units, including: busbar holes and busbar shafts from the underground generator mezzanine to the ground busbar corridor. The finite element model includes key structures such as the casing, conductors and support components, expansion joints, and reasonable modeling is performed inside the pipeline. In the specific work, it is planned to first perform full-process analysis and calculation and model training on the busbar system of one unit, and then expand it to the busbars of other units after the accuracy and requirements are met. In order to ensure the calculation accuracy of the simulation analysis, the model uses high-quality meshes for detailed segmentation (i.e., non-automatic segmentation). The plate unit is segmented using four-node units, and the solid unit is segmented using hexahedral 8-node units. A more detailed mesh is performed on local key structures, such as support components and areas with high temperature and humidity. For example, since the middle section of the closed busbar is connected by a generator circuit breaker (GCB), its temperature rise has a greater impact on the overall thermal stability of the busbar. Therefore, a fine regular mesh is adopted for the connecting part in the middle, with reference to Figure 2 Schematic diagram of the sub-network of the connecting conductor part.

[0026] Step 102: Perform physical field modeling for each segment and optimize the model obtained by modeling, wherein at least one physical field model is coupled during modeling, and the coupled physical field model is optimized based on measured data to obtain a simulation model of the closed busbar.

[0027] In this step, multiple physical field models can be established, and simulation models can be obtained through coupled simulation. Multi-physical field models include but are not limited to temperature fields, stress fields, electromagnetic fields, etc.

[0028] Step 103: obtaining the measurement parameters to be predicted, simulating the measurement parameters to be predicted using a simulation model to obtain simulation results; and determining the state of the closed busbar using the simulation results.

[0029] In this step, simulation prediction is performed through the simulation model, and the predicted value is compared with the set threshold value, so as to timely issue an early warning of the status of the closed busbar.

[0030] As an optional implementation of this embodiment, the physical field includes an electromagnetic field model, and the control equation of the electromagnetic field model is: Where A is the magnetic vector, μ is the magnetic permeability, σ is the electrical conductivity, and J ext (t) is the time-varying current density, and t is the time.

[0031] In this optional implementation, an electromagnetic field is established for the closed busbar, and the interaction between the electric field and the magnetic field is described based on a preset set of equations. Specifically, in the dynamic simulation, the change of current over time will affect the electromagnetic field, thereby generating Joule heat, which in turn affects the temperature field. Based on this, by establishing a specific set of equations to describe the distribution and evolution of the electromagnetic field (electric field E, magnetic field B, current density J), the time derivative term is introduced in a dynamic form. The magnetic vector is A, and the vector function describing the magnetic field distribution satisfies Magnetic permeability indicates the material's ability to conduct magnetism; electrical conductivity indicates the material's ability to conduct electricity, which changes with temperature. t is a time variable. When a short circuit fault occurs, the current density is the time-varying current density driven by the short circuit fault.

[0032] As an optional implementation of this embodiment, the physical field model includes a temperature field model. The temperature field model is established for the interior of the closed busbar housing. The temperature distribution of each segmented closed busbar is determined based on the temperature field model. The control equation of the temperature field model is: Where ρ is the conductor material density of the closed busbar, c p is the specific heat capacity, k is the thermal conductivity, T is the temperature field, is the rate of change of temperature over time, used to represent transient characteristics; is the heat conduction term, which indicates the process of heat conduction through the material; Q joule is the Joule heat source, Q joule =σ|J(t)| 2 , J(t) is the current density, the change of the current density is determined based on the change of conductivity, and the change of conductivity is determined based on the change of temperature, Q external For external heat sources, including additional cooling or heating power.

[0033] In this optional implementation, the transient heat conduction equation is used to describe how temperature changes over time and space, and the temperature distribution is affected by setting different parameters. T represents a function of space and time, represented by T(x, y, z, t).

[0034] This optional implementation can be used for electromagnetic-temperature coupling. Current density affects Joule heating, which affects temperature field distribution. Temperature changes affect conductivity, which affects current density.

[0035] As an optional implementation of this embodiment, before meshing, a co-directional air flow condition is set for the geometric model of the closed busbar; when performing physical field modeling on each segment, the method includes: calculating the convection heat dissipation coefficient, wherein the convection heat dissipation coefficient is Nusselt number, k f Fluid thermal conductivity, D h is the conductor diameter of the closed busbar; the control equation of the temperature field model is determined based on the convection heat dissipation coefficient:

[0036] In this optional implementation, to ensure the safe operation of the enclosed busbar, appropriate ventilation and cooling measures are implemented, taking into account the overall air conditioning and ventilation needs of the underground powerhouse, and in conjunction with the ventilation and cooling requirements during busbar operation. Specifically, an exhaust fan is installed at the exit of each busbar tunnel, located at an elevation of 100 meters above sea level, to exhaust air entering the tunnel from the powerhouse. An air cooler is installed in the lower horizontal section of each underground busbar tunnel to circulate air within the tunnel, reducing its temperature and humidity. Air coolers are also installed in the upper horizontal section of the busbar corridor. By implementing effective measures such as forced ventilation, the temperature of the busbar and outer casing will be further reduced. The designed equipment configuration meets the busbar's heat dissipation requirements while leaving some margin. During operation, the number of air coolers activated and the circulating air volume can be automatically controlled based on the measured temperature, achieving the goal of both meeting operational requirements and conserving energy.

[0037] Therefore, when performing simulation, it is necessary to set the same direction of air flow in the model. The flow rate of the fluid affects the convection heat transfer coefficient, thereby changing the heat dissipation conditions. The boundary condition of the temperature field can be set as the convection heat dissipation function. h(t) is the convection heat transfer coefficient, which changes with time. The temperature distribution can be determined based on the convection heat dissipation coefficient. Tenv is the ambient temperature. The h value provided by the flow field is used to calculate the temperature distribution, and then the heat dissipation of the fluid is taken into account. After the temperature reaches the desired value, the flow rate of the fan is adjusted by a micro-positive pressure control system in practice to further ensure the appropriate temperature. In other words, the temperature field and the flow field are coupled with each other. The fluid flow affects the temperature distribution through convection heat dissipation. Temperature changes cause fluid changes. Specifically, the flow field calculates the fan airflow distribution and determines the convection heat dissipation coefficient, and the temperature field calculates Joule heat and heat dissipation to determine the temperature distribution.

[0038] As an optional implementation of this embodiment, the method further includes: establishing a temperature load at the connection between each segment according to the temperature field model, so as to apply the temperature load to the interface between adjacent sub-segments: Determine the governing equations of the temperature field model based on the temperature load: Where k is the thermal conductivity of the interface material, A contact is the release area of ​​the contact material, Lcontact is the release length of the contact material, T in is the segment inlet temperature, T out The outlet temperature of the segment is used as the inlet temperature of the next adjacent segment.

[0039] In this optional implementation, temperature loads refer to temperature boundary conditions applied to interfaces to describe thermal interactions between adjacent subsegments. In other words, temperature loads at the interfaces between adjacent subsegments are used to describe the heat transfer method (fixed temperature, convection, or conjugate heat transfer) between different subsegments, influenced by different temperature boundary conditions. The inlet temperature defines the starting point of the subsegment thermal analysis and affects the overall temperature rise; the outlet temperature reflects the heat accumulation effect of the subsegment and drives the boundary conditions of adjacent subsegments.

[0040] As an optional implementation method of this embodiment, the physical field model includes a stress field model, determines the temperature distribution based on the temperature field model, and determines the temperature difference ΔT between the closed busbar and the environment at a specified distribution point based on the temperature distribution; determines the thermal stress based on the temperature difference; determines the total strain force based on the stress field model, and solves the displacement field u(x, y, z) based on the total strain force.

[0041] The physical field model includes a stress field model, which determines the temperature distribution based on the temperature field model, and determines the temperature difference ΔT between the closed busbar and the environment at a specified distribution point based on the temperature distribution; determines the thermal stress based on the temperature difference; determines the total strain force based on the stress field model, and solves the displacement field u(x, y, z) based on the total strain force.

[0042] As an optional implementation of this embodiment, the stress field model includes: σ total =σ mech +σ thermal And the governing equations as physical constraints, namely the dynamic equilibrium equations: Among them, σ mech is the mechanical stress, σ thermal is thermal stress, σ total is the total stress; σ mech =C:ε mech , C is the elastic stiffness tensor, ε mech is the mechanical strain; σ thermal =αEΔT·I, where α is the coefficient of thermal expansion, E is the elastic modulus, and ΔT is the temperature difference between the closed busbar and the environment at the specified distribution point; is the inertial force, is the damping force, f ext (t) is the external body force, which is the sum of the electromagnetic body force density and the vibration body force density. The electromagnetic body force density is the force f generated by the electromagnetic field. em=J(t)×B(t), where J(t) is the current density, B(t) is the magnetic field, the vibration volume force density is the force generated by external excitation, i.e., the fan vibration, and ρ is the material density of the closed busbar.

[0043] In this optional implementation, the stress field establishes a balance between force and deformation. It is composed of the superposition of mechanical stress and thermal stress. The thermal stress can be calculated through the temperature field, and the inertia force term is introduced for dynamic analysis. The control equation of the stress field describes the balance between internal force (stress) and external force (such as body force, surface force). The control equation associates the stress field with the displacement field through the following steps. First, the stress and strain are associated with the relationship σ=C:ε, Substituting the stress expression into the equilibrium equation yields a partial differential equation with the displacement field u as the unknown. This step transforms the physical problem into a mathematical equation, providing the basis for solving u. The transient response of a sudden fault is captured through inertial, damping, and transient terms. The total stress comprises mechanical and thermal stresses, and the electromagnetic force and thermal stress act together to cause structural deformation. The temperature field influences thermal strain, which in turn affects thermal stress, ultimately altering the displacement field. Furthermore, the electromagnetic force affects the displacement field, causing geometric deformation of the closed busbar and ultimately a change in current density.

[0044] Furthermore, the governing equations need to be combined with boundary conditions to uniquely solve the displacement field: displacement boundary conditions such as fixed constraints, force boundary conditions: surface forces or pressure loads, and the governing equations ensure that these conditions are strictly satisfied during the solution process.

[0045] When solving coupled physics, the electromagnetic fields J(t) and B(t) at time t are calculated; Joule heating is calculated, solving for the temperature field T(t); thermal stresses and electromagnetic forces are calculated; the dynamic equations are solved, the displacement field is updated, the geometry is updated, and the next time step is entered. The displacement field affects the geometric deformation, which in turn updates the electromagnetic field.

[0046] The above coupling logic yields the following: electromagnetic field → Joule heating → temperature field → flow field (the flow field also affects the temperature field) → stress → displacement field → geometric deformation → electromagnetic field update. By coupling multiphysics models, a closed busbar model consistent with reality can be obtained.

[0047] As an optional implementation method of this embodiment, the coupled physical field model is optimized based on the measured data to obtain a simulation model for the closed bus, including: obtaining historical measured data, dividing the historical measured data of different working conditions into historical measured data to be simulated and verification data in chronological order, wherein different working conditions include steady-state working conditions, startup working conditions, etc.; simulating the historical measured data to be simulated through the model obtained by simulation to obtain simulation data; based on the verification data and the simulation.

[0048] In this optional implementation, simulation can predict the temperature field of the closed busbar, enabling timely warning of anomalies. By performing temperature simulation based on the simulation model, the temperature of any point on the closed busbar under any operating condition can be obtained through simulation, allowing alarms and warnings to be issued at any point.

[0049] As an example, the simulation model described above can support simulations under any operating condition. Based on measured data from any operating condition, the multiphysics model's parameters can be effectively calibrated, significantly improving prediction accuracy and enabling integration into a real-time early warning system. The calibrated model accurately predicts temperatures with an error of <2% and provides early warnings up to 10 seconds before overheating or overload. Robustness is ensured by quantifying confidence intervals through uncertainty analysis to avoid false positives and negatives.

[0050] In the calibration model, the objective function is used to quantify the difference between simulated and measured data and guide parameter optimization. The objective function defines the temperature variable, the core variable in the error calculation. It also optimizes algorithm parameters such as the damping factor and convergence tolerance, which control the convergence and efficiency of the iterative process.

[0051] As an optional implementation of this embodiment, determining the state of the closed busbar through the simulation result includes: determining whether the simulation result meets the warning condition; and determining whether to issue an alarm for the closed busbar based on the judgment result.

[0052] In this optional implementation, warning conditions are set through visual configuration. These warning conditions can include alarm values ​​and warning thresholds for different points under different operating conditions. Specifically, alarm values ​​can be set for different operating conditions, and warning information can be determined based on alarm standard information. For example, the warning threshold can be determined based on the alarm value, and a specified ratio of the alarm value can be used as the warning threshold. When setting the alarm value, it can be formulated based on preset standards.

[0053] For example, for the isolated phase enclosed busbar, the connection parts, fixed brackets and other parts prone to overheating of the isolated phase enclosed busbar should be monitored, such as Figure 3 , when operating under steady-state conditions, that is, under normal operating conditions, the allowable temperature and temperature rise values ​​of various parts of the naturally cooled isolated phase closed busbar, including the maximum allowable temperature and maximum allowable temperature rise of the conductor, the contact surface of the bolted conductor or shell, the shell, the shell support structure, the insulating parts, etc.; the maximum allowable temperature and maximum allowable temperature rise of the contact surface of the bolted conductor or shell, the alarm value and warning threshold can be determined based on the maximum allowable temperature and maximum allowable temperature rise. For example, refer to Figure 4 The allowable temperature of insulation materials of different heat-resistant grades is determined based on the allowable temperature. The alarm value and warning threshold value at different points are determined based on this allowable temperature. Forced cooling of isolated phase enclosed busbars should meet the allowable temperature and temperature rise of each part of the busbar provided by the manufacturer.

[0054] After configuring the warning rules, when simulating based on the real-time data of the closed busbar, the simulation prediction results can be judged based on the set threshold conditions. If the warning threshold is reached, a warning warning will be issued; if the alarm value is reached, an alarm will be issued.

[0055] In this embodiment, the various physical fields interact with each other through their respective control equations to form a coupled model that can objectively simulate the operating status of the closed busbar. Furthermore, users can configure warning rules on demand through visualization, enabling warnings for the closed busbar under different operating conditions.

[0056] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0057] According to an embodiment of the present invention, a closed busbar status early warning device based on the fusion of simulation modeling and online measurement is also provided, including a preprocessing unit, which is used to mesh the geometric model of the closed busbar of each unit according to specified rules; segment the segmented model to obtain multiple sub-segments, wherein the sub-segments include one or more connecting parts composed of generator circuit breakers in the isolated phase closed busbar; a modeling unit, which is used to perform physical field modeling on each segment, wherein at least one physical field model is coupled, and the coupled physical field model is optimized based on measured data to obtain a simulation model of the closed busbar; an early warning unit, which is used to obtain the measurement parameters to be predicted, simulate the measurement parameters to be predicted by the simulation model to obtain simulation results; and determine the status of the closed busbar by the simulation results.

[0058] Although the embodiments of the present disclosure have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A closed busbar status early warning method based on simulation modeling and online measurement fusion, characterized in that: include: Meshing the geometric model of the enclosed busbar of each unit according to a specified rule; segmenting the meshed model to obtain a plurality of sub-segments, wherein the sub-segments include a connection portion formed by a generator circuit breaker in one or more isolated phase enclosed busbars; Performing physical field modeling for each segment and optimizing the model obtained by modeling, wherein at least one physical field model is coupled during modeling, and the coupled physical field model is simulated and optimized based on measured data to obtain a simulation model for the closed busbar; Obtain the measurement parameters to be predicted, simulate the measurement parameters to be predicted using a simulation model to obtain simulation results; and determine the state of the closed busbar based on the simulation results.

2. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 1 is characterized in that: The physical field includes an electromagnetic field model, and the control equation of the electromagnetic field model is: Where A is the magnetic vector, μ is the magnetic permeability, σ is the electrical conductivity, and J ext (t) is the time-varying current density, and t is the time.

3. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 1 is characterized in that: The physical field model includes a temperature field model, which is established for the interior of the closed busbar housing. The temperature distribution of each segmented closed busbar is determined based on the temperature field model. The control equation of the temperature field model is: Where ρ is the conductor material density of the closed busbar, c p is the specific heat capacity, k is the thermal conductivity, T is the temperature field, is the rate of change of temperature over time, used to represent transient characteristics; is the heat conduction term, which indicates the process of heat conduction through the material; Q joule is the Joule heat source, Q joule =σ|J(t)| 2 , J(t) is the current density, the change of the current density is determined based on the change of conductivity, and the change of conductivity is determined based on the change of temperature, Q external For external heat sources, including additional cooling or heating power.

4. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 3 is characterized in that Before meshing, the air flow conditions are set for the closed busbar geometry model; the methods for physical field modeling of each segment include: Calculate the convection heat dissipation coefficient, where the convection heat dissipation coefficient is Nusselt number, k f Fluid thermal conductivity, D h is the conductor diameter of the closed busbar; The control equation of the temperature field model is determined based on the convection heat dissipation coefficient:

5. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 4 is characterized in that: The method also includes: For the temperature field model, establish the temperature load at each segment connection to apply the temperature load at the interface between adjacent sub-segments: Determine the governing equations of the temperature field model based on the temperature load: Where k is the thermal conductivity of the interface material, A contact is the release area of ​​the contact material, L contact is the release length of the contact material, T in is the segment inlet temperature, T out The outlet temperature of the segment is used as the inlet temperature of the next adjacent segment.

6. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 4 is characterized in that The physical field model includes a stress field model, which determines the temperature distribution based on the temperature field model, and determines the temperature difference ΔT between the closed busbar and the environment at a specified distribution point based on the temperature distribution; determines the thermal stress based on the temperature difference; determines the total strain force based on the stress field model, and solves the displacement field u(x, y, z) based on the total strain force.

7. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 6 is characterized in that , the stress field model includes: σ total =σ mech +σ thermal And the governing equations as physical constraints, namely the dynamic equilibrium equations: Among them, σ mech is the mechanical stress, σ thermal is thermal stress, σ total is the total stress; σ mech =C:ε mech , C is the elastic stiffness tensor, ε mech is the mechanical strain; σ thermal =αEΔT·I, where α is the coefficient of thermal expansion, E is the elastic modulus, and ΔT is the temperature difference between the closed busbar and the environment at the specified distribution point; is the inertial force, is the damping force, f ext (t) is the external body force, which is the sum of the electromagnetic body force density and the vibration body force density. The electromagnetic body force density is the force f generated by the electromagnetic field. em =J(t)×B(t), where J(t) is the current density, B(t) is the magnetic field, the vibration volume force density is the force generated by external excitation, i.e., the fan vibration, and ρ is the material density of the closed busbar.

8. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 1 is characterized in that: The coupled physical field model is optimized based on the measured data, and the simulation model for the closed busbar is obtained, including: Obtain historical measured data under different working conditions, and divide the historical measured data into historical measured data to be simulated and verification data in chronological order. Different working conditions include steady-state working conditions and startup working conditions. The historical measured data to be simulated is simulated by the model obtained by simulation to obtain simulation data; the simulation model is optimized based on the verification data and the simulation data, wherein, based on the objective function Optimize, where T sim (t i ) is the temperature distribution of the simulation output at the i-th time step, T meas (t i ), is the measured temperature distribution at the i-th time step.

9. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 1 is characterized in that: Determining the state of the closed busbar through the simulation result includes: determining whether the simulation result meets the early warning condition; and determining whether to issue an alarm for the closed busbar based on the judgment result.

10. A closed busbar status early warning device based on simulation modeling and online measurement fusion, characterized in that: include: a pre-processing unit configured to mesh the geometric model of the enclosed busbar of each unit according to a specified rule; and segment the meshed model to obtain a plurality of sub-segments, wherein the sub-segments include a connection portion formed by a generator circuit breaker in one or more isolated phase enclosed buses; A modeling unit is used to perform physical field modeling for each segment, wherein at least one physical field model is coupled and the coupled physical field model is optimized based on measured data to obtain a simulation model of the closed busbar; The early warning unit is used to obtain the measurement parameters to be predicted, simulate the measurement parameters to be predicted using a simulation model to obtain simulation results; and determine the state of the closed busbar based on the simulation results.

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