Closed busbar state early warning method based on simulation modeling and online measurement fusion

Abstract

The application discloses a closed bus state early warning method based on simulation modeling and online measurement fusion, which comprises the following steps: meshing a geometric model of each unit closed bus according to a specified rule; segmenting the meshed model to obtain a plurality of subsegments, wherein the subsegment comprises one or more connection parts composed of a generator circuit breaker in a phase-separated closed bus; performing physical field modeling on each segment and optimizing the modeled model, 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 bus; obtaining a to-be-predicted measurement parameter, simulating the to-be-predicted measurement parameter through the simulation model to obtain a simulation result; and determining the state of the closed bus through the simulation result. The closed bus can be objectively simulated and predicted through multi-physical field coupling, and the running state of the closed bus can be timely warned.

Description

TECHNICAL FIELD

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

[0002] With the development of the power industry, higher requirements are put forward for the safe and stable operation of power equipment. Especially in hydropower stations, long-distance closed busbars, as important power transmission lines connecting generators and transformers, directly affect the safety of the entire power station and even the power grid.

[0003] The embodiment is aimed at vertical long-distance closed busbars, which are connected to the ground transformer through the busbar hole, busbar shaft and busbar corridor (elevation of hundreds of meters) from the generator interlayer (elevation of hundreds of meters) of the underground powerhouse. The vertical height difference of the closed busbar is up to hundreds of meters, and the vertical height difference of different units is basically hundreds of meters. There is no engineering application example of high vertical arrangement of high-current closed busbars with a height difference of more than 100 m.

[0004] Once the closed busbar is put into normal operation, the maintenance workload is less. The shell, conductor and expansion joint almost do not need maintenance, and the main consideration is to replace the insulator. Therefore, the place where the insulator is installed on the shell is provided with an access hole. In order to protect the insulation between the busbar and the shell, it is necessary to control the running state of the closed busbar during the operation and shutdown of the unit, such as temperature.

[0005] In the related art, there is no solution to the state early warning of vertical long-distance closed busbars. SUMMARY

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

[0007] In order to achieve the above purpose, according to the first aspect of the present application, a closed busbar state early warning method based on simulation modeling and online measurement fusion is provided, which comprises: meshing a geometric model of each unit closed busbar according to a specified rule; segmenting the meshed model to obtain a plurality of subsegments, wherein the subsegment includes one or more connection parts composed of a generator circuit breaker in the phase-separated closed busbar; performing physical field modeling on each segment and optimizing the modeled model, wherein at least one physical field model is coupled during modeling, and the coupled physical field model is optimized based on the measured data to obtain a simulation model of the closed busbar; obtaining a to-be-predicted measurement parameter, simulating the to-be-predicted measurement parameter through the simulation model to obtain a simulation result; and determining the state of the closed busbar through the simulation result.

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

[0009] Optionally, the physical field model includes a temperature field model, the temperature field model is established for inside of the enclosed busbar enclosure, wherein a temperature distribution of each segmented enclosed busbar is determined based on the temperature field model, a control equation of the temperature field model is:

[0010]

[0011] where p is a density of a conductor material of the enclosed busbar, c p is a specific heat capacity, k is a thermal conductivity, T is a temperature field, is a rate of change of temperature with time, used to represent a transient characteristic; is a heat conduction term, representing a process of heat conduction through a material; Q joule is a Joule heat source, Q joule = σ | J(t) | 2 , J(t) is a current density, a change of the current density is determined based on a change of the electrical conductivity, and the change of the electrical conductivity is determined based on a change of the temperature, Q external is an external heat source, including an additional cooling or heating power.

[0012] Optionally, before the mesh is divided, an air flow condition is set for the geometric model of the enclosed busbar; when the physical field is modeled for each segment, the method includes: calculating a convective heat dissipation coefficient, wherein the convective heat dissipation coefficient is Nu Nusselt number, k f thermal conductivity of the fluid, D h is a conductor diameter of the enclosed busbar; a control equation of the temperature field model is determined based on the convective heat dissipation coefficient:

[0013]

[0014] Optionally, the method further includes: establishing a temperature load at a connection of each segment for the temperature field model, to load a temperature load at an interface of adjacent sub-segments: a control equation of the temperature field model is determined based on the temperature load:

[0015] where k is a thermal conductivity of a contact material between interfaces, A contact is an area of the contact material, L contact is a length of the contact material, T in is an inlet temperature of the segment, T outFor the segmented outlet temperature, the outlet temperature of a segment is taken as the inlet temperature of the next adjacent segment.

[0016] Optionally, the physical field model comprises a stress field model, the temperature distribution is determined based on the temperature field model, and the temperature difference ΔT between the enclosed busbar and the environment at the specified distribution point is determined based on the temperature distribution; the thermal stress is determined based on the temperature difference; the total strain force is determined based on the stress field model, and the displacement field u(x, y, z) is solved based on the total strain force.

[0017] Optionally, the stress field model comprises: total = σ mech + σ thermal and a control equation as a physical constraint, i.e., a dynamic equilibrium equation: wherein σ mech is a mechanical stress, σ thermal is a thermal stress, and σ total is a total stress; σ mech = C: ε mech , C is an elastic stiffness tensor, and ε mech is a mechanical strain; σ thermal = αEΔT·I, α is a thermal expansion coefficient, E is an elastic modulus, and ΔT is the temperature difference between the enclosed busbar and the environment at the specified distribution point. is an inertial force, is a damping force, f ext (t) is an external volume force, which is the sum of an electromagnetic volume force density and a vibration volume force density, the electromagnetic volume force density is generated by the force f em = J(t) × B(t), J(t) is a current density, and B(t) is a magnetic field, the vibration volume force density is generated by the force generated by external excitation, i.e., fan vibration, and ρ is the material density of the enclosed busbar.

[0018] Optionally, the coupled physical field model is optimized based on measured data to obtain a simulation model of the enclosed busbar, comprising: obtaining historical measured data, and dividing different working condition historical measured data into to-be-simulated historical measured data and verification data according to time sequence, wherein different working conditions include steady-state working conditions and starting working conditions; simulating the model obtained by simulation of the to-be-simulated historical measured data to obtain simulation data; and optimizing the simulation model based on the verification data and the simulation data, wherein the optimization is performed based on a target function , wherein T sim (t i ) is the temperature distribution of the simulation output of the i th time step, and T meas (t i ) is the measured temperature distribution of the i th time step.

[0019] Optionally, determining the state of the closed bus via the simulation result comprises: determining whether the simulation result satisfies a pre-warning condition; and determining whether to issue a warning to the closed bus based on the determination result.

[0020] According to a second aspect of the present application, a closed bus state pre-warning device based on simulation modeling and online measurement fusion is provided, comprising a preprocessing unit configured to perform mesh partitioning on a geometric model of a closed bus of each generator set according to a specified rule; and configured to perform segmentation on the partitioned model to obtain a plurality of subsegments, wherein the subsegments include one or more connection sections composed of generator circuit breakers in the phase-separated closed bus; a modeling unit configured 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 bus; and a pre-warning unit configured to obtain a to-be-predicted measurement parameter, perform simulation on the to-be-predicted measurement parameter via the simulation model to obtain a simulation result, and determine the state of the closed bus via the simulation result.

[0021] The closed bus state pre-warning method based on simulation modeling and online measurement fusion comprises: performing mesh partitioning on a geometric model of a closed bus of each generator set according to a specified rule; performing segmentation on the partitioned model to obtain a plurality of subsegments, wherein the subsegments include one or more connection sections composed of generator circuit breakers in the phase-separated closed bus; performing physical field modeling on each segment and optimizing the modeled model, 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 bus; obtaining a to-be-predicted measurement parameter, performing simulation on the to-be-predicted measurement parameter via the simulation model to obtain a simulation result, and determining the state of the closed bus via the simulation result. The multi-physical field coupling can objectively simulate and predict the closed bus, and thus the operation state of the closed bus can be pre-warned in a timely manner. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0023] Figure 1 is a flow chart of the closed bus state pre-warning method based on simulation modeling and online measurement fusion of the embodiments of the present application;

[0024] Figure 2It is an application diagram of a closed busbar state early warning method based on simulation modeling and online measurement fusion according to an embodiment of the present application.

[0025] Figure 3 It is a first alarm standard diagram of a closed busbar state early warning method based on simulation modeling and online measurement fusion according to an embodiment of the present application.

[0026] Figure 4 It is a second alarm standard diagram of a closed busbar state early warning method based on simulation modeling and online measurement fusion according to an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the personnel in the art better understand the present application scheme, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0029] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0030] According to an embodiment of the present application, a closed busbar state early warning method based on simulation modeling and online measurement fusion is provided, as shown in Figure 1 The method comprises the following steps 101 to 103:

[0031] Step 101: The geometric model of each unit closed busbar is meshed according to the specified rules; the segmented model is segmented to obtain a plurality of subsegments, wherein the subsegment includes one or more connection parts composed of a generator circuit breaker in the phase-separated closed busbar.

[0032] In this step, to obtain an accurate temperature distribution along the busbar, a complete model of the enclosed busbar system is established. In the geometric model of the enclosed busbar, the conductor material is set to copper, and the outer shell material is set to aluminum. The complete model is then meshed, resulting in the finite element model's nodes and element count. Since the overall busbar model is large and difficult to directly simulate, it is divided into segments. For the finite element model of a phase-separated enclosed busbar, it is necessary to rationally divide it according to the structure, for example, from left to right, into segments one, two, three, and four, and then perform simulation analysis on each segment separately.

[0033] For example, a full-scale model of the enclosed busbar structure of n generating units is performed, including: the busbar tunnel from the underground generator mezzanine, the busbar shaft to the surface busbar corridor. The finite element model includes key structures such as the shell, conductors and supporting components, and expansion joints, and reasonable modeling is applied to the internal piping. In practice, the plan is to first perform a full-process analysis and calculation of the busbar system of one generating unit and train the model to achieve the required accuracy before expanding to other generating unit busbars. To ensure the accuracy of the simulation analysis, the model uses a high-quality mesh for detailed meshing (i.e., non-automatic meshing). Plate elements are meshed using four-node elements, and solid elements are meshed using hexahedral eight-node elements. More detailed meshing is applied to key local structures, such as supporting components and areas with high temperature and humidity. For example, since the middle section of the enclosed busbar is connected by the generator circuit breaker (GCB), its temperature rise has a significant impact on the overall thermal stability of the busbar. Therefore, a fine, regular meshing is used for the intermediate connection section, referencing... Figure 2 A schematic diagram of the network for connecting conductors.

[0034] Step 102: Perform physical field modeling for each segment and optimize the model obtained. During modeling, at least one physical field model is coupled and optimized based on measured data to obtain a simulation model for the closed bus.

[0035] In this step, multiple physical field models can be established, and a simulation model can be obtained through coupled simulation. The multi-physics field model includes, but is not limited to, temperature field, stress field, electromagnetic field, etc.

[0036] Step 103: Obtain the measurement parameters to be predicted, and use a simulation model to simulate the measurement parameters to be predicted to obtain simulation results; determine the state of the closed busbar based on the simulation results.

[0037] In this step, simulation prediction is performed using a simulation model, and the predicted value is compared with the set threshold to provide timely early warning of the status of the closed busbar.

[0038] As an optional implementation of this embodiment, the physical field includes an electromagnetic field model, and the governing equations of the electromagnetic field model are: Where A is the magnetic vector, μ is the magnetic permeability, σ is the electrical conductivity, and J is the magnetic vector. ext (t) represents the time-varying current density, where t is time.

[0039] In this optional implementation, an electromagnetic field is established for the enclosed busbar. The interaction between the electric and magnetic fields is described based on a pre-defined set of equations. Specifically, in dynamic simulation, the change in current over time affects the electromagnetic field, generating Joule heating and consequently influencing the temperature field. Based on this, a specific set of equations is established to describe the distribution and evolution of the electromagnetic field (electric field E, magnetic field B, current density J), introducing a time derivative term in the dynamic form. The magnetic vector is A, a vector function describing the magnetic field distribution, satisfying... Magnetic permeability indicates a material's ability to conduct magnetic fields; electrical conductivity indicates a material's ability to conduct electrical fields, and varies with temperature. t is a time variable. During a short-circuit fault, the current density is the time-varying current density driven by the short-circuit fault.

[0040] As an optional implementation of this embodiment, the physical field model includes a temperature field model, which is established for the interior of the enclosed busbar shell. The temperature distribution of each segment of the enclosed busbar is determined based on the temperature field model, and the governing equations of the temperature field model are: Where ρ is the conductor material density of the closed busbar, and c p Let k be the specific heat capacity, k be the thermal conductivity, and T be the temperature field. This is the rate of change of temperature over time, used to represent transient characteristics; This is the thermal conductivity term, representing the process of heat conduction through materials; Q joule As a Joule heat source, Q joule =σ|J(t)| 2 J(t) represents the current density, the change in which is determined based on the change in conductivity, which in turn is determined based on the change in temperature. external An external heat source, including additional cooling or heating power.

[0041] In this optional implementation, the transient heat conduction equation is used to describe the temperature variation with time and space, and the temperature distribution is affected by setting different parameters. T represents a function of space and time, denoted as T(x,y,z,t).

[0042] This optional implementation can be used for electromagnetic-temperature coupling, where current density affects Joule heating, which in turn affects the temperature field distribution; temperature changes affect conductivity, which in turn affects current density.

[0043] As an optional implementation in this embodiment, before meshing, unidirectional airflow conditions are set for the geometric model of the closed busbar; the method for physical field modeling of each segment includes: calculating the convective heat dissipation coefficient, wherein the convective heat dissipation coefficient is... Nusselt number, k f Fluid thermal conductivity, D h The conductor diameter of the enclosed busbar; the governing equations of the temperature field model are determined based on the aforementioned convective heat dissipation coefficient:

[0044]

[0045] In this optional implementation, to ensure the safe operation of the enclosed busbar, considering the overall needs of air conditioning and ventilation in the underground plant, and combining the ventilation and cooling requirements during busbar operation, corresponding ventilation and cooling measures are implemented. Specifically, an exhaust fan is installed at the exit of each busbar tunnel located at an elevation of 100 meters to expel airflow entering the busbar tunnel from the plant; a cooling fan is installed in the lower horizontal section of each underground busbar tunnel to circulate the air in-situ, reducing the temperature and humidity of the air within the tunnel; and cooling fans are installed in the upper horizontal section of the busbar corridor. After adopting effective measures such as forced ventilation, the temperature of the busbar and its casing will further decrease. The designed equipment configuration meets the heat dissipation requirements of the busbar and allows for some margin. During operation, the number of cooling fans or the circulating air volume can be automatically controlled based on the measured temperature to achieve both meeting operational requirements and saving energy.

[0046] Therefore, during simulation, it is necessary to set up unidirectional airflow in the model. The fluid velocity affects the convective heat transfer coefficient, thereby changing the heat dissipation conditions. The boundary conditions of the temperature field can be set as convective heat dissipation functions. h(t) is the convective heat transfer coefficient, which varies with time. The temperature distribution can be determined based on the convective heat dissipation coefficient. Tenv is the ambient temperature. The temperature distribution is calculated using the h value provided by the flow field, and then fluid heat dissipation is considered. After the temperature reaches the desired value, in practice, the fan flow rate is adjusted through a micro-positive pressure control system to further ensure a suitable temperature. That is, the temperature field and the flow field are coupled. Fluid flow affects the temperature distribution through convective heat dissipation. Temperature changes cause fluid changes. Specifically, the flow field calculates the fan airflow distribution to determine the convective heat dissipation coefficient, and the temperature field calculates Joule heat and heat dissipation to determine the temperature distribution.

[0047] As an optional implementation of this embodiment, the method further includes: establishing temperature loads at the connection points of each segment of the temperature field model, so as to apply temperature loads at the interfaces of adjacent sub-segments. The governing equations of the temperature field model are determined based on temperature load: Where k is the thermal conductivity of the interfacial contact material, and A contactL represents the contact area of ​​the material. contact T is the release length of the contact material. in For segmented inlet temperatures, T out The outlet temperature of a segment is used as the inlet temperature of the next adjacent segment.

[0048] In this optional implementation, the temperature load refers to the temperature boundary condition applied to the interface, used to describe the thermal interaction between adjacent segments. That is, the temperature load at the interface between adjacent segments describes the heat transfer mode (fixed temperature, convection, or conjugate heat transfer) between different segments, influenced by different temperature boundary conditions. The inlet temperature defines the starting point of the segment's thermal analysis and affects the overall temperature rise; the outlet temperature reflects the heat accumulation effect of the segment and drives the boundary conditions of adjacent segments.

[0049] As an optional implementation of this embodiment, the physical field model includes a stress field model, a temperature distribution determined based on a temperature field model, and a temperature difference ΔT between the closed busbar and the environment at a specified distribution point determined based on the temperature distribution; thermal stress determined based on the temperature difference; total strain force determined based on the stress field model, and displacement field u(x, y, z) solved based on the total strain force.

[0050] The physical field model includes a stress field model, a temperature field model to determine the temperature distribution, and a temperature difference ΔT between the closed busbar and the environment at a specified distribution point to determine the temperature distribution. The thermal stress is determined based on the temperature difference. The total strain is determined based on the stress field model, and the displacement field u(x,y,z) is solved based on the total strain.

[0051] As an optional implementation of this embodiment, the stress field model includes:

[0052] σ total =σ mech +σ thermal And the governing equations that serve as physical constraints, namely the dynamic equilibrium equations: Where, σ mech For mechanical stress, σ thermal For thermal stress, σ total For the total stress; σ mech =C:ε mech C is the elastic stiffness tensor, ε mech For mechanical strain; σ thermal =αEΔT·I, where α is the coefficient of thermal expansion, E is the modulus of elasticity, and ΔT is the temperature difference between the closed generatrix and the environment at a specified distribution point; It is an inertial force. For damping force, f ext (t) represents the external volume force, which is the sum of the electromagnetic volume force density and the vibrational volume force density. The electromagnetic volume 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 the external excitation, i.e., the vibration of the fan, and ρ is the material density of the closed busbar.

[0053] In this optional implementation, the stress field establishes a balance between force and deformation. It is composed of the superposition of mechanical and thermal stresses; thermal stress can be calculated using the temperature field, while an inertial force term is introduced for dynamic analysis. The governing equations of the stress field describe the balance between internal forces (stress) and external forces (such as volume forces and surface forces). The governing equations correlate the stress field with the displacement field through the following steps: first, establishing a correlation between stress and strain 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 a foundation for solving u. The transient response of sudden faults is captured through inertial forces, damping forces, and transient terms. The total stress includes mechanical and thermal stresses; the combined action of electromagnetic and thermal stresses leads to structural deformation. The temperature field affects thermal strain, which in turn affects thermal stress, ultimately altering the displacement field. Furthermore, the electromagnetic force influences the displacement field, causing geometric deformation of the closed busbar, ultimately resulting in changes in current density.

[0054] 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 such as surface forces or pressure loads, and the governing equations ensure that these conditions are strictly satisfied during the solution process.

[0055] When solving for the coupled physical fields, the electromagnetic fields J(t) and B(t) at time t are calculated; Joule heating is calculated to solve for the temperature field T(t); thermal stress and electromagnetic force are calculated; the dynamic equations are solved, the displacement field is updated, the geometry is updated, and the process proceeds to the next time step. The displacement field affects geometric deformation, which in turn updates the electromagnetic field.

[0056] The coupling logic described above leads to 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 the multiphysics model, a closed busbar model that closely matches reality can be obtained.

[0057] In one optional implementation of this embodiment, optimizing the coupled physical field model based on measured data to obtain a simulation model for the closed bus includes: acquiring historical measured data, dividing the historical measured data under different operating conditions into historical measured data to be simulated and verification data according to time sequence, wherein different operating conditions include steady-state operating conditions, start-up operating conditions, etc.; simulating the historical measured data to be simulated using the model obtained from the simulation to obtain simulation data; and based on the verification data and the simulation.

[0058] In this optional implementation, the temperature field of the enclosed busbar can be predicted through simulation, thereby enabling timely early warning of anomalies. After performing temperature simulation based on the simulation model, the temperature at any point on the enclosed busbar under any operating condition can be obtained through simulation, and alarms and early warnings can be implemented at that point.

[0059] For example, the simulation model given above can support simulations under any operating condition. Based on measured data under any operating condition, the parameters of the multiphysics model can be effectively calibrated, significantly improving prediction accuracy, and integrated into a real-time early warning system. The calibrated model can accurately predict: temperature error <2%; early warning: an alarm is issued 10 seconds before overheating or overload occurs. Robustness guarantee: confidence intervals are quantified through uncertainty analysis to avoid false alarms / missed alarms.

[0060] In the calibration model, the objective function quantifies the difference between simulation and measured data and guides parameter optimization. The objective function defines temperature as the core variable for error calculation. It also optimizes algorithm parameters such as damping factors and convergence tolerances, which control the convergence and efficiency of the iterative process.

[0061] As an optional implementation of this embodiment, determining the state of the enclosed busbar through the simulation results includes: determining whether the simulation results meet the early warning conditions; and determining whether to issue an alarm for the enclosed busbar based on the judgment results.

[0062] In this optional implementation, early warning conditions are set through visual configuration. These conditions can be alarm values ​​and early warning thresholds for different locations under different operating conditions and states. Specifically, alarm values ​​can be set for different operating states, and early warning information can be determined based on alarm standard information. For example, the early warning threshold can be determined based on the alarm value, or a specified percentage of the alarm value can be used as the early warning threshold. Alarm values ​​can be set based on preset standards.

[0063] For example, for isolated phase enclosed busbars, monitoring should be carried out on all connection points and fixed supports that are prone to overheating, such as... Figure 3 Under steady-state operating conditions, i.e., normal operating conditions, the permissible temperatures and temperature rises of various parts of the naturally cooled isolated phase-enclosed busbar, including the conductors, the contact surfaces of bolted conductors or the outer casing, the outer casing, the outer casing support structure, and the insulation components, are considered. The maximum permissible temperature and maximum permissible temperature rise of the contact surfaces of bolted conductors or the outer casing can be used to determine alarm values ​​and warning thresholds. For example, refer to... Figure 4 The permissible temperatures of insulation materials with different heat resistance grades are used to determine alarm values ​​and warning thresholds for different locations. Forced-cooled isolated phase busbars should meet the permissible temperatures and temperature rises for each part of the busbar provided by the manufacturer.

[0064] After configuring the early warning rules, when performing simulations based on real-time data from the enclosed busbar, the simulation prediction results can be judged based on the set threshold conditions. If the early warning threshold is reached, an early warning will be issued; if the alarm value is reached, an alarm will be triggered.

[0065] In this embodiment, the various physical fields interact through their respective governing equations, forming a coupled model that can objectively simulate the operating state of the enclosed busbar. Furthermore, users can configure early warning rules visually as needed, enabling them to issue warnings for the enclosed busbar under different operating conditions.

[0066] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0067] 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, comprising a preprocessing unit for meshing the geometric model of the closed busbar of each unit according to specified rules; segmenting the meshed model to obtain multiple sub-segments, wherein each sub-segment includes a connection part composed of generator circuit breakers in one or more phase-separated closed busbars; a modeling unit for performing physical field modeling for each segment, wherein at least one physical field model is coupled and optimized based on measured data to obtain a simulation model for the closed busbar; an early warning unit for acquiring 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 based on the simulation results.

[0068] Although embodiments of the present disclosure have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present disclosure, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for early warning of the condition of a closed busbar based on the fusion of simulation modeling and online measurement, characterized in that, include: The geometric model of the enclosed busbar of each unit is meshed according to the specified rules; the meshed model is divided into segments to obtain multiple sub-segments, wherein each sub-segment includes one or more connection parts composed of generator circuit breakers in the phase-separated enclosed busbar; Physical field modeling is performed for each segment, and the model obtained is optimized. In the process of modeling, at least one physical field model is coupled, and the coupled physical field model is simulated and optimized based on measured data to obtain the simulation model of the closed bus. Obtain the measurement parameters to be predicted, and use a simulation model to simulate the measurement parameters to be predicted to obtain simulation results; determine the state of the closed busbar based on the simulation results. The physical field includes an electromagnetic field model, and the governing equations of the electromagnetic field model are: ,in, It is a magnetic vector. Permeability, For electrical conductivity, Let t be the time-varying current density; Optimizing the coupled physical field model based on measured data to obtain a simulation model for the closed busbar includes: acquiring historical measured data under different operating conditions, dividing the historical measured data into simulated historical measured data and verification data according to time sequence, wherein different operating conditions include steady-state operating conditions and start-up operating conditions; simulating the simulated historical measured data using the model obtained from the simulation to obtain simulation data; and optimizing the simulation model based on the verification data and the simulation data, wherein the optimization is based on the objective function. Optimization was carried out, including, The temperature distribution is the simulation output at the i-th time step. , where is the measured temperature distribution at the i-th time step.

2. The closed busbar status early warning method based on simulation modeling and online measurement fusion as described in claim 1, characterized in that, The physical field model includes a temperature field model, which is established for the interior of the enclosed busbar shell. The temperature field model determines the temperature distribution of each segment of the enclosed busbar, and the governing equations of the temperature field model are: ,in, The density of the conductor material of the enclosed busbar, For specific heat capacity, Thermal conductivity, For temperature field, This is the rate of change of temperature over time, used to represent transient characteristics; This is the thermal conductivity term, representing the process of heat conduction through materials. As a Joule heat source, , The current density is defined as the change in current density, which is determined based on the change in conductivity, which in turn is determined based on the change in temperature. An external heat source, including additional cooling or heating power.

3. The closed busbar status early warning method based on simulation modeling and online measurement fusion as described in claim 2, characterized in that... Before meshing, airflow conditions are set for the geometric model of the closed generatrix; the methods for physical field modeling of each segment include: Calculate the convective heat dissipation coefficient, where the convective heat dissipation coefficient is... , Nusselt number, Fluid thermal conductivity, The conductor diameter of the enclosed busbar; The governing equations for the temperature field model are determined based on the aforementioned convective heat dissipation coefficient. .

4. The closed busbar status early warning method based on simulation modeling and online measurement fusion as described in claim 3, characterized in that, The method also includes: Temperature loads are established at the joints of each segment in the temperature field model to apply temperature loads at the interfaces between adjacent segments: ; The governing equations of the temperature field model are determined based on temperature load: ,in, The thermal conductivity of the materials in contact at the interface. The contact area of ​​the material is the area of ​​release. The release length of the contact material. For segmented inlet temperatures, The outlet temperature of a segment is used as the inlet temperature of the next adjacent segment.

5. The closed busbar status early warning method based on simulation modeling and online measurement fusion as described in claim 3, characterized in that... The physical field model includes a stress field model, a temperature field model to determine the temperature distribution, and a temperature difference between the closed busbar and the environment at a specified distribution point to determine the temperature distribution. ; The thermal stress is determined based on the temperature difference; The total strain is determined based on the stress field model, and the displacement field is solved based on the total strain. .

6. The closed busbar status early warning method based on simulation modeling and online measurement fusion as described in claim 5, characterized in that... The stress field model includes: And the governing equations that serve as physical constraints, namely the dynamic equilibrium equations: ; in, Mechanical stress, For thermal stress, The total stress; , For elastic stiffness tensor, For mechanical strain; , The coefficient of thermal expansion is The elastic modulus is the temperature difference between the enclosed busbar and the environment at a specified distribution point. ; It is an inertial force. For damping force, External volume force is the sum of electromagnetic volume force density and vibrational volume force density, wherein the electromagnetic volume force density is the force generated by the electromagnetic field. , For current density, The magnetic field and the vibrational volume force density are generated by external excitation, i.e., the force produced by the vibration of the wind turbine. The density of the conductor material of the enclosed busbar.

7. The closed busbar status early warning method based on simulation modeling and online measurement fusion according to claim 1, characterized in that, Determining the state of the enclosed busbar based on the simulation results includes: determining whether the simulation results meet the early warning conditions; and determining whether to issue an alarm for the enclosed busbar based on the judgment results.

8. A closed busbar status early warning device based on the fusion of simulation modeling and online measurement, characterized in that, include: The preprocessing unit is used to mesh the geometric model of the enclosed busbar of each unit according to specified rules; and to divide the meshed model into segments to obtain multiple sub-segments, wherein each sub-segment includes a connection part composed of generator circuit breakers in one or more phase-separated enclosed busbars. The modeling unit is used to perform physical field modeling for each segment. It couples at least one physical field model and optimizes the coupled physical field model based on measured data to obtain a simulation model for the closed bus. The early warning unit is used to acquire the measurement parameters to be predicted, and to obtain simulation results by simulating the measurement parameters to be predicted using a simulation model; the state of the closed busbar is determined by the simulation results. The physical field includes an electromagnetic field model, and the governing equations of the electromagnetic field model are: ,in, It is a magnetic vector. Permeability, For electrical conductivity, Let t be the time-varying current density; Optimizing the coupled physical field model based on measured data to obtain a simulation model for the closed busbar includes: acquiring historical measured data under different operating conditions, dividing the historical measured data into simulated historical measured data and verification data according to time sequence, wherein different operating conditions include steady-state operating conditions and start-up operating conditions; simulating the simulated historical measured data using the model obtained from the simulation to obtain simulation data; and optimizing the simulation model based on the verification data and the simulation data, wherein the optimization is based on the objective function. Optimization was carried out, including, The temperature distribution is the simulation output at the i-th time step. , where is the measured temperature distribution at the i-th time step.

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