CN115495944A - A method to obtain the electrical-thermal-stress distribution of switchgear under the influence of different factors - Google Patents
A method to obtain the electrical-thermal-stress distribution of switchgear under the influence of different factors Download PDFInfo
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Abstract
Description
技术领域technical field
本发明属于输配电网络的关键设备电气性能研究领域,涉及一种获取不同因素影响下开关柜电-热-应力分布的方法。The invention belongs to the field of electrical performance research of key equipment of a power transmission and distribution network, and relates to a method for obtaining the electric-thermal-stress distribution of a switchgear under the influence of different factors.
背景技术Background technique
电力开关柜作为电力系统的关键设备,广泛应用于输电配电网络,承担着开合、控制和保护用电设备的作用,其运行可靠性直接影响着电力系统供电质量及安全性能。为提高开关柜运行可靠性,降低故障风险,减少因故障引起的经济损失,可在开关柜内加装各类监测设备,并通过分析和处理监测数据,实现其运行状态检测和安全预警,以保证运维人员及时发现问题。加之在智能电网建设的背景下,对开关柜获取数据的实时化、准确化提出了更高的要求。As the key equipment of the power system, the power switchgear is widely used in the power transmission and distribution network, and is responsible for switching, controlling and protecting the electrical equipment. Its operation reliability directly affects the power supply quality and safety performance of the power system. In order to improve the operating reliability of the switchgear, reduce the risk of failure, and reduce the economic loss caused by failure, various monitoring equipment can be installed in the switchgear, and by analyzing and processing the monitoring data, the operating status detection and safety warning can be realized, so as to Ensure that O&M personnel find problems in a timely manner. In addition, under the background of smart grid construction, higher requirements are put forward for the real-time and accurate data obtained by switch cabinets.
但由于开关柜工作时,其涡流损耗、焦耳热会导致温升,而电磁产生的洛伦兹力会对非固定金属元件产生影响,以上因素均会影响传感器对开关柜特征量的测量,严重时甚至影响其使用寿命,影响设备的安全稳定运行。因此,对开关柜温度、电磁分布以及电动力情况进行研究,确定温升最高点的位置和电场强度最大的位置,分析不同因素对温度和应力的影响,对各类传感器位置优化布局具有指导作用,对开关柜的实时监测系统的开发提供帮助。However, when the switchgear is working, its eddy current loss and Joule heat will lead to temperature rise, and the Lorentz force generated by the electromagnetic will affect the non-fixed metal components. The above factors will affect the measurement of the characteristics of the switchgear by the sensor, seriously It may even affect its service life and affect the safe and stable operation of the equipment. Therefore, research on the temperature, electromagnetic distribution and electromotive force of the switchgear, determine the location of the highest temperature rise and the location of the largest electric field intensity, and analyze the influence of different factors on temperature and stress, will play a guiding role in optimizing the layout of various sensor locations , to help the development of the real-time monitoring system of the switchgear.
发明内容Contents of the invention
本发明的目的在于提供一种获取不同因素影响下开关柜电-热-应力分布的方法,立足于开关柜的实际结构和运行条件,采用有限元法建立了基于电磁-温度-固体力学耦合的三维开关柜仿真模型,实现对不同因素影响下开关柜的温度、电场强度分布以及应力的仿真方法。The purpose of the present invention is to provide a method for obtaining the electric-thermal-stress distribution of the switchgear under the influence of different factors, based on the actual structure and operating conditions of the switchgear, and using the finite element method to establish a coupling based on electromagnetic-temperature-solid mechanics The three-dimensional switchgear simulation model realizes the simulation method of the temperature, electric field intensity distribution and stress of the switchgear under the influence of different factors.
为实现上述目的,本发明提供如下技术方案,该方法的步骤如下:To achieve the above object, the present invention provides the following technical solutions, the steps of the method are as follows:
S1:建立多电气室的电气开关柜简化物理模型;S1: Establish a simplified physical model of an electrical switchgear with multiple electrical rooms;
S2:开关柜涉及电磁场、温度传导和固体力学的理论分析;S2: Theoretical analysis of switchgear involving electromagnetic field, temperature conduction and solid mechanics;
S3:添加合适的物理场,进行电磁-传热-固体力学的耦合分析研究;S3: Add appropriate physical fields to conduct coupling analysis research of electromagnetic-heat transfer-solid mechanics;
S4:基于开关柜实际运行状态设置对应合适的物理参数以及各类边界条件;S4: Set appropriate physical parameters and various boundary conditions based on the actual operating state of the switchgear;
S5:根据开关柜各个电气室的几何特点以及计算的精度要求对其进行网格剖分,设置合适的仿真时间及步长,并根据仿真的要求进行求解器的设置;S5: According to the geometric characteristics of each electrical room of the switchgear and the accuracy requirements of the calculation, mesh it, set the appropriate simulation time and step size, and set the solver according to the simulation requirements;
S6:仿真得到不同的环境情况下,开关柜稳态情况下的电磁场和温度场的分布结果,并对其进行后处理得到温度、电场强度和洛伦兹力的分布情况。确定最热点的位置,对比分析不同环境条件对最高温度和平均温度的影响;S6: The distribution results of the electromagnetic field and temperature field in the steady state of the switchgear under different environmental conditions are obtained by simulation, and post-processing is performed to obtain the distribution of temperature, electric field strength and Lorentz force. Determine the location of the hottest point, and compare and analyze the impact of different environmental conditions on the maximum temperature and the average temperature;
S7:通过仿真得到因添加不同固定约束,母线因受力引起的不同的位移量的变化;S7: Through the simulation, the change of the displacement of the busbar caused by the force due to the addition of different fixed constraints is obtained;
S8:通过仿真改变连接处的接触压力,分析其对温升以及对应力的影响;S8: Change the contact pressure at the connection through simulation, and analyze its influence on temperature rise and stress;
进一步,步骤S1具体为,在有限元软件中建立多电气室的开关柜三维物理模型,模型内部结构有一个重要特征是有效和无效,即根据分析问题的类型有时候需要对某些特征进行忽略。重点考虑系统热源、开关柜关键部件,而忽略不影响分析精度的固定螺母、微小电子元器件,将开关柜进行合理简化,减少工作量,提高效率。Further, step S1 is specifically to establish a three-dimensional physical model of a switchgear with multiple electrical rooms in the finite element software. An important feature of the internal structure of the model is valid and invalid, that is, sometimes some features need to be ignored according to the type of analysis problem . Focus on system heat sources and key components of the switchgear, while ignoring the fixing nuts and tiny electronic components that do not affect the analysis accuracy, rationally simplify the switchgear, reduce workload and improve efficiency.
步骤S2具体为,开关柜电磁场、温度传导和固体力学的理论分析:根据开关柜运行的麦克斯韦电磁理论计算涡流损耗,将该损耗作为热源带入固体传热中进行温度分布计算;根据电磁场产生的洛伦兹力来描述开关柜母排的电动力。Step S2 is specifically, the theoretical analysis of the electromagnetic field, temperature conduction and solid mechanics of the switchgear: calculate the eddy current loss according to the Maxwell electromagnetic theory of the switchgear operation, and bring the loss into the solid heat transfer as a heat source to calculate the temperature distribution; The Lorentz force is used to describe the electric force of the switchgear busbar.
(一)电磁场(1) Electromagnetic field
在对似稳态电磁场问题进行求解分析时,可以忽略电场随时间变化所产生的磁场,只针对磁场随时间变化产生的电场进行分析,从而将电磁问题简化。通过麦克斯韦方程组描述了电磁场的宏观性质,其微分形式如式:When solving and analyzing the quasi-steady-state electromagnetic field problem, the magnetic field generated by the change of the electric field with time can be ignored, and only the electric field generated by the change of the magnetic field with time can be analyzed, thereby simplifying the electromagnetic problem. The macroscopic properties of the electromagnetic field are described by Maxwell's equations, and its differential form is as follows:
式中:D为电位移;H为磁场强度;B为磁通密度;E为电场强度;ρ为电荷密度;J为电流密度。Where: D is the electric displacement; H is the magnetic field strength; B is the magnetic flux density; E is the electric field strength; ρ is the charge density; J is the current density.
ε代表磁场煤质的介电常数,单位为F/m;μ代表煤质的磁导率,单位为H/m;σ为电导率,单位为S/m;对于各项同性介质,ε、μ、σ均为标量。ε represents the permittivity of coal in the magnetic field, in F/m; μ represents the magnetic permeability of coal in H/m; σ represents the electrical conductivity in S/m; for isotropic media, ε, Both μ and σ are scalar quantities.
(二)固体传热(2) Solid heat transfer
考虑到柜体的发热损耗来源于涡流损耗,这些热量通过柜体表面的自然对流换热和热辐射两种方式发散到周围环境。母排的焦耳损耗来源于源电流的电阻发热损耗和感应发热,母排的电阻包括载流导体电阻及接触电阻。Considering that the heat loss of the cabinet comes from eddy current loss, the heat is dissipated to the surrounding environment through natural convection heat transfer and heat radiation on the surface of the cabinet. The Joule loss of the busbar comes from the resistance heating loss and induction heating of the source current. The resistance of the busbar includes the current-carrying conductor resistance and contact resistance.
将涡流场计算得到的焦耳损耗作为热源导入,并设定相应的辐射边界条件,和对流散热边界条件,计算开关柜的温度场。温度场的控制方程为:The Joule loss calculated by the eddy current field is imported as a heat source, and the corresponding radiation boundary conditions and convection heat dissipation boundary conditions are set to calculate the temperature field of the switchgear. The governing equation of the temperature field is:
式中,ρ是材料密度,λ和C分别为材料的导热系数和比热,为内热源强度。where ρ is the material density, λ and C are the thermal conductivity and specific heat of the material, respectively, is the internal heat source intensity.
母排的外表面应该满足对流和辐射边界条件:The outer surface of the busbar should satisfy the convection and radiation boundary conditions:
式中,q是热流密度矢量,Ta是环境温度;ke表示母排表面的对流换热系数;ε表示母排表面的热发生率;σ表示史蒂芬-玻尔兹曼常数。In the formula, q is the heat flux vector, T a is the ambient temperature; k e represents the convective heat transfer coefficient on the surface of the busbar; ε represents the heat generation rate on the surface of the busbar; σ represents the Stefan-Boltzmann constant.
(三)固体力学(3) Solid Mechanics
描述扰动力作用下有阻尼强迫振动系统物体的运动微分方程为:The motion differential equation describing the motion of an object in a damped forced vibration system under the action of a disturbance force is:
式中m为振动系统的总质量,C表示物体运动时支承隔振器的粘性阻尼系数,K表示弹簧刚度单位变形的作用力。F0sinωt表示系统受到的扰动力,坐标轴放于物体静平衡位置O上。x、分别表示整体坐标系下节点的位移、速度和加速度。In the formula, m is the total mass of the vibration system, C represents the viscous damping coefficient of the supporting vibration isolator when the object is moving, and K represents the force of the unit deformation of the spring stiffness. F 0 sinωt represents the disturbance force received by the system, and the coordinate axis is placed on the static equilibrium position O of the object. x, Respectively represent the displacement, velocity and acceleration of the node in the global coordinate system.
步骤S3具体为,添加相关物理场,并进行电磁-温度-固体力学多物理场耦合。基于前述理论分析,选择各控制方程对应的物理场,即麦克斯韦方程组对应电磁场,开关柜温度的对流、传导和辐射对应固体传热物理场,在外部大电流的激励下设备的应力对应固体力学物理场。电磁场和温度场基于温度和电磁热效应耦合;固体传热和固体力学基于洛伦兹力和热膨胀效应进行耦合,进而实现多物理场直接耦合;Step S3 specifically includes adding relevant physical fields and performing electromagnetic-temperature-solid mechanics multi-physics coupling. Based on the above theoretical analysis, the physical fields corresponding to each control equation are selected, that is, Maxwell’s equations correspond to the electromagnetic field, the convection, conduction and radiation of the temperature of the switchgear correspond to the physical field of solid heat transfer, and the stress of the equipment under the excitation of an external large current corresponds to the solid mechanics. physical field. Electromagnetic field and temperature field are coupled based on temperature and electromagnetic thermal effect; solid heat transfer and solid mechanics are coupled based on Lorentz force and thermal expansion effect, thereby realizing direct coupling of multiple physical fields;
步骤S4具体为,基于开关柜实际运行状态设置对应参数以及边界条件:参数包括开关柜各个部分的电导率、磁导率、电阻率、导热系数等电磁、温度及固体力学相关参数;边界条件包括加压、接地、电流激励、温度边界、力学固定约束等外部应力及环境限制条件。添加温度和材料电阻率的双向耦合,提高仿真的精度;Step S4 is specifically to set corresponding parameters and boundary conditions based on the actual operating state of the switchgear: parameters include electromagnetic, temperature and solid mechanics related parameters such as electrical conductivity, magnetic permeability, resistivity, and thermal conductivity of each part of the switchgear; boundary conditions include External stress and environmental constraints such as pressurization, grounding, current excitation, temperature boundary, and mechanical fixed constraints. Add the two-way coupling of temperature and material resistivity to improve the accuracy of simulation;
步骤S5具体为,根据开关几何特点对其进行网格剖分,并设置仿真时间及步长:设置全局网格大小,进一步根据局部几何特征将网格进行细化处理,其后构建全部网格,再设置仿真时间和步长,开始计算直到满足时间条件,仿真结果收敛;Step S5 is specifically, meshing the switch according to its geometric characteristics, and setting the simulation time and step size: setting the global mesh size, further refining the mesh according to the local geometric characteristics, and then constructing all the meshes , then set the simulation time and step size, and start the calculation until the time condition is met, and the simulation result converges;
步骤S6具体为,首先仿真得到开关柜稳态情况下的电磁场、温度场和时均洛伦兹力的分布结果,确定最热点的位置,得到额定工况下环境温度为293K,298K,303K,308K,313K时开关柜的平均温升和最大温升。对比分析不同环境温度对开关柜最高温度和平均温度的影响。Step S6 is specifically, firstly obtain the distribution results of the electromagnetic field, temperature field and time-average Lorentz force in the steady state of the switchgear through simulation, determine the location of the hottest point, and obtain the ambient temperature under the rated working condition as 293K, 298K, 303K, The average temperature rise and maximum temperature rise of the switchgear at 308K and 313K. The impact of different ambient temperatures on the maximum temperature and average temperature of the switchgear is compared and analyzed.
步骤S7具体为,通过仿真得到添加不同的固定约束,对不同的部位进行固定,分析在不同的情况下,母线受力变化引起的变形情况,为开关柜母线的固定提供参考。通过固定断路器、绝缘子、母线端部等三部分,分别分析母线受力的不同的变化;Step S7 is specifically to add different fixing constraints obtained through simulation, fix different parts, analyze the deformation caused by the force change of the busbar under different circumstances, and provide a reference for fixing the busbar of the switchgear. By fixing the circuit breaker, insulator, busbar end and other three parts, analyze the different changes of the busbar stress respectively;
步骤S8具体为,开关柜内部的相应的连接处的接触压力会对其的温升和应力产生影响,通过改变连接处的接触压力,进而改变接触阻抗,分析其对温升的影响程度以及对应力的影响;Step S8 specifically is that the contact pressure of the corresponding connection inside the switchgear will affect its temperature rise and stress. By changing the contact pressure at the connection, and then changing the contact impedance, analyze its influence on the temperature rise and the corresponding the influence of force;
本发明的有益效果在于:采用本发明方法可以获得开关柜在不同因素影响下的温度分布和电场分布特性以及受力的特点,通过对不同因素的分析,能够为开关柜的产品设计以及开关柜传感器的优化布置提供可靠的理论依据。The beneficial effect of the present invention is that: adopting the method of the present invention can obtain the temperature distribution, electric field distribution characteristics and stress characteristics of the switchgear under the influence of different factors. The optimal arrangement of sensors provides a reliable theoretical basis.
附图说明Description of drawings
图1为本发明的开关柜电-热-力仿真流程图;Fig. 1 is the electric-thermal-force simulation flowchart of switchgear of the present invention;
图2为本发明的开关柜整体三维物理模型图;Fig. 2 is the overall three-dimensional physical model figure of switchgear of the present invention;
图3为本发明实施例的开关柜整体温度场分布及温升最高点位置图;Fig. 3 is a map of the overall temperature field distribution and the highest point of temperature rise of the switchgear according to the embodiment of the present invention;
图4为本发明实施例的开关柜整体电场强度和电流密度的分布图;4 is a distribution diagram of the overall electric field intensity and current density of the switchgear according to the embodiment of the present invention;
图5为本发明实施例的开关柜在X、Y、Z方向时均洛伦兹力的分布图;Fig. 5 is a distribution diagram of the average Lorentz force in the X, Y, and Z directions of the switchgear according to the embodiment of the present invention;
图6为本发明实施例的不同环境温度下的开关柜平均温度和最高温度对比曲线图;Fig. 6 is a comparison curve of the average temperature and the maximum temperature of the switchgear under different ambient temperatures according to the embodiment of the present invention;
图7为本发明实施例的开关柜不同固定约束下的母线位移分布图;Fig. 7 is a distribution diagram of busbar displacement under different fixed constraints of the switchgear according to the embodiment of the present invention;
图8为本发明实施例的开关柜连接处不同压力下的温度的分布图;Fig. 8 is a distribution diagram of the temperature under different pressures at the junction of the switchgear according to the embodiment of the present invention;
图9为本发明实施例的开关柜连接处不同压力下的应力的分布图;Fig. 9 is a distribution diagram of the stress under different pressures at the connection of the switchgear according to the embodiment of the present invention;
具体实施方式:detailed description:
下面将结合附图,对本发明进行详细说明。The present invention will be described in detail below in conjunction with the accompanying drawings.
本发明为一种获取不同因素影响下开关柜电-热-应力分布的方法,如图2所示,立足于开关柜的实际结构,采用有限元法建立了开关柜基于电磁-温度-固体力学多物理场耦合的三维仿真模型,其中将电磁场的涡流损耗作为温度传导的热源,基于热传导、热对流以及热辐射理论仿真得到开关柜的温度分布和最热温度位置,同时考虑了金属在电磁场中的受洛伦兹力的影响,实现对开关柜电动力的仿真。具体步骤如下:The present invention is a method for obtaining the electric-thermal-stress distribution of switchgear under the influence of different factors. The 3D simulation model of multi-physics field coupling, in which the eddy current loss of the electromagnetic field is used as the heat source of temperature conduction, the temperature distribution and the hottest temperature position of the switchgear are obtained based on the theoretical simulation of heat conduction, heat convection and heat radiation, and the metal in the electromagnetic field is also considered Influenced by the Lorentz force, the simulation of the electric power of the switchgear is realized. Specific steps are as follows:
1、建立开关柜三维物理模型1. Establish a 3D physical model of the switchgear
在有限元软件中绘制开关柜的三维物理模型,如图2所示,进行耦合分析时,模型内部结构有一个重要特征是有效和无效,即根据分析问题的类型有时候需要对某些特征进行忽略。因此在下列假设基础上以10kV/3150A的大电流开关柜为原型进行三维建模:Draw the three-dimensional physical model of the switchgear in the finite element software, as shown in Figure 2, when performing coupling analysis, an important feature of the internal structure of the model is valid and invalid, that is, depending on the type of analysis problem, sometimes some features need to be analyzed neglect. Therefore, based on the following assumptions, a 10kV/3150A high-current switchgear is used as a prototype for three-dimensional modeling:
(1)由于绝缘子仅起到绝缘支撑作用,所以简化绝缘子的形状特征;(1) Since the insulator only plays the role of insulating support, the shape characteristics of the insulator are simplified;
(2)简化螺丝等连接处的细小元件;(2) Simplify the small components at the joints such as screws;
(3)简化断路器为圆柱形;(3) The simplified circuit breaker is cylindrical;
2、添加物理场,设置加多物理场耦合2. Add physics field, set to add multi-physics field coupling
添加电磁场、固体传热、结构力学三个物理场,并进行耦合计算:Add three physical fields of electromagnetic field, solid heat transfer, and structural mechanics, and perform coupled calculations:
(一)电磁场(1) Electromagnetic field
在对似稳态电磁场问题进行求解分析时,可以忽略电场随时间变化所产生的磁场,只针对磁场随时间变化产生的电场进行分析,从而将电磁问题简化。通过麦克斯韦方程组的微分形式可推导出有限元法处理电磁场问题的微分方程:When solving and analyzing the quasi-steady-state electromagnetic field problem, the magnetic field generated by the change of the electric field with time can be ignored, and only the electric field generated by the change of the magnetic field with time can be analyzed, thereby simplifying the electromagnetic problem. Through the differential form of Maxwell's equations, the differential equation for the finite element method to deal with electromagnetic field problems can be derived:
式中:D为电位移;H为磁场强度;B为磁通密度;E为电场强度;ρ为电荷密度;J为电流密度。Where: D is the electric displacement; H is the magnetic field strength; B is the magnetic flux density; E is the electric field strength; ρ is the charge density; J is the current density.
式中:ε代表磁场煤质的介电常数,单位为F/m;μ代表煤质的磁导率,单位为H/m;σ为电导率,单位为S/m;对于各项同性介质,ε、μ、σ均为标量。In the formula: ε represents the dielectric constant of the magnetic field coal, in F/m; μ represents the magnetic permeability of the coal, in H/m; σ is the electrical conductivity, in S/m; for the isotropic medium , ε, μ, σ are all scalars.
(二)固体传热(2) Solid heat transfer
考虑到柜体的发热损耗来源于涡流损耗,这些热量通过柜体表面的自然对流换热和热辐射两种方式发散到周围环境。母排的焦耳损耗来源于源电流的电阻发热损耗和感应发热,母排的电阻包括载流导体电阻及接触电阻。Considering that the heat loss of the cabinet comes from eddy current loss, the heat is dissipated to the surrounding environment through natural convection heat transfer and heat radiation on the surface of the cabinet. The Joule loss of the busbar comes from the resistance heating loss and induction heating of the source current. The resistance of the busbar includes the current-carrying conductor resistance and contact resistance.
将涡流场计算得到的焦耳损耗作为热源导入,并设定相应的辐射边界条件,和对流散热边界条件,计算开关柜的温度场。温度场的控制方程为:The Joule loss calculated by the eddy current field is imported as a heat source, and the corresponding radiation boundary conditions and convection heat dissipation boundary conditions are set to calculate the temperature field of the switchgear. The governing equation of the temperature field is:
式中,ρ是材料密度,λ和C分别为材料的导热系数和比热,为内热源强度。where ρ is the material density, λ and C are the thermal conductivity and specific heat of the material, respectively, is the internal heat source intensity.
其中材料的导电性会随着温度的变化而发生变化,在20℃时铜的电阻率为17.2(mΩ·mm2/m),选择电阻率的温度系数α为0.004。电阻与温度关系的表达式为:The conductivity of the material will change with the temperature. At 20°C, the resistivity of copper is 17.2 (mΩ·mm 2 /m), and the temperature coefficient α of the selected resistivity is 0.004. The expression for the relationship between resistance and temperature is:
ρ(t)=ρ0(1+0.004(t-20)) ⑼ρ(t)=ρ 0 (1+0.004(t-20)) ⑼
上式中,t为当前环境温度,ρ0为20℃时铜的电阻率。In the above formula, t is the current ambient temperature, and ρ0 is the resistivity of
综合母排的集肤效应和邻近效应的影响,总结出铜排的电阻表达式如下:Based on the influence of the skin effect and proximity effect of the busbar, the resistance expression of the copper bar is summarized as follows:
式中,R为母排电阻,ρ0为20℃时铜电阻率,L为母排长度,S表示母排截面积,KJ表示集肤效应系数,KL表示邻近效应系数。In the formula, R is the resistance of the busbar, ρ0 is the
该公式充分考虑了温度对电阻率的影响,设置了温度和电阻率的双向耦合的关系,令仿真过程中的电阻率随着温度不断发生变化,使结果更加的准确。This formula fully considers the influence of temperature on resistivity, and sets the two-way coupling relationship between temperature and resistivity, so that the resistivity changes continuously with temperature during the simulation process, making the results more accurate.
母排的外表面应该满足对流和辐射边界条件:The outer surface of the busbar should satisfy the convection and radiation boundary conditions:
式中,q是热流密度矢量,Ta是环境温度;ke表示母排表面的对流换热系数;ε表示母排表面的热发生率;σ表示史蒂芬-玻尔兹曼常数。In the formula, q is the heat flux vector, T a is the ambient temperature; k e represents the convective heat transfer coefficient on the surface of the busbar; ε represents the heat generation rate on the surface of the busbar; σ represents the Stefan-Boltzmann constant.
(三)固体力学(3) Solid Mechanics
描述扰动力作用下有阻尼强迫振动系统物体的运动微分方程为:The motion differential equation describing the motion of an object in a damped forced vibration system under the action of a disturbance force is:
式中m为振动系统的总质量,C表示物体运动时支承隔振器的粘性阻尼系数,K表示弹簧刚度单位变形的作用力。F0sinωt表示系统受到的扰动力,坐标轴放于物体静平衡位置O上。x、分别表示整体坐标系下节点的位移、速度和加速度。In the formula, m is the total mass of the vibration system, C represents the viscous damping coefficient of the supporting vibration isolator when the object is moving, and K represents the force of the unit deformation of the spring stiffness. F 0 sinωt represents the disturbance force received by the system, and the coordinate axis is placed on the static equilibrium position O of the object. x, Respectively represent the displacement, velocity and acceleration of the node in the global coordinate system.
3、根据实际运行情况进行参数和边界条件的设定3. Set parameters and boundary conditions according to actual operating conditions
电磁场:在A相、B相、C相三相母线上分别施加额定的3.15kA的电流,相位差为120°,设置电缆室输出的三相母排出线接地。通过改变动静触头和梅花触头的接触面以及断路器接触面的电导率来设置接触阻抗,并且添加力计算。Electromagnetic field: Apply a rated current of 3.15kA to the A-phase, B-phase, and C-phase three-phase busbars respectively, with a phase difference of 120°, and set the three-phase busbars output from the cable room to ground. The contact impedance is set by changing the contact surface of the moving and static contact, the plum blossom contact and the conductivity of the circuit breaker contact surface, and the force calculation is added.
固体传热:设置环境温度为T为293K,根据开关柜运行的实际情况来对不同的部分设置不同的对流换热系数;根据表面空气流速大小,将对流冷却的表面分为三部分:Solid heat transfer: set the ambient temperature as T to 293K, and set different convective heat transfer coefficients for different parts according to the actual operation of the switchgear; according to the surface air velocity, the convective cooling surface is divided into three parts:
第一部分为柜内空气流通较充分的母线室,对流换热系数为4W/(m2**K);第二部分为断路器的内部部分,对流换热系数为3W/(m2*K);第三组为柜体和底座,对流换热系数为5W/(m2K)。The first part is the bus room with sufficient air circulation in the cabinet, and the convective heat transfer coefficient is 4W/(m 2* *K); the second part is the inner part of the circuit breaker, and the convective heat transfer coefficient is 3W/(m 2 *K) ); the third group is the cabinet and the base, the convective heat transfer coefficient is 5W/(m 2 K).
设置母排为热传导;同时进行表面的热辐射的设置,设置母线的辐射因子为0.4,绝缘子的辐射因子为0.8。Set the busbar to heat conduction; at the same time, set the surface heat radiation, set the radiation factor of the busbar to 0.4, and the radiation factor of the insulator to 0.8.
固体力学:选取整个开关柜为作用域,分别设置断路器底座、绝缘子支撑、母线端部为固定约束。Solid Mechanics: Select the entire switchgear as the scope, and set the circuit breaker base, insulator support, and busbar ends as fixed constraints.
本发明的材料参数如表1所示。The material parameters of the present invention are shown in Table 1.
表1各种材料参数表Table 1 Various material parameter table
4、基于有限元法对该模型进行网格剖分,并设置仿真时间及步长:设置全局网格大小,进一步根据局部几何特征将网格进行细化处理,其后构建全部网格,再设置仿真时间和步长,开始计算直到满足时间条件,仿真结果收敛。4. Carry out grid division for the model based on the finite element method, and set the simulation time and step size: set the global grid size, further refine the grid according to the local geometric characteristics, and then build all the grids, and then Set the simulation time and step size, and start the calculation until the time condition is met, and the simulation result converges.
5、本发明基于开关柜频域-稳态的研究,首先仿真得到稳态时温度的分布如图3所示:温度较高点集中在通风情况不太好的断路器和梅花触头处。其中最热点出现在断路器的连接处。5. The present invention is based on the frequency domain-steady state research of the switchgear. First, the temperature distribution in the steady state is simulated as shown in Figure 3: the higher temperature points are concentrated at the circuit breaker and the plum blossom contact with poor ventilation. The hottest of these occurs at the connection of the circuit breaker.
电场强度的分布如图4(1)所示:触头处,以及母排的弯曲处电场强度比较大。电流密度分布如图4(2)所示:在断路器的连接处电流最为集中,梅花触头和母排的弯曲处电流密度较大,可以清晰的看出母排的集肤效应,电流多集中于母线的表面。The distribution of the electric field intensity is shown in Figure 4(1): the electric field intensity at the contact and the bend of the busbar is relatively large. The current density distribution is shown in Figure 4(2): the current is most concentrated at the connection of the circuit breaker, and the current density is relatively high at the bend of the plum blossom contact and the busbar. The skin effect of the busbar can be clearly seen, and the current is high. Concentrate on the surface of the busbar.
在X、Y、Z三个平面上时均洛伦兹力的分布如图5所示:时均洛伦兹力较大的部分也是集中断路器、梅花触头和母排的弯曲处,这些部分需要进行加固,防止因为电动力的原因导致事故,通过仿真可以进一步探究其他部分的受力情况,并进行调整,提高开关柜的安全稳定性。The distribution of the time-average Lorentz force on the three planes X, Y, and Z is shown in Figure 5: the part with the larger time-average Lorentz force is also the bend of the integrated circuit breaker, the plum contact and the busbar. Some parts need to be reinforced to prevent accidents caused by electrodynamic forces. Through simulation, the stress of other parts can be further explored and adjusted to improve the safety and stability of the switchgear.
其次,通过仿真,对比分析额定工况下环境温度为293K,298K,303K,308K,313K,时开关柜的平均温度和最大温度,如图6所示:相同热源及条件下改变环境温度不影响温度的分布趋势只影响温升的大小,将计算的到相关数据进行比较可知:随环境温度的上升,开关柜的最大温升及平均温度都随之上升,并且两者大致呈线性关系。Secondly, through simulation, compare and analyze the average temperature and maximum temperature of the switchgear when the ambient temperature is 293K, 298K, 303K, 308K, and 313K under rated working conditions, as shown in Figure 6: changing the ambient temperature under the same heat source and conditions does not affect The temperature distribution trend only affects the temperature rise. Comparing the calculated and related data, it can be seen that as the ambient temperature rises, the maximum temperature rise and the average temperature of the switchgear rise accordingly, and the relationship between the two is roughly linear.
6.步骤S7具体为,通过固体力学接口,设置不同的固定约束,分析其对母排因受力引起的位移变化的影响;6. Step S7 is specifically, through the interface of solid mechanics, setting different fixed constraints, and analyzing its influence on the displacement change of the busbar due to the force;
根据多物理场的耦合分析,耦合固体传热和固体力学,可以得到热膨胀引起的位移的影响如图7所示:(1)当固定断路器时,电缆室和母线室的母排形变较为明显,最大位移可达1.7mm;(2)当固定绝缘子时,有绝缘子支撑的母线形变较小,但是断路器和缺乏支撑的母线形变比较明显,最大的位移可达1.43mm;(3)当固定母线室和电缆室的母线端部时,导致断路器和母线的弯曲处形变明显。最大位移可达1.08mm。According to the coupling analysis of multi-physics fields, coupling solid heat transfer and solid mechanics, the influence of displacement caused by thermal expansion can be obtained as shown in Figure 7: (1) When the circuit breaker is fixed, the deformation of the busbar in the cable room and the busbar room is more obvious , the maximum displacement can reach 1.7mm; (2) When the insulator is fixed, the deformation of the busbar supported by the insulator is small, but the deformation of the circuit breaker and the busbar without support is more obvious, and the maximum displacement can reach 1.43mm; (3) when the fixed When the end of the busbar in the busbar room and the cable room is damaged, the bending of the circuit breaker and the busbar will be deformed significantly. The maximum displacement can reach 1.08mm.
综上所述,对以上的部位进行固定对开关柜的安全稳定运行十分重要,可以最大程度减少母排的形变。同时可以设置不同的固定位置,进一步探究对其对母排稳定性的提高。To sum up, fixing the above parts is very important for the safe and stable operation of the switchgear, and can minimize the deformation of the busbar. At the same time, different fixed positions can be set to further explore the improvement of the stability of the busbar.
7.步骤S8具体为,通过仿真改变连接处的接触压力,进而改变接触阻抗,分析其对温升的影响程度以及对应力的影响;如图8所示:无论是在梅花触头处还是在断路器处改变接触阻抗来改变压力,该部位的平均温度都与接触阻抗的变化近似成线性关系,由图可知,当接触压力变大时,该部位的温升会小幅度降低,有利于开关柜的稳定运行;7. Step S8 is specifically to change the contact pressure at the connection through simulation, and then change the contact impedance, and analyze its influence on temperature rise and stress; as shown in Figure 8: whether it is at the plum blossom contact or at the The contact impedance at the circuit breaker is changed to change the pressure. The average temperature of this part is approximately linear with the change of the contact impedance. It can be seen from the figure that when the contact pressure becomes larger, the temperature rise of this part will be slightly reduced, which is beneficial to the switch. The stable operation of the cabinet;
同理,如图9所示,设置不同的接触阻抗的两个部位,随着接触电导的增加,平均应力随着接触压力的增加而降低,说明适当的增加接触压力可以减小母排的应力变化。Similarly, as shown in Figure 9, when two parts with different contact impedances are set, as the contact conductance increases, the average stress decreases with the increase of contact pressure, indicating that an appropriate increase in contact pressure can reduce the stress of the busbar Variety.
采用本发明方法可以通过修改电流激励和材料的特性来仿真得到不同情况下开关柜的温升、电场强度以及电动力的分布特性。计算结果可以对开关柜的运行情况进行分析,不但可以能够为开关柜传感器的优化布局提供理论依据,还为开关柜的工程设计优化及散热结构设计提供了基础。By adopting the method of the invention, the distribution characteristics of temperature rise, electric field intensity and electromotive force of the switchgear under different conditions can be simulated by modifying the current excitation and the characteristics of the material. The calculation results can analyze the operation of the switchgear, which can not only provide a theoretical basis for the optimal layout of the switchgear sensors, but also provide a basis for the engineering design optimization and heat dissipation structure design of the switchgear.
以上优选实施例仅为说明本发明的技术方案,并不限于此,对于本领域的技术人员而言,可以在不偏离权利要求书限定范围的基础上,针对形式、细节进行修改、替换或优化等各种改变。采用本发明方法可以获得开关柜在不同因素影响下的电场强度和最热温度分布特性,以及电动力的分布特性。The above preferred embodiments are only to illustrate the technical solutions of the present invention, and are not limited thereto. Those skilled in the art can modify, replace or optimize the forms and details without departing from the scope of the claims. Wait for various changes. By adopting the method of the invention, the electric field intensity and the hottest temperature distribution characteristics of the switchgear under the influence of different factors, as well as the distribution characteristics of the electromotive force can be obtained.
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CN119783420A (en) * | 2025-03-12 | 2025-04-08 | 正泰电气股份有限公司 | Determination method and device of electrodynamic force, electronic equipment and storage medium |
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CN119783420A (en) * | 2025-03-12 | 2025-04-08 | 正泰电气股份有限公司 | Determination method and device of electrodynamic force, electronic equipment and storage medium |
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