故障条件下中压开关柜温升特性的仿真研究

Simulation Study of Temperature Rise Characteristics of Medium Voltage Switchgear Under Fault Conditions

中压开关柜发热故障占比较高,故障条件下难以满足温升标准,因此研究中压开关柜在故障状态下的温升特性对于电网的安全运行具有重要意义。论文首先利用有限元仿真软件ANSYS apdl和CFX建立了电磁–流体–温度场耦合的仿真模型,分析了1.1倍额定电流下的温升分布,并通过实验进行了验证;之后分别仿真分析了真空灭弧室内和梅花触头处的接触压力对温升的影响;最后分析了两处接触压力同时变化对温升的影响,并且基于仿真结果进行函数拟合得到了接触电阻与温升之间的关系式。研究结果表明:由于接触压力减小导致的接触电阻增大将导致温升升高,通过观察其变化趋势可以发现接触电阻对温升的影响呈线性关系;梅花触头处接触电阻与真空灭弧室内接触电阻对温升的影响相互独立。

The heating faults of the medium voltage switchgear account for a relatively high proportion, and it is difficult to meet the temperature-rise standard in the case of a fault. Therefore, it is of critical significance for the safe operation of power system to investigate the temperature-rise characteristics of a switchgear under the fault state. Firstly, we established the simulation model of electromagnetic-fluid-temperature coupling by using the finite element simulation software ANSYS apdl and CFX. Meanwhile,we analyzed the temperature rise distribution at 1.1 times the rated current and verified it through experiment. Secondly, the influences of the contact pressure in vacuum interrupter and plum contact on the temperature rise were simulated and analyzed, respectively. Finally, the influence of the simultaneous changes of the two contact pressures on the temperature rise was analyzed. Based on the simulation results, function fitting was performed to obtain the relationship between contact resistance and temperature rise. It is found that the increase in contact resistance caused by the decrease in contact pressure will lead to an increase in temperature rise. By observing its change trend, it can be found that the influence of contact resistance on temperature rise is linear. The contact resistances in the vacuum interrupter and plum contact have independent effects on the temperature rise.