换流变阀侧套管数字孪生建模及热特性分析

Establishment of Digital Twin Model of Converter Transformer Valve-side Bushing and Analysis of Its Thermal Characteristics

针对换流站变压器阀侧套管现场缺乏有效手段对其内部状态进行检测评估,建立了换流变阀侧套管数字孪生模型,并基于该模型确定了换流变阀侧套管内部缺陷下的热分布特性。首先,建立了阀侧套管数字孪生架构以及基于物联网的数字孪生实现框架,提取了换流变阀侧套管运行电流等参数,通过傅里叶分析确定了阀侧套管实际运行电流谐波特性。基于该特性,提出了考虑多频谐波电流集肤效应的套管热损耗计算方法。其次,设立实体信息采集端口,建立了基于现场数据的换流变阀侧套管数字孪生计算流程及仿真模型,并通过温升试验验证了模型的准确性,试验结果表明模型温度误差绝对值<1℃。最后,基于该模型,计算了阀侧套管内部表带触指连接缺陷下的温度场分布,并确定了不同缺陷程度下的阀侧套管内部温度分布特性。研究结果可为现场分析阀侧套管内部状态提供有效支撑。

Aiming to solve the lack of effective methods to detect and evaluate the internal state of the valve-side bushing in converter station,we established a digital twin model of the valve-side bushing and determined the heat distribution characteristics under the internal defects of the valve-side bushing based on the model.Firstly,the digital twin architecture and IoT-based digital twin implementation framework of the valve-side bushing were established.The parameters such as the running current in the valve-side bushing were extracted and the harmonic characteristics of the actual running current in the valve-side bushing were determined by the Fourier analysis.Based on the characteristics of running current,a calculation method of heat loss in bushing in which the skin effect of multi-frequency harmonic current was taken into account was proposed.Then,collection ports for entity information were set up,and a digital twin calculation flowchart and a digital twin simulation model of the valve-side bushing was established based on field data.The accuracy of the model was verified by field tests.The test results show that the error of the model is less than±1℃.Finally,the model was used to calculate the temperature field distribution in the valve-side bushing with the connecting defect of the contact finger,and the temperature distribution characteristics in the valve-side bushing with different defect degrees were determined.The research results can provide effective supports for the field analysis of the internal state of the valve-side bushing.