【作者】 孙海峰；

【导师】 崔翔；

【作者基本信息】 华北电力大学（北京） ， 电工理论与新技术， 2010， 博士

【摘要】 建立高压直流换流站换流系统宽频等效电路模型,是准确计算换流阀系统过电压分布以及准确预测换流站电磁骚扰水平的关键,也是我国换流站电磁兼容技术国产化的基本要求。本文结合国家自然科学基金项目“高压直流换流阀系统参数提取及宽频等效电路模型的研究”(50707008)和“十一五”国家科技支撑重大项目课题20“±800kV直流输电线路表面电晕起始场强计算和±800kV换流站阀厅的电磁兼容问题研究”(2006BAA02A20),重点研究了高压直流换流阀系统以及换流站关键设备的宽频电路建模方法,测量结果验证了本文所提出的换流系统宽频等效拓扑的有效性和实用性。基于阀系统宽频等效电路,研究了换流阀系统过电压分布特性及其影响因素；基于换流站换流系统宽频拓扑,研究了±800kV高压直流换流站的传导电磁骚扰特性以及辐射电磁骚扰水平。本文主要研究成果如下：1.提出了基于黑箱理论与传统等效电路相结合的建模方法,该方法不但可以保持传统等效电路参数的意义,还可以考虑高频下器件的频变效应,有效的解决了黑箱理论与传统等效电路存在的问题。基于该方法,建立了换流阀主要器件的宽频等效电路。研究表明,采用所提方法建立的模型在较宽的频率范围内均有效,能够应用于电力电子系统的宽频建模。2.对不同型式的换流阀系统的各项寄生电容参数和寄生电感参数进行了提取,结合换流阀主要器件的宽频模型,建立了用于过电压计算与分布的换流阀系统宽频等效电路；对高压直流换流站交直流场内的关键设备进行了宽频建模研究,建立了换流站换流系统宽频拓扑。3.对阀模块以及多重阀塔开展了过电压实验研究,实验结果验证了换流阀宽频等效电路的有效性；对换流站内各种类型的电磁骚扰进行了现场测量,测量结果验证了换流站换流系统宽频拓扑的有效性。4.根据换流阀系统宽频等效电路,对各种型式的阀模块以及阀塔在各种过电压作用下的电压分布特性进行了计算,并对影响阀层电压梯度和晶闸管压降的各项参数进行了分析,得出了高压直流换流阀过电压分布规律。该研究可用于换流阀系统国产化过程中的均压和绝缘设计。5.根据换流站换流系统宽频拓扑,对±800kV高压直流换流站的传导电磁骚扰特性进行了仿真计算,以传导骚扰电流为激励,对换流站内以及周边的辐射电磁骚扰水平进行了预测计算,计算结果对换流站的电磁屏蔽设计以及设备的抗扰度要求有一定的工程参考价值。更多还原

【Abstract】 Wideband modeling of converter systems is essential to predict the electromagnetic environment and calculate overvoltage distributions of thyristor valves in High Voltage Direct Current (HVDC) converter stations. This tenology is also the basic equirement of the national independent innovation of electromagnetic compatibility (EMC) in HVDC converter stations in China. Supported by the National Natural Science Foundation of China (Grant No.50707008) and the Eleventh Five-Year Plan for National Science and Technology (Grant No.2006BAA02A20), the modeling methodology of wideband equivalent topology of converter systems in HVDC converter stations is proposed to calculate the overvoltage distributions in the thyristor valves and to predict the electromagnetic environment of±800kV converter station. Compared with the measured results, the proposed methods are proved to be efficient. The main innovative achievements are as follows:1. An efficient method is proposed to model the passive devices with traditional equivalent circuit combined with black-box theory. The new method enables the designers to retain their existing physical models while providing a means to capture the high frequency effects accurately. Based on this method, wideband equivalent circuits of the valve components, such as thyristor, saturable reactor and snubber circuits, are obtained based on impedance measurement.2. Stray capacitances and inductance of different type of thyristor valves are extracted and analyzed. Combined with the wideband models of valve components, wideband model of the whole valve system is presented. The wideband models of the key equipments in AC and DC yard are also proposed in this paper, such as converter transformer, smoothing reactor, filters, et al.3. Overvoltage testing expriments are carried out. Voltage distributions are measured both in valve modules and valve tower. The experimental results verify the validity of the proposed wideband model of thyristor valves. Electromagnetic disturbances are measured on site and the results indicate that the wideband topology of the whole converter systems is effective.4. Based on the wideband equivalent circuit of the thyristor valves, the voltage gradient of valve layers and voltage distribution among valve components were calculated under different kinds of overvoltages including switching, lightening and fast front overvoltage, and the influence factors were also discussed. Some regularity was obtained, e.g. the stray capacitances of the valves have an effect on the overvoltage distribution among valve components, while the parameters of the valve components can influence the voltage drop on thyristors. Lastly, some improved measures are proposed.5. Based on the wideband topology of the whole converter systems, the characteristic of the conductive electromagnetic disturbances in±800kV HVDC converter station is simulated and anslyzed. And the radio interference level is also calculated both inside and surrounding the converter station. These results could have a guide on immunity and valve hall screening design of future HVDC converter stations in China.更多还原