特高压电力变压器波过程及绕组模型研究

发布时间：2018-10-15 12:31

【摘要】：特高压电力变压器是特高压智能电网的骨干设备,其显著特点是电压等级高、负载容量大,其运行可靠性是电网安全稳定运行的基础。在系统运行过程中,电力变压器易受各种内外部过电压的影响,尤其是雷电冲击过电压,对变压器绕组绝缘结构的影响更大。特高压变压器的电压水平高,并受运输条件的限制,其尺寸、绝缘距离、绝缘厚度等不能无限增大。因此,在进行特高压变压器设计时,首先应解决产品雷电冲击下产品波过程问题,以保证绕组结构的合理性和可靠性,从而确保产品挂网运行的安全、可靠。本文通过查阅相关文献,对目前电力变压器波过程研究现状进行了深入分析。首先,详细研究了在雷电冲击电压作用下,变压器绕组等值电路电容、电感参数计算问题。然后,结合实际工程经验,分析了多种绕组结构形式下电容补偿作用的效果,以典型1000kV特高压自耦变压器为例,设计了高压、中压、低压、调压、励磁补偿等绕组的结构形式。最后,应用专用雷电冲击电压计算软件,对各工况下绕组的雷电冲击情况进行建模仿真分析,最终确定了特高压变压器各类绕组的类型。为验证雷电冲击理论分析与实际的情况的差异性,对实际绕组模型的冲击电压试验及测试方法进行了研究。首先,研究目前已有几种绕组模型试验测量方法原理和特点,对比分析其优缺点。然后,针对以往测试方法的不足,提出了一种利用耦合传感器测量雷电冲击下绕组电压的测量方法,研究制作了比例模型,并对模型进行低电压测试,将软件仿真结果与实测的电压分布情况进行对比,证明了专业软件的准确性。最后,研究了高电压雷电冲击试验方法,并对模型进行了雷电冲击试验,以考核模型绕组结构绝缘的强度。经分析,该绕组结构无击穿、放电现象,通过高电压型式试验考核,为特高压变压器的产品设计奠定了坚实基础。
[Abstract]:UHV power transformer is the backbone equipment of UHV smart grid, its remarkable characteristics are high voltage grade, large load capacity, and its operation reliability is the basis of safe and stable operation of power grid. During the operation of the system, power transformers are susceptible to various internal and external overvoltages, especially lightning impulse overvoltages, which have a greater impact on the insulation structure of transformer windings. The voltage level of UHV transformer is high and limited by transportation conditions. Its size, insulation distance and insulation thickness can not be increased indefinitely. Therefore, in the design of UHV transformer, the problem of product wave process under the impact of product lightning should be solved first, so as to ensure the rationality and reliability of the winding structure and ensure the safety and reliability of the operation of the product grid. In this paper, the current research status of power transformer wave process is analyzed by consulting relevant documents. Firstly, the calculation of the equivalent circuit capacitance and inductance of transformer winding under the action of lightning impulse voltage is studied in detail. Then, combined with practical engineering experience, the effect of capacitor compensation under various winding structures is analyzed. Taking typical 1000kV UHV autotransformer as an example, the structure forms of high voltage, medium voltage, low voltage, voltage regulating and excitation compensation windings are designed. Finally, by using the special lightning impulse voltage calculation software, the lightning impulse situation of the windings under various working conditions is modeled and analyzed, and the types of various windings of the UHV transformer are finally determined. In order to verify the difference between the theoretical analysis of lightning shock and the actual situation, the impulse voltage test and test method of the actual winding model are studied. Firstly, the principle and characteristics of several winding model test methods are studied, and their advantages and disadvantages are compared and analyzed. Then, in view of the shortcomings of the previous testing methods, a method of measuring winding voltage under lightning shock by coupling sensor is proposed, and the proportional model is developed, and the model is tested at low voltage. The accuracy of the software is proved by comparing the simulation results with the measured voltage distribution. Finally, the high voltage lightning shock test method is studied, and the lightning shock test is carried out on the model to assess the insulation strength of the model winding structure. The analysis shows that the winding structure has no breakdown and discharge phenomenon. Through the test of high voltage type, it lays a solid foundation for the product design of UHV transformer.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41

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