干式空心电抗器故障不平衡电流及检测系统的研究

发布时间：2018-04-12 08:10

本文选题：干式空心电抗器 + 不平衡电流　；参考：《重庆理工大学》2017年硕士论文

【摘要】：干式空心电抗器具有价格低、结构简单、重量轻、电抗值线性、损耗低、维护方便等技术优势,已广泛应用于现代电力系统中并起到无功补偿、高次谐波抑制、特高压输电滤波、中性点接地、冲击电流、短路电流抑制等作用,是保证电力系统安全、稳定运行的重要设备。然而,干式空心电抗器在运行中易出现短路、断线,匝间放电等故障,这严重降低了电力系统的稳定,因此电抗器的故障检测意义重大。在电力系统中,当前投入使用的检测方法如阻抗检测、温度检测、零序功率检测等方法灵敏度低。因此,研究更灵敏的故障检测方法对电抗器及电力系统的稳定具有极大的实际价值。本文首先针对干式空心电抗器故障检测灵敏度的不足,提出了故障不平衡电流检测法。这种方法利用干式空心电抗器结构的对称性,通过测量干式空心电抗器故障后其汇流母排产生的不平衡电流,从而判断其是否发生故障。其次,建立了单包封四绕组干式空心电抗器的物理模型,在此基础上利用解析法得到了汇流母排电流的数学解析模型。物理模型和对应的数学解析模型均包括无故障、单匝短路、两绕组匝间短路、多绕组匝间短路、断线五种情况。以上五种模型均计算了干式空心电抗器各汇流母排电流,并采用matlab进行仿真计算,分析了故障前后各汇流母排不平衡电流的分配规律及相位变化规律。对比分析发现不平衡电流法比依托相位变化的零序功率方向保护法效果更好,同时还发现五种故障中两绕组匝间短路故障最难检测。最后,本文对最难检测的两绕组匝间短路模型从稳态与暂态两个方面进行了实验研究,分析了母排电流的稳态数据与暂态波形,得到了不平衡电流与短路位置的关系,进一步验证了故障不平衡电流法的可行性。并根据干式空心故障不平衡电流法搭建了无线检测系统。本研究对空心电抗器故障检测以及电抗器的制造都具有重要意义。
[Abstract]:The dry hollow reactor has the advantages of low price, simple structure, light weight, linear reactance value, low loss and convenient maintenance. It has been widely used in modern power system and has played a reactive power compensation, high harmonic suppression, etc.UHV transmission filtering, neutral grounding, impulse current, short circuit current suppression and so on, are important equipment to ensure the safe and stable operation of power system.However, the dry type hollow reactor is prone to short-circuit, breakage, inter-turn discharge and other faults in operation, which seriously reduces the stability of power system, so the fault detection of reactor is of great significance.In power system, the current detection methods, such as impedance detection, temperature detection, zero-sequence power detection, are of low sensitivity.Therefore, it is of great practical value to study more sensitive fault detection methods for reactor and power system stability.In this paper, the fault unbalance current detection method is proposed to solve the problem of fault detection sensitivity of dry hollow reactor.By using the symmetry of the dry hollow reactor structure, the unbalanced current produced by the busbar of the dry hollow reactor is measured after the failure of the dry type hollow reactor, and the failure of the reactor can be judged by this method.Secondly, the physical model of the single-encapsulated four-winding dry hollow reactor is established, and the mathematical analytical model of the busbar current is obtained by using the analytical method.Both the physical model and the corresponding mathematical analytical model include five cases: no fault, single turn short circuit, two winding inter-turn short circuit, multi-winding inter-turn short circuit, and broken wire.All of the above five models have calculated the busbar current of the dry hollow reactor and simulated it by matlab, and analyzed the distribution law and phase change law of the unbalanced current of each busbar before and after the failure.It is found that the unbalanced current method is more effective than the zero-sequence power direction protection method based on phase change. At the same time, it is found that the two-winding inter-turn short circuit fault is the most difficult to detect among the five kinds of faults.Finally, the most difficult two-winding inter-turn short circuit model is experimentally studied from two aspects of steady state and transient state. The steady state data and transient waveform of the bus current are analyzed, and the relationship between the unbalanced current and the short circuit position is obtained.The feasibility of fault unbalanced current method is further verified.The wireless detection system is built according to the dry hollow fault unbalanced current method.This study is of great significance to the fault detection of hollow reactor and the manufacture of reactor.
【学位授予单位】：重庆理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM47

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