共查询到19条相似文献,搜索用时 171 毫秒
1.
2.
变压器局部放电综合判断分析 总被引:1,自引:0,他引:1
指出了变压器局部放电定位的重要性,简述了多端子测量多端子校正、变电位多端测量、脉冲极性鉴定法和超声波定位法的原理,通过实例分析了局部放电定位过程和处理方法, 并得出要根据产品的不同结构和类型,灵活选择不同的方法, 且相互验证,互为补充,才能较准确地进行局放定位的结论。 相似文献
3.
4.
局部放电信号在电力变压器绕组传播过程中的畸变 总被引:16,自引:2,他引:16
由于变压器是绕组类设备,变压器内部的局部放电信号将经绕组向两端传播至监测装置,从而导致作为故障诊断基础信息的放电脉冲信号发生一定程度的畸变,该文根据对脉冲信号在绕组中传播过程的实际测量结果,获得了绕组的基本冲击响应特性,利用典型模型放电的纳秒级快速变化波形测量结果,研究了不同情况(不同放电类型、不同放电部位以及不同的测量点)下放电脉冲信号在绕组中的传播规律,并提出了一种从实际测量波形中有效分析原始放电波形的方法,为实际的局部放电脉冲波形监测提供了试验依据。 相似文献
5.
6.
7.
考虑到高电压电力变压器中套管和绕组绝缘问题所引起的故障较多 ,研究诊断起始故障的方法 ,用以避免长时期停用及其后果是重要的。为了评定设备危害程度 ,本工作的目的是要研究有关判断变压器内部局部放电位置的检定和测量方法。这套方法是基于从变压器套管进行的局部放电的非侵害性测量。考虑了变压器绕组模型以及对局部放电脉冲响应的测量和适当评定 ,判断出局部放电源的位置。通过适当的模拟、测量和判断 ,可以做到该问题的定位。测量时使用了 IEC2 70标准建议的传统检测技术。 (译者按 :作者对支持者的感谢一句 ,此处略去不译 )。 相似文献
8.
变压器线圈中局部放电脉冲的传播过程可以用谐波振荡和行波过程来解释。局部放电在线圈端子上的响应可以认为是数个谐波叠加的结果,且各次谐波的幅值与局部放电的位置有关。在进行变压器局部放电试验时,测试系统的频带应尽量包括线圈基波频率。线圈主绝缘中放电的响应比纵绝缘中放电的响应大一个数量级以上,因此,现行的局部放电测试和标准不能确定纵绝缘中是否存在危及绝缘安全运行的局部放电。 相似文献
9.
10.
11.
Xuzhu Dong Deheng Zhu Changchang Wang Kexiong Tan Yilu Liu 《Dielectrics and Electrical Insulation, IEEE Transactions on》1999,6(6):803-813
This paper discusses the development of a simulation model to study the propagation of partial discharge (PD) pulses of transformers in a 500 kV substation. The results will be used to design an on-line PD monitoring system for transformers. The impedance matrix of a 500 kV, single-phase transformer is computed based on geometry data and its external coupling network (often referred to as coupling impedance) is calculated with electromagnetic transients program (EMTP). It was found that the frequency characteristic of the coupling network is complex and that the traditional lumped coupling capacitance representation is only feasible at <60 kHz. The entire substation network was included to calculate the PD propagation of the transformer. PD responses are obtained at the tank grounding and 500 kV bushing tap grounding with a simulated PD pulse injected at the 500 kV terminal and 220 kV terminal of the transformer, respectively. Simulation shows that, using the resonant frequency of the substation network as monitoring frequency, one effectively can increase the monitoring sensitivity. The off-line and on-line PD calibration can also be made based on the developed simulation model 相似文献
12.
《Electric Power Systems Research》1999,50(1):47-54
Partial discharge (PD) is one of the major factors causing insulation damage of power transformers. This paper describes the development of on-line partial discharge monitoring system for transformers. The developed set can monitor up to four power transformers continuously. It uses various methods to reject interference and enhances monitoring sensitivity of PD effectively. The optical cable is applied to communicate between measurement system near transformers and the upper computer in the main control building. On-line calibration of partial discharge quantity is requisite for on-line detection or monitoring. This paper describes an on-line calibration method using pulse injection through tap of high voltage transformer bushings. It also discusses the influence of limit inductance and bushing capacitance, from tap of bushing to ground, in on-line calibration circuits. Influences of multi-grounding of the transformer tank for monitoring and calibration are also discussed. Simulation in laboratory and site test shows that the method is practically valid for on-line PD calibration of power transformers within permissible engineering error range under certain defined conditions. This system has been in operation steadily in 500 kV substations for more than 2 years. 相似文献
13.
Transfer function-based partial discharge localization in power transformers: a feasibility study 总被引:1,自引:0,他引:1
Statistical studies have shown that failures of bushings, winding insulation, and online tap changers are the main causes for long-duration outages of transformers. This article investigates the development of an instrument for supervising the conditions of transformer units. The use of sectional winding transfer functions (SWTFs) for online PD evaluation in power transformers has several advantages: localization of PD sources, discrimination between PDs inside or outside of the transformer, and evaluation of actual PD amplitudes along the winding. Direct measurement of SWTFs-when different points along the coil are accessible-and use of these SWTFs for PD evaluation and localization has shown excellent results. In order to use this method at transformers on site, an appropriate modeling method is needed for the computation of the SWTFs using only measurements at the transformer terminals. A detailed modeling approach based on discrete RLC circuit elements has been studied and different algorithms used for parameter estimation and optimization. This model is applicable in practical cases for a limited frequency range if genetic algorithms (GAs) are used for parameter optimization. A new method based on traveling wave theory has been investigated using genetic algorithms to search for the optimum parameters of a partial differential equation that describes the transient behavior of the coil. This method has shown potential in solving SWTF calculation problems for different transformers. 相似文献
14.
Partial discharge localization in transformer windings using multi-conductor transmission line model
Multi-conductor transmission line model (MTLM) of transformer winding has been used to find partial discharge (PD) location in transformers. To decrease computational complexity of the model, two methods for calculation of model parameters were studied and the most suitable method was chosen based on comparison between measured and calculated transfer functions of a 132 kV/20 kV transformer. To investigate the accuracy of MTLM in PD localization, PD pulses produced by a PD calibrator were injected into different points of a research 20 kV/0.4 kV transformer and measured at both ends of the winding. The sectional winding transfer functions computed by the model were used to refer measured PD signals to possible PD locations. Then by comparison of referred signals, PD location in the winding was estimated. 相似文献
15.
16.
17.
18.
19.
Partial Discharge (PD) characteristics of four typical transformer oils, having respective viscosities of 3.5, 9.1, 13.0, 18.3 cSt at 40/spl deg/C, were examined under ac conditions, using a needle-to-plane electrode system. Wide and narrow bandwidth measurements were carried out to determine simultaneously the apparent charge transfers associated with the overall PD pulse bursts in the oil as well as that of the individual discrete PD pulses within the PD pulse bursts themselves. Based on the apparent charge transfer value, the size or depth of the PD initiating microcavities in the field direction within the oils, producing the first detected discrete PD pulse, were estimated to be in the order of 2 /spl mu/m. The recurrence rate of the PD pulse bursts was found to increase with voltage above the PD inception voltage; this increase was accompanied by both an increase in number of discrete PD pulses and their amplitude within the pulse burst itself. These increases were reflected by a substantial rise in the apparent charge transfer per PD pulse burst. The charge transfer levels of the PD pulse bursts associated with the highly pressurized gas microcavities were of the same order of magnitude as those produced within the normally much larger macroscopic cavities that exist under atmospheric pressure in conventional oil-impregnated insulating systems of power transformers. 相似文献