油浸式电力变压器铁心接地故障诊断与处理

铁心接地故障是电力变压器频发性故障之一,本文介绍了变压器铁心接地故障的原因、类型、故障诊断及处理方法。     

油浸式电力变压器铁心接地故障诊断与处理

铁心接地故障是电力变压器频发性故障之一,本文介绍了变压器铁心接地故障的原因、类型、故障诊断及处理方法.     

变压器铁芯多点接地故障的判断及处理

介绍了电力变压器铁芯接地故障的类型、原因及危害,并结合银川供电局沙渠变1号变压器铁芯多点接地故障处理实例,对变压器铁芯多点接地故障的分析判断及现场简易处理方法作了探讨。     

核电500kV主变压器C相故障原因分析及处理

介绍了某核电站500kV主变压器故障情况,对故障原因进行了分析。通过变压器油中溶解气体分析、故障波形分析、常规试验数据分析和内检,确定了主变压器故障类型,并提出了处理措施。     

大型变压器铁心多点接地故障的分析与处理

介绍了大型变压器铁心发生多点接地故障类型,分析了各类型故障的原因,提出了处理对策,并给出了铁心故障处理实例。     

浅谈三比值法在变压器故障诊断中的应用

变压器在电力系统中具有很重要的作用,同时因为变压器结构繁杂、运行时间长,变压器故障频发,所以电力变压器的故障诊断显得非常重要。分析了变压器不同故障类型产生的不同类型气体,运用基于溶于油中气体的三比值法来初步判断变压器的故障,便于电力运检人员有针对性地进行故障排查和检修,缩短变压器故障处理时间,提高维护检修的效率和系统供电可靠性。     

一起500kV变压器内部放电故障的检修

变压器的安全运行关系到电网的稳定性,对一起500 k V变压器内部放电故障案例进行分析,探讨该主变放电原因,并对该主变故障采取相应的处理措施,为变电站变压器设备的该类型放电故障原因分析、故障检修提供了借鉴。     

油中溶解气体分析法在变压器故障诊断中的应用

在对某变电所的1号主变压器运行状况及故障后诊断数据分析的基础上,前期用特征气体法和改良三比值法分析与判断了变压器故障类型,估算了热点温度、故障面积和故障部位,后期做了处理后续跟踪与分析,印证了所做变压器故障类型的正确性,指出应该采用多种不同类别的方法同时进行判断才能得到较为准确的结果。     

一起变压器铁心接地故障性质判断及处理

介绍了变压器铁心多点接地的几种类型,并以一起变压器铁心接地故障为例,采用多种方法对变压器故障性质进行分析、判断并处理.处理过程完全按照文中所列的流程进行,结果证明了分析流程的有效性及实用性.     

电力变压器故障分析及处理

变压器的故障原因、故障类型比较多,也比较复杂.下面,笔者仅就自己在基层供电部门从事变压器检修、试验、日常维护等工作的过程中,遇到的变压器绝缘老化、中性点过电压、变压器套管故障、铁心多点接地、分接开关故障等,进行分析,并给出部分处理实例.     

非晶合金铁心变压器的特点分析

非晶合金应用于电力变压器,将会成为一种能够大幅度降低变压器空载损耗的节能材料,介绍了非晶合金材料的优缺点,并对非晶合金铁心变压器与硅钢片铁心变压器的性能进行了分析比较,为研制非晶合金铁心变压器提供了参考。     

中小型变压器噪声

介绍了有关声学、噪声的基础知识,概要论述影响中小型变压器噪声的变压器本体振动、冷却装置振动、变压器容量、硅钢片材质、铁芯结构、磁通密度和冷却装置振动特性等主要因素及降低中小型变压器噪声的先进工艺、材料和隔声技术等有关的技术措施.     

电流互感器饱和及其影响因素的仿真研究

电流互感器（TA）是电力系统中的重要传变设备,但电流互感器的铁芯饱和可能引起微机继电保护误动和拒动。首先分析了电流互感器的饱和过程,得出了影响互感器暂态特性的主要因素。然后应用电力系统仿真软件MATLAB,建立了电流互感器模型,对电流互感器的饱和特性进行了详细分析和仿真;仿真结果与理论分析完全一致。     

Measurement of eddy-current loss coefficient PEC-R,derating of single-phase transformers, and comparison with K-factorapproach

A power amplifier is used to supply sinusoidal currents of different frequencies for measuring eddy-current losses of a 25 kVA single-phase transformer under short-circuit condition. Measured data show that eddy-current loss is a linear function of frequency with power of 2 and the eddy-current loss coefficient P_EC-Rlinear is computed. New measurement techniques are applied to determine the derating of single-phase transformers with full-wave diode and thyristor rectifier loads. The derating of transformers has been defined such that for the (apparent, real) power transfer of a transformer the total losses are identical to the rated losses at rated temperature. A relation between apparent power, derating and K-factor is given taking into account iron-core and stray-power losses. Measured derating values are compared with computed results based on the eddy-current losses, iron-core losses, stray-power losses, and K-factors. The eddy-current loss coefficient P_{EC-Rnonlinear} is computed from harmonics caused by diode/thyristor bridge loads     

Characteristics analysis of superconducting power transformer without iron core

With the progress of superconducting wires for ac power use, research on superconducting power transformers is increasing. These transformers can be divided into two types: the iron-core type [1, 2]; and the air-core type [3–9]. The latter type has such advantages as absence of iron losses and magnetic saturation, and greater possibility of reduction of size and weight. However, the air-core transformer has a large magnetizing current due to the absence of iron core. Hence, research has been carried out on the possibility of using the air-core transformer also as a shunt reactor in a power transmission system. However, the operating characteristics of the air-core transformer, such as voltage regulation and reactance voltage, are not clear at present. In this paper, the equivalent circuit without losses is proposed first. Since this equivalent circuit is expressed by means of the magnetic coupling factor and self-inductances of windings, the effect of these parameters on the transformer characteristics can easily be investigated. Then, based on this equivalent circuit, the per-unit expressions for the air-core transformer characteristics are derived and the characteristics are analyzed in detail. The validity of the theoretical results are confirmed by experimental results obtained by the use of an experimental superconducting transformer.     

Transformer magnetizing current and iron-core losses in harmonicpower flow

The problem of modifying the harmonic power flow analysis to permit the inclusion of nonlinear anisotropic transformers and computation of their iron-core (and copper) losses are discussed. The nonlinear model used for transformers is capable of simulating saturation of iron-cores, anisotropy of laminations, and the iron-core and copper losses associated with anisotropic transformers, but simple enough to be included in the harmonic power flow algorithm without deteriorating its convergence properties. The dependency of iron-core losses on the maximum value of the total (fundamental and harmonic) flux density and the fact that iron-core losses are a function of the waveform of the induced voltage-that is its harmonic phase shifts with respect to the fundamental phase angle-are included. The induced voltage is transformed from frequency domain to time domain: the instantaneous induced voltage and the computed λ-i characteristics are employed to compute the instantaneous magnetizing and core-loss currents. Thereafter a transformation is made from time domain back to frequency domain to compute the fundamental and harmonic components of the above-mentioned currents. Therefore, transformer harmonic couplings are properly modeled and included in the analysis. The modified harmonic load flow formulation is applied to a balanced three-phase feeder consisting of a grounded-wye, grounded-wye nonlinear anisotropic transformer and linear and nonlinear loads     

《变压器》杂志对变压器运行维护工作的推动--纪念《变压器》杂志诞生40周年

介绍了40年来变压器发生的典型故障类型及变压器维护、检修技术的发展历程,概述了<变压器>杂志对提高变压器的运行维护水平所起的作用.     

成套开关设备用接触式在线监测温度传感器电源的研制

接触式温度传感器应用于成套开关设备,其前端电源的获取是一个主要问题。笔者利用磁饱和原理,在开关柜母线上安装一电流互感器,使其铁心在小电流时正常励磁,大电流时磁饱和,并通过计算确定其尺寸,研制了满足功率和电压要求的前端电源,从而为后端的接触式传感器和温度在线监测系统提供了稳定、不间断的电源。     

集成滤波电感变压器在10 kV箱式变电站谐波治理中的应用

针对10 kV变电站谐波污染问题,提出了一种将特定次滤波电感集成于配电变压器中的技术方案,避免了传统无源滤波装置中空心电抗器占用空间大或铁心电抗器噪音严重的缺点。首先分析了将滤波电感集成于变压器中的解耦技术;然后对某一容量800 kVA的样机进行有限元仿真,理论分析降阶电感矩阵法,计算出变压器绕组间耦合度和电感矩阵,并以电感矩阵为接口进行系统的场路耦合仿真;最后对样机滤波效果进行实验测试。仿真和实验结果表明：集成滤波电感配电变压器能达到很好的谐波抑制与无功补偿效果,且集成滤波电抗器具有与变压器其它绕组低耦合、占用空间较小、不增加噪音等特点。     

地震灾害下变压器的损毁情况及对策研究

归纳了地震灾害下变压器的三种主要损毁形式,从设备选型、安装和运行维护方面提出了提高变压器抗震性能的措施,进而从变压器的内部结构、变压器套管、变压器整体与基础的连接及变压器油箱外部易损附件四个方面提出了变压器抗震设计应注意的问题。