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目前对工频试验变压器的常规测量均为稳态工频参数,未涉及试验变压器高压绕组高电位电流的暂态状况。研制了一套基于Rogowski电流传感器和光电传输技术的高电位电流测量系统,可测量最大冲击电流峰值1 000 A,最大工频电流有效值6 A、频率范围50 Hz~20 MHz;进行了频率响应试验、工频小电流和冲击大电流的性能试验,实测了绝缘子工频闪络时和GIS隔离开关开合感性小电流试验时流经试验变压器高压绕组的电流波形。通过试验数据分析了高陡度暂态电流对变压器的绝缘损伤和测量的意义,探讨了通过比较测得的暂态电流最大陡度以衡量试验变压器保护措施有效性的方法。该系统可为衡量试验变压器保护措施的有效性、改进试验回路以及试验变压器损伤、故障等相关的研究提供参考数据,避免盲目使用造成试验变压器绝缘损伤,对保障其安全运行和科研研究具有重要意义。 相似文献
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脉冲频率响应分析法(IFRA)相比广泛应用于离线检测的扫描频率响应分析法(SFRA)在变压器绕组在线监测中有更好的适用性。目前,离线IFRA方法的激励脉冲波形特征尚未标准化,其可靠性、灵敏性、重复性需要深入研究。通过实验提取了适合于变压器绕组变形IFRA检测的激励脉冲波形特征,采用分频段分层小波阈值去噪提取IFRA频响曲线。在一台配电变压器上模拟了三种程度的轴向绕组变形,在两种接线方式下,均依次用IFRA方法和SFRA方法进行检测,并用斯皮尔曼相关系数和欧式距离对IFRA频响曲线进行量化分析,验证了纳秒级IFRA方法的可靠性和灵敏性,并进行了重复性验证。 相似文献
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Turnbull Fred G. Tompkins Russell E. 《Industry Applications, IEEE Transactions on》1987,(6):1016-1021
The design and fabrication of a parallel resonant converter circuit and a high-frequency step-up transformer used to supply an adjustable dc voltage to a load is described. The 500-W system is operated from 115/230 V single-phase 60-Hz power, which is rectified and filtered to form a 310-V dc link. A two-transistor half-bridge circuit operating at a fixed frequency above the circuits resonant frequency converts the dc voltage to an ac voltage at approximately 20 kHz. This high-frequency voltage is transformed with a low-capacitance oil-impregnated ferrite transformer. The output voltage is rectified to form a dc voltage with a maximum value of 90-kV peak. The output voltage is adjustable using pulsewidth modulation of the conduction time of the two transistors in the power circuit. The energy stored in the resonant circuit provides a sinusoidal transformer voltage at fixed frequency over a wide range of control. The system is provided with a closed-loop peak-voltage regulator and an on-off capability from the control electronics. The transformer is designed for a specific value of inductance and capacitance to operate at the desired resonant frequency and characteristic impedance. 相似文献
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基于单周控制的基波磁通补偿串联混合型有源电力滤波器 总被引:8,自引:0,他引:8
介绍了基于变压器基波磁通补偿的串联混合型有源电力滤波器,将一变压器的一次侧串联在电网与谐波源之间,当串联变压器二次侧注入的基波电流与电网电流的基波分量满足补偿条件时,串联变压器可以实现对基波呈低阻抗,而对谐波呈很高的励磁阻抗,实现谐波与电网的隔离。将单周控制代替传统的滞环控制来获得补偿电流的跟踪,使得开关频率恒定,从而可以精确地设计高频滤波电容,提高系统的补偿性能和鲁棒性。推导了采用单周控制时系统的控制方程,分析了系统的工作过程。利用MATLAB对采用单周控制时系统的补偿性能进行仿真,结果表明系统具有较好的动稳态补偿性能。通过实验进一步证明了采用单周控制的可行性。 相似文献
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智能万用变压器(IUT)是一种含有电力电子变换器且通过高频变压器进行磁耦合实现电力系统中的电压变换和能量传递的新型电能转换设备。其突出特点在于它可以实现对变压器原副方电压幅值和相位的灵活控制,它能使系统具有更高的稳定性,实现更加灵活的输电方式,整合各种交直流分布式电源,以及实现电力市场下对功率潮流的实时控制。提出一种智能万用变压器的电路拓扑结构,搭建了变压器模型,着重分析了变压器的电压、功率、频率的控制原理,并以此提出了10kV系统中智能万用变压器的控制策略,用DSP芯片TMS320C28343对PWM信号进行控制,做出了Matlab/simulink仿真,仿真结果表明,该控制策略对10kV系统的电压、功率、频率控制效果良好,改善了电压特性,提高了系统的稳定性。 相似文献
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This paper presents the development of a wavelet-based scheme, for distinguishing between transformer inrush currents and power system fault currents, which proved to provide a reliable, fast, and computationally efficient tool. The operating time of the scheme is less than half the power frequency cycle (based on a 5-kHz sampling rate). In this work, a wavelet transform concept is presented. Feature extraction and method of discrimination between transformer inrush and fault currents is derived. A 132/11-kV transformer connected to a 132-kV power system were simulated using the EMTP. The generated data were used by the MATLAB to test the performance of the technique as to its speed of response, computational burden and reliability. The proposed scheme proved to be reliable, accurate, and fast. 相似文献
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电力变压器绝缘局部放电的声发射频谱 总被引:2,自引:0,他引:2
本文针对电力变压器绝缘局部放电的几种典型形式进行了实验室模拟,用微机测量系统采集了六种模型局部放电的声、电信号,得出了声发射频谱、声、电信号时延关系,以及在较厚的绝缘纸内发生放电时声信号的衰减规律和频谱的变化。用声发射法在线监测变压器的局部放电时,变压器铁心的磁噪声是稳定而严重的干扰信号、本文分析了磁噪声信号的时域及频域特征。基于变压器绝缘局部放电模型的声频谱和磁噪声的频谱,本文给出了用声发射法检测电力变压器绝缘局部放电的频带范围,并论述了根椐不同的放电声频谱判断故障类型的可能性。 相似文献
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综合暂态与工频信息的谐振接地系统小电流接地故障选线 总被引:4,自引:0,他引:4
对于谐振接地系统,利用工频电流的小电流接地故障选线方法不再适用,而受现场普遍存在的电压互感器/电流互感器接线极性反接问题影响,利用暂态电流极性比较与暂态无功功率方向的选线方法也易出现误选。文中在分析过补偿方式谐振接地系统中接地故障暂态与工频零序电流/无功功率分布差异的基础上,提出两种综合利用故障暂态与工频分量的全信息量选线方法,即:与任一其他线路暂态零序电流极性关系与工频零序电流极性关系均不一致的线路为故障线路;或暂态无功功率与工频无功功率流向不一致的线路为故障线路。两种方法均可有效避免因电压互感器/电流互感器接线极性反接或不确定造成的误选,扩大了对现场条件的适用性,提高了选线可靠性。仿真与现场数据验证了算法的有效性。 相似文献
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《International Journal of Electrical Power & Energy Systems》2013,44(1):6-10
This paper presents the equivalent circuit and the parameters of a Tesla transformer. The resonance frequency to generate a high test voltage in the air-cored transformer is determined.An experimental Tesla transformer system is designed by using a few simple tools such as a Tesla coil, function generator and ultra-fast semiconductor switch. By using high frequency DC chopper, a resonance voltage induced between the primary and secondary coils. Result is a power supply that generates test voltages in the level of 200.000–250.000 V. The paper presents the input/output relations of the Tesla transformer and properties of semiconductor controlled driver system. 相似文献
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Shih‐Jen Cheng Huang‐Jen Chiu Yu‐Kang Lo Shu‐Wei Kuo Kuo‐Kuang Jen Kuo‐Sheng Fu Gwo‐Huei You Kun‐Feng Chen Chien‐Min Kao 《International Journal of Circuit Theory and Applications》2014,42(6):584-604
In this paper, a contact‐less power charger for robot applications is studied and developed. Contact‐less charging can be achieved by a separable transformer design. The transformer primary core is in the charger unit, and the secondary core is in the robots. The transformer air‐gap is equal to the distance between these two parts. By theoretical analysis, software simulations, and circuit implementation, the relationship among the transformer's coupling coefficient, the core geometry, and gap are formulated. In addition, a high‐efficiency circuit topology for the studied contact‐less charger is fulfilled. It is anticipated that the research results of this paper can contribute to the development of the contact‐less charging techniques for robot systems. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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一种全数字化高压电流互感器在线校验系统 总被引:3,自引:0,他引:3
随着电子技术和数字信号处理技术广泛应用于电力系统,电子式互感器技术日趋成熟。由于动态范围广、频带宽、无磁饱和等优点,电子式互感器已经开始取代传统式互感器应用于电力系统和其他工业领域。本文提出一种以高准确度的钳形空心线圈为电流传感器,以光纤传输系统为信号传输和供电方式,并通过虚拟仪器实现软件的数字积分器和加四阶矩形卷积窗运用FFT算法的全数字化高压电流互感器的在线校验。可以在不断电的情况下对现有的高压电流互感器进行监控,大大地提高了电力系统一次设备的可靠性。实验结果表明,该系统具有0.05级以上的准确度[1],挂网运行试验证明该系统易于现场操作,可靠性强。 相似文献
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A new electronic system to assist high-voltage measuring transformers is proposed. This system compensates the voltage drops in the series impedances of the transformer, which are the main cause of errors at power frequency. The nonlinear behavior of the magnetizing branch has no influence on the results. The proposed compensator also reduces the influence of the burden impedance on the transformer errors. Any auxiliary winding or core is not necessary so that conventional units can be compensated 相似文献
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为在线测量变压器油中局部放电产生的超声波,建立了非本征型光纤法珀(FP)传感系统,传感器的传感单元FP腔由石英膜和尾纤端面组成,声波作用于石英膜上产生振动调制入射光波,通过解调含有局放信息的输出信号,可对变压器运行状态进行在线检测。针对FP传感器加工工艺要求高且工业上难以实现的问题,建立了光纤光栅解调系统,该系统具有全介质结构和抗电磁干扰特性。系统仿真和计算结果表明,增加石英膜半径和FP腔的端面反射率,可提高系统灵敏度;通过选择合适的FBG,可得到理想的系统传递函数。 相似文献