In the leakage current test, through the high speed data collection and digital filtering to the output voltage of the human body impedance network, leakage current test that is in accordance with many kinds of electr...In the leakage current test, through the high speed data collection and digital filtering to the output voltage of the human body impedance network, leakage current test that is in accordance with many kinds of electrical safety standards can be realized, and the frequency distribution information of the leakage current can be got as well, which can be used to much more completely evaluate the possible damage degree of the leakage current to the human body and analyze the reason for the appearance of the leakage current in the electric equipment.展开更多
Eddy current testing is one of the most effective methods for evaluation of metallic tubes.In practice,however,the signal is often contaminated by the vibration of the probe,namely radial offset.This work deals with t...Eddy current testing is one of the most effective methods for evaluation of metallic tubes.In practice,however,the signal is often contaminated by the vibration of the probe,namely radial offset.This work deals with the analytical solution to a T-R probe with radial offset,as shown in Fig.1.展开更多
There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cab...There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cable simultaneously, a double differential-mode current in- jection test method (DDMCI) is proposed. The method adopted the equivalence source wave theorem and Baum-Liu-Tesche(BLT) equation as its theory foundation. The equivalent corresponding relation between injection voltage and radiation electric field intensity is derived, and the phase relation between the two injection voltage sources is confirmed. The results indicate that the amplitude and phase of the equivalent injection voltage source is closely related to the S parameter of directional coupling device, the transmission line length, and the source vector in BLT equation, but has nothing to do with the reflection coefficient between the two equipment pieces. Therefore, by choosing the right amplitude and phase of the double injection voltage sources, the DDMCI test is equivalent to the radiation test for two interconnected equipment of a system.展开更多
随着新能源占比的大幅提升以及发、输、用电各环节电力电子设备所占比重的不断提高,高比例新能源电网由于缺乏传统常规同步发电机等主动支撑型电压源,系统短路容量、转动惯量下降,频率、电压稳定问题频发,电网稳定性问题日益凸显。对此...随着新能源占比的大幅提升以及发、输、用电各环节电力电子设备所占比重的不断提高,高比例新能源电网由于缺乏传统常规同步发电机等主动支撑型电压源,系统短路容量、转动惯量下降,频率、电压稳定问题频发,电网稳定性问题日益凸显。对此,重点围绕构网型静止无功发生器(static var generator,SVG)进行研究。在构网型SVG仿真分析的基础上,开展新疆电网220 kV风电汇集站构网型SVG人工三相短路试验,系统性地验证了构网型SVG的同步电压支撑、暂态瞬时响应、3倍10 s的过载能力,并总结了计算值与实测值存在误差的影响因素。试验达到了预期的目的和效果,试验表明,构网SVG在短路故障期间,能保持一定的构网特性,具有良好的系统支撑能力。展开更多
文摘In the leakage current test, through the high speed data collection and digital filtering to the output voltage of the human body impedance network, leakage current test that is in accordance with many kinds of electrical safety standards can be realized, and the frequency distribution information of the leakage current can be got as well, which can be used to much more completely evaluate the possible damage degree of the leakage current to the human body and analyze the reason for the appearance of the leakage current in the electric equipment.
文摘Eddy current testing is one of the most effective methods for evaluation of metallic tubes.In practice,however,the signal is often contaminated by the vibration of the probe,namely radial offset.This work deals with the analytical solution to a T-R probe with radial offset,as shown in Fig.1.
基金Project supported by Arm Pre-research Program （51333040101）, National Defense 973 Program （6131380301 ）, National Natural Science Foundation of China （61040003）.
文摘There are the application scope limits for single differential-mode current injection test method, so in order to carry out injection susceptibility test for two-pieces equipment interconnected with both ends of a cable simultaneously, a double differential-mode current in- jection test method (DDMCI) is proposed. The method adopted the equivalence source wave theorem and Baum-Liu-Tesche(BLT) equation as its theory foundation. The equivalent corresponding relation between injection voltage and radiation electric field intensity is derived, and the phase relation between the two injection voltage sources is confirmed. The results indicate that the amplitude and phase of the equivalent injection voltage source is closely related to the S parameter of directional coupling device, the transmission line length, and the source vector in BLT equation, but has nothing to do with the reflection coefficient between the two equipment pieces. Therefore, by choosing the right amplitude and phase of the double injection voltage sources, the DDMCI test is equivalent to the radiation test for two interconnected equipment of a system.
文摘随着新能源占比的大幅提升以及发、输、用电各环节电力电子设备所占比重的不断提高,高比例新能源电网由于缺乏传统常规同步发电机等主动支撑型电压源,系统短路容量、转动惯量下降,频率、电压稳定问题频发,电网稳定性问题日益凸显。对此,重点围绕构网型静止无功发生器(static var generator,SVG)进行研究。在构网型SVG仿真分析的基础上,开展新疆电网220 kV风电汇集站构网型SVG人工三相短路试验,系统性地验证了构网型SVG的同步电压支撑、暂态瞬时响应、3倍10 s的过载能力,并总结了计算值与实测值存在误差的影响因素。试验达到了预期的目的和效果,试验表明,构网SVG在短路故障期间,能保持一定的构网特性,具有良好的系统支撑能力。
