光伏直流升压汇集系统经较大过渡电阻的故障清除后,存在直流变压器难以切换回原有控制策略的问题.针对此,在分析故障点过渡电阻和直流电压波动量之间关系的基础上,提出了一种基于电网电压增量前馈补偿的故障后恢复控制策略.在故障清除时,通过监测电网电压增量值,采用修正逆变器控制外环直流电压参考值的方式短时增大直流母线电压的波动量,从而使直流变压器实现控制策略的可靠切换.仿真结果表明,所提方法在交流电网经较大过渡电阻发生的故障被清除后,光伏侧控制策略能可靠且快速地进行切换,有效提高了光伏的利用率.

随着大容量、高频化电力电子系统的应用日益广泛,功率器件将面临来自高温、复杂电磁环境等方面的挑战,融合器件与电路中多方面因素的建模与分析方法成为该领域的研究难点。现有的等效电路建模法侧重于器件的电压与电流,半导体物理场建模与分析侧重于表征器件内部载流子浓度、温度等参数的动态分布情况。如何考虑换流回路与器件内部场效应的共同影响并分析相互关系,成为完善半导体器件建模研究工作的重要环节。通过数值计算实现了半导体物理场与换流回路的组合,阐述了基于场路耦合特性的电力电子装置半导体器件综合分析方法。重点论述了场路耦合分析的边界条件设定机理与信息交互的实现等方面内容,并应用于PiN二极管反向恢复特性的建模。对1 200 V/40 A的IGBT反并联二极管的反向恢复过程进行仿真与实验验证,参考经验公式与模型的对比结果,验证了该方法对分析器件结温与换流回路杂散电感等参数综合影响的有效性。

To meet the requirement of dispatching center and improve the defects in the master station's fault record analysis software nowadays, a power fault waveform recurrence and analysis system, in which following modules such as remote data transmission, format conversion of data, information management and fault analysis are involved, is developed by use of Visual C++6.0. With this system different types of recorded fault data can be transformed into standard COMTRADE format, so at the dispatching center the fault data of the whole power network can be unitedly managed and the commonly used functions such as waveform recurrence, harmonic and vector analysis, power analysis and fault analysis are realized. In addition, solutions of some concrete problems in the application of Visual C++6.0, which appear during the development of remote transmission and communication, design of loading structure of COMTRADE formatted data, display of GUI and the special design of scrolled graphical interface, are expounded.

微机故障分析平台可以远程调取各种型号录波器的数据和修改参数,并且将故障数据转换为标准的COMTRADE格式数据,分析了录波器自带分析软件的不足之处,增加并完善了数据分析功能,建立统一的数据库,加强了对故障数据的管理.

The obstacle recurrence device of power system could recur the fault recording data based on standard COMTRADE into real voltage or current wave,which can use in fault analysis,studying motion of relay test system and testing secondary equipment of power system.The device,which adopts double-CPU design of embedded PC and DSP,needs communicating massive data,for reasons of less nonlinear distortion.So an exact and fast communication between PC and DSP becomes an important problem for advancing capability of the device.This paper details the elements and structure of the device,and describes the serial communication at large.The device shows its powerful practical value after test.

This paper presents a new single terminal method of traveling wave fault location using wavelet transform for transmission line The proposed method ean effectively extract the characteristic of traveling wave, eliminate the effects of the traveling wave dispersion on the fault location accuracy, and make the definition of arrival time and the choice of propagation velocity more reasonable A large amount of fault location results show that the new method is more accurate and reliable, and can meet the accurate fault location requirement when single terminal methods of traveling wave can be used in some position