电容式电压互感器-----外文翻译.doc

外文文献及译文 文献、资料题目：CAPACITIVE VOLTAGE TRANSFORMERS 文献、资料来源：/view doc/download ?doi=22. 5015 rep=rep1type=pdf 文献、资料发表（出版）日期：2000.3.25 院 （部）： 信息与电气工程学院 专 业： 电子信息工程 班 级： 电信0832 姓 名： 王鑫燕 学 号： 2008083105 指导教师： 王桂娟、刘斌 翻译日期： 2012.3.16外文文献： CAPACITIVE VOLTAGE TRANSFORMERS Capacitive Voltage Transformers (CVTs) are common in high-voltage transmission line applications. These same applications require fast, yet secure protection. However, as the requirement for faster protective relays grows, so does the concern over the poor transient response of some CVTs for certain system conditions. Solid-state and microprocessor relays can respond to a CVT transient due to their high operating speed and increased sensitivity .This paper discusses CVT models whose purpose is to identify which major CVT components contribute to the CVT transient. Some surprises include a recommendation for CVT burden and the type of ferroresonance-suppression circuit that gives the least CVT transient. This paper also reviews how the System Impedance Ratio (SIR) affects the CVT transient response. The higher the SIR, the worse the CVT transient for a given CVT . Finally, this paper discusses improvements in relaying logic. The new method of detecting CVT transients is more precise than past detection methods and does not penalize distance protection speed for close-in faults. INTRODUCTION Poor CVT transient response and the distance element overreach it causes are a serious concern for high-speed line protection. For faults that cause very depressed phase voltages, the CVT output voltage may not closely follow its input voltage due to the internal CVT energy storage elements. Because these elements take time to change their stored energy , they introduce a transient to the CVT output following a significant input voltage change. In this paper, we define the duration of CVT transient as that time period during which the CVT output voltage does not match the ratio input voltage. This paper addre