英文 power engineering

题目

英文 power engineering
1 list two advantages in maintaining a high power factor in industrial
2 list two advantages in the use of a three phase system instead of a single phase system in large power applications
3 give two reasons as to why most appliances contain an earth
4 the reliability of two transformers connected in parallel at a zone substation is 99%and 99.9% what is the overall raliability of the two transformers
5 suggest two means of impoving the reliability of the power distribution system in an urban area
6 briefly explain the function of the freewheeling diode of a semiconductor switch
7 what are the essential features of an on-line UPS
8 what is a MOV Explain its features
不是翻译 是回答上面的问题 200分奉上
回答 4 5 6 就行

答案

动力工程