Research On The Medium-Voltage-System’s Protection And Operation Mode Of Wuhan Metro Line 4

With the rapid development of the national economy and the growth of urban traffic lines, metro is widely used in China. At present, China is in a golden period of development of urban rail transit, the construction of urban rail transit is being implementing in many large and middle cities.Based on results of previous studies, detailed research on various medium pressure ring network protection schemes which are using in domestic rail power supply system is carried out in this paper, including the coordination scheme between differential and overcurrent range, near field instant protection scheme, hard line atresia scheme in substation, accelerating scheme, selective current tripping protection scheme and communication networks based on the scheme of GOOSE protection.It takes a reasonable protection scheme at Wuhan Metro Line 4. The first stage engineering takes this scheme that includes differential protection and overcurrent stage difference coordination. The second stage engineering takes the scheme of hard line atresia. The scheme was schemed and simplified in order to improve the reliability of protection at the second stage engineering.It realizes a nice tie between the first stage engineering and the second stage engineering. And it makes Wuhan Metro Line 4 to be a whole.