To identify the applical condition of grounding lines current of EHV substation appliances and supply the testing data for the research on the coron of current to grounding grid

the five EHV substations in southeast were selectied. The resean of grounding lines current of HGIS（GIS）and air insulated appliances was analyzed and the currents were measured by huoer theory. The results demonstrated that the currents in the appliances grounding lines with enclosure（for example

HGIS

GIS

tank type circuit breaker） were more larger than those in the air insulated appliances grounding lines

whose frequency was 50 Hz. There were many factors on the amplitude of the current in grounding line

such as soil characteristics

load current

substation layout

grounding line connection

external interference

etc. There existed a positive correlation relationship between the grounding line current and load current of 550 kV HGES

and the oscillatory wave relationship was found between the currents and grounding line numbers. However

this relationship had nothing to do with air insulated appliances grounding lines.The cur-rents in outlet bushings of 252 kV GIS were the maximum

and the least one was phase B which was approach to 100 A. The currents at other position were very small.