Meteorology is the key factor in icing of power system.The study on the relation of meteorology and icing has been delayed due to the absence of field icing data.An online monitoring system of transmission line conductor icing based on GSM SMS had been developed by the authors to monitor the real-time local meteorology and the icing.In this paper

the relation of meteorology and icing was investigated based on the measured icing data.The results show that the formation and dropping of transmission line icing depend on special meteorology

the icing forecasting based on single meteorological factor

such as temperature

humidity

or wind speed

etc.

is unreliable with a large error

e.g.the error is 248% when only use temperature for forecasting.The accuracy

error

and failure of forecasting are 67%

18%

and 39% when multi-meteorological factors are used

and they are further improved to 86%

13% and 3% when the fuzzy theory is adopted.