Patent ID: 7447567

Claim:
An electric power system comprising: a weather data input means for inputting weather data, temperature, atmospheric pressure and weather, at predetermined time intervals, in a district of operating transmission lines; a digital processing unit; a memory means for storing transmission line data that shows relations between a corona discharge start voltage and weather conditions at each transmission line, and processed data by said digital processing unit; and a power system analysis means, wherein said digital processing unit calculates the corona discharge start voltage at said each transmission line based on weather forecast data and said transmission line data, if the calculated corona discharge start voltage is lower than a normal transmission voltage of the transmission line, a countermeasure transmission voltage that is recorded in said memory means in advance is selected to set a transmission voltage of the transmission line or stop transmitting electric power on the transmission line, and if the calculated corona discharge start voltage is above the normal transmission voltage of the transmission line, the normal transmission voltage is selected as the set transmission voltage of the transmission line, and wherein said power system analysis means analyzes loads of apparatuses of the power system.