Method and system for the determination of wind speeds and incident radiation parameters of overhead power lines

Abstract

The present invention relates to a method and system for the determination of parameters related to the speed of wind that blows near an overhead electrical power line (single or bundle conductors). The parameters include an “effective wind speed” as well as an “effective incident radiation” acting on a power line span. The measurement is made by using the combination of mechanical vibrations and movements/positions in two or three dimensions through sensors in direct link with the power line conductor.

1 . A method for the determination of wind speed to be used for evaluation of the ampacity in using real-time monitoring of at least one span of overhead power lines, comprising the steps of: measuring Aeolian vibration frequency by using outputs of at least one oscillation sensor; and determining wind speed component perpendicular to the conductor axis according to the following equation:
     V=f·d/S      wherein f is the Aeolian vibration frequency (Hz), S is the Strouhal number, V is perpendicular wind speed (m/s), and d is conductor diameter (m).   
     
     
         2 . The method according to  claim 1 , comprising the steps of: acquiring monitoring information from at least one monitoring device of the power line by using at least one oscillation sensor; performing a frequency or time-frequency analysis from at least one monitoring device of said oscillation measurement signals ranging from 0 to about 100 Hz with a sensitivity of about or more than 100 micro-G for accelerations; determining a fundamental frequency from said frequency or time-frequency analysis; and determining sag of the span, on which at least one monitoring device is clamped. 
     
     
         3 . The method according to  claim 2  further comprising the step of determining signature of Aeolian vibrations. 
     
     
         4 . The method according to  claim 2  further comprising the step of determining the frequency spectrum partly or totally, including DC component, of a transversal inclination of the overhead line in service in the range of about 0 to mechanical fundamental frequency of the span, the DC component being proportional to the square of the mean wind speed component perpendicular to the power line measured for about 5 minutes, wherein self-calibration of the conversion from inclination to the effective wind speed is obtained owing the recovery range with the same wind speed deduced by Aeolian vibration. 
     
     
         5 . The method according to  claim 2 , further comprising the determination of effective incident radiation by using the sag of the span, the relationship between sag and conductor temperature, the measured ambient temperature, the electrical current flowing in the line and the effective wind speed. 
     
     
         6 . A device for the determination of wind speed for evaluation of the ampacity in using real-time monitoring of at least one span of overhead power lines, comprising:
 a sensor for attaching to a conductor of the power line, said sensor comprising an accelerometer; and   a processor in connection with the sensor for calculating the wind speed;   
       wherein the processor determining wind speed component perpendicular to the conductor axis according to the following equation:
     V=f·d/S    
 wherein f is the Aeolian vibration frequency (Hz), S is the Strouhal number, V is perpendicular wind speed (m/s), and d is conductor diameter (m). 
 
     
     
         7 . The device according to  claim 6 , wherein the sensor is an oscillation sensor measuring Aeolian vibration frequency. 
     
     
         8 . The device according to  claim 6 , wherein the accelerometer is able to detect accelerations about maximum 100 micro-G in a vertical direction and a transversal direction. 
     
     
         9 . The device according to  claim 6 , wherein the accelerometer is able to measure acceleration in three-dimensional directions.