Method and apparatus for limiting lightning overvoltage of direct-current power transmission line

A method for limiting lightning overvoltage of a direct current power transmission line, comprising:

• S1, acquiring static operation data of the direct current transmission line and lightning current monitoring data of the line subjected to lightning strike through a monitoring instrument, wherein the static operation data comprises voltage and current of the line not subjected to lightning strike, and the lightning current monitoring data comprises lightning current amplitude, lightning current waveform and lightning strike time;
• superimposing an impact of the lightning current monitoring data on line operation onto the static operation data by electromagnetic transient simulation software to form dynamic operation data comprising voltage and current values;
• and establishing a coordinate system with time as a horizontal axis and the voltage of the dynamic operation data as a vertical axis to draw a line dynamic operation function curve;
• S2, correcting lightning protection performance parameters of the direct current power transmission line in real time according to environmental factor data, wherein the lightning protection performance parameters comprise an air clearance of a tower head at a line tower and a lightning impulse discharge voltage of a line insulator, and the environmental factor data comprises topography, landforms, temperature, humidity, contamination level and air pressure values in an environment where the line is located;
• and establishing a coordinate system with time as the horizontal axis and the lightning impulse discharge voltage as the vertical axis to draw a line lightning protection performance function curve;
• and
• S3, subtracting a voltage value on the line dynamic operation function curve from a voltage value on the line lightning protection performance function curve at any moment in the same coordinate system to obtain a voltage difference, and a lightning arrester arranged in the line activating discharge protection and recording discharge data of the lightning arrester when the voltage difference is less than 15%-20% of dynamic operating voltage at the moment.