Shanghai Subway Line

The Industry

        By the end of 2020, China had a total of 146,000 kilometers of railways in operation and 37,900 kilometers in operation, ranking first in the world.High-speed rail traction transformer generally adopts 12 or 24 pulse rectification, will produce 11th and 13th order harmonics; distribution transformer load mainly includes frequency converter, UPS, elevator, lighting, 3rd,5th,7th,11th and 13th order harmonics.

Background

        Because the transportation power grid system contains a large number of non-linear equipment, the equipment will produce a large number of harmonics. When the harmonic content of the power grid is high, it will cause certain harm to the transportation power and lighting system.

• The relay protection equipment and automatic device in the power system mistakenly move or refuses, which directly endangers the safe operation of the power grid, and causes serious system collapse and user power failure accident.

• All kinds of electrical equipment will produce additional loss and heating, and will increase the vibration and noise of the motor and transformer.

• The harmonic current will interfere with the communication system and reduce the transmission quality of the signal.

• Increase the possibility of resonance in the power grid, causing over-current or over-voltage causing danger.

• The capacitor reactive power compensation device produces harmonic amplification, making the capacitor damage or even explode.