Anti-disturbance problem of electromagnetic flowmeter (3)

1.2 External disturbance

The disturbance sources outside the system can be divided into:

(1) Natural disturbance. Natural disturbances include lightning and changes in the electric field of the atmosphere. The lightning energy generates high-frequency surge voltage with high amplitude on the transmission line, which disturbs the system.

(2) Electricity disturbance. As more and more electronic devices are connected to the power backbone network, there will be some potential disturbances in the system. These disturbances include power line disturbances, electrical fast transients, surges, voltage changes, lightning transients and power line harmonics.

(3) Power frequency interference. Power supply equipment and output lines both produce power frequency disturbance. If a section of the signal transmission line is parallel to the power supply line, this low frequency disturbance will be coupled to the signal line and become a disturbance.