ABB 129740-002 Anti Interference Equipment

ABB 129740-002 Anti Interference Equipment

129740-002 space radiation electromagnetic field (EMI) is mainly generated by the power network, transient processes of electrical equipment, lightning, radio broadcasting, television, radar, high-frequency induction heating equipment, etc., usually known as radiated interference, its distribution is extremely complex. If the PLC system is placed in its radio frequency field, it will be subject to radiation interference, the impact of which is mainly through two paths: one is directly to the PLC internal radiation, by the circuit inductance of the interference; the second is to the PLC communication network, the radiation, by the communication line inductance of the introduction of interference. Radiation interference and field equipment layout and equipment generated by the size of the electromagnetic field, especially the frequency, generally through the setting of shielded cables and PLC local shielding and high-voltage relief elements for protection

129740-002 introduced mainly through the power supply and signal lines, usually called conduction interference. This interference is more serious in China’s industrial site, the normal power supply of PLC systems are powered by the grid, due to the wide coverage of the grid, it will be subject to all the space electromagnetic interference and the induction of voltage and current on the line, in particular, the internal changes in the power grid, switching operation surges, large-scale power equipment starting and stopping, AC and DC drives caused by harmonics, grid short-circuit transient shocks, and so on, through the transmission line to the original side of the power supply. PLC power supply usually uses isolated power supply, but because of its organization and manufacturing process and other factors make its isolation is not ideal. In fact, due to the existence of distributed parameters, especially distributed capacitance, absolute isolation is impossible.