More and more welding machine, inverter and other loads are used in shipbuilding, automobile manufacturing process which occur a serious harmonic pollution. These harmonics can interfere with control systems, resulting in the production line or even the entire production circuit interruption tripping.
There are a lot of intermediate frequency furnace and electric arc furnace load? in metallurgical industry .The working process does a lot of harm on the grid and has a significant impact on harmonic generation of power transformers, lines and peripheral equipment, even to stop the relevant device working.
In the electrified railway and modern airport, there are many harmonic sources, such as central air conditioning, stereo and modern lighting, etc. They can produce large amounts of harmonic currents, which interfere with nearby communications equipment, affecting the normal operation of communications equipment
More and more modern buildings energy-saving products such as air conditioning and energy saving lamps are widely used, which will produce different levels of harmonics, resulting in unbalanced three-phase, neutral line current increases and other issues, leading the current exceed the rating of the transformer windings and even serious accidents
In some hospitals there are a large number of NMR, X-ray machine, spiral CT and other medical devices, which all belong to non-linear load and itself will produce a large number of harmonics. They are very sophisticated instruments, when they’re interfered by harmonic, they will lead unpredictable consequences