1. Non-linear problems existing in power system components
The non-linear problems of components in the power supply system include: harmonics generated during normal operation of generators; harmonics generated by various transformer equipment in the power grid; harmonics generated by DC transmission; harmonic amplification by transmission lines after high voltage effect. In addition, factors such as the setting of shunt capacitors in the substation will also cause the appearance of harmonics. Among these factors, the direct current transmission factor is the main factor that generates harmonics in the current power system.
2. Non-linear load
The non-linear load takes a large proportion in the industrial and domestic electricity consumption, which is the main source of harmonics in the power system. The main load of non-linearity is the electric arc furnace, and the arc furnace arcing time delay and the serious non-linearity of the arc produce harmonics.
In the daily life and production load of residents, the volt-ampere characteristics of the fluorescent lamps used are also non-linear, and serious harmonic currents will also be generated, of which the highest content is the third harmonic. In addition, the use of high-power rectifier and frequency conversion devices will also produce serious harmonic currents, which seriously affects the safety of the power grid.
3. Power system failure
Power quality will also be affected by internal and external faults during the operation of the power system. For example, various natural disasters, man-made abnormal operations, short circuits of various lines, changes in the working status of generators and excitation systems when the power grid fails, etc. will all affect the power. The quality has a big impact.
