In electrical system, the harmonics are electric voltages and currents that appear on electric power system, which are because of uncertainty in loads. Normally, voltage varies sinusoidally with say, 50 Hz frequency and the same varies without any change in case of linear loads.
But, in case of non-linear loads like rectifiers or inverters, the system draws non-linear current which leads to generation of harmonics in the HVDC transmission system. It should be noted that these harmonics will not cause any harm to the converters but they travel along the transmission path.
Some problems due to harmonics are listed below
But, in case of non-linear loads like rectifiers or inverters, the system draws non-linear current which leads to generation of harmonics in the HVDC transmission system. It should be noted that these harmonics will not cause any harm to the converters but they travel along the transmission path.
Some problems due to harmonics are listed below
- Extra power loss in capacitors, transformers, rotating machines etc..
- Overheating of machines
- Due to the above reason, life span of machines reduces
- Noise from machines increases
- Power factor becomes poor
- Interference with nearby communication increases, such as Radio interference or telephone interference
- False tripping of Circuit Breakers
There are some methods to minimize the harmonics such as by increasing pulse number, using DC smoothing reactor, DC harmonic filter, AC harmonic filter.
0 comments:
Post a Comment