With the extensive use of variable speed drive, servo, ups and other products, a large number of harmonics have appeared in the power grid, and harmonics have brought about very big power quality problems. In order to solve the harmonic problem in the power grid, our company has developed a three-level active filter based on the two-level active filter.
Active harmonic filter can be widely used in industrial, commercial and institutional distribution networks, such as: power systems, electrolytic plating enterprises, water treatment equipment, petrochemical enterprises, large shopping malls and office buildings, precision electronics enterprises, airport/port power supply systems, medical institutions, etc. According to the different application objects, the application of active power filterwill play a role in ensuring the reliability of power supply, reducing interference, improving product quality, increasing equipment life and reducing equipment damage.
The 3rd harmonic in most semiconductor industries is very serious, mainly due to the large number of single-phase rectification equipment used in enterprises. The third harmonic belongs to zero sequence harmonics, which has the characteristics of gathering in the neutral line, resulting in excessive pressure on the neutral line, and even ignition phenomenon, which has great hidden dangers in production safety. Harmonics can also cause circuit breakers to trip, delaying production time. The third harmonic forms a circulation in the transformer and accelerates the aging of the transformer. Serious harmonic pollution will inevitably affect the service efficiency and life of the equipment in the power distribution system.
Most of the inverter rectification links are the application of 6 pulses to convert AC to DC, so the harmonics generated are mainly 5, 7, 11 times. Its main hazards are the hazards to power equipment and the deviation in measurement. The use of active filter can be a good solution to this problem.
The usage of active harmonic filter:
1. Filter out the current harmonics, which can efficiently filter out the harmonics of 2-25 times in the load current, so as to make the distribution network clean and efficient, and meet the requirements of the national standard for the distribution network clipping. Active filter truly adaptive tracking compensation, can automatically identify the overall load changes and load harmonic content changes and quickly track compensation, 80us response to load changes, 20ms to achieve full tracking compensation.
2. Improve the system imbalance, can completely eliminate the system imbalance caused by harmonics, in the case of equipment capacity permits, can be set according to the user to compensate the system fundamental negative sequence and zero sequence imbalance components and moderate compensation reactive power.
3. Inhibit the resonance of the power grid, which will not resonate with the power grid, and can effectively simulate the resonance of the power grid itself within the scope of its capacity.
4. A variety of protection functions, with over current, over voltage, under voltage, high temperature, measurement circuit fault, lightning strike and other protection functions.
5. Full digital operation, with friendly man-machine interface, making the operation simple, easy to use and maintain.
Post time: Oct-21-2023