There are many equipments in the factory, and a large number of power grids need to be laid. There are many harmonic sources in the power grid, such as various rectification equipment, AC/DC switching equipment, electronic voltage regulating equipment, non-linear loads and lighting equipment, etc. These loads distort the voltage and current waveforms in the power grid, thereby causing harmful interference to other equipment in the power grid. So will the factory's power grid interfere with the HVLS Fans?
The interference of the power grid in the factory to the HVLS Fans is mainly interference only to the converter and frequency converter part, that is, interference to the
Hvls Ceiling Fans inverter. If the power supply of the inverter is interfered by a polluted AC grid, the noise from the grid will interfere with the inverter through the power supply circuit of the grid.
When the three-phase voltage of the power grid is unbalanced, the waveform of the inverter input current will be distorted. When the unbalance rate is greater than 3%, the peak value of the inverter input current will become significantly larger, resulting in a serious imbalance of the three-phase current, causing the connection The wires are overheated, the frequency converter is over-voltage and over-current, the rectifier diode is burned due to excessive peak current, and the electrolytic capacitor may be damaged. In order to reduce the negative impact caused by unbalanced three-phase voltage, AC reactors can also be installed on the input side of the frequency converter, and DC reactors, power factor compensation capacitors, and thyristor rectifiers can be installed on the DC side to connect to the distribution network. They are connected to the frequency converter. in the same network. When the compensation capacitor is put into use or the thyristor is commutated, the input voltage waveform of the frequency converter will be distorted. When the distorted voltage is input to the frequency converter, the peak value of the input current will increase, thus increasing the load of the rectifier diode and electrolytic capacitor of the frequency converter. burden, resulting in over-voltage or over-current, causing abnormal operation, and may also cause the motor to fail to operate normally, or even burn out the rectifier diodes and electrolytic capacitors in the inverter. Therefore, various countermeasures must be taken to prevent this phenomenon.
(1) When there are many fans in series and the frequency converter capacity is large, such as above 100KVA, you can consider configuring a separate power transformer.
(2) When the distribution transformer has a large capacity and the transformer capacity is more than 10 times that of the frequency converter, an AC reactor can be installed on the input side of the frequency converter.
(3) When power factor compensation capacitors or thyristor rectifiers are installed in the distribution network, if an AC reactor is connected to the AC side of the frequency converter, the harmonic current generated by the frequency converter will be sent to the compensation capacitor and distribution system through the AC reactor; When the inductance of the power distribution system resonates with the compensation capacitor and presents the minimum impedance, the compensation capacitor and the power distribution system will present the maximum current, which will damage the frequency converter and the compensation capacitor. In order to prevent resonance, a reactor with appropriate resistance should be connected in series before the compensation capacitor to make the current with higher harmonics of five times or more become inductive and avoid resonance.
