2.The Distortion Rate of The Harmonic Current Exceeds the Standard
The non-ferrous metal refining adopts the electrolysis process and cannot work without the high-power rectifying device. The high-power three-phase full-control bridge 6-pulse rectifying device will generate nearly 25-33% harmonics, with the characteristic harmonics as 5 times and 7 times, 11 times, and 13 times, among which the 5th and 7th harmonicsare the largest part. Harmonics can cause distribution cables, transformers to heat up, and the reactive power compensator devices unable to be put into operation, and the machine surge. In the larger power grid system, Creat-Poreen filter compensator device can effectively filter out the characteristic harmonics and meet the objectives of control.
Qinghai Electrolytic Aluminum Filter Compensator (FC) Project
Qinghai Aluminium Electric Co., Ltd. Phase II 150kT electrolytic aluminum project, out of the problem that the rectification load production of electrolytic aluminium will generate a large number of ultraharmonics injected into the grid, causingthe system voltage waveform distortion, and that the power factor is low, it decided to install the filter device to filter the harmonicsto compensate for the fundamental reactive power and improve the power factor.
1. Harmonic generation: In the productionof electrolytic aluminum, a large number of harmonics are generated, which will threaten the safety of equipment such as motors, transformers, inverters and relay protection devices, and the harmonic currents will generate harmonic voltage on the impedance of the power grid, causing the grid voltage distortion and affecting the power quality and operational safety.
2. Voltage fluctuation: During the productionof electrolytic aluminum, the distortion of voltage and current waveforms will come about.
3. Power factor: According to the Technical Guidelines for Power System Voltage and Reactive Power, fro the high-voltage power supply industrial users and power users of the high-voltage power supply device with load-adjusting voltage devices, the power factor should be more than 0.9. Otherwise, the user will have to pay fines for the low power factor, directly affecting the economic benefits of the enterprise, increase the system losses, and reduce the power supply capacity.
■Put into Operation: December 2009
■ Operation effect: The filter compensator (FC) effectively limits the harmonic current injected into the grid, so that the harmonic currents injected into the system when the rectifier of the aluminum plant is working normally are within the allowable value, and can flexibly adapt to different operation of the equipment to satisfy the regulation requirement of the reactive power compensation in the mode.
Wiring Diagram Of The Power Supply System
Supporting Filter Of Rectifier Unit