The The Zhongfu 300ka Aluminum Electrolytic Power Supply System Harmonic Detection And Early Warning System

With the rapid development of the power electronic technology, harmonics caused by various power electronic devices become more and more serious. Based on the condition of Zhongfu 300kA aluminum electrolyzation rectifying power grid, the characteristic of harmonic and detection of harmonic are studied, the harmonic online detection and fault prewarning system for aluminum electrolyzation rectifying power grid are designed to lay the foundation for harmonic suppression and fault prewarning.The characteristic, the cause and main harm of harmonic are introduced. By analyzing harmonic character in aluminum electrolyzation rectifying power grid, a new method based on variable step size adaptive filter algorithm is proposed. Harmonic models of transformers, transmission lines, filtering devices and high voltage power system in rectifying power grid are established. Series resonance and parallel resonance of the power network are analyzed, and model of resonance prewarning is established. Models of harmonic rate prewarning, three-phase unbalance prewarning, and overload prewaring are researched, thus the model of large aluminum electrolytic rectifying power grid fault prediction based on harmonic analysis is established.Harmonic detection and fault prewarning system is completed and applied in the aluminum electrolyzation rectifying power grid. The practical effect proves that the designed system can accurately detect the magnitude of each harmonic element, and provide a basis for harmonic suppression and breakdown detection. It is also very important to reduce the failure rate.