Research On Trace Of Flicker Sources With Multiple Fluctuating Loads

Voltage flicker is an important evaluation index of power quality, and it is an important cause of electrical equipment malfunction and failure. Impact load can easily lead to flicker, and the recent rise of new energy power generation and network like wind energy and solar energy impact on the distribution network, which become new continuous voltage fluctuation and flicker sources. Existing flicker detection technology mainly focus on the detection and calculation of voltage flicker value, however research on trace of flicker sources and assessment of flicker pollution is shortage. It is impossible to mitigate the flicker problem and improve power quality when the location of flicker sources is unknown. Quickly and efficiently locating flicker source, clearing the responsible party of flicker pollution, and accurately assessing the pollution degree of each flicker source with multiple flicker sources, can provide scientific basis for professional management of flicker problem and resolving conflicts between electricity supplier and user.The theoretical background and research significance of flicker sources trace are briefly introduced. Then the part is dedicated to the main source of flicker and its harm. After discussing the basic principle of methods proposed currently of tracing flicker source and each method's application scope, the method of trace of flicker sources with multiple fluctuating loads is presented.To solve the existing problem of quickly tracing flicker sources, the equivalent analysis model of flicker source is established. Through the establishment of equivalent model, the theoretical background of tracing flicker sources by flicker power is analyzed. To accurately estimate flicker power, the flicker envelope parameters are obtained by using improved Teager-Kaiser energy operator and the improved FFT with the Rife-Vincent window. To rapidly trace flicker sources and accurately assess the pollution level of flicker sources, the method of trace of flicker sources based on fluctuating load power analysis is proposed.To solve the existing problem of tracing flicker sources with multiple fluctuating loads, characteristics of fluctuating loads' position is analyzed. Based on the position characteristics, the relationship between voltage increment vector and fluctuating loads' position is constructed. The equation of voltage sensitivity vector and voltage increment vector is also derived. The fault dictionary is made up based on location characteristics of flicker sources. A novel method of tracing flicker sources with multiple fluctuating loads is proposed by combining flicker power and voltage sensitivity vector to achieve quickly identifying flicker sources with multiple fluctuating loads and accurately assessing the pollution level of each flicker source.To verify the effectiveness and accuracy of the proposed method of tracing flicker sources based on fluctuating load power analysis, simulations are analyzed for calculation results of flicker power under the influence of one single frequency and multi-frequency envelope component, harmonic sources. The typical flicker source model, which is established based on energy conversion equation of fluctuating load, is put into power system simulation model to verify the validity of the proposed method of tracing flicker source. The IEEE 13 bus test system is built for simulating the method of tracing flicker sources with multiple fluctuating loads based on flicker power and voltage sensitivity vector. The simulation analysis and experiment results show that this approach can achieve the identification of multi-flicker sources rapidly and the assessment of each flicker source's pollution liability.The software of tracing flicker sources with multiple fluctuating loads system which is combined with virtual instrument technology is designed. On the basis of using a small amount of hardware devices, trace of flicker sources with multiple fluctuating loads system, which is based on flicker power and voltage sensitivity vector, is established.