Study On Power Quality Monitoring And Load Control For Intelligent Switch In Distribution Networks

The electric energy shortage situation was more and more serious, and the electric power quality requirements were higher. At present, the application of load control and power quality monitoring system were attracted much more attention. In order to realize the on-line monitoring and load control, the permanent fixed equipments were used in the main power supply terminal, but it was uneconomical from the aspect of the construction of smart distribution network. A new intelligent power distribution switch with the functions of distributed load control and power quality monitoring were proposed in this thesis.The power quality signal was complex and non-stationary because of a large number of nonlinear loads in it. In the thesis, the classification and standards of power quality were summarized in the first place. Then, on the problem of the complex power quality signal detection, the Hilbert-Huang transform (HHT) was adopted. Based on the introduction of the principles of HHT, the HHT implement method and its superiority were put forward for the detection of complex power quality signal. The simulation results proved that this method could detect the start/end time and the amplitude of the disturbance in a real-time, and it was appropriate for the multi-interfere power quality detection and identification systems.Then, aiming at the load controlling problem, this thesis introduced the general strategies; for the load dispatch problem at the seriously lacking situations, a kind of interruptible load control model was built; in order to get the optimal solution of multi-criteria and multi-constraint conditions, the PSO was applied in this thesis. The actual count column was used, which satisfies the requirement of orderly power utilization and demand side management.Finally, the hardware and software design process of the intelligent switching system were given. The hardware overall block diagram and its important parts were described respectively; then, the overall block diagram of the software design was presented, as well as parts of the design ideas and some functional program flow charts.The intelligent switch designed in this thesis is technically feasible and very economical. It will provide much more for the aspects of the power quality monitoring and the power supply order adjustment.