Design Of The Monitoring System Of The SEMS

With the continuous development of our economy, the demand for power is increasing and the problems of the stability of the grid and the power quality have gradually emerged. As the continuous progress in modern superconducting power technology has been made, Superconducting Magnetic Energy Storage (SMES) has broad prospects in the application in power system. The SMES has many subsystems and operating parameters, so it needs a monitoring system to assist its operation. In this paper, the current status of the monitoring system of the SMES is analyzed. Then the research of the application of the SMES in voltage-sag compensation and low-frequency oscillation inhibition is done, and the design of the monitoring system is realized. Details include the following.First, the common methods of voltage-sag are analyzed, then theαβtransformation is proposed as the detection method of Three-Phase voltage-sag. In the detection, first determine whether the Three-Phase is symmetrical, when it is symmetrical, the symmetric voltage-sag detection module is used; when it is asymmetrical, the voltages of the three-phase is tested one by one. From the simulation results, we can see that the method can detect the voltage-sag timely, and it is easy to implement.Secondly, it analyzes the existing low-frequency oscillation detection method, the change of the tie-line power is analyzed to determine whether the low-frequency power oscillation happened. In order to reduce the amount of the calculation, the integration of the active power with the entire cycle is used, the cycle of which is calculated by the three-phase locked loop, and the calculation act once with one cycle. From the simulation, we can see that the waveform of the active power achieved by the integration of the entire cycle is similar to the waveform of the real active power.Finally, it analyses the need of the function of the monitoring system, refinements the functions of the monitoring system, selects the appropriate equipments and devices, realizes the function of the monitoring system. The acquisition and processing of the signal of the power is done by the DSP combined with FPGA. The acquisition and processing of other status and the management of the system is done with the virtual instruments, realize the aim to ensure the operation safe and stable, and easy the manual control.