Transient stability is recognized as a critical problem for modern electrical power systems, since the deregulation could involve more and more restricted margins. Continuous improvements in power electronics technology gives the possibility to improve significantly the dynamic behaviour. Recently, a great attention in the relevant literature has been paid to Superconducting Magnetic Energy Storage (SMES) devices, showing their intrinsic ability to improve power transmission capability. In the paper, a control strategy for these devices is derived starting from a Control Lyapunov function, thus determining reference values for SMES active and reactive powers injections, able to counteract the effects of large disturbances. Hence, a new topology of the power conditioning system for interfacing SMES device with a power system is proposed. Finally, a control law based upon quasi-sliding technique is employed for tracking the required active and reactive powers. In the last part of the paper an application is presented, with reference to a test system, allowing to outline the flexibility and the goodness of the proposed control strategy.
LOAD FREQUENCY CONTROL IN DEREGULATED ENVIRONMENT OF AN INTERCONNECTED POWER SYSTEM WITH MULTI SOURCE GENERATION USING SUPERCONDUCTING MAGNETIC ENERGY STORAGE DEVICE
