A Plug and Play, Approximation-Based, Selective Load Shedding Mechanism for the Future Electrical Grid

Abstract

As soon as a load disturbance occurs in a power system, such as the unexpected outage of a generation unit or the introduction of a big load, the electric frequency declines from its nominal value. This is a highly unwanted situation that limits machine and other power system auxiliaries life time. Contemporary power systems employ conventional load shedding practices as a last resort, in order to achieve frequency stability. However, these practices, which are determined a priori, are very conservative and result in over-shedding. In this paper, an intelligent load shedding scheme that combines approximation-based feedback linearization and load disturbance adaptive bounding is presented. The proposed scheme provides the minimum amount of load that should be shed in order to maintain the power system stability. It prevents over-shedding practices as a result of conventional load shedding that the proposed scheme is compared with. Furthermore, the mechanism under consideration provides smooth and seamless load restoration, preventing oscillations between shedding and restoration. It is robust to functional approximation errors, measurement noise and sudden load disturbances.