Power System Stability

An electrical power system is a fundamental infrastructure of a society. As a large‐scale time‐varying dynamic system, maintaining its stability is a basic and essential requirement during its operation and planning decision‐making process. In general, the stability of a power system refers to its ability to regain a state of operating equilibrium after being subjected to a physical disturbance (such as a short‐circuit fault). In practice, the stability of the power system depends on both its dynamic characteristics, i.e. how the system would behave in response to disturbances, and its steady‐state operating conditions, i.e. how the power system is dispatched. In recent years, modern power systems started to integrate high shares of renewable energy sources, such as solar photovoltaic and wind power, which are inherently stochastic and intermittent in their power outputs and are interfaced with the power grid through power electronic converters. While these renewable energy‐based converter interfaced generators (CIGs) are environmentally beneficial, they significantly complicate the power grid's static and dynamic characteristics. As a result, the dynamic behaviors of the power system become much more complex, which introduces a series of challenges to the control, operation, and planning for maintaining system stability.In a nutshell, this chapter gives a brief introduction to the modern power system stability, including its definition, classification, and phenomenon.