Transient Stability Analysis in Power Systems

Transient stability analysis in power systems refers to the ability of the system to return to stable operation after being subjected to major disturbances such as short-circuit faults or generator tripping. This analysis is crucial for ensuring grid security, particularly in the context of large-scale integration of renewable energy sources.

The segmented calculation method is a commonly used approach for transient stability analysis, whose core concept involves dividing the simulation time period into several small segments and performing linearized approximate calculations within each time segment. This method effectively reduces computational complexity while maintaining accuracy, making it suitable for handling complex dynamic processes in multi-machine systems. In MATLAB implementation, this typically involves using time-step discretization with adaptive step size control to balance computational efficiency and numerical precision.

The analysis process generally consists of three key phases: Pre-fault Steady State - Calculating the system's initial operating point Fault-on Dynamics - Simulating generator swing curves under disturbances like short circuits Post-fault Recovery - Verifying whether the system can maintain synchronous operation

When implementing in MATLAB, differential-algebraic equation systems are used to describe generator dynamics and network equations, solved step-by-step through numerical integration methods such as the Modified Euler method. The program structure typically includes modules for network admittance matrix construction, generator model discretization, and stability criterion evaluation based on power-angle curves. Key functions often involve solveDAE for equation solving and ode45 for numerical integration with automatic step size control.

The advantage of this method lies in its ability to clearly reflect the relative swinging conditions of each generator during transient processes. However, attention must be paid to the impact of step size selection on accuracy and computational load. Modern implementations often incorporate parallel computing techniques to enhance analysis efficiency for large-scale power grids, utilizing MATLAB's Parallel Computing Toolbox for distributed processing of multiple generator models.