Grid-Based Transient Stability Analysis Using Dynamic Simulation In PSS/E

Power system transient stability refers to the ability of the synchronous motors to keep synchronous and running at new or origin state under large disturbance. The Primary purpose of power system transient stability analysis is to check if the system remains stable under groups of preassigned typical large disturbances. Numerical simulation method in time domain is widely used in transient stability analysis and typical softwares for power system simulation. Dynamic simulation in these softwares is essential to effectively strengthen the security and stability of power system. However, for the interconnection of large-scale power grid, the size of modern power systems is becoming increasingly large. Numerical simulation method takes too much time for computing, and could not give stability margin. So it encounters difficultes to directly apply transient stability analysis to the online security analysis.PSS/E is popular and powerful software for power system simulation. By combining dynamic simulation in PSS/E and transient energy function method, this paper proposed two improved hybrid methods for transient stability analysis, improving reliability of the analysis, canculating stability margin and then measuring critical clearing time.By adopting sample-ruler technique and analysing the conservation of transient energy function in post-fault duration, this paper proposed a hybrid methods based on improved sample-ruler technique, which could measure critical clearing time using linear interpolation of stability margin, and then applied this method in PSS/E.This paper proposed corrected sample-ruler technique based on corrected transient energy function,and also proposed sustained fault simulation method refer to potentical energy boundary surface method and the feature of PSS/E. Combined with corrected transient energy function, these methods further improved computing accuracy and could canculate critical clearing time through one time simulation. Cases studies on IEEE 50 Machines 145 buses system and East China power system showed that these two improved hybrid methods based on corrected energy function make both accuracy and computing speed improved compared to the traditional hybrid method and they are practical and promising transient stability analysis methods.This paper introduced gird computing into dynamic simulation in PSS/E. And through properly task scheduling, it applied improved hybrid methods on GridGain, a platform for grid computing. Case studies showed that grid-based transient stability analysis using PSS/E impoved computing speed linearly, and provided a practical and effective way to the application of transiendt stability analysis on the online security assessment.