1 AIT Asian Institute of Technology

A hybrid approach to transient stability analysis

AuthorKhin Sandar Win
Call NumberAIT Thesis no.ET-99-8
Subject(s)Transients (Electricity)

NoteA thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development
PublisherAsian Institute of Technology
AbstractTransient stability is the ability of a power system to maintain synchronism when subjected to large and severe disturbance. An efficient algorithm is essential to assess the transient stability in the modern power system. Several algorithms are developed for the analysis of Transient Stability. A hybrid method developed by Y Zhang et.al [ZWRP 97} assess the transient stability quite effectively since it couples both the time domain program and the direct method. The strength of this method is namely: the modeling of each machine and analysis of detail dynamic behavior during disturbance of Time Domain Simulation and calculation of stability limit and margin of the whole system for any condition using direct method. This thesis presents an algorithm based on the hybrid (time domain- direct method) for assessing the transient stability analysis combining the Time Domain as well as the direct method. First, the system stability is checked based on the Time Domain Simulation Algorithm. This algorithm uses the loadflow output obtained from the software package developed by D. Thukaram, IISc Bangalore, India as the input data along with machine details and system parameters and generates the reduced Y-bus for all conditions viz. Prefault, During and Post fault conditions. Further swing equation is solved for each machine using the Predictor Corrector method as a part of time domain analysis. The result obtained from time Domain Simulation Algorithm is compared with the developed algorithm by D. Thukaram, !!Sc Bangalore, and India. This thesis also presents an algorithm from the Time Domain Simulation to assess the transient stability of multimachine system via a Single Machine Infinite Bus system. Here the stability margin and stability limit for SMIB is computed by the equal area criterion. The stable margin is computed if the system is stable. Else, the unstable margin is found out for the specified clearing time. Further, the clearing time is modified and the system stability is checked again based on time domain simulation. This is done iteratively modifying the clearing time till the system become stable. The stability limit (Critical Clearing Time) is calculated by using the pair of relevant unstable as well as stable margin to interpolate the stability level corresponding to zero stable margin. This gives the complete assessment of the system during any disturbance. The algorithm is tested on two sample systems as well as on one practical system.
Year1999
TypeThesis
SchoolSchool of Environment, Resources, and Development
DepartmentDepartment of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC))
Academic Program/FoSEnergy Technology (ET)
Chairperson(s)Thukaram, D.;
Examination Committee(s)Surapong C. ;Yu, Cunyi;
Scholarship Donor(s)Asian Development Bank;
DegreeThesis (M.Eng.) - Asian Institute of Technology, 1999


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