ANALYSIS OF 16.5 KV/ 110 V GENERATOR PT FAILURE AT NTPC DADRI FROM FERRORESONANCE POINT OF VIEW USING ANALYTICAL TECHNIQUE AND EMTP SIMULATION
Ferroresonnace is a little understood phenomenon affecting the power system, distribution system. It has a potentially devastating effect ranging from simple overheating to burning out of core and cascaded failure of nonlinear power system device at the point of occurrence.
Method’s has been developed to predict the behavior of a system from local to global pattern of ferroresonance. These methods are essentially based on decomposing complex nonlinear system to a set of linear algebraic system. The variables in the algebraic system are the Fourier component of the nonlinear circuit variables. Geometrical plotting like power spectral density or poincare map can also used for predicting the local as well as global behavior.
Electromagnetic transient program like EMTDC/PSCAD or ATP can also used for simulation of simple to complex ferroresonnace circuit. This program is generally robust and use numerically stables algorithms. However the accuracy of the simulation depend on the modeling of various components. Transformer modeling is area of concern. 3-phase transformer modeling has not developed in comparison to 1-phase modeling.
Attempt has been made during this project to develop fast, efficient MATLAB program for analytical study based on 'GELRKIN'S method. And to validate this using EMTDC/PSCAD. Both the methods have been applied to a complex system to study the ferroresonance phenomena.
It has been concluded by both the methods that the system require further modeling and inclusion of system complexities. It is further concluded that the analytical programming has to include higher order polynomial for exact system representation. Transformer modeling in EMTDC environment may require custom-based modeling.
* Mr. Debasis Rath is presently working as DCDE (PE-Elect) in Engineering Office Complex of NTPC at Noida. His communication address is Engineering Office Complex, NTPC, Sector-24, Noida – 201301 (U.P.).