A COMPARATIVE STUDY OF PERFORMANCE OF TCSC AND IMDU FOR DAMPING SSR IN SERIES COMPENSATED POWER SYSTEM

Abstract

iii ABSTRACT Series capacitive compensation has long been used as a means to increase the power transfer capability of a transmission line by reducing the inductive reactance of the line. This, however, may lead to sub-synchronous resonance (SSR). An IMDU is a special high-power, low energy induction machine, with small rotor resistance and leakage reactance values, designed to operate close to synchronous speed. It is mechanically coupled to the turbo-generator (T-G) shaft and electrically connected to the generator bus. The IEEE First Benchmark Models for subsynchronous studies is used to conduct eigenvalue analyses and time domain simulations. Time domain simulation studies were conducted with the IMDU in the mechanical system and TCSC along the network system. Simulations to study large transients were conducted. The coupling coefficient between IMDU and different turbine was fixed at the same value, and its effects on SSR mitigation and transient stability were observed. The best location providing maximum damping is next to the HP turbine at the end of the shaft. This thesis present a simple design for TCSC scheme in which constant firing angle model is used. This thesis also shows that damping characteristics obtained by using IMDU are better than TCSC, But TCSC can be used for damping SSR as well as Controlling the active power flow. The system results are obtained by modelling a linearized system in MALAB.