4. 2 Analysis of induction generator effect: frequency scanning method 83 4. 3 Analysis of torsional interaction(TI) 87 4. 4 State equations and eigenvalue analysis 96 4. 5 An algorithm for computing torsional modes 108 4. 6 Countermeasures for SSR III 4. 7 Torsional oscillations in parallel connected turbine generators 120 121 5. INTERACTIONS WITH POWER SYSTEM STABILIZER 5. 1 Introduction 121 5. 2 Basic concept in the application of PSS 122 5. 3 Design of PSS 126 5. 4 Torsional interaction with PSS 130 5. 5 A case study 132 6. INTERACTIONS WITH HVDC CONVERTER CONTROL 137 6. 1 Introduction 137 6. 2 HVDC converters and control 138 6. 3 Modelling of HVDC system for study of torsional interactions 147 6. 4 Analysis of torsional interactions -A simplified approach 153 6. 5 A case study 156 6. 6 A simplified damping torque analysis 161 6. 7 Control of torsional interaction 167 7. INTERACTIONS WITH SHUNT COMPENSATORS 169 7. 1 Introduction 169 7. 2 Static Var Compensator 171 7 . 3 Torsional Interactions with SVC 186 7. 4 Static Condenser(STATCON) 189 7. 5 Torsional interactions with STATCON 196 7. 6 A simplified analysis of torsional interaction with voltage controller 200 8. INTERACTIONS WITH SERIES COMPENSATORS 205 8. 1 Introduction 205 8. 2 Thyristor Controlled Series Compensator 206 8. 3 Modelling of TCSC for SSR studies 216 8. 4 Mitigation of SSR with TCSC 223 8. 5 Static Synchronous Series Compensator (SSSC) 229 8.