Analysis of Operation and Stability of Ultra-long Transmission Lines with Controlled Shunt Compensation

The study of operation and stability of ultra-long AC transmission line with maximum length of 4000 km with controlled shunt compensation has been carried out. It is shown that parallel operation of static var compensators / controlled shunt reactors and low capacity synchronous condenser in one node allows to realize active power transfer that is larger than surge impedance level by 10-40%. Synchronized coordination for static var compensator control systems as well as generator and condenser PSS settings is performed on the basis of eigenvalue shift approach. It is demonstrated that simultaneous optimization of control system parameters together with compensator time response allows to enlarge the limit of transmitted power up to 1.1 p.u. and reach improved level of small signal stability. By increasing condenser capacity twice, limit of active power is achieved to 1.2 p.u.