Auxiliary control of static var system to improve the dynamic performance of long transmission lines

Computer representation of excitation systems

Abstract: The availability of large digital computers has permitted more extensive computation of power system stability, a subject of increasingly greater importance. This paper suggests a common nomenclature and control system representation of the various excitation systems now available. It can be used to define input data requirements for computer programs, and can provide a consistent format in which manufacturers can respond to requests for excitation system data to be used for system studies.

Damping torque analysis of static VAR system controllers

Abstract: The use of a damping torque technique to examine the efficacy of various control signals, for reactive power modulation of a midpoint-located static VAr system (SVS) in enhancing the power transfer capability of long transmission lines is considered. A new auxiliary signal, the computed internal frequency (CIF), is proposed which synthesizes the internal voltage frequency of the remote generator from electrical measurements at the SVS bus. It is demonstrated that this signal is far superior to other conventional auxiliary control signals in that it allows full utilization of the network transmission capacity. The damping torque results are correlated with those obtained from eigenvalue analysis. >

Dynamic Stability of Long Transmission Systems with Static Compensators and Synchronous Machines

Abstract: This paper deals with the dynamic stability of long distance a.c. transmission systems operating at above 1 surge impedance loading and compensated entirely by automatically controlled shunt inductance device referred to as Static Compensators. Generalised system equations in the form X = AX, with a careful choice of state variables are developed via the subsystem concept and the eigenvalue technique used to establish the stability limits. The static compensator and the excitation system control parameters are chosen in a coordinated manner from the stability limit plots, the extension of stability limits with a Static Compensator are quantised, later a second compensator is included for improving the system performance and interaction studies.

Application of power system stabilizers and static VAr compensators on a longitudinal power system

Abstract: The dynamic stability improvement of a longitudinal power system using a power system stabilizer (PSS) and a static VAr (reactive volt-ampere) compensator (SVC) is reported. An analytical approach is developed for the determination of PSS parameters. The effect of static VAr compensators installed at several different locations along 345 kV trunk lines on system responses is examined. Results from time-domain simulations indicate that the PSS and the SVC are very effective in damping system oscillations. >