Search

This paper details a technique in the time domain for the fast periodic steady-state solution of systems with unified power-flow controllers (UPFCs) incorporating three strategies for the practical representation of the UPFC commutation process. The computation of the periodic steady-state solution of power systems with UPFCs including the proposed UPFC control strategies is efficiently obtained by extrapolation to the limit cycle using a Newton method based on a numerical-differentiation procedure. The periodic steady-state solution is validated against the solution obtained with the electromagnetic transient program PSCAD/EMTDC and against an implementation with the power system blockset of SIMULINK. Index Terms--Commutation process, electromagnetic transient program, fast periodic steady state, limit cycle, Newton method, numerical differentiation, unified power-flow controllers (UPFCs).

The development of a revolutionary design for transmission lines was recently introduced by shifting phase configurations and sub-conductors into “unconventional” arrangements that were geometrically optimized to maximize natural power. The objective of this paper is to study the electromagnetic transients that result from the simultaneous and sequential line energization and re-energization of the previously developed unconventional high surge impedance loading (HSIL) lines. Statistical switching overvoltage (SSOV) studies are performed using a frequency domain method based on the inverse numerical Laplace transform. Compared to a conventional line, all unconventional HSIL line designs studied in this paper lead to very similar surges for long line lengths (400 km) and similar values for short line lengths (100 km), indicating additional advantages of these lines. The use of a frequency domain method for SSOV studies offers enhanced accuracy, simulation flexibility, and substantially lower computational burden compared with traditional time-domain methods. [ABSTRACT FROM AUTHOR]