Power flows are widely used by engineers and remain essential for steady state analysis, short circuit and transient studies on power systems. Robustness of power flow methods is important for facilitating engineering studies on difficult network configurations. This paper presents a review of different techniques for improving the convergence of power flows. The methods under investigation consist essentially in adjusting the Jacobian and the incremental voltage. These adjustments incorporated within the Newton Raphson method are used to obtain a faster rate of convergence, to provide a larger region of convergence or both. Different techniques are first presented from an investigation of various schemes available in the literature. A power flow method consisting of a scaled Levenberg-Marquardt scheme is introduced and its property is compared along with other traditional methods. Comparisons of the region of convergence on a power system consisting of a 3000-bus model are presented.

The purpose of this paper is to present an application which historically, did not make use of computing methodology in the solution of design problems. The design of High Voltage Direct Current (HVDC) ground electrodes involves the careful selection of several parameters in order to meet strict operating constraints. In particular, the operation of HVDC ground electrodes, results in a rise of the surrounding soil temperature which must be reasonably computed so as to permit safe operation of the grounding network.