PC applications measure EMFs induced by power lines

Abstract

Recent advances in microcomputer hardware provide t h e feasibility of coding and computing of largesized algorithms by a personal computer (PC). Relevant PC application software, with comprehensive menus and dialogue-box techniques, enable enhanced user productivity. This article describes an example application that transforms a normally mainframe sized problem into a code compatible for PC applications. The relevant algorithm refers to the evaluation of electromagnetic fields (EMFs) induced b y high-voltage p o w e r l i n e s b y s o l v i n g t h e Laplace/Poisson equation via boundary-element technique.Evaluating the intensity of magnetic fields induced by buried and overhead power lines is of interest in modern times. Accurate evaluation of EMFs emanating from various types of transmission lines are based on rigorous algorithms and computer-based solutions. Typically, t h e numerical computation strategy (such as the boundary-element method) involves large-sized matrix inversions, which are done normally in the domain of mainframe computers. However, the engineers involved in EMF coordination projects in electric power utility companies would prefer codes that are capable of being handled by PCs compatible with office environments. Hence, there exists a niche to segment a large-sized numerical calculation that can b e accommodated in t h e code conducive for PC handling and user friendliness. This article focuses on the features of the FloridaPower & Light Buried Power Line (FPLBPL) and the Florida Power & Light Overhead Line (FPLOVR) programs, two software packages developed t o evaluate buried and overhead transmission-line-induced EMF. These are based on new techniques utilizing the common methods of solving boundary-element problems. The technique has a built-in strategy t o segment the domain or region in which EMF is evaluated with appropriate matching of the boundary conditions. The outcome of this method is that a huge matrix of 22.58 million elements is solved by a PC (8386-based machine) in about 1.5 hours. The computational protocol, however, maintains the same accuracy as would be realized in mainframe environments. Thus, these software packages provide accurate field tal-* Florida Atlantic University culations and, at the same time, are user friendly and suitable for office environments. (These programs were developed under a research contract from Florida Power & Light, which is gratefully acknowledged.) Program Structure and Functional AspectsFPLBPL and FPLOVR are stand-alone packages of computer codes written in Microsoft FORTRAN v5.1 with the following functional attributes: rn FPLBPL receives input from the user on the physical, geometrical, and phase current data on a three phase line enclosed by a plastic polyvinyl chloride (PVC) conduit and buried directly in the soil or encased in a concrete duct at particular depth from the surface of the earth (Figure 1). FPLOVR receives data on the physical, geometrical, and phase current data of an overhead high-voltage power line (Figure 2), as w...