Some Initial Results of Recent Developments in Graphic Power-line Disturbance Monitoring

Abstract

Recent developments in the technology available for power-line disturbance monitoring include the use of sub-microsecond sampling times, new disturbance capture algorithms, and sophisticated graphics software. One implementation of these developments is described. Some power-line disturbances which have been captured by this implementation are presented, with tentative explanations. These developments may allow the compilation of a set of signatures which will identify the causes of power-line disturbances. L. Introduction IN GENERAL, power-line disturbances have been recognized as a significant cause of disruption and damage of sensitive electronic devices and systems. Studies over the last 25 years have examined various types of power-line disturbances: impulses, surges, sags, frequency errors, power failures, and harmonic distortion in various forms. Initially, these studies were carried out using recording oscilloscopes [1][9]; later, microprocessor-based instruments were developed that printed text lists of power disturbances[3] [5] [7] [15].These text-list instruments provided important statistical data about the magnitude of power-line disturbances in the field. They also were employed successfully as tools for separating intermittent failures caused by power-line disturbances from intermittent failures caused by other factors. However, the text-list approach could at times provide ambiguous results (see the discussion with reference [15] , for example), and did not necessarily identify all power-line faults correctly. Now, with the development of microprocessor-controlled digital oscilloscopes, data which is less ambiguous is available. Special purpose oscilloscopes have been developed specifically to look for power-line faults. These special purpose instruments auto-range both in vertical and horizontal deflection rates, allowing the accurate capture and presentation of a wide range of power-line disturbances.