A simple and economical technique for measuring voltage phase angles and generator shaft angles is reviewed. The principle is briefly exposed and its practical operation is illustrated by an experiment in a real power system. Due to the importance of accurate time for this application a short survey on time dissemination systems is included. The main part of the paper is devoted to the possible applications of phase angle measurements for the control and monitoring of power systems. The discussion deals with various topics and makes ample reference to available literature. The paper is intended as an information survey for assessing the practical significance of phase angle measurements

Phase Angle Measurements with Synchronized Clocks-Principle and Applications

An analysis of the most important time dissemination methods in current use is presented and the difficulties encountered or foreseen in applying such methods in electrical substations is described. The latter part of the paper is devoted to methods developed and applied at Hydro-Qu??bec. There are many requirements for a common time scale in electric power systems. For example, interest has arisen in the chronology of protection operations, where the accuracy must be in the order of milliseconds. A more recent application is for measurement of the voltage phase-angle (or power angle) between remote points on a power system, a technique which calls for an accuracy in the order of 10 ??s. A distinction is established here between time dissemination and frequency dissemination, which are often confused.

Study of Time Dissemination Methods Used on an Electric Power System with Particular Reference to Hydro-Quebec

The ever increasing complexity of electrical networks combined with the increasing cost of power losses during a network failure has led public utilities to become equipped with more powerful and precise tools for pinpointing the causes of such a fault. Hydro Quebec has developed and is now using a time dissemination system which uses a modified IRIG B code transmitted on its own telecommunication network. The reasons for using such a system and the way it was carried out are discrete.

L. Laroche

Papers

Time dissemination in the Hydro Quebec network