Synopsis.-The quality of service that can be rendered during principles to obtain reasonably accurate quantitative records of unavoidable system transients produced by short circuits must be transients to be expected on the 220-kv. interconnection between given careful consideration in the analysis of proposed intercon-the Philadelphia Electric Co., Pennsylvania Power & Light Co., and nection and transmission projects. An analysis of present systems the Public Service Electric & Gas Co. These records are obtained that have grown until such limitations have apparently been reached, by taking motion pictures of the equivalent mechanical system. will frequently reveal comparatively inexpensive changes in equip-Resistance or reactance short circuits on transmission lines are ment or operating practise which will permit good service to be duplicated mechanically by applying forces of the proper magnitude given and defer large investments in additional lines for a con-and direction to the spring representing the line in trouble, and siderable period.clearing this spring at each end by blowing fusible links from relays The fundamental mathematical methods for calculating system timed to represent the circuit breaker operations on the electrical transients have been presented by other writers during the last few system. The resulting mechanical oscillations will correspond to years. These mathematical calculations are of necessity qtite those of the electrical system because the inertias, spring characterinvolved and consequently can only be applied to very simple power istics, and torques of the mechanical model elements have been systems. The calculations must be made by thoroughly experienced proportioned to the corresponding elements in the electrical system; engineers and the results are not readily understood by the operating namely, stored energy, reactance, and kilowatts. The inherent staff.limitation due to imperfect springs has been overcome sufficiently toIn the May 1926 issue of the Electric Journal, under the title give results that are accurate within practical limits. "A Mechanical Analogy to the Problem of Transmission Stability,"It will be shown that the actual setting up of a system on the Mr. S. B. Griscom proposed the use of an accurate equivalent mechanical model is comparatively simple, and does not require a mechanical analogy to the electrical system provided perfect springs great deal of experience or mathematical skill. Slow motion pictures for representing line reactance could be obtained. A simple me-of the disturbance can be taken with amateur cameras that are chanical model for qualitatively illustrating the fundamental available on the market, and curves of the oscillations plotted from principles has been demonstrated before various local A. I. E. E. the projection on a screen. The slow motion pictures can be used sections and has resulted in a wide general knowledge of the transient also for acquainting the operating staff with the effect of various behavior of power systems. types of dis...

No abstract

No abstract

No abstract

No abstract