Experiences with Grounded-Neutral, Y-Connected Potential Transformers on Ungrounded Systems

Abstract

Synopsis.-The application of Y-connected transformers to three-pated from the suppression of the third and its multiple harmonics, phase, three-wire systems, in such a manner that the third and may not be generally appreciated, so this paper outlines experiences its multiple harmonics of the exciting currents woutld ordinarily with two such applications. The peculiar and dangerous "saturabe suppressed, is not in aceordance with the best practise. How-tion phenomena" obtained and the methods of preventing their ever, such applications of grounded-neutral, Y-connected potential occurrence are described and considerable data thereon included.transformers, particularly to temporarily ungrounded systems, The phenomena are discussed from theoretical standpoints in have been made for relaying and other purposes. The resulting companion papers by A. Boyajian and 0. P. McCarty and by complications, which are of a different nature than would be antici-C. W. La Pierre.2. The abbreviations L/L for "line-to-line" and L/N for

Ferroresonant Configurations in Power Systems

“…When phase-to-ground voltage transformers are connected to an ungrounded neutral system, a ferroresonant circuit is formed between the nonlinear inductance of the voltage transformer and the phase-to-ground capacitance ( Figure 2) [4,[13][14][15][16][17][18][19][20][21][22]. Under these situations, the protective devices associated with these voltage transformers can identify the disturbance as an earth fault, causing undesired misoperations [15,16].…”