301. — NETWORK» ANALYZER STUDIES OF UNBALANCED CONDITIONS ARISING FROM SINGLE PHASE LOADS IN A THREE PHASE POWER SYSTEM
by J. DAYCARD
Empirsa IWioiKil de Eleotricidad S.A. (ENDESAi, Chile.
The present report describes the methods employed to estimate the unbalances introduced in a three phase, power system, when supplying single phase systems through Scott connected transformer banks. A network analyzer was used and, upon estimating tfie relative merits of available methods to solve the problem, it was found that the generally called Alpha, Beta, Zero system of components would give tfte best solution for the case in hand.
A brief outline of the method itself and of the network analyzer procedure is given.
(a) Single phase loads on three phase systems, quite common on the low voltage distribution level, generally present no speciai unlw-limve problems in that case due to their smallpaagnitude and specially to the large Dumber of load points,, which permit to allocate them equally to eacli phase in order to achieve balanced conditions.
The problem differs considerably in the case of important single. Phase loads thai generally occur in connection with large eleclrical turnaecs or with alternating current railroad electrification. In these instances the relalhe high magnitude of (he single phase loads