Behavior of transformer insulation under short-time overvoltage
This paper reports on a series of tests made on transformer insulation samples with automatically applied short-time a.c. overvoltages above the corona inception level to determine the conditions under which damaging corona occurs. Modified dielectric tests for power transformers are discussed.
A method for wide frequency range modeling of power transformers and rotating machines
Wide frequency range representation of power system components such as power transformers, reactors, and rotating machines is mainly needed for the analysis of electromagnetic transients in power systems. A method is presented for state space formulation of machine windings. The described procedure is completely based on external terminal impedance measurements, and data related to the internal structure are not required. The wide frequency behavior of machine windings is reviewed, and the nonlinearity effects of the iron core are discussed. A numerical method is given for calculation of the state equation parameters directly from the measured terminal impedance characteristics. The presented modeling method is applicable to any transformer, reactor, or rotating machine in service where sufficient information on the internal design is not available. The canonical structure of the model offers advantages in terms of computer memory and computational effort in time domain analyses of complex power systems.<<ETX>>
Allegheny Power System Design of 500-kV Towers
In this paper, the philosophy pertaining to the design of the 500-kV towers is outlined, starting with the economic studies to determine conductor type and size, phase spacing, insulator arrangement, span length, and loading. Particular attention is given to a discussion of unbalanced ice loading as well as realistic summertime wind loading.