Analysis of high voltage impulse generator circuits

Haddow, L. Martin (1959) Analysis of high voltage impulse generator circuits. PhD thesis, University of Glasgow.

Abstract

A study is made of transient or oscillatory voltages which arise in an impulse generator of the two-column Marx type during the firing process (i.e. between the breakdown of the first and the last spark-gap and immediately thereafter). These voltages are liable to appear on the external test and measuring equipment, but this aspect is not dealt with, nor are the spark-gap characteristics investigated systematically. The voltages are shown to be relatively independent of the main circuit elements, but to be set up in the stray capacitative and inductive fields in the generator, structure. These fields are resolved into an equivalent circuit involving measurable parameters. A matrix method is developed to analyze its dynamic properties, the solution being given in terms of eigenvalues. It is particularly suited to numerical treatment on a digital computer. The theory is extended, tentatively, to the evaluation of optimum damping resistances. By a second approach, the generator is represented by a one-dimensional lattice circuit. Although an explicit solution is not obtained, some propagation characteristics are determined, enabling comparison to be made with the one-column type of generator (and with such analogous problems as transformer windings). The gaps cannot in general be assumed to fire simultaneously. The transient voltages are of primary importance in causing their successive breakdown, but the instant of breakdown due to an overvoltage cannot be determined from present data. Again, the firing of the gaps constitutes the excitation to the circuit, but it is doubtful whether they behave as ideal switches. These two factors make a complete solution impracticable. The experimental work made use of a four-stage generator. Voltages calculated from measured parameters are compared with oscillographic measurements. Sources of error in the capacitance-divider circuit are investigated and compensation for the connecting leads shown to be desirable.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: F M Bruce
• Keywords: Electrical engineering
• Date of Award: 1959
• Depositing User: Enlighten Team
• Unique ID: glathesis:1959-73628
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73628