FAST-TRANSIENT VOLTAGE DISTRIBUTION IN HVDC THYRISTOR VALVE AND INFLUENCE OF VARIOUS FACTORS.

The paper deals with the theoretical analysis of fast-transient voltage distribution in a thyristor valve for HVDC transmission. On the basis of a complete equivalent circuit of thyristor valves, a nested circuit model, which is convenient to analyze and gives consideration to the peculiarities of all sections in a valve, is set up. The analysis of fast-transient voltage distribution on stages, modules, and thyristor levels is carried out by means of operational calculus. The corresponding computer program is also developed. Recent achievements in computer-aided analysis of electrical networks are adopted to calculate all transient characteristics within a valve by applying a versatile program (SPICE) with the aid of the model. As a result, a method of digital computation with the advantages of making full use of its strong points is established. The voltage distribution and the effects of various factors on it are studied by both methods mentioned.