Representation of faults in the dynamic simulation of h.v. d.c. systems, by digital computer

The paper introduces and develops digital-computer techniques for the representation of faults in the dynamic simulation of h.v. d.c. systems. The authors have employed the central-process method of representation, which is based on the fact that h.v. d.c. convertor operation consists of similar consecutive processes. This method enables convertor bridges, their control systems, the transmission line and the a.c. systems to be represented as a mathematical model by a set of differential, algebraic and Boolean equations. Repetitive use of the central-process technique enables continuous h.v. d.c. system operation to be represented under normal and abnormal conditions. The resulting digital-computer program, in which the system parameters are represented numerically, provides a versatile, accurate and inexpensive means of studying the response of an h.v. d.c. system to a specified condition. It is, for some purposes, an alternative to a physical model. The program described in the paper represents dynamically a complete 2-bridge h.v. d.c. system. Some of the transient waveforms of system voltages and currents resulting from convertor faults such as backfire, failure to fire, fire through, and commutation failure are given in the paper.