Quantitative Reliability Analysis of HVDC Transmission Systems Part II Composite System Analysis

The application of Markov analysis1 and recursive techniques2 to the determination of the required number of mercury arc valves to achieve a given bridge reliability was illustrated in Part I " Spare Valve Assessment in Mercury Arc Bridge Configurations". It was shown in this paper that the number of states required to model a particular configuration increases rapidly with the number of bridges and the number of spare valves. This is particularly true in multiple bridge configurations when the identities of the individual bridges are maintained. While the bridge configuration is a major component of the dc link, it is still only one of the many subsystems which make up the entire dc system. It is, therefore, necessary to combine all these models to generate a complete model for the system. This combination becomes quite difficult while maintaining the complex models for the bridge configuration. A similar situation exists in generating capacity reliability evaluation when considering multiple boiler turbines3. This paper illustrates the reduction of the complex bridge configuration models to their equivalents and their combination with other subsystem models to obtain reliability indices for the complete system.