Availability evaluation of flow networks with varying throughput-demand and deferred repair

The author presents some simple formulas for availability of flow networks with several levels of performance and variable throughput demands. The system comprises highly available independent components. Two main types of component failure are considered: (1) those where the corresponding repair can be deferred to a more convenient time, and (2) all other failures. This more convenient time is set to a fixed date in the present model. This model is relevant to gas/oil production and transportation systems. Such availability concepts as throughput, demand, and onstream are discussed; the throughput availability is usually the most important. The computation of these measures can be time consuming; therefore, efficient algorithms and formulas are vital. The calculations are fast, so that sensitivity of various factors can be studied easily. The calculations show which components are contributing the most to unavailability