RELIABILITY AND RELATIVE COST OF STEAM TURBINE GOVERNING AND STOP VALVE ARRANGEMENTS

The relative reliability of five steam turbine governing and stop valve arrangements is mathematically determined. The actual valve reliabilities are determined from field performance data and the expected number of failures for each arrangement, for the life of a turbo-generator set, is calculated.

The relative initial, system failure, maintenance and downtime costs for each system of the five governing and stop valve arrangements are determined, and the optimum arrangement giving the minimum relative total system cost is arrived at. Thus, the great value of the application of reliability engineering to commercial equipment is brought out.