A methodology of functional and reliability requirements definition for uninterruptible power system design following ISO 9000 recommendations

Loads, requiring an auxiliary source of power, have requirements of functional type and of reliability type. Both of them must be analyzed in depth because power system reliability behavior can be defined correctly only on the basis of stated functional performances. The objective of this paper is to prove that power supply quality standards are a powerful means to improve the design activity, especially when reliability requirements are fundamental for critical loads supply.