Recent trends in reliability of large industrial power systems

The author stresses the challenges and complexities facing an engineer when designing a new facility or retrofitting an existing industrial power system. Industrial facilities are making more efficient use of their energy from all sources, with cogeneration being prevalent, as plants generate electricity for self-consumption and for sale to utilities. Inverter systems for uninterruptible power supplies and adjustable speed drives for AC motors also generate harmonic voltages which adversely affect the power quality. Power quality affects the reliability of the plant system. Plant shutdowns due to computer or machine tool logic failures can be as expensive as those caused by a power supply interruption or an inadequately designed industrial facility