Auxiliary power systems for steam-electric generating stations [includes discussion

Abstract

Among the most significant present trends in steam-electric generating stations is the increasing use of larger single blocks of generation with higher steam conditions. Both these factors greatly increase the amount of auxiliary power required for single units of generation. It therefore seems appropriate to re-examine the present status of auxiliary power-system design and also to indicate how present practice can be extended to provide adequately for the much larger auxiliary power requirements of future generating units. It is concluded that: 1. With the increase in the size of generating units and the use of higher steam pressures, the auxiliary power required for a single generating unit may increase to 30,000 kw or more within the next few years. 2. An extension of present auxiliary power system designs using three auxiliary power busses at 4,160 volts will allow this amount of power to be handled within present circuit-breaker ratings. 3. The conventional radial auxiliary power system will continue to be most widely used because of its proven reliability and generally lower first cost. 4. Motor sizes that probably will be used in the next few years will not present a serious voltage regulation problem on 4,160- volt auxiliary power systems. 5. The use of grounded auxiliary power systems reduces the probability of multiple outages