Abstract :
TWO PRIME CONSIDERATIONS in any refinery electric system should be flexibility and dependability. These factors entered markedly into the selection and design of the distribution system which consists of a primary selective combined with a secondary selective system, see Figure 1. The common secondary tie is an aerial loop which is sectionalized by means of pole-mounted switches, normally open. The loop serves the twofold purpose of a secondary tie, when needed, as well as a wide-area distribution feeder covering several miles with numerous loads tapped off, somewhat on the order of a public utility system serving a populated area. The other secondary feeders out of the substations are underground cables direct to points of usage.
