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Page 267

| Figure 14-2 (A) Typical time-current curves for link fuse. |

| The general plan for coordinating relays on a local distribution system is shown in Fig. 14-3. Some typical time settings are given to illustrate the gradual increase in minimum settings for relays as they approach the source. The characteristics of various induction types of overcurrent relays, each of which may be further modified by imposing a definite minimum time setting, are shown in Fig. 14-4. By choosing the proper minimum time settings, it becomes possible for several of these relays (and their breakers) to be in series and still operate properly in event of a fault anywhere in the circuit. Several relays in series can be set for the same time to handle faults immediately beyond them. Thus set, they can still provide the requisite quarter second or more margin for faults beyond the next relay because of the smaller fault current that will flow for a fault in that direction. |

| Subtransmission-Substation |

| The intermediate system of electric supplyusually consisting of several incoming high-voltage transmission lines and moderate-voltage subtrans- |

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