Relays
Figure 1: Tree Structure of Relay
Device Function: A tripping characteristics with only one time-overcurrent and one instantaneous overcurrent tripping functions. Device functions are listed as the ANSI code numbers or their combinations. You may enter your own device function names.
Single Function Relay: A single function relay has only one device function. If this is selected in the Relay Info tab while entering data, then you can select only one set of relay settings in the database edit mode.
Multi-function Relay: A multi-function relay has more than one device function. If this is selected in the Relay Info tab while entering data, then you can select multiple sets of relay settings in the database edit mode. If multi-function is selected and only one device function is entered in the library, then you can select different trip settings at the same time. Multiple curves can be plotted in coordination from the same relay. This feature is applicable to relays which can sense more than one current but operate with similar device functions.
Relay Class: You can choose from “Generator Relay,” “Motor Relay,” and “Other.” The choice of Relay Class affects the calculation method. For Generator Relay class and Motor Relay class, the trip settings are in multiples of full load amps (FLA). For the Other class the trip setting may be in multiples of relay rating, CT ratio, CT primary amps, and so on.
