5-104 C70 Capacitor Bank Protection and Control System GE Multilin5.4 SYSTEM SETUP 5 SETTINGS5The relay using a given FlexCurve applies linear approximation for times between the user-entered points. Specialcare must be applied when setting the two points that are close to the multiple of pickup of 1; that is, 0.98 pu and1.03 pu. It is recommended to set the two times to a similar value; otherwise, the linear approximation may result inundesired behavior for the operating quantity that is close to 1.00 pu.b) FLEXCURVE CONFIGURATION WITH ENERVISTA UR SETUPThe EnerVista UR Setup software allows for easy configuration and management of FlexCurves and their associated datapoints. Prospective FlexCurves can be configured from a selection of standard curves to provide the best approximate fit,then specific data points can be edited afterwards. Alternately, curve data can be imported from a specified file (.csv format)by selecting the Import Data From EnerVista UR Setup setting.Curves and data can be exported, viewed, and cleared by clicking the appropriate buttons. FlexCurves are customized byediting the operating time (ms) values at pre-defined per-unit current multiples. Note that the pickup multiples start at zero(implying the "reset time"), operating time below pickup, and operating time above pickup.c) RECLOSER CURVE EDITINGRecloser curve selection is special in that recloser curves can be shaped into a composite curve with a minimum responsetime and a fixed time above a specified pickup multiples. There are 41 recloser curve types supported. These definite oper-ating times are useful to coordinate operating times, typically at higher currents and where upstream and downstream pro-tective devices have different operating characteristics. The recloser curve configuration window shown below appearswhen the Initialize From EnerVista UR Setup setting is set to “Recloser Curve” and the Initialize FlexCurve button isclicked.Figure 5–29: RECLOSER CURVE INITIALIZATIONThe multiplier and adder settings only affect the curve portion of the characteristic and not the MRT and HCT set-tings. The HCT settings override the MRT settings for multiples of pickup greater than the HCT ratio.NOTE842721A1.CDRMultiplier: Scales (multiplies) the curve operating timesAddr: Adds the time specified in this field (in ms) to eachoperating time value.curveMinimum Response Time (MRT): If enabled, the MRT settingdefines the shortest operating time even if the curve suggestsa shorter time at higher current multiples. A composite operatingcharacteristic is effectively defined. For current multiples lowerthan the intersection point, the curve dictates the operating time;otherwise, the MRT does. An information message appearswhen attempting to apply an MRT shorter than the minimumcurve time.High Current Time:HCT RatioHCTAllows the user to set a pickup multiplefrom which point onwards the operating time is fixed. This isnormally only required at higher current levels. Thedefines the high current pickup multiple; the defines theoperating time.NOTE
