GE C70 Instruction Manual page 250

SYSTEM SETUP
5.5.6.2 FlexCurve configuration with EnerVista software
The EnerVista software allows for easy configuration and management of FlexCurves and their associated data points.
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 EnerVista Import Data From setting (Settings > System Setup > FlexCurves > FlexCurve).
Curves and data can be exported, viewed, and cleared by clicking the appropriate buttons. FlexCurves are customized by
editing 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.
5.5.6.3 Recloser curve editing
Recloser curve selection is special in that recloser curves can be shaped into a composite curve with a minimum response
time and a fixed time above a specified pickup multiples. There are 41 recloser curve types supported. These definite
operating times are useful to coordinate operating times, typically at higher currents and where upstream and
downstream protective devices have different operating characteristics. The recloser curve configuration window shown
here appears when the Initialize From setting in the EnerVista software is set to "Recloser Curve" and the Initialize
FlexCurve button is clicked.
5
The Multiplier and Adder settings only affect the curve portion of the characteristic and not the MRT and HCT
settings. The HCT settings override the MRT settings for multiples of pickup greater than the HCT ratio.
NOTE
5.5.6.4 Example
A composite curve can be created from the GE_111 standard with MRT = 200 ms and HCT initially disabled and then
enabled at eight times pickup with an operating time of 30 ms. At approximately four times pickup, the curve operating
time is equal to the MRT and from then onwards the operating time remains at 200 ms.
5-126
Figure 5-52: Recloser curve initialization
Multiplier: Scales (multiplies) the curve operating times
Addr: Adds the time specified in this field (in ms) to each
operating time value.
Minimum Response Time (MRT): If enabled, the MRT setting
defines the shortest operating time even if the curve suggests
a shorter time at higher current multiples. A composite operating
characteristic is effectively defined. For current multiples lower
than the intersection point, the curve dictates the operating time;
otherwise, the MRT does. An information message appears
when attempting to apply an MRT shorter than the minimum
curve time.
High Current Time:
from which point onwards the operating time is fixed. This is
normally only required at higher current levels. The
defines the high current pickup multiple; the
operating time.
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
Allows the user to set a pickup multiple
HCT Ratio
HCT defines the
842721A1.CDR