CHAPTER 7: PROTECTION
CONTROL ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
379
Figure 316: FlexCurve™ display example
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. Click the
Initialize FlexCurve
button to populate the pickup values with the points from the curve
specified by the
Initialize From
setting. These values can then be edited to create a custom
curve. Note that the pickup multiples start at zero (implying the reset time), operating time
below pickup, and operating time above pickup. Click on the
Clear FlexCurve
button to
reset all pickup values to zero.
Curve data can be imported from CSV (comma-separated values) files by clicking on the
Import Data From
button. Likewise, curve data can be saved in CSV format by clicking the
Export Data To
button. CSV is a delimited data format with fields separated by the comma
character and records separated by new lines. Refer to IETF RFC 4180 for additional
details.
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 below appears when the
Initialize From
setting is set to
“Recloser Curve” and the
Initialize FlexCurve
button is clicked.