Stage with Independent Characteristic Curve
Function Description
Logic
[lodtchuf-080513-01.tif, 1, en_US]
Figure 6-243
Logic of the Overexcitation Protection with Inpendent Characteristic Curve (Definite-Time
Stage)
Method of Measurement
This stage evaluates also the V/f value that is identical to the input value of the thermal stage.
Measurement-relevant details can be found in chapter 6.39.3 Stage with Dependent Characteristic Curve
(Thermal Stage).
How the Definite-Time Stage Works
The stage comprises a threshold and a time-delay stage. If the V/f value is greater than the set threshold value
((_:13621:3) Threshold), then the stage is tripped after an adjustable time delay has elapsed. You can
set the time delay with the parameter (_:13621:6) Operate delay.
The dropout ratio for the Threshold is fixed to 98 %.
Application and Setting Notes
The definite-time stage can be applied when fast tripping is required in the presence of high V/f values. In this
case, the stage acts superimposed on the thermal, dependent stage.
Parameter: Threshold Value
•
Default setting (_:13621:3) Threshold = 1.40
The Threshold parameter is used to describe the overexcitation value that causes the tripping function.
The default value matches a feasible upper limit.
6.39.4
6.39.4.1
6.39.4.2
Protection and Automation Functions
6.39 Overexcitation Protection
824 SIPROTEC 5, Overcurrent Protection, Manual
C53000-G5040-C017-8, Edition 07.2017
To Next Page
Loading...
