2Nd Harmonic Block/Inrush Restraint (81Hbl2) - Siemens Reyrolle 7SR46 Manual

Functions

3.7 2nd Harmonic Block/Inrush Restraint (81HBL2)

3.7

2nd Harmonic Block/Inrush Restraint (81HBL2)

Overview of the Function (81HBL2)
The inrush-current detection is used to:
•
Recognize an inrush process on transformers and other inductive loads
•
Generate a blocking signal for protection functions when transformers are switched on
•
Allows a sensitive setting of the protection functions
Structure of the Function (81HBL2)
The inrush current detector supervision function element has group-dependent settings, these settings can be
different in each settings group – group numbers (Gn) 1 and 2.
The function monitors the primary system current using the 3-phase current transformer inputs, for example
CT1/2/3.
The inrush current detector function (81HBL2) is summarized as:
•
High speed (instantaneous) operate characteristic
•
All phases are inhibited when any phase detects an inrush current condition.
Logic of the Function (81HBL2)
[lo_7sr46_HarmonicBlockFeatureFn, 1, en_US]
Figure 3-9
Application and Settings Notes
81HBL2 Setting
Default setting: 0.20 ⋅ I
58
Logic Diagram of the 2nd Harmonic Block/Inrush Restraint (81HBL2)
Reyrolle, 7SR46 Device, Manual
C53000-G7040-C103-1, Edition 10.2022