Siemens Reyrolle 7SR5 - 5.5 37 Undercurrent Protection - Phase

37 Undercurrent Protection – Phase
Overview of Functions
Phase undercurrent protection is used to :
•
Detect loss of current flow after the primary circuit‑breaking device is opened
•
Detect the loss of loads e.g. this could indicate loss of cooling capacity
•
Detect and protect pumps from running idle
Structure of the Function
The undercurrent function elements have group dependent settings. These settings can be different in each
settings group – group numbers (Gn) 1 to 4.
This function corresponds to the logical node A37PTUC* in IEC 61850.
The function monitors the primary system using the 3 phase current inputs e.g. CT1/2/3.
Function operation is selected to Any or All phases.
Blocking of the Stage
When a binary input configured as Inhibit 37-n is operated, the picked up relevent function element will
reset.
5.5
5.5.1
5.5.2
Protection and Automation Functions
5.5 37 Undercurrent Protection – Phase
Reyrolle 7SR5, Transformer Protection Device, Device Manual 171
C53000-G7040-C015-1, Edition 11.2019