Instantaneous Measured Earth Fault Protection (50G) - Siemens Reyrolle 7SR45 Argus Device Manual

Functions

3.6 Instantaneous Measured Earth Fault Protection (50G)

3.6

Instantaneous Measured Earth Fault Protection (50G)

Overview of the Function (50G)
The instantaneous measured earth fault protection is used to provide:
•
Short circuit detection in electrical equipment
•
High speed protection where appropriate to its location in the power-system network and/or network
impedances
•
Backup or emergency protection in addition to other protection functions or devices
•
Coordinated operation with other devices using time graded settings
Structure of the Function (50G)
The instantaneous measured earth fault protection 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 earth fault CT input for example CT4.
The basic instantaneous measured earth fault protection function (50G) is summarized as follows:
•
Current measurement is based on the fundamental current.
•
Elements operate with a definite time lag (DTL) characteristic.
•
LED operations are provided for earth fault. A general pickup and 50G‑n output are also provided.
Logic of the Function (50G-n)
[lo_7sr45_50G_TimeDelayedMeasuredEFFn, 2, en_US]
Figure 3-6
Application and Settings Notes
Gn 50G-n Element
Default setting: Disabled
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Logic Diagram of the Instantaneous Measured Earth Fault Protection (50G)
Reyrolle, 7SR45, Device Manual
C53000-G7040-C101-2, Edition 09.2020