Three-Phase Underimpedance Protection Uzpdis - ABB RELION REX640 Technical Manual

Section 4
Protection functions
4.7.4
4.7.4.1
4.7.4.2
4.7.4.3
4.7.4.4
942

Three-phase underimpedance protection UZPDIS

Identification
Function description
Three-phase underimpedance
protection
Function block
GUID-6CD1E41A-4095-4647-861D-C99A5D243D96 V1 EN
Figure 509: Function block
Functionality
The three-phase underimpedance protection UZPDIS is generally applied as a backup
protection for generators and transformers against short circuit faults.
The protection is based on the origin-centric circular characteristics on the impedance
plane. The function calculates the impedance value from the voltage and current
phasors. If the impedance vector enters the origin-centric circle, the function produces
the operating signal after a set delay. The operating time characteristics are according
to definite time (DT).
This function contains a blocking functionality. It is possible to block the function
outputs, reset timer or the function itself.
Analog channel configuration
UZPDIS has two analog group inputs which all must be properly configured.
Table 877: Analog inputs
Input
I3P
U3P
See the preprocessing function blocks in this document for the
possible signal sources.
There are a few special conditions which must be noted with the configuration.
IEC 61850 IEC 60617
identification identification
UZPDIS Z<G
Description
Three-phase currents
Three-phase voltages
1MRS759142 C
ANSI/IEEE C37.2
device number
21G
REX640
Technical Manual