7.7.8
Technical data
Table 121:
LEXPDIS technical data
Function
Range or value
Accuracy
X offset of Mho top point for Zone
1 and Zone 2
(–1000.00–1000.00)% of Z
Base
±5.0% of U
r
/I
r
Diameter of Mho circle for Zone 1
and Zone 2
(0.0–3000.00)% of Z
Base
±5.0% of U
r
/I
r
Independent time delay for Zone
1 when impedance jumps from
the outside the set circle to the
center of the set circle
(0.00-6000.00) s
±0.2% or ±60 ms whichever is
greater
Independent time delay for Zone
2 when impedance jumps from
the outside the set circle to the
center of the set circle
(0.00-6000.00) s
±0.2% or ±60 ms whichever is
greater
Operate time, start when
impedance jumps from the
outside the set circle to the center
of the set circle
Min. = 35 ms
Max. = 50 ms
-
7.8
Sensitive rotor earth fault protection, injection based
ROTIPHIZ
7.8.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Sensitive rotor earth fault protection,
injection based
ROTIPHIZ
Rre<
64R
7.8.2
Functionality
The sensitive rotor earth fault protection (ROTIPHIZ) is used to detect earth faults in
the rotor windings of generators. ROTIPHIZ is applicable for all types of synchronous
generators.
To implement the above concept, a separate injection box is required. The injection
box generates a square wave voltage signal at a certain preset frequency which is fed
into the rotor winding.
The magnitude of the injected voltage signal and the resulting injected current is
measured through a resistive shunt located within the injection box. These two
measured values are fed to the IED. Based on these two measured quantities, the
protection IED determines the rotor winding resistance to ground. The resistance
value is then compared with the preset fault resistance alarm and trip levels.
1MRK502052-UEN B
Section 7
Impedance protection
279
Technical manual
Summary of Contents for Relion REG670
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