Wattmetric-Based Earth-Fault Protection Wpwde - ABB RELION Series Technical Manual

Section 4
Protection functions
4.2.6
4.2.6.1
4.2.6.2
4.2.6.3
360
Characteristic
Operate time accuracy in definite time mode
Operate time accuracy in IDMT mode
Suppression of harmonics
1) Fundamental frequency current = 1.0 × I
Start value , results based on statistical distribution of 1000 measurements
current 2.0 ×
2) Includes the delay of the signal output contact
3) Maximum Start value = 2.5 × I

Wattmetric-based earth-fault protection WPWDE

Identification
Function description
Wattmetric-based earth-fault protection
Function block
GUID-EDE21448-13FD-44E3-AF7C-CFD47A5C99DC V1 EN
Figure 187: Function block
Functionality
The wattmetric-based earth-fault protection function WPWDE can be used to detect
earth faults in unearthed networks, compensated networks (Petersen coil-earthed
networks) or networks with a high-impedance earthing. It can be used as an alternative
solution to the traditional residual current-based earth-fault protection functions, for
example, the IoCos mode in the directional earth-fault protection function
DEFxPDEF.
WPWDE measures the earth-fault power 3UoIoCosφ and gives an operating signal
when the residual current Io, residual voltage Uo and the earth-fault power exceed the
set limits and the angle (φ) between the residual current and the residual voltage is
inside the set operating sector, that is, forward or backward sector. The operating time
characteristic can be selected to be either definite time (DT) or a special wattmetric-
type inverse definite minimum type (wattmetric type IDMT).
The wattmetric-based earth-fault protection is very sensitive to current transformer
errors and it is recommended that a core balance CT is used for measuring the residual
current.
Value
±1.0% of the set value or ±20 ms
±5.0% of the set value or ±20 ms
3)
-50 dB at f = f
-3 dB at f = 13 × f
, harmonics current before fault = 0.0 × I
n
, Start value multiples in range of 2...20
n
IEC 61850
identification
WPWDE
1MRS758755 A
n
n
, harmonics fault
n
IEC 60617 ANSI/IEEE C37.2
identification device number
Po> -> 32N
REC615 and RER615
Technical Manual