Name Values (Range) Unit Step Default Description
ClockNumberW3 0 [0 deg]
1 [30 deg lag]
2 [60 deg lag]
3 [90 deg lag]
4 [120 deg lag]
5 [150 deg lag]
6 [180 deg]
7 [150 deg lead]
8 [120 deg lead]
9 [90 deg lead]
10 [60 deg lead]
11 [30 deg lead]
- - 5 [150 deg lag] Phase displacement between W3 &
W1=HV winding, hour notation
ZSCurrSubtrW1 Off
On
- - On Enable zero sequence subtraction for W1
side, Off/On
ZSCurrSubtrW2 Off
On
- - On Enable zero sequence subtraction for W2
side, Off/On
ZSCurrSubtrW3 Off
On
- - On Enable zero sequence subtraction for W3
side, Off/On
6.1.2.5 Monitored data
Table 28: T3WPDIF Monitored data
Name
Type Values (Range) Unit Description
IDL1MAG REAL - A Magnitude of
fundamental frequency
differential current, phase
L1
IDL2MAG
REAL - A Magnitude of
fundamental frequency
differential current, phase
L2
IDL3MAG
REAL - A Magnitude of
fundamental frequency
differential current, phase
L3
IBIAS
REAL - A Magnitude of the bias
current, which is common
to all phases
IDNSMAG
REAL - A Magnitude of the
negative sequence
differential current
6.1.3 Operation principle
The task of the power transformer differential protection is to determine whether a
fault is within the protected zone, or outside of the protected zone. The protected zone
is limited by the position of current transformers (see figure 31), and in principle can
include more objects than just a transformer. If the fault is found to be internal, the
faulty power transformer must be quickly disconnected from the system.
1MRK 502 048-UEN A Section 6
Differential protection
85
Technical manual