ABB RELION REX640 Technical Manual page 965

1MRS759142 F
The TLT_ANG_CONFLICT monitored data is an assisting integer output which
supervises the validity of a tilt angle of quadrilateral characteristics so that the
characteristics always produce a closed boundary.
Impedance measurement
DSTPDIS provides three independent phase-to-earth and phase-to-phase
measuring elements per zone. The three-phase fault is measured with a dedicated
measurement element.
The impedance measurement is done similarly regardless of the zone shape. The
operation is based on impedance mapping where the fault loop impedance is first
calculated and then compared with the zone boundaries. If impedance is recognized
inside the operation zone, the corresponding operate output is activated after the
operate time has elapsed.
Phase-to-earth impedance measuring elements
The phase-to-earth impedance measuring elements provide the basic earth-fault
protection in direct or low-impedance earthed networks. The earth-fault protection
is enabled with the setting
requires that all three phase-to-earth voltages are measured. Otherwise, the release
of the earth-fault measuring elements is automatically blocked.
The reach of phase-to-earth measuring elements is based on loop impedance
+
Z
1
~
Figure 537: The fault loop impedance model for phase-to-earth impedance
measuring elements
R
1
X
1
Table continues on the next page
REX640
Technical Manual
−

R R
0 1
+ = +
Z RF R

N 1

3
The earth return path impedance is included in the calculated fault loop
impedance of the phase-to-earth measuring element.
R X
1 1
R X
N N
Positive-sequence resistance from measuring point to fault location
Positive-sequence reactance from measuring point to fault location
Op Mod Gnd loops Znx (x = 1...5) = "True". The enabling
−
  
X X
0 1
 + ⋅ +  +
j X RF

1
  
3
X + X
1 N
R
F
Protection functions
(Equation 267)
X
R
F
R
R + R
1 N
965