Distance Measuring Zones Operating Principles - GE MiCOM P40 Technical Manual

Chapter 7 - Distance Protection
3

DISTANCE MEASURING ZONES OPERATING PRINCIPLES

All distance zone characteristics in this product are constructed with one or more comparators. The comparators
are used to construct either Mho, or Quadrilateral characteristics. This section outlines the principles behind the
construction of the characteristics in order to provide an understanding of how best to set them.
The following table details signal definitions used to construct the measuring zone characteristics.
Name
Current
I
Current used by the Distance protection measuring element
I
I
Residual current of parallel line (mutual current)
M
I
Neutral Current (derived)
N
Faulted phase current (for example IA for A-N fault)
I
ph
The complex operator
j
Mutual compensation co-efficient
k
M
Residual compensation co-efficient
k
ZN
Distance polarizing factor. A percentage of the memory voltage polarizing signal that is added to the self-
p
polarizing voltage signal to dictate the level of Mho expansion and help establish a directional decision.
Resistance
R
Forward Resistance Reach
R
Reverse Resistance Reach
R'
A voltage vector value comprising one or more voltage components
S
S A voltage vector input to a comparator
1
S A second voltage vector input to a comparator
2
Voltage
V
Voltage used by the Distance protection measuring element
V
Impedance measured by the Distance protection element
V/I
V Voltage memory signal used for polarization
mem
V Faulted phase voltage (for example VA for A-N fault)
ph
V /I Loop impedance measurement
ph ph
V Source voltage
S
Reactance
X
Impedance Reach setting
Z
Reverse Impedance Reach setting
Z'
Positive sequence impedance
Z
1
Loop impedance
Z
LP
Forward replica reach in the loop impedance plane = Z(1+kZN.IN/Iph+kZM.IM/Iph)
Z
replica
Reverse replica reach in the loop impedance plane = Z'(1+kZN.IN/Iph+kZM.IM/Iph)
Z'
replica
Source impedance
Z
S
An angle (in degrees) usually associated with the tilt of a reactive line on a Quadrilateral characteristic
σ
Ðσ
A vectorial operator that rotates a vector quantity by an angle of σº (alternative representation e
110
Description
P446SV
jσ
)
P446SV-TM-EN-1