3.2 Connections
V = Voltage of the generator (supply
G
Z = Impedance of the Line wire from the transformer,
L
Z = Impedance of the Neutral wire from the transformer,
N
Z = Impedance of the Earth wire, including the Earth
E
Z
=Line (Hot) wire impedance including the transformer impedance.
L
Z
=Neutral wire impedance.
N
Z
=Earth (Ground) path impedance including all the connections.
E
PSC
V
G
V
L-N,
Page 8
Fault Finding and Analyzing
the Electrical Network
Total Line (Hot) Path including the transformer
Z
L
V
G
Z
N
Z
E
Electrical Supply
and
Distribution
(internal impedance of transformer = X-Form)
up to the test point (Z displayed by Instrument also
includes X-Form). If this impedance is too high, check
the connections of the Line wiring, check the quality
of the line wiring and the switches / contacts in the
line circuit.
up to the test point.
check the connections of the Neutral wiring, check
the quality of the line wiring and the switches or
contacts in the Neutral circuit.
Impedance itself, as seen by the protection system.
Similar checking, specially at the bounding points
should be done is this path impedance is too high.
PSC
= Prospective Short Circuit Current (L to N) & (L to E).
L-E,
L-N
=Electrical Network Supply Voltage Transformer (without Load).
V
=Voltage between L-N & L-E (without Load).
L-E
Please note: Instrument accuracy
depend of VG stability while testing.
Figure 2.- Electrical Network scheme
L
User's Board, future Load Side, Test point,
socket outlet,etc...
V
PSC
L-N
L-N
N
PSC
L-N
V
L-E
E
PSC
L-E
Point of Test,
or
Socket Outlet
transformer
L
If this impedance is too high,
USER'S MANUAL. PE-425
PSC
L-E
)
05/2015