Bender EDS3090, Manual

Page: 17 / 68

System description
17 EDS309x_D00012_03_M_XXEN/11.2014
3.3.3 Definitions
I
L
= Locating current that flows through the locating current injector while the fault location
is running (EDS mode).
I
Δ
L
= Locating current measured by the insulation fault locator (EDS mode).
I
Δ
n
= Residual current produced by an insulation fault (RCM mode).
3.3.4 Currents in the EDS system
As an addition to the schematic diagram on page 16, here the path of the residual currents and the
locating current is shown:
The following residual currents flow through the measuring current transformer of the EDS195P:

The locating current caused by the insulation fault R
F-N

The residual currents I
Δ
n
that flow through the system leakage capacitances C
E-V
and
C
E-N
, or that are caused by R
F-V
and R
F-N

Transient leakage currents that are caused by switching and control activities in the system

Low-frequency leakage currents generated by the use of converters
.............
Locating current circuit due to the insulation fault R
F-N
. .. .. ..
Residual currents I
Δ
n
(example)
I
Δ
L
Locating current measured by the EDS195P
C
E-V
Upstream capacitances, system leakage capacitances upstream of the
measuring current transformer
C
E-N
Downstream capacitances, system leakage capacitance downstream of
the measuring current transformer
R
F-V
Insulation fault upstream of measuring current transformer
R
F-N
Insulation fault downstream of the measuring current transformer
U
n
IT-System
PSA...
EDS195P
PE
R
F-N
R
F-V
C
E-N
C
E-V
PGH...
1
2
3
I
Δ
n
I
Δ
L
I
L