Bender EDS460 - Settings Menu 10: Factory Settings Reset; Menu 4: Device Control Functions; Control Menu 1: Execute Test; Control Menu 2: Initiate Reset

System description
18
EDS460-490_D00085_01_M_XXEN/02.2016
The following residual currents flow through the measuring current transfor-
mer of the EDS… :
 The locating current I
∆s
caused by the insulation fault R
Fd
 Residual currents I
∆
flowing through the system leakage capacitances
C
Lu,
and C
Ld
, respectively which are caused by R
Fu
and R
Fd
 Transient leakage currents caused by switching and control activities in
the system
 Low-frequency leakage currents caused by the use of converters
3.2.4 Requirements for reliable insulation fault location
The EDS… is intended to locate insulation faults downstream of the measu-
ring current transformer R
Fd
. For this purpose, the locating current caused by
the insulation fault has to be detected reliably, subject to the condition that:
 The locating current I
∆s
for the EDS460/490 is more than 1.5 mA and
less than 50 mA.
 The locating current I
∆s
for the EDS461/491 is more than 0.15 mA and
less than 5 mA.
 The upstream capacitances C
Lu
must be at least as large as the down-
stream capacitances C
Ld.
 The system leakage capacitance does not have to be too large (see
„Response sensitivity characteristics“ on page 74).
 The total residual current through the measuring current transformer
(locating current and residual currents etc.) may be a maximum of 10 A
(EDS460/490) respectively 1 A (EDS461/491).
 Not only does the amplitude influence the reliable detection of the
locating current but also the residual current frequency. This effect is
illustrated in the following fault curve.