Sepam series 20 Sepam series 40 - POWERLAB

Connection diagrams
Residual current input
MT10991
Variant 1: residual current calculation by sum of 3 phase currents
The residual current is obtained by taking the vector sum of the 3 phase currents I1,
I2 and I3, measured by three 1 A or 5 A CTs or by three LPCT type sensors.
See current input connection diagrams.
Variant 2: residual current measurement by CSH120 or CSH200 core balance CT (standard connection)
Arrangement recommended for the protection of isolated or compensated neutral
systems in which very low fault currents need to be detected.
Setting range from 0.1 In0 to 15 In0, with In0 = 2 A or 20 A (or 5 A for series 40)
according to parameter setting.
MT11045
Variant 3: residual current measurement by 1 A or 5 A CT and CSH30 interposing ring CT
The CSH30 interposing ring CT is used to connect Sepam to 1 A or 5 A CTs to
measure the residual current.
b connection of CSH30 interposing ring CT to 1 A CT: make 2 turns through the CSH
primary winding
b connection of CSH30 interposing ring CT to 5 A CT: make 4 turns through the CSH
primary winding
b with series 40, the sensitivity can be multiplied by 10
by parameter setting of In0 = In/10.
Setting range from 0.1 In to 15 In, or 0.01 In to 1.5 In (series 40)
with In = CT primary current.
DE50589
MT11046
Variant 4: residual current measurement by core balance CT with ratio 1/n (n between 50 and 1500)
The ACE990 is used as an interface between a MV core balance CT with ratio 1/n
(50 < n < 1500) and the Sepam residual current input.
This arrangement makes it possible to keep the existing core balance CTs in the
installation.
Setting range from 0.1 In0 to 15 In0, with In0 = k.n,
with n = number of turns through core balance CT
and k = factor to be determined according to the wiring of the ACE990 and the
parameter setting used by Sepam, among 20 discrete values from 0.00578 to
0.26316.
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