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Installation and operation instruction for THF filter and
protective unit THF 1_
The function of Protective unit (THF1_)
The protective unit shall always be used when the THF is installed in the star point on TN-C- and
TN-S-circuits. It can also be used in TN-S-system, when THF is installed in N-conductor.
The purpose of the protection unit is:
•
to prevent harmful effects of 150/180Hz
fault current by measuring the current.
•
to protect the network against high
50/ 60Hz voltage drop.
•
to protect THF against overload.
The function of the protection unit
The protection unit controls the by-pass-contactor
( K1) in case the 50/60Hz or 150/180Hz current
exceeds the set level.
The factory settings:
•
150/180 Hz current: 7% of the rated primary current of current transformer ( T1).
This current can cause overheating in case of fault in the TN-S-system.
•
Time settings 0,5 sec.
•
50/60Hz current exceeds 50% of the rated primary current of current
transformer (T1). This current is a cause of increased unbalance voltage.
Installation and operation instruction for THF filter and
protective unit THF 1_
Connection to the network need to be done by authorised and skilled personnel only.
Summary of Contents for THF 1BS Series
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Page 11: ...11 0 8Nm M4 1 2Nm ...
