CSN EN 62689-1

CSN EN 62689-1 IEC 62689-1:2016 defines the minimum requirements (therefore performances) and consequent classification and tests (with the exception of functional and communication ones) for fault passage indicators (FPIs) and distribution substation units (DSUs) (including their current and/or voltage sensors), which are, respectively, a device or a device/combination of devices and/or functions able to detect faults and provide indications about their localization.
Original English text of CSN EN Standard.
The price of the Standard included all amendments and correcturs.