IEC 61869-14:2018 provides all requirements specific to current transformers to be used in DC applications (DCCTs), whatever the technology used. The output signal can be analogue or digital.
It is applicable to newly manufactured current transformers used for measuring, protection and/or control applications in DC power systems with a rated voltage above 1,5 kV.
The general configuration of a single-pole low-power instrument transformer is described in Figure 601 of IEC 61869-6:2016.
The DCCTs intended for current measurement in the transistor branch of the VSC valve (referred to as CT4a and CT4b in Figure 1403 and Table 1402) are not covered by this document, and will be considered in a future revision.
IEC 61869-14:2018 applies to current transformers intended to be used in DC applications with at least one of the following functions:
• measure DC current (with significant harmonics);
• withstand DC voltage.
Depending on the position on the DC system, different kinds of application exist, which are briefly described below, together with the approximate voltage or current wave shape.