IEC 61869-15-2018 pdf download.Instrument transformers – Part 15: Additional requirements for voltage transformers for DC applications.
5 Ratings
5.1 General
Subclause 5.1 of IEC 61 869-1 :2007 is replaced by the following one:
If applicable, the ratings of voltage transformers, including their auxiliary equipment, shall be selected from the following ones:
• highest voltage for equipment (U m );
• rated primary voltage (U pr );
• rated delay time (t dr );
• rated secondary voltage (U sr );
• insulation level;
• rated burden (R br );
• rated accuracy class;
• rated step response time (T sr ).
The rating applies at the standardized reference atmosphere (temperature 20 °C, pressure
1 01 ,3 kPa, and humidity 1 1 g/m 3 ) as specified in IEC 60071 -1 .
NOTE The ratings are specified by the purchaser depending on the characteristics of the whole DC system application.
5.2 Highest voltage for equipment
There are no standard values for highest voltage for equipment.
However, a tentative list of standard values is given in Annex 1 5A.
5.3 Rated insulation levels
5.3.1 General
Subclause 5.3.1 from IEC 61 869-1 :2007 is replaced by the following one:
The standard values of insulation level of IEC 60071 -1 are not applicable to DC systems.
Methods of calculation for applied dielectric test voltages are given in the relevant clauses of this document.
Additionally, indication for impulse withstand voltage values are given in Annex 1 5A.
5.3.3 Other requirements for insulation of primary terminals
5.3.3.1 Partial discharges
Subclause 5.3.3.1 of IEC 61 869-1 :2007 is replaced by the following one:
The partial discharge level measured during the power-frequency voltage withstand test, shall not exceed the limits specified in Table 3.
5.4 Rated frequency
Subclause 5.4 of IEC 61 869-1 :2007 is replaced by the following one:
The rated frequency is equal to 0 (which means DC).
5.5 Rated output
5.5.602 Standard values for the rated delay time (t dr )
Subclause 5.5.602 of IEC 61 869-6:201 6 is replaced by the following one:
The standard values for rated delay time are:
5 µs – 25 µs – 1 00 µs
In the case of a pure passive DCVT, the rated delay time is 0.
5.5.1 501 Standard values of rated secondary voltage
The standard values of rated secondary DC voltage are:
5 V – 1 0V – 50 V
5.6 Rated accuracy class
5.6.1 501 Accuracy class designation
The accuracy class is designated by the highest permissible percentage of voltage error at
rated primary voltage and with the rated burden.
5.6.1 502 Standard accuracy classes
The standard accuracy classes are:
0,1 – 0,2 – 0,5 – 1 – 3
5.6.1 503 Limits of ratio error The ratio error for the DC component, measured at the secondary terminals, shall not exceed the values given in Table 1 502, expressed as a percentage of the measured voltage. A graphical representation of error limits is shown in Figure 1 503. The accuracy shall be guaranteed for the whole range of temperature, both for the outdoor and the indoor part of the voltage transformer and for both polarities.IEC 61869-15 pdf download.