Protection Testing in Systems with AC Binary Signals

Renewable energy systems such as wind energy plants often do not have battery arrangements for the provision of an auxiliary DC supply. In these installations the use of AC mains voltage for the binary outputs thus has become an alternative.

The rectifier bridge of the CMTAC 1 converts an AC input voltage into a DC pulsating voltage. The output of the CMTAC 1 is connected to a binary input of the CMC test set. To use the CMTAC 1 as a trigger source, use the deglitch function of the binary input. Otherwise the CMC test set would trigger on every half wave of the signal.

Connect 0…300 V AC at the input of the CMTAC 1. Connect its DC output to the BINARY INPUT of the CMC test set.

To trigger on 50/60 Hz AC signals, confure the potential voltage and the deglitch and debounce settings in Universe, RelaySimTest, or CMC Swift:

Vth = Vnominal ⁄ 3

Tdeglitch = 3 ms

Tdebounce = 0 ms

Example:

Vnominal = 230 V (Nominal voltage)

Vth = Vnominal ⁄ 3 = 230 ⁄ 3 = 77 V (Threshold voltage)

Compared to the direct connection of the AC signal, this significantly reduces the maximum time error (max. 3.5 ms).

CMTAC 1 can be used with CMC 256-6, CMC 256 plus, CMC 356, CMC 353 and CMC 310 test sets.