Developing an analog and discrete signal input device for applying new detuning algorithms

One of the important parts of relay protection and automation devices (IEDs) is analog and discrete input devices. Nowadays, such parts of the IEDs have not changed significantly since their first implementation. However, for the past decades, a lot of issues in analog and discrete circuits have been found, thus, it requires revision in their design. Traditional analog input devices are current and voltage transformers. However, with the growth of the IEDs functions, it is necessary to consider the use of new types of converters, for example, Hall sensors. For receiving signals from other IEDs, discrete input devices are used. Its’ principle of operation is the transferring logic signals to the microprocessor. But since various kinds of interference may appear in the direct current system (DC system) to which the discrete input device is connected, it is necessary to detune from different disturbances.