Study of differential chronometric selectivity

VAL-SELEC is a teaching device that brings together the main elements necessary for studying differential time-domain selectivity.
This study is carried out using adjustable differential relays, equipped with separate current transformers. If necessary, these current transformers can be disconnected from the differential relays to simulate a hardware fault. The silkscreen printing on the faces clearly identifies the role of each component. Resistive dipoles, integrated into the case, allow the simulation of variations in earth fault currents. For more precise adjustment of the fault current, a rheostat (supplied with the model) can be used instead of the resistive dipoles. The components are wired using 4 mm terminals, with as many terminals as possible accessible to the student.