This presentation reviews the established principles and the advanced aspects of the selection and application of protective relays in the overall protection system, multifunctional numerical devices application for power distribution and industrial systems, and addresses some. This presentation reviews the established principles and the advanced aspects of the selection and application of protective relays in the overall protection system, multifunctional numerical devices application for power distribution and industrial systems, and addresses some. The selected protection principle affects the operating speed of the protection, which has a significant im-pact on the harm caused by short circuits. The faster the protection operates, the smaller the resulting ha-zards, damage and the thermal stress will be. Further, the duration of the voltage. The Distance Protection module adds features specific to distance protection, such as zone reach calculation. 1 Requires Stability Analysis Functions (RMS) or Electromagnetic Transients (EMT) licence 1 Requires Stability Analysis Functions (RMS) or Electromagnetic Transients (EMT) licence 2. Relay is an electrical control device. It is an electrical appliance that makes the controlled quantity have a predetermined step change in the electrical output circuit when the change of input quantity (excitation quantity) meets the specified requirements. Fundamentally they are protection schemes that adjust settings and/or logic of operations based on the prevailing conditions of the. Long term cost reduction (TCO) for trainings and maintenance by reduce variety of relays A fast and selective arc fault mitigation for air-insulated LV & MV switchgear and Relion protection and control relays and sensor technology protect staff and plant facilities for many years.