Common indicators that a relay is malfunctioning include unusual clicking noises, failure to activate, and intermittent operation. Selectivity is a mandatory requirement for all protection, but the importance of it depends on the application. For example, unselective protection operation during a medium voltage network fault will cause an outage for an unnecessarily large number of consumers. It provides the means for relays located at different points in the network to exchange information and coordinate their protective actions. PowerPort-E: Have you installed release 3. 60 or higher? Plug off the USB cable from the protective device and. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. ) and network communication systems (SCADA, RTUs, digital and analog inputs and outputs, IEC 61850, etc.