Definition of Protective Relay A protective relay is an automatic device that detects abnormalities in an electrical circuit and closes its contacts. Engineering use: Relays are used on feeders, transformers, buses, motors, generators, and transmission lines to protect equipment and improve system. Core idea: A relay uses one electrical signal to switch, isolate, interlock, alarm, or command another circuit. Engineering use: Relays are used in control panels, motor circuits, PLC interfaces, alarms, breaker trip circuits, and power system protection schemes. They are activated by means which are not dependent on a continual AC supply.
[pdf] Port aggregation allows you to group multiple physical ports into one unit. Link aggregation increases total bandwidth beyond what a single connection could sustain, and provides redundancy where all but one of the physical links. An aggregation switch is a network device that consolidates traffic from multiple access switches, wireless access points, or other edge devices and forwards it to core switches or routers. By bundling multiple network connections into a single high-bandwidth link, aggregation switches help. Port aggregation can increase maximum throughput, and allow for network redundancy.
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