Connecting primary equipment with cable and secondary equipment with fiber, IED can measure and control primary devices like circuit breaker, switch blade and main transformer. As the equipment in process layer, it can gather information within certain intervals, control and monitor some protection equipment like circuit breaker, knife switch and grounding switch. Currently optical fibers with IRIG-B or IEEE1588 technology are commonly used to synchronize IED.
IED response delay is the time it takes when IED receives the switch-in signals from the hard contacts and transforms to GOOSE signals. The requirements for the delay are as follows.
√ Conversion time of switch command at tripping position <5ms（without anti-shake time）√ Conversion time of switch command at detent position <5ms（without anti-shake time）
Fig 1 Response Delay Measurement on IED