What happens in an Electrical System within the first milliseconds of a Fault?
An electrical protection system works away silently saving lives and protecting equipment that all in milliseconds.
Basic components which make this happen:
๐๐๐ฌ (๐๐ฎ๐ซ๐ซ๐๐ง๐ญ ๐๐ซ๐๐ง๐ฌ๐๐จ๐ซ๐ฆ๐๐ซ๐ฌ)
Step down high current to a value safe to monitor and into the input of the relay.
๐๐๐ฌ/๐๐๐ฌ (๐๐จ๐ฅ๐ญ๐๐ ๐ ๐๐ซ๐๐ง๐ฌ๐๐จ๐ซ๐ฆ๐๐ซ๐ฌ)
Step down voltage to value for metering and protection logic.
๐๐ซ๐จ๐ญ๐๐๐ญ๐ข๐ฏ๐ ๐๐๐ฅ๐๐ฒ๐ฌ
Essentially the โbrainsโ comparing the current/voltage against configurable settings.
When a fault is detected, they send a trip signal to the circuit breaker.
๐๐ข๐ซ๐๐ฎ๐ข๐ญ ๐๐ซ๐๐๐ค๐๐ซ๐ฌ (๐๐๐ฌ)
Circuit breaker that interrupt power flow isolating the fault and preventing more damage.
๐๐๐ญ๐ญ๐๐ซ๐ข๐๐ฌ & ๐๐ซ๐ข๐ฉ ๐๐ข๐ซ๐๐ฎ๐ข๐ญ๐ฌ
Battery provide the required DC energy to instantaneously operate the breaker trip coil even when AC is lost.
Timing
๐๐๐ฅ๐๐ฒ ๐ญ๐ข๐ฆ๐
Time from fault detection to command time (usually <50mS)
๐๐ซ๐๐๐ค๐๐ซ ๐ญ๐ข๐ฆ๐
Time from command to contact separation time
๐ ๐๐ฎ๐ฅ๐ญ ๐๐ฅ๐๐๐ซ๐ข๐ง๐ ๐ญ๐ข๐ฆ๐
Time from fault detected until safety is restored.
It is the coordination between the relay and the breaker that keeps essential infrastructure safe, continuous and protected all automatically.
if you are designing substations, inspecting switchgear (or) analyzing disturbances, having a fundamental understanding of these protection systems is essential.