SACE EMAX 2 NEW LOW VOLTAGE POWER C I RCUI T BRE AKERS TO ANS I C37 / UL 1066 / CSA STANDARDS
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— Description of protection functions
Zone selectivity for S, I and G protections (ANSI 68) : can be used to minimize circuit- breaker trip times closer to the fault. The protection is provided by connecting all the zone selectivity outputs of the trip units belonging to the same zone and taking this signal to the trip unit input that is immediately upstream. Each circuit breaker that detects a fault reports it to the circuit breaker upstream; the circuit- breaker thus detects the fault but does not receive any communication from those downstream and opens without waiting for the set delay to elapse. It is possible to enable zone selectivity if the fixed-time curve has been selected and the auxiliary supply is present.
Current thresholds : this function enables indicators for four independent thresholds to enable corrective action implementation before the overload L protection trips the circuit breaker. For example, by discon- necting loads located downstream from the circuit breaker that are controlled by Ekip Signalling.
Advanced protection functions A different operating mode can be chosen for the following protection function: 1. Active: protection enabled by opening of the circuit- breaker when the threshold is reached; 2. Only alarm: protection active, with only alarm indication when the threshold is reached; 3. Deactivated: protection disabled.
t
Extremely Inverse Very Inverse Standard Inverse Extremely Inverse Very Inverse Standard Inverse Extremely Inverse Very Inverse Standard Inverse
t t
8
8 8
Furthermore, when the voltage and frequency protections are activated, they indicate an alarm status even when the circuit breaker is open so that a fault can be identified before the circuit breaker closes.
I
I I
Undervoltage (UV - ANSI 27) : with constant trip time (t = k), function is tripped when phase voltage falls below set threshold.
t
t t
UV UV UV
U8
U8 U8
t8
t8 t8
V
V V
t
Overvoltage (OV - ANSI 59) : with constant trip time (t = k), function is tripped when phase voltage exceeds the set threshold.
t t
OV OV OV
U9
U9 U9
t8 9
t8 9 t8 9
V
V V
t
t t
Underfrequency (UF - ANSI 81L) : with constant trip time (t = k), function is tripped when network fre - quency falls below set threshold.
f12
UF UF UF
f12 f12
t12 1 t12 t12
f
f f
t
t t
OF OF OF
f13
f13 f13
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