t7
I I
PROTECT ION TR I P UNI TS
3/37
t t
100% 200%
50% 150% steady state
start-up
L
S
I
I I
t t
100% 200%
50% 150%
L
I4
S
t4
I
I
MCR – Closing on Short-circuit This protection uses the same algorithm as the l protection, limiting the operation to a settable time win- dow starting from the closing of the circuit-breaker. The protection can be disabled, when needed. The function is active with an auxiliary supply.
t t
I3
I4
t4
I I
t t
Iinst This guarantees the integrity of the circuit-breaker and installation in the case of particularly high current va- lues requiring shorter reaction times than those provided by the instantaneous short-circuit protection. The protection cannot be disabled, and the tripping threshold and time are defined by ABB.
I3
I2
t2
I I
IU - Current unbalance (ANSI 46) This function protects against an unbalance between the currents of the single phases protected by the circuit-breaker.
t
t
I1
t1
I7
I2
t2
t7
I
I
Harmonic distortion This allows a control alarm to be activated for a distorted waveform. If enabled, an alarm is activated for waveform factors higher than 2.1.
t
t
steady state
I1 Distorted waveform: Base + 3rd Harmonic start-up
t1
240 V
0 V
3rd Harmonic (150 Hertz)
-240 V
I I
Base Sine Waveform (50 Hertz)
T - Temperature This protects the circuit-breaker against abnormal temperatures recorded by the unit. It is always active, and has two states, according to the temperature: • Warning: -25 < t < -20 or 70 < t < 85 Display off; Warning LED on @ 0.5Hz. • Alarm: t < -25 o t > 85 Display off; Alarm and Warning LEDs on @2Hz; Circuit-breaker opening command. Hardware Trip This protects against internal disconnections of the circuit-breaker. If enabled, a fault is signaled and an opening command is sent if one or more of the following events are detected: • Current sensors disconnected (phase or external if enabled) • Rating plug disconnected (only for XT5 and XT7) • Trip coil disconnected (only signaling) • Incompatibility between protection release and mainboard (only for XT7) • Internal problems with the release. Current thresholds This function enables the realization of four independent thresholds to be indicated to enable corrective actions before the overload L protection trips the circuit-breaker. For example, by disconnecting the loads controlled by an Ekip Signalling device positioned downstream of the circuit-breaker.
t
100% 200%
50% 150%
L
Set B
S
Set A
I
I
Trigger event
t t
IEC 60947-4-1 Table 2
I4
t4
I I
t t
I3
Ij/Is
ti/tj
I f
t
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