Instantaneous Overcurrent Protection (I or ANSI 50)
Instantaneous protection helps to protect equipment against phase-to-phase, phase-to-neutral and phase-to-ground short circuits. The protection operates with a definite time characteristic. It trips without additional time delay as soon as the setting current is exceeded.
The protection offers two tripping modes, with different breaking times:
oStandard: breaking time of 50 ms, used for applications requiring selectivity. Full selectivity can be provided with any Compact NSX or PowerPact H-, J-, L-frame circuit breaker installed downstream of a MasterPact MTZ circuit breaker (Refer to selectivity tables for details for Ue ≤ 440 Vac).
oFast: breaking time of 30 ms, typically used for applications where the thermal constraints of the equipment need to be limited and when selectivity is not required. For more information, refer to LVPED318033EN Complementary Technical Information.
NOTE: On MicroLogic 2.0 X, instantaneous protection is based on short-time protection without time setting with standard breaking time of 80 ms.
Instantaneous overcurrent protection is available on:
oMicroLogic 2.0 X, 5.0 X, 6.0 X, and 7.0 X control units for IEC standard
oMicroLogic 3.0 X, 5.0 X, and 6.0 X control units for UL standard
o3-pole and 4-pole circuit breakers
It is powered by the current flowing through the internal current transformers of the circuit breaker and it does not require an additional external power supply.
The instantaneous overcurrent protection threshold sets the level of short-circuit current at which the circuit breaker trips with no intentional time delay.
For MicroLogic 5.0 X, 6.0 X, 7.0 X control units for IEC and UL standards, instantaneous overcurrent protection can be disabled.
For MicroLogic 2.0 X control units for IEC standard and MicroLogic 3.0 X control units for UL standard, instantaneous overcurrent protection cannot be disabled.
Instantaneous overcurrent protection overrides short-time overcurrent protection when the instantaneous overcurrent threshold is adjusted to the same or a lower setting than the short-time overcurrent threshold.
Setting the Protection for MicroLogic 2.0 X
|
The instantaneous overcurrent protection setting for MicroLogic 2.0 X is: oIsd: instantaneous overcurrent protection threshold (corresponds to a short-time overcurrent protection threshold without time setting) It can be set as follows: oOn the MicroLogic X display screen, at Home > Protection > I Instantaneous oWith EcoStruxure Power Commission software (password-protected) oWith EcoStruxure Power Device app (password-protected) oBy sending a setting command using the communication network (password-protected). Instantaneous overcurrent protection can be duplicated when dual settings are activated. |
Protection Settings for MicroLogic 2.0 X
|
Setting |
Unit |
Range |
Step |
Factory setting |
|---|---|---|---|---|
|
Isd |
A |
1.5–10 x Ir |
0.5 x Ir(1) |
1.5 x Ir |
|
(1) Finer resolution settings are possible with EcoStruxure Power Commission software and EcoStruxure Power Device app. |
||||
For more information, refer to the setting guidelines.
Protection Characteristics for MicroLogic 2.0 X
|
Characteristic |
Unit |
Value |
|---|---|---|
|
Breaktime at 2 x Isd threshold |
ms |
≤ 80 |
|
Non-tripping time |
ms |
> 20 |
|
Accuracy on threshold |
% |
+/- 10 |
Setting the Protection for MicroLogic 3.0 X
|
The instantaneous overcurrent protection setting for MicroLogic 3.0 X is: oIi: instantaneous overcurrent protection threshold It can be set as follows: oOn the MicroLogic X display screen, at Home > Protection > I Instantaneous oWith EcoStruxure Power Commission software (password-protected) oWith EcoStruxure Power Device app (password-protected) oBy sending a setting command using the communication network (password-protected). Instantaneous overcurrent protection can be duplicated when dual settings are activated. |
Protection Settings for MicroLogic 3.0 X
|
Setting |
Unit |
Range |
Step |
Factory setting |
|---|---|---|---|---|
|
Ii tripping mode |
– |
Standard/Fast |
– |
Standard |
|
Ii |
A |
1.5–12 x In |
0.5 x In(1) |
1.5 x In |
|
(1) Finer resolution settings are possible with EcoStruxure Power Commission software and EcoStruxure Power Device app. |
||||
For more information, refer to the setting guidelines.
Protection Characteristics for MicroLogic 3.0 X
|
Characteristic |
Unit |
Ii tripping mode is set to Standard |
Ii tripping mode is set to Fast |
|---|---|---|---|
|
Breaktime at 2 x threshold |
ms |
≤ 50 |
≤ 30 |
|
Non-tripping time |
ms |
> 20 |
0 |
|
Accuracy on threshold |
% |
+/- 10 |
+/- 10 |
Setting the Protection for MicroLogic 5.0 X, 6.0 X, 7.0 X
|
The instantaneous overcurrent protection settings are: oIi mode: enables (ON) or disables (OFF) instantaneous overcurrent protection oIi tripping mode: sets tripping time to standard or fast oIi: instantaneous overcurrent protection threshold They can be set as follows: oOn the MicroLogic X display screen, at Home > Protection > I Instantaneous oWith EcoStruxure Power Commission software (password-protected) oWith EcoStruxure Power Device app (password-protected) oBy sending a setting command using the communication network (password-protected). Instantaneous overcurrent protection can be duplicated when dual settings are activated. |
Protection Settings for MicroLogic 5.0 X, 6.0 X, 7.0 X
|
Setting |
Unit |
Range |
Step |
Factory setting |
|---|---|---|---|---|
|
Ii mode |
– |
ON/OFF |
– |
ON |
|
Ii tripping mode |
– |
Standard/Fast |
– |
Standard |
|
Ii |
A |
2.0–15 x In |
0.5 x In(1) |
2.0 x In |
For more information, refer to the setting guidelines.
Protection Characteristics for MicroLogic 5.0 X, 6.0 X, 7.0 X
|
Characteristic |
Unit |
Ii tripping mode is set to Standard |
Ii tripping mode is set to Fast |
|---|---|---|---|
|
Breaktime at 2 x threshold |
ms |
≤ 50 |
≤ 30 |
|
Non-tripping time |
ms |
> 20 |
0 |
|
Accuracy on threshold |
% |
+/- 10 |
+/- 10 |
Predefined Events for MicroLogic 2.0 X
The function generates the following predefined events:
|
Code |
Event |
History |
Severity |
|---|---|---|---|
|
0x6401 (25601) |
Isd trip |
Trip |
High |
|
0x6301 (25345) |
Isd operate |
Protection |
Medium |
|
0x6201 (25089) |
Isd start |
Protection |
Low |
Predefined events cannot be modified by the user. For general information about events, refer to Event management.
Protection events are generated as follows:
oThe start event is generated when the protection picks up.
oThe operate event is generated when the protection time delay elapses.
oThe trip event is generated when the circuit breaker tripping voltage release (MITOP) activates.
|
Code |
Event |
Recommended actions |
|---|---|---|
|
0x6401 (25601) |
Isd trip |
Reset the device or use the Power restoration assistant within the EcoStruxure Power Device app. |
Predefined Events for MicroLogic 3.0 X, 5.0 X, 6.0 X, 7.0 X
The function generates the following predefined events:
|
Code |
Event |
History |
Severity |
|---|---|---|---|
|
0x6402 (25602) |
Ii trip |
Trip |
High |
|
0x6302 (25346) |
Ii operate |
Protection |
Medium |
Predefined events cannot be modified by the user. For general information about events, refer to Event management.
Protection events are generated as follows:
oThe operate event is generated when the protection time delay elapses.
oThe trip event is generated when the circuit breaker tripping voltage release (MITOP) activates.
|
Code |
Event |
Recommended actions |
|---|---|---|
|
0x6402 (25602) |
Ii trip |
Reset the device or use the Power restoration assistant within the EcoStruxure Power Device app. |
For information about resetting the circuit breaker after a trip due to an electrical fault, refer to the relevant document:
oMasterPact MTZ1 - Circuit Breakers and Switch-Disconnectors - User Guide
oMasterPact MTZ2/MTZ3 - Circuit Breakers and Switch-Disconnectors - User Guide
