Unable to Recharge the prepaid meter

Solution: Connectivity Check: Confirm the meter is successfully communicating with the server. Serial Number Verification (SmartComm): Access the SmartComm Customer Master and ensure the serial number recorded matches the physical serial number of the connected meter. Duplicate Configuration Check: Verify that no two meters are incorrectly configured with the exact same serial number in the system.

Email Configuration SMTP Details Outlook

Solution: SMTP Host/Server Name: For Outlook.com: smtp-mail.outlook.com For Office 365/Microsoft 365: smtp.office365.com SMTP Port:587 (recommended) Encryption Method: STARTTLS Authentication: Your email account needs to be authenticated, so enable login or use the ""My outgoing server (SMTP) requires authentication"" option in your email client. Username: Your full Outlook email address (e.g., yourname@outlook.com or yourname@domain.com) Password: Blank

Email Configuration App Password creation for Gmail account

Reason - Gmail will work only with a secure encrypted app password Solution: Go to your Google Account settings. Navigate to the Security tab. If you don't have it enabled, turn on Two-Step Verification. Find and click on App passwords. Select an app name (like ""SMTP"" or ""Mail Client"") and click Generate. Copy the generated 16-character password and use it in your mail client's password field instead of your main Gmail password.

Email Configuration SMTP Details Gmail

Solution: Gmail SMTP Settings SMTP Server: smtp.gmail.com Port: 587: (requires STARTTLS/TLS) 465: (requires SSL) Authentication: Required Username: Your full Gmail address (e.g., user@gmail.com) Password: An App Password generated from your Google Account security settings Security/Connection: TLS or SSL, depending on the port chosen

Transfer existing sensor to a different gateway

Reason - Loss of old data stored under device id created Solution: To prevent data loss, edit the sensor and use the "Move to Gateway" option to transfer the sensor to a different gateway.

Asset list is not available in the filter

Reason - The asset is not assigned to the organization Solution: Check the asset selection settings in organization settings

Reason - Sensor/gateway limit exceeded Solution: Check license information for sensor/gateway limit

Cannot change the ip address of gateway

Reason - The ip address should is not available Solution: 1. if company network is being used check the accesibility to access 2. check if set ip is with in subnet range 3. Check if Primary and Secondary DNS is correct as per network settings 4. Set the Default Gateway IP to match the router's IP or the company network's default gateway IP.

3rd part meter not communication

Reason - 1. Memory map configuration wrong 2. (10 power -4 )Conversion factor is not available in third party memory map configuration 3. Data on modscan and software is matching but not matching with meter display readings Solution: 1. Verify data via Modscan, check wiring, confirm the meter parameter's datatype/function code in the memory map, and ensure the gateway supports that parameter datatype. 2. Can be added from conversion factor available in Master settings

Could not download certificate

Reason - All mandatory fields are not saved in organisation info settings Solution: All details should be given in mandatory field of organisation settings

Application Note on Directional Short Circuit Protection

Updated: Aug 31, 2026 | 6 min read

Technical Articles

Published: Mar 05, 2026 by Sourav Dasmodak

Technical Articles

Click on any topic to jump to that section

What is Directional Short Circuit Protection?

The ability of circuit breakers to operate only if the short circuit current is in a particular direction and refuse to operate when current is in the other direction is called directional short circuit protection.

A directional relay/protection release will operate only if the short circuit current is in a particular direction and is above a certain threshold value, called the pickup current.

We use directional relays/protection release where, if in the event of a fault, there is a possibility current reverses its direction and starts flowing in a direction opposite to its original direction.

Whenever there is an line-ground fault on the Transmission line, current from every possible source start feeding the fault, as it is in the path of the least impedance. It is pertinent to note that the load, if passive, will not feed the fault (Active Loads like Synchronous machines can act like synchronous generators)

Illustrative Case

Consider a parallel feeder system as shown in Figure 1A having two generators and one load. The system is in synchronism and running at the rated voltage and frequency. In the healthy condition, the current flows as indicated by the blue lines. Now suppose if a Line-Ground fault occurs at point A (Fig1B). Then, the current from all sources start feeding the fault. Circuit Breaker 3 senses the fault in its Zone of Protection and isolates the faulted line from the circuit while Circuit Breaker 4 does not trip. After isolating the faulted line, the circuit looks as follows:

Without Directional Short Circuit Protection

Now it would seem that opening of circuit breaker 3 would isolate the faulty line and system would return to healthy state. But even after that, the short circuit fault current can keep flowing through the paths shown in figure 1C. This means that circuit breaker 4 would have to be opened as well. In cases like these, directional short circuit protection comes to our rescue.

With Directional Short Circuit Protection

If Circuit Breaker 4 could somehow trip by sensing that the direction of current that was previously passing through it in healthy condition has now reversed in faulty condition, our problem would be solved at once. That is exactly what directional short circuit protection offers. Circuit Breakers with directional short circuit protection sense that the direction of current is reversed and trip if the value is above a certain threshold (called the pickup point).

At this point, we are tempted to conclude that directional short circuit protection is quintessential at the feeder end. But if we take a step back, we can notice that this might not hold true when the load is an active load.

Application wise

Directional Protection equipment come at a higher cost, so economic aspect also needs to be considered. The general practice followed is that directional protection is required wherever load/source current may reverse its direction in case of a fault occurrence. In our example, directional relays are required for CB2 and CB4.

L&T’s Omega range of ACBs

All Omega ACBs with Protection Release MTX3.5 and above are equipped with inbuilt Directional Short Circuit Protection with Pickup Value adjustable from 0.6 times to 12 times the rated current (adjustable in steps of 0.05). Time Delays of 20ms, 100ms, 200ms, 300ms, 400ms. A feature for Pre-trip alarm is also offered, with an adjustable setting of 0.5 to 0.95 times the short circuit current.

As a general practice, the time delay of the directional short circuit is kept lower than the normal short circuit protection. This ensures that the circuit breaker in which fault is flowing in the opposite direction trips first.

	Parameter	UW-MTX3.5	UW-MTX3.5EC	UW-MTX3.5H	UW-MTX3.5H/4.5
Directional Short-Circuit	Protection: Enable/Disable	✓	✓	✓	✓
	Direction: Top/Bottom	✓	✓	✓	✓
	I²t: ON/OFF	✓	✓	✓	✓
	Pick-up(Is): In x ...	0.6 to 12 In in step of 0.05
	Delay(ts)	20-100-200-300-400 ms
	Pre-alarm	0.5 to 0.95 in step of 0.05 x Is
	Cold Pick-Up ON/OFF	✓	✓	✓	✓
	Cold Delay	100 ms 10s in step of 0.05 x Is

	Parameter	UW-MTX3.5	UW-MTX3.5EC	UW-MTX3.5H	UW-MTX3.5H/4.5
Directional Short-Circuit	Protection: Enable/Disable	✓	✓	✓	✓
	Direction: Top/Bottom	✓	✓	✓	✓
	I²t: ON/OFF	✓	✓	✓	✓
	Pick-up(Is): In x ...	0.6 to 12 In in step of 0.05
	Delay(ts)	20-100-200-300-400 ms
	Pre-alarm	0.5 to 0.95 in step of 0.05 x Is
	Cold Pick-Up ON/OFF	✓	✓	✓	✓
	Cold Delay	100 ms 10s in step of 0.05 x Is

In L&T’s Omega ACB, if the Directional SC Setting is set to “Top” then

If Voltage is incoming from top and leaving from bottom, and current (within rated limits) is entering from top and leaving from bottom, the ACB will not trip. Even if, the direction remaining the same, the magnitude increases, then the ACB will follow Short Circuit settings (pick up current and delays).
If Voltage is incoming from top and leaving from bottom, while current (within rated limits) is entering from bottom and leaving from top, the ACB will trip as soon as the current crosses the pickup value in the Directional SC Setting.

If the Directional SC Setting is set to “Bottom”, then

If Voltage is incoming from top and leaving from bottom, and current (within rated limit) is entering from bottom and leaving from top, the ACB will not trip. Even if, the direction rating remaining the same, the magnitude increases, then the ACB will follow Short Circuit Pickup settings (pick up and current delays).
If Voltage is incoming from top and leaving from bottom, and current (within rated limit) is entering from top and leaving from bottom, the ACB will trip as soon as the current crosses the pickup value in the Directional SC setting.

Spec-in point

“The protection release shall offer feature of Directional Short Circuit to protect system from the Short Circuit faults in the reverse direction.”

Competition Landscape

Feature	OMEGA	MTZ	NW	MVS	Emax2	Emax	Formula	3WL	3WT
Directional Short Circuit	MTX3.5 onwards	Yes (Optional)	No	No	Ekip Hi-Touch	PR123	No	ETU76B	No

Feature	OMEGA	MTZ	NW	MVS	Emax2	Emax	Formula	3WL	3WT
Directional Short Circuit	MTX3.5 onwards	Yes (Optional)	No	No	Ekip Hi-Touch	PR123	No	ETU76B	No

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About the Author

Sourav Dasmodak,

Product Management & Marketing (Powergear - ACB)

Product Owner of Air Circuit Breaker (ACB) of Lauritz Knudsen for Domestic & International Market. I can talk to you about Electrical Products' Sales, Business Development, Market Expansion, Cracking Critical Strategic Account, handling Key Account & of course how to develop & motivate Channels along with the organizational growth. Having near about one and a half decade of experience across the country with major electrical manufacturers (Top 4).