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

Basics of Active Harmonic Filter

Updated: Sep 08, 2026 | 6 min read

Technical Articles

Published: Jul 14, 2026 by Abhinav L Purkar

Technical Articles

Click on any topic to jump to that section

Modern industries are defined by widespread use of non-linear loads such as DC drives, VFDs etc. which introduce large content of harmonics into the system and its subsequent effects. There arises the need for intelligent solutions for harmonic mitigation. Active harmonic filters have developed as the most ideal solution for harmonic filtering in both industrial and commercial facilities. Added advantage is that they also offer solutions for phase balancing and power factor improvement. This article briefs about its basic principle of operation, need for active compensation and sizing.

Principle of Operation

An active harmonic filter is based on the following principle:

It detects the difference between the ideal current sine wave (I_MAIN) and the actual current which has been deformed by harmonics (I_LOAD). It, then, injects this difference (I_FILTER), which is the negative of the harmonic currents present in the load current, into the system on a real-time basis. This cancels out the high frequency harmonics and results in almost pure sine wave.

The active filter monitors the line current in real time and converts the data to digital signals. The compensating current, as already explained, is generated by an IGBT bridge using Pulse Width Modulation (PWM) technology. Source of IGBT Bridge is a DC link capacitor which is charged simultaneously with generation of compensating current to the network. The generated output is injected into the network via a reactor or filter circuit.

Advantages over Detuned & Tuned Filters

Active Harmonic Filters provide many advantages over the various solutions for harmonic mitigation as under:

Need for Active Compensation

Unlike detuned passive filters, active filters provide actual reduction in THD as recommended by IEEE. The IEEE 519-2014 guidelines on limits for current and voltage harmonics at Point of Common Coupling (PCC) are as under:

Maximum Harmonic Current Distortion in % IL
Individual Harmonic Order (Odd Harmonics)
Isc / IL	3 ≤ h < 11	11 ≤ h < 17	17 ≤ h < 23	23 ≤ h < 35	35 ≤ h < 50	TDD
<20	4.0%	2.0%	1.5%	0.6%	0.3%	5.0%
20 - 50	7.0%	3.5%	2.5%	1.0%	0.5%	8.0%
50 - 100	10.0%	4.5%	4.0%	1.5%	0.7%	12.0%
100 - 1000	12.0%	5.5%	5.0%	2.0%	1.0%	15.0%
>1000	15.0%	7.0%	6.0%	2.5%	1.4%	20.0%

Maximum Harmonic Current Distortion in % IL
Individual Harmonic Order (Odd Harmonics)
Isc / IL	3 ≤ h < 11	11 ≤ h < 17	17 ≤ h < 23	23 ≤ h < 35	35 ≤ h < 50	TDD
<20	4.0%	2.0%	1.5%	0.6%	0.3%	5.0%
20 - 50	7.0%	3.5%	2.5%	1.0%	0.5%	8.0%
50 - 100	10.0%	4.5%	4.0%	1.5%	0.7%	12.0%
100 - 1000	12.0%	5.5%	5.0%	2.0%	1.0%	15.0%
>1000	15.0%	7.0%	6.0%	2.5%	1.4%	20.0%

where

I_sc = maximum short-circuit current at PCC [Can be calculated as MVA / (%Z x V)

I_L = maximum demand load current (fundamental frequency component) at PCC

	Voltage Distortion Limits
Bus Voltage at PCC	Individual Voltage Distortion	VTHD
V ≤ 1.0 kV	5.00%	8.00%
1 kV < V ≤ 69 kV	3.00%	5.00%
69 kV < V ≤ 161 kV	1.50%	2.50%
> 161 kV	1.00%	1.50%

	Voltage Distortion Limits
Bus Voltage at PCC	Individual Voltage Distortion	VTHD
V ≤ 1.0 kV	5.00%	8.00%
1 kV < V ≤ 69 kV	3.00%	5.00%
69 kV < V ≤ 161 kV	1.50%	2.50%
> 161 kV	1.00%	1.50%

The use of active harmonic filters helps in reducing harmonics as can been seen under:

Some of the areas where active harmonic filters can be used are:

In areas with critical loads like automobile industry, precision equipment manufacturing etc., the harmonic load may vary frequently. This may have immediate adverse impacts like poor quality of manufactured products and equipment failures leading to huge monetary losses. Active filters prove to be suitable as they provide real-time reduction of THD.
Certain segments like textile industry, having huge VFD loads suffer from high harmonics. Due to this, the use of detuned filters may not be adequate, resulting in frequent capacitor failures and overheating or saturation of reactors. Only active harmonic filters provide necessary solutions in such cases.
Active harmonic filters have an added advantage of providing unsymmetrical reactive power compensation and also, provide load balancing.
Even usage of 14% reactor may not be sufficient to reduce neutral overloading due to triple-N harmonics. However, 3 phase, 4 wire active filter helps in achieving the same more effectively.

Selection / Sizing of Nominal Current of Active Harmonic Filter

Active harmonic filter is rated in Amperes. The current rating is decided on the basis of harmonic content (THD) in the system which can be obtained from harmonic study. The required nominal current can be obtained by multiplying the initial current of harmonics measured in the load by a safety factor (SFh) of 20%. In other words,

Where,

I_filter (AHF) : Nominal Current of Active Filter (A)

I_load : Maximum Load Current (A)

% THD(I) : Load Current Harmonic Distortion (%)

Majority of the energy saving devices are non-linear in nature. Consequently, the problem of harmonics has become inevitable. Advanced devices like active harmonic filter provide an ideal solution to this problem. These filters help in maintaining a stable and healthy power system thereby increasing productivity and efficiency.

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About the Author

Abhinav L Purkar,

Manager Product Management & Marketing (PMM)

Abhinav Purkar is a Product Management, Marketing, and Application Engineering professional with over 10 years of experience in the Power Quality domain. He has extensive expertise in power quality analysis, harmonic mitigation, reactive power compensation, energy efficiency, and electrical system optimization, helping customers improve system reliability and operational performance. With proven experience in product lifecycle management, market development, portfolio growth, and go-to-market strategy, Abhinav has successfully driven initiatives that enhance customer value and strengthen market presence. His strong technical foundation, combined with strategic business acumen, enables him to bridge the gap between customer requirements and innovative product offerings.