Tag Archives: Active harmonic Filter

Active Harmonic Filter- Mitigation Of Harmonics in a Poor Power Quality Environment-Case Study

Doctor_Character-04-1 Hello Everybody today’s article is a case study from our beloved Advanced Power Quality Solutions team. They have very neatly narrated how they helped a Steel Rolling mill with a unique power quality problem to extract more business benefit by cutting down their power quality problems. Interesting read don’t miss it.

InPhase has come across many customers dealing with various Power Quality problems. Our strength lies in providing customized and unique solutions, keeping in mind the problems that the customer confronts. In this article we share our experience with one of our customer, their problems, losses, and solutions. This customer is one of the largest steel manufacturers in India. Their annual production is in Billions of Rupees, but their production began to fall and penalties from Electricity Board increased because of presence of harmonics in their plant. So they decided to install Active Harmonic Filter to mitigate harmonics in their plant.  Initially the company had gone with a well known brand of Active Harmonic Filter but the filters had miserably failed owing to the unique situation of the customer. Luckily the customer came to know about InPhase and  Our Active Filter  through a channel partner, and approached us. InPhase conducted a Power Quality Analysis and suggested a cost effective solution accordingly (which cost lesser than the initial solution that failed) despite the challenging problem. The problem faced by the customer is outlined here,

  • Harmonic currents were high, the THDi was between 17-20% which is higher than the IEEE 519-2014 norms.
  • High Voltage Notches were also present in the plant.
  • Presence of even order harmonics which is normally zero in other plants.
  • Hot rolling mill loads were highly fluctuating and load patterns were abnormal.
  • The voltage varied up to 470V which is an abnormal behaviour.

Here, the main challenge faced while giving solution was to suppress current harmonics or THDi to less than 8% in an environment with high voltage spikes and indefinitely fluctuating plant load condition.

SOLUTION PROVIDED BY INPHASE:  InPhase proposed 2 x 450 Amps, 415V Active Harmonic Filter (Model:IPC150-AHF-450-V415) with CAN-bus communication that acts as a single 900A system. Specially designed RC tank circuits were incorporated  to handle notches and rigorous algorithm for high fluctuating loads. This was the  most cost effective, as well as the technically correct method to handle the situation. The 2 number of AHFs were connected in BUS A & BUS B, as the load distributes in those buses. The whole system has been pictorially described in the diagram below.


The major loads used by the customer are electric pre-heating furnace and rolling mill that generates the maximum harmonic current leading to increased losses in transformer, overheating of cables and thus polluting the electric network. The LT loads distributed among the Bus A & B are connected by an ACB Bus Coupler (Normally Closed). AHF calculates harmonic current, reactive current and unbalance current present in the entire plant from the current signal received from the CTs of respective transformers through the summation CT. Based on the on the dominance of power quality issue (harmonic, power factor or unbalance current) at any instant the AHF system injects the respective compensation current. InPhase AHF can achieve high level of modularity of up to 32 Equipments in parallel. CAN bus communication is used to communicate between two Active Harmonic Filters and operate in parallel to inject up 900A of compensation current.


The graph indicates the harmonic currents of various orders (3rd to 13th) before and after installation of Active Harmonic Filter. The successful installation of 2 x 450A Active Harmonic Filter has reduced the THDi from 17% to 4-5%, well below than the limits mentioned in IEEE 514-2014. This solution has helped the customer not only to cut down penalties but also to reduce failure of sensitive equipments which are vulnerable to harmonics. Also, various production losses were averted. Overall, InPhase was able to solve a problem of harmonics in very poor power quality environment. This was another feather in InPhase‘s cap. We would be extremely happy to help customers who face such outrageous Power Quality problems because at InPhase we are happy to tackle power quality challenges for our customers.

Get in touch today.

Meet you again with a interesting article, until then bye from Dr.InPhase

Thank you!


Thanks for reading…if you have questions don’t forget to ask me. You could write to me to info@inphase.in or call +919632421402

IInphaseLogo(300dpi) (1)nPhase Power is a Power Electronic Product company manufacturing products for Power Quality and Power Conversion. InPhase is manufacturer of Active Filter, Active Harmonic Filter, Solar Inverter. InPhase majors in power system design for power quality and conversion. Driven by a management that has a combined experience of over 60 years in power system and power electronics InPhase nurtures innovation and passion in this field.

Active Harmonic Filter – Working Principle

Doctor_Character-71The quest for human existence boils down to solving problems around us in the process to making the world a better place. What is generally observed is that a new problem pops up every time we think we have a solved a longstanding issue. This is a perpetual cycle, probably even necessary for our existence. Nevertheless, the big problems of our times in the Power Quality domain are power factor, harmonics and unbalance. The  many reasons for poor power quality can be attributed to the types of loads in use. More complex loads lead to more power problems.

Many solutions have been proposed for power quality problems. But there is one that stands out – the IGBT based voltage source converter, popularly known as Active Harmonic Filter. This article is an attempt to convey just how much the Active Harmonic Filter is capable of and how it makes it all possible. In simple terms we have set foot to explain the working principle of Active Harmonic Filter Shortly the Active Filter. 

The ever increasing load complexity

At first, consider the load to be purely resistive; a simple incandescent lamp maybe, just to make things more “real” (pun intended). In such a case, only real power will be drawn from the grid. Just when things are going smooth, we decide to connect an induction motor at the load end. But, the induction motor requires an excitation current in the field coils for its desired operation. Hence, drawing pure real current from the grid is no more sufficient. Therefore, in addition to the real power, a new component, namely reactive power is drawn from the grid.

As our next step in this experiment, we introduce a new “problem” in our setup. We deliberately rearrange our loads such that they are not balanced, i.e. the current drawn in the three individual phases are not equal. In technical terms we call this phenomenon, load unbalance. Just for representation, it is shown as if unbalance is a new component being drawn from the grid. In reality, however, unbalance is a “phenomenon” and not a “component”. The idea of this representation will be disclosed in the following lines.

Just as we might begin to think that things couldn’t get any worse, drives-based motor control system is introduced! This power electronic marvel starts functioning; and consequently introduces harmonics in our power system. Therefore at this point in time, our power system suffers from the following problems – low power factor, load unbalance and harmonics.

The solution

Now that all possible problems have arisen in the system, it is time to introduce the hero – the Active Filter. For the sake of representation, let us assume that the Active Filters kills the problems one-by-one. Starting with reactive power, it is seen that the reactive power being imported from the transformer is compensated by a counter-acting power from the Active Filter. In an alternate view, it can also be seen as if the reactive power requirement of the load is fed by the Active Filter. Unbalance in a system can be attributed to presence of negative sequence components and zero sequence components of currents.  Active filter is capable of eliminating the negative sequence and zero sequence components from the electrical system, as shown. Here is a case study on Unbalance Compensation if you want to learn more about it. Subsequently, on elimination of unbalance, harmonics is the only problem left to be solved in the system.

The Active Filter senses the current from the CTs connected within the plant. With this input, the controller present in the Active Filter catches the harmonic content and pumps the same current in anti-phase. In this manner the harmonics are cancelled out in the system.

We hope that this article answers, in brief, the million dollar question of “How exactly does an Active Filter work?” Thank you for reading and hope to see you soon with a new article!

Meet you again with a interesting article, until then  bye from Dr.InPhase

Thank you!


Thanks for reading…if you have questions don’t forget to ask me. You could write to me to info@inphase.in or call +919632421402

IInphaseLogo(300dpi) (1)nPhase Power is a Power Electronic Product company and manufacturer of products for Power Quality and Power Conversion. InPhase is manufacturer of Active Filter, Active Harmonic Filter, Solar Inverter. InPhase majors in power system design for power quality and conversion. Driven by a management that has a combined experience of over 60 years in power system and power electronics InPhase nurtures innovation and passion in this field.

Active Harmonic Filter Technology History, Evolution and Future


Doctor_Character-04-1Hello Readers, this article discusses the evolution of active filters as a harmonic mitigation solution and where it is getting to in the future. 


With the increasing number of power electronic equipment’s in the power system, the need to maintain sinusoidal line voltages and currents have become the need of the hour.

Harmonics in power system is caused by both domestic and industrial loads. Traditionally, harmonic distortion has been dealt with the use of passive LC filters. However, their application may result in parallel resonances with the network impedance, over compensation of reactive power at fundamental frequency, and poor flexibility for dynamic compensation of different frequency harmonic components.

Therefore, to overcome these problems and to provide adaptability to load variations in network and instantaneous adjustable solutions, Active Harmonic Filters were implemented. They regulate terminal voltage to improve voltage balance, compensate harmonics and reactive power and suppress flicker in electrical systems. The controller is the most indispensable part of the Active harmonic filter. The performance and reliability of the system greatly relies on it.


Starting from 1971, a number of configurations, such as the active series filter, active shunt filter, and combination of these filters have been developed and materialized for UPS applications. From 1976, a significant number of publications have reported on three phase three wire Active Harmonic Filter’s. Active shunt, active series, and combinations of both, named as active power quality conditioners, as well as passive filters combined with active shunt and active series Harmonic Filter’s are some typical configurations used. These configurations are used to resolve the problems of excessive neutral current, unbalanced load currents, heating issues and the previously mentioned problems which mainly occur due to nonlinear unbalanced loads and other power quality issues.


Passive Harmonic Filter


One of the major factors in advancing the Active Harmonic Filter technology was the invention of fast self-commutating solid-state devices. With the introduction of IGBT’s, the evolution of Active Harmonic Filter technology got a real boost and, at present, they are considered as ideal solid-state devices for Active Harmonic Filter’s. The improved sensor technology has also contributed to the enhanced performance of the Active Harmonic Filter. The next breakthrough in the evolution of Active Harmonic Filter development has resulted from the microelectronics revolution. Now, it is feasible to implement complex algorithms online for the control of the Active Harmonic Filter at a reasonable cost.

igbt                  18722-3172117


Selection of the Active Harmonic Filter for a particular application is an important task for end users and application engineers. There are widely varying application requirements, such as single-phase or three-phase, three-wire and four wire systems, requiring current-or voltage-based compensation. Moreover, there is a number of Active Harmonic Filter configurations which may cater to the needs of individual users. The proper rating of a passive harmonic filter must be concluded from the rating of a non-linear load without a harmonic filter and that of an active harmonic filter based on rectifier parameters without a filter. Selecting an Active Harmonic Filter of the correct size is the key to achieve optimum cost/benefit ratio, i.e. desired current harmonic reduction with minimum filtering effort.

Some of the leading Active Harmonic Filter manufacturers of today’s market are COMSYS, MERUS POWER, INPHASE POWER, SCHAFFNER and ABB. The InPhase Power Active Harmonic Filter stands out in the crowd in a number of ways. InPhase Power which is an Indian company provides 100% indigenous technology with up to 1000A in a single equipment. It has emerged as the only one in the market to provide Direct High Voltage Compensation with advanced DSP control and INPHASE CLOUD Computational system for online monitoring of faults in electrical systems with SMS alert facility. Application of LCL filters and rigorous algorithm for better compensation makes it the right choice power quality issues. InPhase Power also offers direct 690v Active Harmonic Filters  typically used in Furnace kind of applications. To top it all InPhase Power won the Ministry of MSME Award for Innovation in Renewable Energy & Power Quality Solutions which shows the reliability and dependability of InPhase Power products.

       ahf                                                    Active Harmonic Filter                                              


Today, Active Harmonic Filter technology is well matured, and a number of manufacturers are producing Active Harmonic Filter’s with large and varied capacities. The utilities in the long run will induce the consumers with nonlinear loads to use the Active Harmonic Filter’s for maintaining the power quality at acceptable levels. Many Active Harmonic Filter configurations are available to compensate harmonic current, reactive power, neutral current, unbalance current and harmonics these days.

With the advent of new and improved technology implementing faster devices the filter size and its performance can greatly improve, increasing the reliability and adaptability to perturbations in our power system network. The future looks promising as the IGBT technology  which is the key system component in Active Filters are evolving very faster and with robust capability.  The futuristic Active Filters might be compact, modular with ability to compensate higher orders and respond much quicker. Not leaving the reliability of these Active Filters will also be high in comparison to the current generation filters with more rugged capability for Industrial environments. InPhase as a pioneer in power quality and as a manufacturer of Active Harmonic Filter is working towards bringing these latest generation products to your door steps.

Meet you again with a interesting article, until then  bye from Dr.InPhase

Thank you!


Thanks for reading…if you have questions don’t forget to ask me. You could write to me to info@inphase.in or call +919632421402

IInphaseLogo(300dpi) (1)nPhase Power is a Power Electronic Product company manufacturing products for Power Quality and Power Conversion. InPhase is manufacturer of Active Filter, Active Harmonic Filter, Solar Inverter. InPhase majors in power system design for power quality and conversion. Driven by a management that has a combined experience of over 60 years in power system and power electronics InPhase nurtures innovation and passion in this field.

InPhase Insight: Why minimalistic design is essential in Power Electronics

This article is about how mimimalistic design is made a philosophy at InPhase Power to achieve simple but effective solutions

Dr InPhaseHello Readers, Good day. After quite some effort i have pulled out one of our Research Fellows to come out and write to the world about our design Philosophy which puts simplicity at the forefront before all. This article will give you a very good idea on how the Research team at InPhase is working tireless to create beautiful Products that looks simple but  functions extra-ordinary. Happy Reading.

Why actually we need a minimalistic approach in design ?

The concept of minimalistic approach in design varies with different field of applications. Design for Minimal Execution time is critical in many cases like in high speed networking devices. Design for Minimal Power consumption is critical for low-power battery-operated devices e.g. mobile phones or digital watches. Design for Maximal Fault tolerance is critical for cases where manual inspection (or repair) is difficult or impossible e.g. submarine systems and electronic devices on Mars Missions. Design for Minimal Radiation leakage is critical for removing interference between medical electronics Devices (and aircraft systems etc). Design for Testability is another critical aspect. Even though minimal hardware helps in certain aspects it might not always be the right objective to achieve it mandatorily. A good design happens not by the only objective to minimize the hardware, but it comes along with the optimized use of all the available resources in a cost saving package without compromising the output.

Minimalism is Also an Iceberg!

What we see from minimalism at first is only the success part. We imagine a clear home with no mess, we see a nice wardrobe that is never outdated and a bank account full of savings. But minimalism is about sacrifices, resilience and change. Minimalists do a lot of things differently from the majority. They face judgement and criticism. To work well, minimalism has to be in your head and in your heart. It has to be thought about and felt. It’s more than owning less. It’s focusing on what truly counts. This is the same case as we do a design in Power Electronics at InPhase . To keep the design minimal and powerful, a lot of work is done in the background.


Fast Changing digital domain!

When we think about ‘low power electronics circuits’ the first image that come across our mind is a Printed circuit board with a number of integrated circuits mounted on it . Gone are those days where analog circuits dominated the electronics manufacturing process. This is the age of high end Digital Signal Processors, FPGAs, FPAAs and other high speed processing devices that can do the mathematical and logical calculations within a minimal footprint of 5 x 5 mm. A single FPGA chip can do the job of more or less 50 Analog ICs thus saving time, cost with increased precision. Analog system just aides the digital controller in the processing. But still, the scope of analog ICs and associated devices exists only because rapid change in technology is reaching the industries in a much slower pace and many industries inhibit to get adapted to the change. InPhase stands out in this and uses the advanced DSP technology for the design of its master controller, which is used as the main control board for its prime products like Active Harmonic Filters and Solar central Inverters.

What InPhase Provides

pecInPhase currently uses Dual Core Delfino Microcontroller with a processing speed of 200MHz. The Delfino™  Microcontroller is a powerful 32-bit floating-point microcontroller unit (MCU) designed for advanced closed-loop control applications such as industrial drives and servo motor control; solar inverters and converters; digital power; transportation; and power line communications. The integrated analog and control peripherals also let designers consolidate control architectures and eliminate multiprocessor use in high-end systems. Digital signal processing (DSP) devices currently have higher central processing unit (CPU) performance (clock rates over 100 MHz) and integration of advanced high-speed peripherals. Great strides have been made in DSP power reduction through CMOS process technology. These advances have increased the complexity of the DSP board design, which provide more analog challenges than a simple digital design. Thus great care is required while designing the board and InPhase  Controller does that without much complications. The main attractions of InPhase  Controller are

  1. A single versatile controller capable of controlling Active harmonic filter, 2 level and 3 level solar central inverters and various custom converters. This uniqueness actually reduces the discrepancy of selecting controller for different applications.
  2. The InPhase  Controller is a single board which is capable of producing up to 24 PWMS. It also have capabilities to process several analog I/Os and digital I/Os. The integrated communication system works based on advanced communication protocols like CAN, RS485 and RS232.
  3. The InPhase  Controller is designed in such a way that low voltage and high voltage components are separated with necessary isolation. This reduces the EMI interference and gives protection for low power ICs.
  4. Use of minimal components reduces the size of the Printed circuit board and thereby reduces the number of board traces.
  5. The reduction in number of board traces will eventually leads to reduction in power loss and thus increases the overall efficiency.

All these features of InPhase Controller provides utmost satisfaction for its customers who uses any of its products like InPhase Active harmonic filters , Solar central Inverters or other custom converters.

Doctor Hi

Well Overall simple design means also there are less number of interconnections, lesser components and eventually Lesser maintenance. Will see you back with another wonderful article soon.

IInphaseLogo(300dpi) (1)nPhase Power is a Power Electronic Product company manufacturing products for Power Quality and Power Conversion. InPhase is manufacturer of Active Filter, Active Harmonic Filter, Solar Inverter. InPhase majors in power system design for power quality and conversion. Driven by a management that has a combined experience of over 60 years in power system and power electronics InPhase nurtures innovation and passion in this field.

InPhase Power Active Harmonic Filter and Load Unbalance Compensation – A Case Study

Doctor_Character-04-1Well Good day readers, Today I bring to you a very interesting case study of how InPhase helped one of our customers to achieve Unbalance compensation. I was very impressed with our team on the effort that they have given on this as they made the customers extremely delighted. I hope you all enjoy reading it as well.

The brief story

InPhase Active Harmonic Filters are an all-in-one package, capable of compensating for reactive currents, harmonic currents and unbalance currents, we claim. However, in most sites InPhase was tasked to compensate for reactive and harmonic currents alone. Then, came along a company. We will call it ‘ABC’. ABC approached us saying they had a problem of current unbalance, and that they were being threatened penalisation and disconnection of the supply by the Utility, for the same.

ABC had approached various other well-known names in the PQ industry, but none were prepared to propose a solution. And so, InPhase conducted a PQ Analysis at their site. The study results were appalling. Currents in the 3 phases read: 175A, 352A and 174A respectively.

InPhase proposed to install our beloved Active Harmonic Filter to mitigate this problem. ABC said “Go ahead, do anything. Just fix this problem for us.” And so, the InPhase Active Harmonic Filter was installed at the site.

Everybody, including us, held their breaths. “Will it work?” was the question in everyone’s minds. Then came the time, to find the answer. Annnnd Lo! The phase currents read: 52A, 50A and 51A.

Everyone’s apprehension about the InPhase Active Harmonic Filter had turned into awe. The Managing Director of ABC going to the extent of saying “Dr. InPhase has come down to save us like Lord Vishnu (Hindu god; Preserver of everything and everyone in the Universe).” Not only did the Active Harmonic Filter go on to mitigate the unbalance, it was also compensating for reactive and harmonic currents, all at the same time.

If ever there was a happy ending, this was it. 🙂

The technical explanation

Moving on to the technical side of the problem. The cause for current unbalance of such magnitude was the nature of load being 2-phase. The currents before compensation in R, Y and B phases were 175A, 352A and 174A respectively. You might notice how the current in Y-phase was double that of R and B phases. Excellent observation, that! Now, here is the explanation:


The above diagram shows a delta-star step-down transformer. The outer windings represent the primary of the transformer. The windings on the inner side represent the secondary. Notice that the load is connected to the secondary across two phases only i.e. R and B.

The load forces the current direction in the secondary windings as indicated by Ir and Ib. Since the phase r and b are connected in series, Ir= Ib.

Ir and Ib are secondary currents induced from primary currents IRY and IRB. Subsequently,
IRY = IRB = I. Note also, how the direction of secondary currents differ from their corresponding primary currents.

From Kirchoff’s current law, incoming current at node R must be I+I = 2I.

The outgoing currents from node Y and B are ‘I’ each. What is observed here is that one phase carries twice the amount of current than the other two individual phases. This explains the observed readings of 175A, 352A and 174A.

It is a known fact that current has three components viz. positive sequence, negative sequence and zero sequence. Since our incoming current is through a 3-ph 3-wire system, we can ignore the zero sequence component.

Also, let us recall that both positive and negative sequence components are “balanced”, individually. It is only when they combine, unbalance occurs in the load current.  Just to be on the same page, let us understand what a “balanced current” means. In a 3-ph system, is the current flowing in each phase is equal, the system is said to be balanced in simple terms.

The magnitude of unbalance is calculated in percentage.


The calculation for this case would go as follows:

IR=352A ; IY=175A ; IB=174A

The average current,


Maximum deviation from Iavg = 352-233.67 = 118.33A



As a consequence of NEMA Standard MG-1, acceptable limit on current unbalance is 10%. Clearly, the unbalance in this industry was far from acceptable.

Now that the cause and magnitude of the problem were known, the next step was to mitigate it. And, to meet this objective, InPhase Active Harmonic Filter was installed.

It should be noted that the initial current readings IR=352A, IY=175A, IB=174A are a combination of reactive currents, harmonic currents and unbalance currents. And because we are concentrating exclusively on unbalance, let us take an arbitrary example to understand the same.


In the above example, the incoming currents are 100A, 100A and 40A. The underlying assumption here is that these currents are purely unbalance currents and they have no reactive or harmonic component.

InPhase Active Harmonic Filter takes feedback from 3-ph CTs. This allows the Active Harmonic Filter to measure current flowing in each line. Subsequently, this input is processed by the main controller in the equipment. The Active Harmonic Filter being an AC-DC-AC converter, can absorb and pump current from the line to the load such that the incoming current from the metering point is balanced.

The controller is capable of calculating the positive sequence component and negative sequence component from this input. Once this is calculated, it is a simple case of pumping the counteractive current to the negative sequence component, so that all that remains is the positive sequence. Recollect that positive sequence current is balanced and thus consequently, the line current is also balanced.


The above diagram is a representation of the aforementioned compensation process. Note how the line currents are balanced (80A each) whereas the load currents (100A, 100A and 40A) remain unchanged.

This way, the customer is happy that his electrical system is healthy, and the Utility is happy that the consumer’s loads are balanced and the grid is stable. Lastly, Dr. InPhase is also happy that he made it all possible. 🙂

It is time now, for you to experience the InPhase Active Harmonic Filter. Get in touch with us, we’ll help you to get your Power Quality problems resolved.

Thank you!



Thanks for reading…if you have questions don’t forget to ask me. You could write to me to info@inphase.in or call +919632421402

IInphaseLogo(300dpi) (1)nPhase Power is a Power Electronic Product company manufacturing products for Power Quality and Power Conversion. InPhase is manufacturer of Active Filter, Active Harmonic Filter, Solar Inverter. InPhase majors in power system design for power quality and conversion. Driven by a management that has a combined experience of over 60 years in power system and power electronics InPhase nurtures innovation and passion in this field.

Dr.InPhase Edu Series – How to use FLUKE 434-SERIES II for Power Quality Analysis

Dr InPhase Edu Series PQ

Hello Everybody, Hi from Dr.InPhase. In our today’s educational series we are going to learn something very important and rudimentary for Power Quality. That is learning how to measure power quality using one of the popular Power Quality analysis equipment in the market the Fluke 434-II Series. If you have feedback don’t forget to write to info@inphase.in or drinphase@inphase.in

Power Quality is gaining a lot of prominence and priority in the market. The first step towards a better Power Quality is to conduct an analysis. Carrying out complete Power Quality requires a very good Power Analyzer.

At InPhase Power we carry out a lot of Power Quality Analysis study at various industries like Steel/Cement/Automobile/Paper/Process… etc. We use Fluke 434-II and Krykard ALM 33 Power Analyzers for this purpose.

In this multi-part series blog I am going to walk you through on how to carry out Power Quality Study to analyze and record various Power Quality factors like Harmonics, Unbalance, Power Factor, Flickers, etc…

The first part we will focus on Fluke 434-II which is a popular Power Quality analyzer and the posts to come later will focus on using Krykard ALM 33 and the process to analyse this data .


Fluke 434-II

  • Used for energy logging.
  • Measure the before and after installation improvement in Power Quality or Energy Consumption to justify the devices like Active Harmonic Filters, APFC, etc.
  • Detect and prevent Power Quality issues before they cause any issues.
  • Verify electrical system capacity before adding loads, and to Amylase the load pattern.


Basic operations-1

1– Press to power up or down the Fluke Analyzer. The home screen shows what                   Analyzer settings are currently in use.


Display info

  • This is home screen when the analyzer gets TURN ON.
  • In this screen we can see basic configurations like Phase colors, Connection configuration, Choosing of CT probe and ratios.


Menu navi


  • In home screen Press Setup Button
  • Press F4(MANUAL SETUP)
  • Select TIME in Home screen
  • Press ENTER
  • Made the changes in TIME & Press ENTER
  • Press F3 it will switch to DATE Adjustments
  • Made the changes in DATE & Press ENTER
  • Press F5 (Back to Home Screen)


  1. Measuring results belongs to different phases are presented with individual colors. Every region in the world having different sets of color code for the Phase sequences.
  2. Here we proceed with UK region which is used in India also.
  3. The following steps are configuring the Phase Colors as well as Languages also.

Lang&Phase colours

  • Press Setup Button
  • Select F1 (USER PREF.)
  • Select Language –> Press ENTER
    • In that menu Select the Language desired & Press F5
  • Select Phase Colors –> Press ENTER.
    • In that menu select the region or customize the Colors & Press ENTER.
  • Press F5 (Back to Home screen)


  1. FLUKE 434-II has a several pre-programmed wiring setups of electrical system/equipment.
  2. Based on the system configuration like Three Phase, Two Phase, Single Phase we can choose accordingly in the analyzer also.

The following steps are configuring the available wiring setup of FLUKE 434-II for the electrical system which we want to analyze.

Wiring sys config

  • Press Setup Button
  • Select F4 (MANUAL SETUP)
  • Select Config: –> Press ENTER
    • In that menu Select the Appropriate Configuration

Wiring sys config-2

  • Select Freq:–> Press ENTER.
    • In that menu select the Nominal Frequency.
    • 50 Hz is used in Europe, most of Africa, most of Asia, most of South America and Australia.
  • Select Vnom:–> Press ENTER.
    • In that menu select the Nominal Frequency.
    • 230V is used in Europe, most of Africa, most of Asia, most of South America and Australia.
  • Press F5 (Back to Home screen)

*In North America, the most common combination is 120 V and a frequency of 60 Hz



Fluke 434 connec config

NOTE: For connecting in 3-Phase 3-Wire system, Neutral probe connection can be neglected for CT as well as PT.

Fluke 434 connec config-2Fluke 434 connec config-3

  • Connection example shown in the above picture.
  • Analyser we could use to connect in HT side (like 11kV, 33kV), LT side (like 415V, 690V) by taking CT and PT reference from the Breaker panel (ex. VCB).
  • We can analyse the load in feeder wise as well as connecting the particular load also (like VFD, DC Drive, etc.)


  • This probe for connecting the PT reference side or PRIMARY side or Direct BUS BAR SIDE.


  • Press Setup Button
  • Press F4(MANUAL SETUP)
  • Press ENTER
  • Press F4 –>
    • Change PT ratio as per the Primary Voltage.
    • 110V is common PT secondary voltage.
    • Connecting in Live BUS BAR side PT ratio should be 1:1
    • Example: Connecting in 11kV side VCB means PT ratio will be 11000:110 or 100:1
  • Press Enter after made the changes.
  • Press F4 do the changes in Neutral probe connection (OPTIONAL).
  • Press F5(Back to the Home Screen)

CT flex

  • This probe for connecting to the PRIMARY side or direct BUS BAR side.
  • For this CT ratio should be 1:1.

CT i430

  • Press Setup Button
  • Press F4(MANUAL SETUP)
  • Press ENTER
  • Select AMP CLAMP –>
    • Change as per the Clamp connected (i430Flex, i5s, others)
  • Press Enter after made the changes (CT Ratio).
  • Press F4 do the changes in Neutral probe connection (OPTIONAL).
  • Press F5(Back to the Home Screen)

CT i5s

  • This probe is for connecting in Measuring or Protection CT side.

CT i5s last

  • The picture shows how to connect the probe in to the CT reference side.CT Clamp
    • Press Setup Button
    • Press F4(MANUAL SETUP)
    • Press ENTER
    • Select AMP CLAMP –>
      • Change as per the Clamp connected (i430Flex, i5s, others)
    • Press Enter after made the changes (CT Ratio).
    • Press F4 do the changes in Neutral probe connection (OPTIONAL).
    • Press F5(Back to the Home Screen)


    *After this above setup the Analyser is ready for measurement.



    1. After doing the initial setup now the Fluke Analyzer is ready for taking the measurements.
    2. The following steps are for checking the connection and then proceed to start the measurement.


    * The figures below explained for the correct connection setup.

    This is the first thing have to check for the connection verification.

Scope screen buttonScope Screen

  • After made the connection, Select Scope–>The above screen will appear
  • Press F1–>Switch to see Voltage or Current waveform
  • F2–>Cursor will appear for see the particular instant values (Use navigation keys to move the cursor)
  • F4–>Zoom in or Zoom out the waveform (Use navigation keys to Zoom in or Zoom out)
  • F5–>Back to the Home Screen
  • F3–>Vector view of Current & Voltage (Explained detailed in below)
    • These two screens are vector view of Voltage and Current
    • Press F1–>for switching the screen from Voltage to Current or Current to Voltage.
    • The directions should be clockwise & order should be Red-Yellow-Blue (RYB)


  • Compare the Amperes and with Analyzer and the connected Breaker panel side or Load side.
    • Check the amperes in the Multi-functional meter or Ammeter of the Breaker panel.
    • If the Ampere not matching with the load side check the CT ratio fixed. If it is wrong change it accordingly.
  • Amperes are matched check the Directions of vector as per the above diagrams.
    • If the directions are not proper check the CT Probe direction in the breaker panel.
  • Both Amperes should match.
  • After this check go to–>MENU



  • Select–>POWER & ENERGY
    • Check the Actual Power(W), Apparent Power (VA)
    • Both values should be in Positive(+ve)
    • If the values are Negative (-ve) invert the CT probe direction fixed in the breaker panel.
    • Check for the fixing of CT probe direction in Breaker panel.
  • Press–>F5 (HOLD OR RUN)
  • Select–>F1 (DISCARD & EXIT)–>MENU Screen will appear.



  • Select–>HARMONICS
    • We can see the harmonics % in voltage as well as current by scrolling down in the screen.
    • Till 50th order voltage and current harmonics recording available.

indiv harm

    • We can see individual order of harmonics % and Amperes in each Phase.
    • Press–>F1 (Switch to see Voltage, Current, Watt Harmonics)
    • Press–>F2 (Viewing of individual phase Harmonics)
    • Press–>F3 (Back to Recording screen)
  • Press–>F5 (HOLD OR RUN)
  • Select–>F1 (DISCARD & EXIT)–>MENU Screen will appear.



Logger button

LOGGER is the function used to Start Measurements & Monitor the readings.


  • After selected the LOGGER button the above screen will appear
  • INTERVAL is the sampling time for data saving.
    • 10s (seconds) means the analyzer will record every 10 seconds per data.
    • The data will be the Maximum & Average of 10 seconds data.
    • In Fluke Analyzer the Interval limit from 0.25s (Seconds) to 2h (Hours)
  • Press–>F2 (CHANGE NAME for changing the measurement name as per wish)
  • Press–>F1 (SETUP READINGS)


  • This screen will appear
    • This is for selection of parameters we wants to record.
    • Each CATEGORY having set of parameters displayed in READINGS column.
    • Press–>F3 for Selecting the parameters we want.
    • Like this we have to do for each CATEGORY.
  • Screens displayed below explain about the parameter selection.

Screen-11 Screen-12 Screen-13 Screen-14 Screen-15 Screen-16 Screen-17

  • The parameters chosen here all are standard Power Parameters with 25th order Voltage & Current harmonics recording are used to analyze the load pattern of an Industry power, Understanding of Power Quality problems like Harmonic & Reactive power compensation.
  • Press–>F5–>After selecting all the parameters wants to measure–>LOGGER Screen will appear.


  • Duration of recording from minimum 1hr to maximum of 7days in Immediate
  • We can able to start measurement by scheduling in timed
  • After setup the measurement duration PressàF5 (START the measurement)
  • The below screen will appear.

logger measurement

By scrolling down this screen we can see the parameters we have selected before starting the measurement.

  • After finishing the measurements it will ask for SAVE.
  • If we want to STOP in between the measurement PressàF5(HOLD or RUN)
  • Press–>F1(DISCARD & EXIT)
    • To stop the measurement at any time.
  • Press–>F2(DISCARD & RESTART)
    • To restart the measurement.
  • Press F4–>(SAVE)
    • Save the recorded data–>SAVE Screen will appear.
    • In that screen, we can change the recorded data name as we want.
    • Press F5–>OK to save the data.




  • This is function for save the Running display as an image during Measuring time
    • We can save the SCOPE screen, LOGGER screen for the reference.
  • Press SAVE SCREEN–>Save Screen Menu will appear
  • Fix the name as we want or the default will be SCREEN XX (Number).
  • Press ENTER–>Save the screen
  • Press F5–>BACK to previous screen


After finishing the measurement we can see the recorded files and delete the unwanted recordings from MEMORY function.

  • Press MEMORY Button
  • Press F1–> RECALL or DELETE
    • In that menu the recorded files will appear.
    • Select the desired data by using the navigation keys.
    • Press F2–>VIEW the selected data.
    • Press F3–>DELETE the selected data.
    • Press F4–>RENAME the selected data.
    • Press F5–>RECALL the selected data.
      • This option will replay the entire measurement.
    • Press F1–>Back to the previous screen.

Thanks for reading this article. I hope this was helpful to you. In the upcoming parts I will detail about how to measure using Krykard ALM 33 Power Quality Analyzer and also discuss in detail how the data extracted from these equipment’s can be used to analyze power quality.

If you are interested to conduct a Power Quality Study InPhase Power is ready to support you. Contact us @ info@inphase.in or +919632421402


Dr.InPhase Reading
Dear Readers, InPhase recently participated in India’s premiere event for Power Quality “CAPCIT2014“.(You can read more about it here). This blog is to share the abstract of the paper that we presented at CAPACIT2014. If you are interested in receiving the full version of this paper please email to info[@]inphase.in






Natesh Mayavel, InPhase
Panna Lal Biswas, InPhase
Thiyaneswar MS, Inphase


Consumer electronics, Data Centers, HVAC systems and a large range of industrial applications, namely power electronics based, can cause high disturbances into the supplied electricity. The disturbances comprise of harmonic current generated by such loads, and the voltage distortion created by the harmonic currents. The main problem with the harmonic currents is that, they can cause overheating in the local supply distribution transformer and in the installation itself. Indian Electric utility companies are starting to be more concerned about harmonics in the transmission and distribution network, and imposing strict harmonic limits on consumers. Active harmonic filter is a potential solution to mitigate harmonics problems. The usage of active harmonic filter is expected to increase drastically in Indian industries, to meet utility requirements. This paper discusses technology variants of Active Harmonic Filter from different aspects, and their advantages and disadvantages.

Active harmonic filter; STATCOM; Active filter technology; Power quality; Harmonic currents; Voltage distortion; Electrical installations;

InPhase Active Harmonic Filter Technology Review

InPhase Active Harmonic Filter Technology Review

1. Introduction
2. Active Harmonic Filter Principle
3. Active Harmonic Filter in Electric Network
4. Technology Review
4.1 Control System Schemes
4.2 Control Mode
4.3 Speed of Response
4.4 Unbalance in Harmonics
4.5 Power Hardware
4.6 Input passive network
4.7 STATCOM Vs Active Harmonic Filter
4.8 Networking
5.0 Conclusion

If you are a Power Quality or Active Harmonic Filter enthusiast please contact us today at info[@]inphase.in to receive the full copy of this paper.

Meet you again with a interesting read. until then bye bye!! from Dr.InPhase Power. Your Power Quality Partner.

Doctor welcome

At InPhase Power we are very serious about improving the power quality of the nation. Our products provide unmatched improvement in Power Quality by effectively curbing harmonics and maintaining steady power factor. Explore our Products Active Harmonic Filter(IPC150-AHF) and STATCOM (IPC150-SCOM) to find how they can improve your power quality.