We use our own and third-party cookies to improve browsing and provide content of interest.

In continuing we understand that you accept our Cookies Policy. You can modify the cookies storage options in your browser. Learn more

I understand


Harmonics: Today’s problems and its solution


The most versatile solution for power quality problems


Domestic and industrial loads contain increasing numbers of electronic circuits that are supplied with currents that are not purely sinusoidal. For example, engines increasingly use frequency regulation, which requires converting alternating current (AC) to direct current (DC) and then DC back to AC. Given that the supply is normally in AC, this requires increasing use of electronic power converters (rectifiers, inverters, etc.) for these DC-AC and AC-DC transformations. The same thing happens with common loads like computers, LED and discharge lighting, lifts, etc.

This means that the electrical network must supply a large number of charges that rectify the current, distorting the wave shape of the current being consumed so that it is not a purely sinusoidal wave but rather a superposition of sinusoidal waves with frequencies that are multiples of the network frequency (harmonics). Figures 1 and 2 show the typical consumptions of one network with single-phase rectifiers and one with three-phase rectifiers. This type of current is most abundant in installations like offices, shopping centres, hospitals, etc., and it is formed by a 50 or 60 Hz component (network fundamental frequency) and a set of different percentages of components with multiple frequencies. These percentages may be measured using a harmonics analyzer, which can also measure the total distortion rate, or THD, which gives the ratio between the effective value of the ripple and the effective value of the fundamental component.

Fig. 1 - Typical wave shapes of distorted networks

The result of non-sinusoidal consumption is that the voltage also suffers some distortion due to the voltage drops in the impedances of lines and transformers. In the logs we can note a slight voltage distortion in the single-phase network (low THD) and a stronger distortion in the three-phase example. In both cases the current shape differs greatly from the sinusoidal current, and the THD values are higher.

To regulate this issue and limit the voltage distortion levels at connection points to public networks, there are international standards that establish harmonic emission limits for units and systems connected to the network (Table 1). The most significant are those associated with compatibility levels.


Table 1 - International standards on harmonic emission limits


Some key concepts regarding harmonics

We can better understand harmonics problems by looking at some basic concepts which have been published in several articles and books, and which are summarised below:

  • The origin of harmonics problems are receivers that consume distorted currents (called "non-linear" receivers).
  • The problem spreading to other users connected to the same network depends on the impedance of the network, which depends on the distribution company. This impedance is not usually direct, but can be calculated from the short-circuit power available (the more short-circuit power, the less impedance).
  • Users have a section of the distribution lines before they reach the final load. Thus, the problems that may arise at the mains connection of their installation may be attributed to a lack of short-circuit power, but in many cases, the problems that may arise at points farther down the line from the mains connection are often due to impedances in the installation itself.
  • Furthermore, in terms of distortions farther down the line from the mains connection, we must remember that line impedance has a very significant inductive component. Therefore, many times it is not a question of using distribution cables with larger cross-sections, but of limiting inductance per metre of cables. This is achieved by braiding and twisting the distribution cables (often rejected by installations due to aesthetics).
  • The problem of voltage distortion at the PCC point can be aggravated due to of resonances between the power factor compensation capacitors and the inductance of the distribution lines (transformers and lines).
  • Corrective measures (filters) must be installed as close as possible to the loads that are generating harmonics.

In short, the solution to the harmonics problem is two-pronged: On the one hand, users must limit the number of harmonic currents generated by their receivers and must try to distribute electricity in their plants with low impedance per metre of cable. On the other hand, the distribution company must ensure minimal short-circuit power and must ensure that users do not exceed certain distortion limits, so as not to cause harm to their neighbours sharing the network.

When the harmonic levels generated by receivers are not permitted for the distribution system supplying them, corrective filters must be installed. In this article we are going to focus on explaining the concept of filtering.


Compatibility limits due to harmonics

The presence of harmonics in a network has several consequences. The most significant are described below.

  • Deterioration of the voltage wave quality, affecting sensitive receivers.
  • Overloading and possible parallel resonance between the line inductance and the power factor (PF) compensation capacitors.
  • Worsening of the power factor. The network power supply capacity is therefore diminished, due to being oversized.
  • Overloading of cables and especially transformers (very sharp increases in iron losses).
  • Problems of unwanted tripping of protection devices.

To avoid these issues, there are standards that establish a minimum power quality which limits the maximum distortion levels for the voltage wave supplied at the connection point to the public network (PCC). These limits are called compatibility limits. Table 2 presents a summary of these limits for harmonics in industrial LV networks. The different classes mentioned in this table correspond to:

  • Class 1: Industrial environment intended for power supply to sensitive electronic units
  • Class 2: Normal industrial environment. Usual limits for public networks
  • Class 3: Deteriorated industrial environment (generally due to the presence of transducers). Not suitable for power supply to sensitive units.
Table 2 - Compatibility limits: Voltage harmonics (Un %) in industrial LV networks (IEC-61000-2-4)

AFQevo. Multifunction Active Filter


Voltage harmonics are due to the voltage drop produced by current harmonics on distribution line impedances. This is illustrated in Fig. 2. So, reaching these limits depends on two factors:

  1. Emission level of the receivers: The more emissions, the more distortion caused by the voltage drop produced by harmonic currents in the network
  2. Network impedance: The more impedance, the larger voltage drop for the same emission value of the receivers


Table 3 - Emission limits for Sunit 33 x Scc (EN-IEC-61000-3-4)

Table 3 gives the emission limits for low voltage networks established by the EN-IEC-61000-3-4 standard for mains connection at which the installed power in the disturbing elements does not exceed (33xScc), where Scc is the short-circuit power corresponding to the mains connection (Proportional share of the total short-circuit power of the contracted power).


Fig.2 - Single-line diagram showing the deterioration of the voltage wave due to non-linear loads


Which installations need active filters?

Some of the disturbances mentioned above can be mitigated and corrected through filters. Active filters are the perfect solution for installations with a large number of single-phase and three-phase loads that generate harmonics and that have different consumption regimens.

Active filters are units based on transducers that modulate the PWM pulse width. There are two kinds: Serial filters and parallel filters. Parallel filters are often used to comply with the IEC-61000-3.4 and IEEE-519 standards, as they are based on using an inverter to inject the harmonics consumed by the load into the network in anti-phase. Fig. 3 illustrates this operating principle, showing the load, filter and network currents. We can see that the sum of ILOAD + IFILTER gives us a sinusoidal INETWORK current. Fig. 4 shows a parallel active filter and its schematic diagram.

Airports and infrastructures - Automotive Industries - Large supermarkets and shopping centers - Paper industries

Fig. 3 - Operating principle of a parallel active filter


The solution

Filtering units have been adding complementary functions to adapt to changes in installations, whether they be expansions or changes to the machinery. This may require more filtering of specific harmonics or phase balancing. It can also be useful to have power factor correction in these units.

"User-friendly with
touch screen display"


As a solution to the mentioned problems, CIRCUTOR has developed the new AFQevo Active Filter. Its new design offers advantages such as:

  • Filtering capacity for 30 A currents per phase and 90 A of neutral.
  • If more filtering capabilities are required, the system can be extended with up to 100 AFQevo active filters connected in parallel.
  • Reduced metallic enclosure for wall assembly. Its compact dimensions make it easy to install.
  • Communications for better electric energy management of the installation.
  • Voltage and frequency multi-range (50/60 Hz).
  • Reduction of harmonic currents up to the 50th harmonic (2500 Hz).
  • Selectable filtering of harmonic frequencies to achieve higher filtering efficacy.
  • Power factor correction (inductive/capacitive).
  • Phase current balancing. In the 4W model, it helps to reduce consumption in neutral.

The importance of a good installation

To get the best results, it is useful to have filters like AFQevo that are easy to install and manage. Start-up is made easier with the following functions:

  • 3-step start-up: Connect, Set up and Start
  • Touch screen display for quick management
  • Alarms such as configuration error, polarity, temperatures, resonance, voltages, overload, contactors, DC bus, etc.

"Energy management improvement"


Multipurpose: Various configurations and priorities

AFQevo active filters are Very versatile because they allow Different configurations and modes Of operation. Everything for To use them in installations Of different types and in the most Different situations.

Multipurpose: Various configurations and priorities

Application type with Active Filters Multifunction AFQevo in header and next to the load.



The presence of harmonics in distribution lines is increasing, causing a set of problems related to deteriorating voltage wave quality. This forces oversize installations, causing significant additional losses. Despite existing standards that limit the consumption of these harmonics, it is useful to filter them as it lets you optimise cable sections and powers to MV substations, reduce losses in installations and avoid production losses.

The solution to the problem is a rational and comprehensive design of harmonic filters (see related article about sizing the right active filter), like active filters, which helps solve the problem with affordable costs easily offset by savings in losses, improves the life of some of the components in installations and optimises their distribution infrastructure (cable conduits, transformers, etc.).


Click here to download this document in PDF format pdf es  en  fr  de  pl  pt  


Contact us:
t. (+34) 93 745 29 00


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

European Directive 2012/27/EU, an opportunity for the sector


What system do I need to install to comply with it?

Initial situation

The European Directive 2012/27/EU detailed the objectives for improving energy efficiency, it is focused basically on large companies. These objectives are aimed at decreasing energy consumption, reduced emissions of greenhouse gases and incentive the installation of renewable energy systems.

The main objective of the member states is what is called 20+20+20, for which three key targets have been set:


Reduction of
in energy consumption
Reduction of
in emissions
Reduction of
in renewable energies


In Spain's case, the companies and social groups obliged to comply with the National Electric Code have two alternative options to achieve the set objectives:

  • To carry out an energy audit, as set out in section 3 of article 3.
  • To install an Energy Management System (EMS), in accordance with international standards such as ISO 50001, provided that an energy audit is included.

Designed for efficiency

The Solution

The Directive establishes the possibility of installing an Energy Management System (EMS) to record, verify and display actual energy consumption and emissions data.

To install an EMS heavy investment is normally required in energy measurement equipment and a software application that monitors and manages the information, as well as communications cabling, but CIRCUTOR offers a revolutionary solution through its CVM-B100 and CVM-B150 electrical power analysers with EMS functionality. In other words, these analysers have a built-in energy management system and there is no need to install any additional components.

These units have an Ethernet port that allows them to be accessed directly from any PC, to record over a year of data on energy, CO2 emissions and operating time. Additionally, the EMS comes with powerful integrated software to monitor any variable in real time, record it and display it in a graphical format or in a table, to be exported in various formats. Its internal alarm system ensures the detection of any incidents and is capable of sending an email so that they can be quickly resolved.


CVM-B100/B150 electrical power analysers

CVM-B100/B150 analysers with datalogger modules are units that are installed on panels, whose dimensions are 96x96 millimetres and 144x144 millimetres respectively, with integrated energy management (EMS) software that complies with the new industry standards.

These systems have high measurement accuracy and are able to analyse numerous electrical parameters, as well as harmonic decomposition in voltage and current, up to the 50th order.

Integrated management software (EMS). Compatible with various web browsers (Firefox, Chrome, Safari etc.)
Integrated management software (EMS). Compatible with various web browsers (Firefox, Chrome, Safari etc.)

Graphical representation thanks to the VGA monitor, which allows the user to enjoy a new concept of power analysers based on a new SCV interface (slide, choose & view), designed exclusively and entirely by CIRCUTOR.

Some of the most outstanding features are:

  • Integrated EMS software (through the datalogger module).
  • Access via web browser (integrated web server).
  • Data storage for over a year.
  • Measures energy consumed and generated (0.5S accuracy class).
  • Measures CO2 emissions (overall and by tariff).
  • Measures costs in EUROS and other currencies (total and by tariff).
  • Records operating time for maintenance tasks.
  • Measures over 500 electrical parameters.
  • IP 65 front panel protection (with sealing gasket).
  • Ethernet and RS-485 point-to-point communication (Modbus RTU/ BACnet).
  • High-resolution colour VGA monitor with customisable screens.
  • Modular (option to connect up to 3 expansion modules + datalogger).
  • Touch scroll buttons.
  • 3 tariffs (can be selected by digital input or RS-485 communications).
  • 2 outputs to relay for alarms.
  • 2 outputs to transistor for alarms and impulse generation.
  • 2 outputs for tariff selection or management of logic states.


Where are the analysers installed?

Where are the analysers installed?

More features:

Energy metering

  • Electrical energy metering (consumed and generated)
  • Pulse counting (water, gas, heating etc.)
  • CO2 emissions metering
  • Operating time counter (preventive maintenance)
  • EUROS counter

Alarm management

  • Put that it has 4 outputs for managing alarms and sending emails.


  • Describe how the system internally records up to 500 variables for over a year.

Creates and sends consumption reports using PowerStudio Scada:

  • Using PowerStudio Scada it is possible to create energy reports and automatically send them to different departments to make expenditure forecasts.

Datalogger module

Datalogger module

It provides the system with memory:

  • With records for up to one year (over 500 variables)
  • Integrated web server (via IP) with access to embedded PowerStudio through a browser (Internet Explorer, Firefox, Chrome etc.) or via XML requests for reading and configuration.
  • Capable of reporting the data being monitored and recorded to a higher PowerStudio.
Up to 4 expansion modules connectable

Communication modules

Communication modules

Adapts the system to multiple protocols:

  • Modbus TCP (bridge)
  • LonWorks
  • Profibus
  • M-Bus

Input/output modules

Input/output modules

Monitors your systems and processes:

  • 8 transistor outputs + 8 digital inputs
  • 8 relay outputs + 8 digital inputs
  • 8 outputs + 4 analogue inputs (0/4 ... 20 mA)


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Protect your home


Avoid service interruptions with the resulting high costs

Preventing the undesirable consequences associated with an interruption in the electric supply of your home is possible. Unexpected interruptions caused by unwanted tripping of the RCCB of a home can result in high economic losses. CIRCUTOR's REC 3 earth leakage protection unit offers the best solution to this problem, thanks to its leakage detection and automatic reclosing system.

Nowadays, most homes have appliances and devices that can become deteriorated or completely damaged in the event of an interruption in the electric supply, even if the interruption only lasts a few hours. Food in a fridge, fish tanks, swimming pools, garage doors or the Internet connection of our homes are some examples. In second homes or homes that are not visited often, the consequences can be even worse if the interruption in the electric supply lasts for days or weeks. At these locations, an interruption in the electric supply can cause damage if the interruptions affect specific units, such as automatic sprinkler systems, refrigerating chambers, swimming pool pumps or outdoor lighting systems.

What does CIRCUTOR's REC 3 offer?

REC 3 is a self-reclosing RCCB, with the capacity to autonomously restore the service of the installation in the event of unwanted tripping. It features a system that measures the installation to detect leakage currents after a disconnection caused by tripping. If the unit is not disconnected it is reset, restoring the normal electric service. If the leakage persists, the REC 3 performs 3 reconnection attempts, after which it is locked and must be manually reset. The unit features two LEDs that indicate its status at all times. In addition, the REC 3 C range of products features two output contacts that can communicate the status of the RCCB to other applications. REC 3 is also very useful in installations that are hard to access or in geographically scattered areas, such as communication antennas or weather stations, as well as for critical production processes of the industrial or service sectors.

All in all, when facing events that can cause unexpected tripping of the RCCB, such as storms or other occasional insulation faults, REC 3 is the earth leakage protection solution that guarantees reconnection of the electric supply, protecting your devices and appliances while you are away.


More information:  Self-reclosing RCCB. REC3/REC3C series


Consult the article:  Don't worry, it will be back



Subscribe to our Newsletter for more information about CIRCUTOR's products.
You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Advantages of Smart Grids


The definitive solution for managing the grids of the future


With the recent requirement to install smart energy meters in Germany and other European Union Companies, Smart Grids are becoming the definitive solution for managing the grids of the future.

At this point the advantages they bring to both utilities and consumers are not in question. But of all their benefits, which are most important for European Union countries?

In this article we describe all the different benefits they provide, taking the "Benchmarking smart metering deployment in the EU-27 with a focus on electricity" as reference.

At CIRCUTOR we have a full range of smart energy meters with PLC PRIME technology as well as Data Concentrators (the Compact DC series), which read and programme the energy meters and send all the information about the units connected to the central management system.

The main advantages identified in this document are:

Energy savings through reducing consumption

One of the advantages of smart grids is that they can tell us the consumption at an energy meter at any time, so users are better informed of their real consumption. Moreover, with better consumption monitoring, contracted power can be adjusted to meet the real need of each consumer. These two factors result in users reducing their consumption and tailoring their contracted power to their real needs.

Smart grids represent a new era in the electrical sector, as we go from static one-way management to dynamic two-way management. This increases efficiency and energy savings.


Smart Grids have two-way exchange of energy and information, facilitating the integration of renewable energies and electric vehicles.This system can act remotely on network incidents, improving our supply and our relationship with the environment.

Smart Grids have two-way exchange of energy and information, facilitating the integration of renewable energies and electric vehicles. This system can act remotely on network incidents, improving our supply and our relationship with the environment.


Better customer service and more accurate bills

Another key advantage offered by telemanagement systems is that bills are more accurate. They always reflect the real consumption of each month instead of estimates, reducing the cost of the old system of manual energy meter readings. In addition to being able to access information about the installation remotely, problems become easier to diagnose and solutions can therefore be implemented faster, improving customer service.

Nowadays customers have to notify companies for them to take action. But with remote management the system itself automatically reports all incidents to the electric company so it can respond faster to users.

Fraud detection and technical losses

How does fraud being perpetuated by other customers affect me?

According to data from the Spanish National Commission for Markets and Competition, electricity fraud reached €150 million last year, equivalent to the consumption of Seville and Valencia combined. This does not negatively impact the utilities however, but rather translates into increased electricity bills for customers.

Telemanagement systems can detect fraud much more accurately, as the units do not contain any parts that are subject to mechanical wear. Moreover, the new energy meters with PLC PRIME communications have systems that detect the opening of the terminal strip cover and send an automatic alert to the managers of the grid warning of potential fraud.

Units with PLC technology can perform energy balances. The system adds together the energy of all the energy meters installed and compares it to the measurement taken by a totaliser at the head of the line to see if there are any losses (or theft) at any point that the company is not aware of.

Compact DC PLC PRIME Concentratorfrom CIRCUTOR. Compact DC PLC PRIME Concentrator from CIRCUTOR. 
At CIRCUTOR we have a full range of smart energy meters with PLC PRIME technology as well as Data Concentrators (the Compact DC series), which read and programme the energy meters and send all the information from the units connected to the central management system.

Reduced balancing cost

Smart Grids can collect much more data than the manual energy meter reading system. This permits the use of data analysis techniques and the preparation of highly realistic consumption forecasts as many more variables are taken into account.

Utilities can then better tailor their production to consumption (balances) and reduce energy surpluses.

Increased competition

Having real load curve data invites marketing companies to adjust their prices based on energy demand. When the marketing companies have more data they can make better offers that are more in line with their customers' reality, increasing competitive options through a wider variety of offers (hourly tariffs, energy packages, etc.).

This benefits consumers in that more competition leads to more competitive pricing.

Levelling of the demand curve (Peak reduction)

Through the use of different pricing profiles, utilities can level out the daily demand curve to shift consumption peaks to times with lower demand, optimising usage of the electrical network. So customers can intentionally connect loads at off-peak times when each kWh is less expensive. As an example: a customer may decide to change their consumption habits by using the washing machine during off-peak hours, at night, instead of when each kWh is more expensive, saving money and helping the utility balance consumption and avoid line saturation during peak hours.

Having consistent consumption means that power plants do not have to switch on and off as many times to generate energy, which lowers generation costs.

Through the use of different pricing profiles, utilities can flatten the daily demand curve to shift consumption peaks to times with lower demand, optimising usage of the electrical network.

Through the use of different pricing profiles, utilities can flatten the daily demand curve to shift consumption peaks to times with lower demand, optimising usage of the electrical network.

Reduction of carbon emissions

All the benefits above involve reducing consumption, which entails a reduction in CO2 emissions.

We can thus say that Smart Grids lead to a more sustainable future. All this will directly contribute to the future integration of electric vehicle charging systems on the mains. The deployment of renewable energy systems is also made easier as utilities gain greater control of their grids.


Click here to download this document in PDF format pdf es  en  fr  de  pl  pt


Contact us:
t. (+34) 93 745 29 00


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Electric vehicles: Will they fix any problems?


Electric mobility offers a tremendous advantage in all impact categories that might be considered.

For a number of years there has been news indicating that our mobility model is becoming obsolete. They all relate to the serious ramifications of using energy resources, pollution in towns and cities and people's health.

The scandal in how various car manufacturers - not just VW - have tampered with emissions; the shameful permissiveness of the European Parliament, raising the limits on unit emissions, when they have been trying to reduce them for decades, the emission limits set by Directives repeatedly being exceeded in many European cities, the lack of dynamism of the sector's leading manufacturers compared to the innovations of those that have recently emerged –such as Tesla– etc.; all of this reminds us of a similar scenario that occurred decades ago in the industrial world, with image and communications, when disruptive digital technologies emerged.

We can tell that the current scenario is in an even more confused state by the misguided forecasts by one ministry or another and the confusion about the possibilities and impacts of the newlyemerged electric mobility. An example of this can be found in one of the interesting "la Contra" interviews (La Vanguardia 09/10/13) with Stephen Emmott, a renowned researcher who is critical of the current economic system and somewhat apocalyptic about the current environmental situation, where he categorically stated that "electric vehicles don't solve anything, they just transfer the problem from the exhaust pipe to the power plant chimney".

The combination of photovoltaic canopies and EV charging systems, helping you to foster the huge energy, environmental and mobility opportunities presented by EVs.

Without wanting to question his expertise, and also agreeing with much of analysis, we chose this opinion because it is typical of the general confusion about electric vehicles (VE) and the changes to mobility that their introduction will lead to. Such misinformation covers at least three different aspects: with regard to the implications of energy efficiency, the possibility of generating electricity using numerous sources and technologies and the reduced environmental impact inherent in reinventing mobility with these new EVs.

Current internal combustion engine vehicles (ICE) are simply highly sophisticated thermal machines inside a casing that may or may not be to your taste. They all have an efficiency of around 30% (of every 100 units of energy, we only use 30, the rest becomes degraded energy and pollution); while the new EVs have an efficiency of more than 80%, which shows that, in order to achieve the same result –transporting people or goods– we will waste more resources and have a far greater environmental impact if we continue as we have to date with ICEs.

Reinventing mobility has far-reaching energy, economic, social and environmental implications.

The opinion that this technological change will only shift the problem from the exhaust pipe to the chimney of a power plant, ignores the fact that it is one thing to control hundreds of thousands of exhaust pipes subject to the arbitrary actions of each driver in the middle of crowded cities and roads and quite another to control a small number of large point sources, far from the cities and with modern anti-pollution systems. In the current context, we also cannot accept that electricity generation has to be associated with certain ways of generating electricity with fossil resources or radioactive materials, when it is clear that wind power has no chimney and photovoltaic generation does not even make any noise.

Installing only 2.5 kWp of photovoltaic panels generates the electricity that would be consumed by an EV that is driven over 10,000 km per year.

The above points are only for clarification purposes, we are now in a scenario where, despite the fact that ICEs will continue to dominate mobility and the market in the coming years, the electrification and hybridisation of vehicles, in all ranges, will advance at an unstoppable rate, even if some representatives from the old automotive industry feel threatened by the emergence of EVs, when the smartest thing to do would be to come together and benefit from the huge energy, environmental and mobility opportunities that they present.

Electric vehicles: Will they fix any problems?For most people, EVs are still a great unknown. Besides the crisis, the biggest problem today is not the cost of buying a vehicle, as there is a wide range of vehicles, prices and features. The problems are the growing running costs with fuel, the taxes and fees, the high costs in repairs, maintenance, parking etc. which, altogether, make up all of the hidden costs increasingly levied on anyone who owns an ICE.

However, although the emergence of electric vehicles is no panacea to fix the numerous energy/environmental problems that threaten our way of life, it does represent an opportunity to mitigate and reduce many of the known impacts of "fossil mobility". In the absence of any rigorous life cycle analyses comparing ICEs with EVs, and given the high efficiency of the latter, it seems clear that implementing electric mobility offers a tremendous advantage in all impact categories that might be considered.

Over the coming years there will be an increase in the range of makes and models of new EVs, with better performance and the anticipated reduction in prices. There are currently only two limitations to EVs: the high initial purchase price and their limited range (originally around 100 km, this is now being doubled in new EVs). Their supposed shortcomings and issues with charging can now be considered nothing more than urban legends.

In the immediate future, the crucial point where clarification is required relates to the new lithium-ion batteries (their charge cycles, life, replacement, second life and value). Despite their temporary nature and the fact that some regard the technology and materials as transitional, with a few minor tweaks they could be with us for a relatively long time to come. Especially bearing in mind that all of the miracle products that are regularly announced as the ultimate solution for energy storage are nothing more than speculation, with varying degrees of success.

We are strongly in favour of the development of EVs and their charging infrastructures and, although our country seems to be lagging behind, as this is a global phenomenon, no rules or barriers from the world of fossil fuel vehicles will be able to stop it. Reinventing mobility has far-reaching energy, economic, social and environmental implications. The key issue is whether we want to be actors or merely passive spectators


  More information: Smart electric vehicle charging system

Contact us:
t. (+34) 93 745 29 00


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Consumption analysis method for optimizing reactive compensation at MV



Many times we find the question that how many reactive power to be compensated must be chosen after making a measurement with a network analyzer. This situation is crucial in determining proper reactive compensation system in MV.

The presence of harmonics in the electrical system may also influence considerably, not only upon the operation of the capacitor bank, but the entire system power quality.

This article will explain how to define the power and steps that power factor correction in MV should be, using a simple statistical method, and assess risks to the presence of harmonics in the electrical system.

Electrical measurements

We must start any analysis of reactive power compensation with a measure carried out with a network analyzer (CIR-e3, AR5L or AR6), where we record the consumption of reactive power to compensate of the installation.

We should proceed according to the following principles so that a correct data logging is achieved for further accurate analysis:

  • Period: The period for registration must be large enough to be considered as a representative and realistic sample of normal consumption of the installation. It is advisable for at least a period of one week.
  • Sampling frequency: It is recommendable to use a sampling rate as low as possible to observe more closely the fluctuations of loads. If we consider a system with little load variations one can use a higher sample rate. It is suggested to use a sampling rate between ten seconds and fifteen minutes, also considering the memory capacity of the recording data logger.
  • Seasonality: Depending on the facility activity sector, the power consumption may differ depending on the time of year, even between days along a week. It is, therefore, essential to assure the recorded values are as representative as possible of the real profile consumption of the installation.
  • Existing capacitor bank: The presence of a capacitor bank will interfere with the acquired data and distort the data collected. So, ensure that during the registration period no kind of power factor correction equipment is connected.

Analyzing the measurements

After obtaining the data, we must analyze them. We will use a very simple but yet very useful statistical method such as histograms.

A histogram is a graphical representation of a frequency distribution given values. The distribution of values is divided into intervals. These intervals could be selected as one decides, but too short or too large intervals could be impossible to analyze.

One method to determinate the optimal interval size is with the following formula [1.1]:

determinate the optimal interval size

XMAX is the maximum value, XMIN is the minimum value, and k is the number of intervals calculated according to the Velleman method, k = 2·N1/2, where N is the number of values. To avoid deviations you can delete outliers that could affect the correct approach.

Let we go through an example of analysis using reactive power histogram. We can observe the three-phase inductive reactive power consumption at a voltage of 6,6 kV in an industry, where they are paying penalties for low power factor, in Figure 1.

Three-phase Inductive reactive power consumption in kvarL

Figure 1. Three-phase Inductive reactive power consumption in kvarL

By applying formula [1.1], the proposed interval value that is got would be:

applying formula

Anyway, since usually, M.V. automatic capacitor banks are based on 100 kvar multiples, in this case we choose this interval of 100 kvar, which will better suit to the compensation requirements of this installation. Thus, the result of applying this interval is the histogram of Figure 2.

Results of histogram (100 kvarL interval)

Figure 2. Results of histogram (100 kvarL interval)

Histogram Graph (Frequencies and %Accumulative)

Figure 3. Histogram Graph (Frequencies and %Accumulative)

As you can see from the results, most of the consumption of reactive power is 1400 kvar, followed of 1000 kvar and 500 kvar. Therefore, with a configuration of steps will be 1x500 and 1x1000 kvar.

In this way, we can choose an optimized configuration of the capacitor bank that we could compensate the installation more than 98% of the time.

Presence of harmonics in the installation

Obviously this method allows us to determine the steps to form the capacitor bank, but we must not forget other factors that may influence the selection of the capacitor bank.

The presence of harmonics can affect the performance of the equipment and the power quality of the entire installation.

When we carry out inductive reactive power compensation, the incorporation of a parallel capacitor bank is logical to attenuate this demand in order to bring the demanded apparent power (kVA) nearest to the active power (kW), which is really used to carry out to the purpose it is designed for. This simple concept can be summarized as a parallel circuit with inductance (L – Transformer and Grid) and capacity (C – Capacitor bank).

If we observe the frequency response of the system, we see that for a frequency fR the impedance of the system is much greater than its normal performance.

Presence of harmonics in the installation

The existence of current with frequencies higher than the fundamental frequency at 50 or 60 Hz, mean that the resonance conditions could be complied with. This would basically cause:

  • Amplification of the distortion in voltage for the entire installation (this could affect the equipment and sensitive electrical elements).
  • Greater absorption of current by the capacitors, with their consequential overheating, reduction of their capacity and useful life, and in some cases the destruction of the capacitor.

Blow-up MV capacitor due a resonance effect

Image 1. Blow-up MV capacitor due a resonance effect

There are two methods to check or detect the risk of resonance. First method is to calculate the frequency of resonance with the following formula:

to calculate the frequency of resonance

Where SSC is the short-circuit power of the power transformer (kVA), Q is the reactive power of the capacitor bank (kvar) and f is the rated frequency of the system (50 or 60 Hz).

Then you can check if the frequency of resonance could be close or not to harmonic current presence in the installation, therefore could produce a resonance between the capacitor bank and the network.

The second method is to detect if the capacitor bank is producing or not a parallel resonance with a measurement. We just need to take measurements with and without the capacitor bank connected, and see the performance of THDU%.

measurements with and without the capacitor bank connected

If the THDU% increases so much when you connect the capacitor bank, it will means that exists an important resonance and it will damage the capacitor bank, as well as, the whole equipment connected in that installation.

The only way to avoid this risk of resonance is to install a detuned capacitor bank that reject the parallel resonance this the most common harmonics presence in the installation.

Final conclusion

A brief summary of this paper may conclude that the right choice of a capacitor bank to compensate any M.V. must take into account two essential points:

  • The accurate selection of the stages that compose the capacitor bank, trying to get the most cost-effective arrangement.
  • A thorough analysis of the need of using detuned reactors to avoid possible harmonic amplification phenomena.



Click here to download this article in PDF pdf format: en


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Consume or store?


This is the dilemma often faced by anyone who wants to produce their own energy.

Fortunately, the technical/legal energy regulations have lifted the ban on storage systems being integrated into self-consumption equipment with renewable energies.

It is a logic-based online recognition system and it stores any surplus power that may be produced by generation systems with renewable energies during off-peak hours when there is high solar production so that it can later be consumed when the resource decreases and demand increases.

Spanish Electric Code RD900/2015, approved on 10 October 2015, allows storage systems to be integrated into any self-consumption project with renewable energies.

Despite storage systems becoming legal, there is still one final hurdle to overcome. In this case, it comes in the form of a tax, included in the aforementioned Code that governs self-consumption. Indeed, the so-called "fixed charge" of the tax on the sun only applies to systems that are defined as manageable. In other words, that are capable of producing energy on demand and not only depending on the whims of the resource that they are using.

It appears that being able to manage when you self-consume is a greater privilege, which has led to the lawmakers adding a specific additional cost. This is in contrast with the incentives to implement storage systems being applied in other countries in the European Union, not only in new self-consumption projects, but to improve the management of existing ones.

Leaving aside the temporary setback presented by this tax on storage that is sure to disappear soon, as it represents an administrative barrier to the development of an activity which the European Commission itself has established as a priority in the fight against climate change.

Storage systems are quickly becoming popular, although they are facing other challenges such as cost, efficiency, their service life and their management.

Installation of photovoltaic panels in a residential area

Installation of photovoltaic panels in a residential area.

Impact of the cost of an electrochemical battery on a self-consumption system:

Integrating an electrochemical battery into a self-consumption system can increase the investment required by 60% to 100%. Which makes it very difficult to obtain a reasonable return.

Given the cost of storing electricity, this should be the last thing you should choose when selecting what system to implement in a self-consumption project. Before evaluating the capacity of the battery, you need to know exactly what the facility's energy demand will be like and explore how consumption can be reduced by improving efficiency or what loads can be moved to daylight hours so that they can be covered by instantaneous self-consumption.

Impact of integrating an electrochemical battery on the efficiency of a self-consumption system:

It should be noted that producing solar power for self-consumption can instantly have an average yield that is above 90%, while energy that is stored to be consumed in the future can struggle to achieve an average yield above 80% and in some cases it is even lower than 70%.

Therefore, changing consumption habits will always be more efficient and useful, planning for certain loads to be connected and consumed during the middle of the day rather than storing this energy in batteries and then consuming it during hours of low solar radiation.

Programming the domestic water heating and the running of a swimming pool filter system, increasing the setpoint temperature of the heating at the beginning of the afternoon or cooling the air conditioning system's buffer tank are solar power storage systems that do not require a lot of investment and, in many cases, they can make it possible to minimise the size of the batteries that are really required and, therefore, improve the financial return provided by the system simply by avoiding losses during battery charging and discharging processes.

CIRCUTOR's photovoltaic kits foroff-grid systems contain all of thedevices necessary to autonomouslyself-consume energy for systemsthat are off-the-grid.

CIRCUTOR's photovoltaic kits for off-grid systems contain all of the devices
necessary to autonomously self-consume energy for systems that are off-the-grid.

Impact of an electrochemical battery on the durability of a self-consumption system:

One of the appeals of instantaneous self-consumption systems is the long service life of photovoltaic modules. With manufacturers providing 25-year warranties for the power that they produce, we can safely say that a self-consumption system will be able to operate for over 30 years generating electricity, without anticipating any further costs, other than occasionally repairing and/or replacing one of the inverter's electronic components.

However, when we include a battery component in the self-consumption system, using existing technologies, the life of the battery will force the user to invest more money to replace it far sooner than the rest of the system. Five years in the case of lead-acid batteries with gelled electrolyte and 10 years in the case of lithium-ion batteries.

These three impacts are forcing the designers of self-consumption systems to figure out how to make the benefits of using storage systems outweigh these disadvantages.

Advantages of self-consumption systems with storage:

Without a doubt, the main draw of energy storage systems used for self-consumption is energy independence. To be able to produce and consume the energy produced in a building and reduce consumption from the grid to a minimum or even go off-grid. Indeed, storing the surplus solar power from the middle of the day allows you to increase your energy self-sufficiency. In the residential sector and similar, where loads tend to become concentrated in the late afternoon and early evening, storage can enable the levels of self-consumption to increase from 30% to levels of between 60% and 90%, with the corresponding reductions in greenhouse gas emissions.

As well as increasing the percentage of self-consumption, storage systems allow the supply security of buildings to be increased. As there is an energy backup supply, if there is a grid failure, certain sensitive loads can continue to receive power from the solar power system, even in the absence of solar radiation. Finally, a property that has a self-consumption system with storage can use the stored energy to minimise peak power demand from the grid and therefore reduce its contracted power. This reduction in contracted power can, in many cases, be extremely helpful for increasing the return on investment. Especially in those cases with extremely sporadic peak consumption, such as in weekend homes. Or in seasonal water pumping systems.

This advantage offered by storage systems is also extremely useful in those places where the infrastructure of the distribution lines means that it is not possible to increase the contracted power without requiring a disproportionate investment. In those cases, a self-consumption system can generate and store the energy to provide the additional power required that cannot be supplied by the grid.

CIRCUTOR energy storage batteries.
REA-Pb Lead-acid battery REA-Li Lithium-ion battery CirPower The most complete inverter
Lead-acid battery
Lithium-ion battery
The most complete inverter

Using existing technologies, the life of the battery will force the user to invest more money to replace it far sooner than the rest of the system. Five years in the case of lead-acid batteries with gelled electrolyte and 10 years in the case of lithium-ion batteries.

The Cirpower Hybrid by CIRCUTOR are hybrid inverters for self-consumption photovoltaic energy systems. They are able to manage surplus energy loads in batteries and their subsequent discharge in order to power consumption when the instantaneous power of the solar generator is not enough.

Second home in mountain area withself-consumption system.

Second home in mountain area with self-consumption system.

Case study.

The case described below is that of a weekend home high in the mountains with a harsh climate, especially in the winter. These types of properties keep their heating systems on throughout the winter to prevent the temperature inside from falling below a certain security value (14 … 16 C) to prevent the accelerated deterioration of their walls and avoid the difficulty of achieving setpoint temperatures again at the weekend.

View of a system's energystorage and conversiondevices.

View of a system's energy storage and conversion devices.


Oil boiler consumption in this type of property is normally between 3,000 and 5,000 litres per season. By incorporating a modular radiant heating system powered by a photovoltaic module installation with storage, 4 kW of power and a capacity of 7.2 kWh, as well as an EDS load management system, it has been possible to reduce the amount of fossil fuel used to maintain temperatures on unoccupied days to zero. Also, by changing the operating mode, the system is able to cover the property's power needs during the rest of the year and guarantee a basic supply in the event of a grid failure, which is quite common in mountain areas. Despite having a high cost, this system has a payback period of six years and prevents 14 T of CO2 from being emitted into the atmosphere.

Diagram of a self-consumptionsystem connected to an internalnetwork with storage.

Diagram of a self-consumption system connected to an internal network with storage.

These photovoltaic systemswere installed with the assistanceof:TIRDI (www.todoinstalaciones.com) and Eticenergy SL. These photovoltaic systems were installed with the assistance of:
TIRDI (www.todoinstalaciones. com) and Eticenergy SL.



Click here to download this document in PDF format pdfes  en  fr  de  pl  pt  


Contact us:
t. (+34) 93 745 29 00


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Kenya project


Self-sustainability in the heart of the savanna

In September 2015, a team of engineers from the renewable energies consulting firm SULMAG travelled to the ADCAM project in the Maasai Mara (Kenya) to install a solar photovoltaic system via a microgrid. The system will provide electricity from 100% renewable sources to the Mara Vision school, the student residence and the ecotourism camp managed by the Maasai community.

The Mara Vision school, located in the heart of the savanna and founded in 2011, provides nursery and primary education to more than 300 Maasai children. It has a residence where students from remote areas can live, receive full board and participate in extracurricular activities. The school provides quality education adapted to the Maasai culture.

The eco-lodge has all the comforts necessary for tourism and one of its main draws is being located next to the school and the Maasai Manyatta (village), which allows visitors to have a unique experience interacting with the community.

In order for the educational project to be self-sustaining in the long term, an ecotourism camp has been constructed where Maasai warriors introduce visitors to their customs, landscapes, wildlife and lifestyle.

Kenya project

Project data

An electrical system using solar photovoltaic energy was designed to supply the existing installations (school, residences and camp) with electrical energy. There is no existing energy supply in the area and this new energy has the added value of coming from 100% clean and renewable sources. It is a centralized photovoltaic energy installation, commonly known as a solar microgrid, which optimises the investment with a single generation point for subsequent distribution via a small network to the points of consumption.

This allows a quality system equivalent to a local electrical network, involving users in the management and sensible use of energy. The estimated consumption is 24,000 Wh/day and the system has been sized to provide three days of autonomy.

The solar microgrid is made up of: a generator field of 10 kW of solar modules (40 x 250 W modules) and a field of 2830 Ah OPzV batteries for energy storage.

CIRCUTOR dispensers: The perfect solution for managing microgrids.

To prevent any misuse of the installation, CIRCUTOR energy dispensers were installed in the different energyuse areas, allowing users to know how much energy they have available.

The energy dispensers ensure a long useful life for the system, as they allow the maximum power and total daily energy available to be configured separately for each of the existing lines, thanks to the EDA (guaranteed daily energy) technology patented by TramaTechnoAmbiental.

The CIRCUTOR dispensers ensure the system will not fail due to the connection of excessive instantaneous power and that the battery bank will not discharge from one of the lines due to improper use of the system.

Kenya project

Each dispenser is configured with its power and guaranteed daily energy based on the needs of each point of consumption. For example, each tent in the lodge has a dispenser via which the user can find out how much energy they have available. The software is controlled and managed by local personnel, whom SULMAG trained during the implementation of the project. They can connect remotely to supervise proper use and provide ongoing support to the local team.

The dispensers are configured and managed through DISPENSER-SOFT, a software that enables the creation of a large database that contains all the users and dispensers of the microgrid. Once all the dispensers, users, energy parameters, tariffs, etc. have been created and configured, the software stores all the information on RFID cards.

There are countless benefits for the project and the community, from the creation of a computer room for the students of ADCAM Mara Vision school, to the ability to project films for young children and impeccable lighting in the camp.

The CIRCUTOR Dispenser is a single-phase/three-phase meter with an electrical energy dispenser function to control demand. The two functions it performs are to control the maximum power allowed and to regulate the daily energy consumption of users of a permanently powered microgrid. Its four built-in working modes enable maximum energy optimisation of the microgrid. It also allows users to intelligently manage the energy available in networks, with limited or pulsed generation, such as the energy available from renewable energy sources. It features a main switch that controls maximum power and an auxiliary relay that can be used to connect or disconnect non-essential consumption.


  More information: Renewable energies
  Product datasheet: Dispenser series

Contact us:
t. (+34) 93 745 29 00


You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

How can the correct EnPIs be chosen?


Once the goals have been established after an energy audit, the way in which the goals of an energy efficiency plan or plan for the implementation of the ISO 50001 will be achieved must be studied.

EnPIs (Energy Performance Indicators) are indicators that can be used to measure, assess and control the most relevant aspects of the installation, which can affect the achievement of goals.

EnPIs must be jointly defined with the supervisors of each area or department in which these can have an impact when an energy efficiency project is commissioned or during the continuous improvement and monitoring process.

EnPIs must be of the most suitable type for each specific area, process or organisation and adapted in each case. EnPIs are established with the purpose of being specific, measurable, achievable, relevant and time-bound (SMART), so they can be as stable and specific as possible over time.

Basically, we must answer the following questions:

  • What will we measure?
  • What ratio will we use?
  • How will we measure it?
  • How can we achieve the goal?
  • How important is it for the company?
  • How long does it take to achieve the goal?

Each company or business is different, so a copy-paste of the same EnPi in each energy efficiency project is simply not enough.

Now think about it - What will your EnPI be? 

You can read our news in the news section.
You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

More Articles ...



Vial Sant Jordi s/n, 08232
Viladecavalls (Barcelona) Spain
Tel: (+34) 93 745 29 00
Fax (+34) 93 745 29 14

SATTechnical Support
(+34) 93 745 29 19

© 2015 circutor.com. All rights reserved.