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Static capacitor banks: a reality


For many years now, power factor correction has been one of the first steps to improving the energy efficiency of installations. Since their beginnings, compensation techniques have grown and developed over the years, adapting to new needs (basically the types of loads that must be compensated) and to new technologies that have become available.

At first, the most common compensation technique was to use capacitor banks with contactor operation. This compensation system is optimal for balanced systems and to compensate loads with connection and disconnection rates that are not too fast, on the order of seconds, and it is currently the most common system in most installations despite increasing numbers of unbalanced installations.

The passage of time and the growing use of more dynamic loads in many installations has led to the emergence of a new technique: the use of static contactors (solid-state relays or thyristors) to operate the capacitors in a capacitor bank. This technique has a set of important advantages over compensation with contactor operation:

  • Response speed: the use of thyristors enables compensation in installations with highly fluctuating load variations (in cycles, on the order of ms), making it the optimal solution for cosφ correction of very fast loads. The paradigmatic case would be the compensation of welds, although lifts, freight elevators, compressors, etc. would also be on the list of likely loads.
  • Elimination of mechanical wear: contactors have a limited mechanical life, which incurs the need for regular maintenance to ensure the capacitor bank is functioning properly. The use of thyristor operation eliminates this need, extending the useful life of the capacitor bank assembly and reducing maintenance costs.
  • Less noise: the use of electronics during contactor operation eliminates mechanical noises generated by the contactors, which can become an annoyance in service installations.
  • Elimination of connection transients: the use of zero switching control boards ensures the elimination of transients when the capacitor connects, giving it a longer useful life and eliminating disturbances on the electrical network.

In the early days of this new technology its main drawback was its high price, which meant that investing in this type of unit necessitated long repayment periods for most companies, making it difficult to justify the expenditure, even more so if compared to traditional compensation with contactors.

FO OPTIM EMS-C 250x250

CIRCUTOR was a pioneer in developing the technology used in static capacitor banks and has included them in its catalogue for more than 20 years, making the company a leader in this technique within the electricity market. In recent times, significant R&D efforts have been made to adapt the new emerging technologies to this compensation technique, developing a new range of static capacitor banks that drastically reduce the price difference between the two compensation systems (contactors / thyristors), thus eliminating the main obstacle to choosing a static capacitor bank as a compensation method.

To this end, CIRCUTOR has launched the new range of EMS-C static capacitor banks which are ideal for industrial applications, such as arc welding, compressor start-up, cranes and hoists. But they are also suitable for the service sectors, such as compensating lifts in communities of residents, given that the traditional contactor technique does not compensate them well due to their quick input and output rate.

Thanks to minimising the cost difference between classic compensation with contactors and advanced static compensation, CIRCUTOR has turned the choice of a static capacitor bank from a technical whim to a tangible reality within the reach of all budgets.


More information about OPTIM-EMS-C Series. Automatic capacitor banks with static contactor


Documentation about Automatic capacitor banks


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

Cómo evitar penalizaciones por máxima demanda

How to improve efficiency in Data Processing Centres (DPCs)


The importance of knowing the PUE. Managing effective energy use

We can calculate the energy efficiency of any production system by comparing the useful energy with the total energy needed by the system. With this information and knowing where the inefficiencies are, we can achieve substantial savings and more environmentally friendly operations.

As a practical example, an average data processing centre with installed power of 100 kW can achieve savings of €8,000 to -€16,000 in the electricity bill as a result of improved energy efficiency. To do so, it is as important to detect the points of consumption as it is to assess the corrective measures.

The energy factor is so critical in data processing centres that it has its own indicator: PUE or Power Usage Effectiveness, defined by a standard issued by The Green Grid, a global environmental agency comprised of over 175 internationally renowned companies.

The European Commission also has a code of conduct for reducing the impact of data centres' growing energy consumption.

It periodically publishes best practices for data processing centres, most recently in 2013.


These centres have a peculiar profile due to their uninterrupted working hours. Because of the great importance of service continuity when powering servers, computers and communications, they have three main groups of units for their exclusive use:

  • Energy supply and control units (electricity and other sources, such as diesel oil, gas, etc.) essential for the functioning of these continuous operation units. This group includes supply connections and switchboards, lighting and refrigeration systems, air conditioning of the corresponding rooms, etc.
  • One or several units to supply power computer equipment (IT), comprised of UPS (Uninterruptible Power Supply) units .
  • The distribution panels and systems for this energy to power the computer equipment.

Broadly speaking, we can say that of the 100% total energy consumed in a DPC, 60% corresponds to the infrastructure's electrical consumption and the remaining 40% to refrigeration systems.

So we can undoubtedly see the need for coefficients (PUE) that make it possible to prepare comparative studies aimed at determining actions for optimising the energy consumption of these centres.

Calculation guidelines

As we have already seen, we normally use the standard issued by The Green Grid to calculate the parameters for DPC efficiency. We will distinguish two key indicators:

1. PUE: Power Usage Effectiveness, calculated with the formula:


2. DCE: Data Centre Efficiency, calculated as a percentage with the formula:


In addition, the Environmental Protection Agency of the United States (EPA) provides the following PUE values as a reference:

  • Historic 2.0
  • Current trend 1.9
  • Optimised operations 1.7
  • Best practices 1.3
  • State-of-the-art 1.2

Companies like Google have gotten the average PUE of their DPCs down to 1.22, and sometimes as low as 1.15.

In the historic frame of reference (PUE 2.0), typical consumption for different DPC elements is:


Therefore, one of the keys to the success of an energy improvement project is measuring the consumption of each unit type in order to be able to recognise the most affordable areas of improvement.

There are three general measurement levels* shown in the table below, with measuring points that correspond to the indicators in the diagram also shown below, with energy measured in kWh. A 12-month cycle is taken as a comparative reference for all levels.

There is also a Level 0, which only includes power measurements (kW), measuring the general demand of the installation and that of the UPS output.

measuring the general demand


CIRCUTOR with its decades of experience in energy efficiency, solutions, offers a wide range of products that facilitate continuous data gathering for controlling PUE and DCE, UPS unit performance, electric energy management and DPC maintenance. These include energy meters, power analyzers, ultra-immunised earth leakage protection, harmonic filtering systems, PowerStudio Scada management software and power factor correction systems.

CIRCUTOR’s Solution with the SCADA system

For the study, two implementation phases and a third study phase are required:

  1. Measurement: with the addition of CVM power analyzer units, with their corresponding current transformers, equipped with RS485 serial communications to measure circulating energy.
  2. Analysis: installing the PowerStudio Scada application, calculating and viewing the resulting values and running the corresponding reports.
  3. Improvements: analysing the collected data lets us see which units are consuming.


The application features:

A start screen in single-line diagram format (Fig.1) with data corresponding to all the concurrent energy types (converted to KWh).   single-line diagram
A second summary screen (Fig.2) with performance calculations (Fig.3), enabling you to create and display reports with results for different periods (daily, weekly, monthly and yearly).    performance calculations

By way of example, here are the screens displayed when installing CVM analyzers and programming a specific Scada application.

On the first one you can see the installation diagram and unit connections; on the second one you can see the resulting data online for a single DPC; and on the third one is a weekly Level 1 report with continuous measuring frequency.

   Weekly PUE calculation report
CIRCUTOR’s Solution with a local display screen

For the study, two implementation phases are required:

  1. Addition of CVM power analyzer units with their corresponding current transformers, equipped with RS485 serial communications to measure circulating energy.
  2. Addition of an EDS energy controller with storage and data processing functions and its built-in programming, along with a local display screen.

By way of example, here is the communication topology displayed when installing CVM analyzers, the EDS energy controller and the local display screen.

Solution with a local screen

How to improve the efficiency of a data processing centre

To improve the efficiency of a data processing centre, we must follow measuring and analysis by implementing improvement actions. There are actions that do not require any investment, such as reducing the contracted power to save on direct costs, and other actions that do require investment, such as replacing units with more efficient ones.

To organise these improvement actions you can prioritise them in accordance with the efficiency that can be achieved with each one. This prioritisation is calculated by comparing the improvement obtained with the investment required to make the improvement.

Action priority   

Pa: Action priority
CEa: Current energy consumption
CEm: Energy consumption with the new measure.
Investment: investment needed to achieve the savings

Performing this calculation for each possible improvement action helps us prepare a list of actions and sort them from highest to lowest priority.

Possible short-term measures include:

  • Analysing usage patterns for the environments where they have been deployed.
    • Calculating the minimum server group sizes to maintain service levels.
    • Switching off unused capacity, as long as proper availability is maintained.
  • Virtualisation and consolidation
  • Replacing hardware
    • Virtualising test environments.
    • Replacing obsolete hardware.
  • Changes in room management
    • Correct control and adjustment of room temperature.
  • Changes to the refrigeration infrastructure.
    • New efficient refrigeration machinery.
    • Hot aisle/cold aisle layout.
    • Elimination of "gaps" in the racks.
    • Future: use of outside air.
  • Lighting optimisation

For a more thorough list of Data Centre improvements, see the "2013 Best Practices issued by the European Commission's Renewable Energies Unit."


DPCs (Data Processing Centres) are major consumers of electrical energy and their consumption can be divided in useful energy for computer equipment and the additional energy necessary for their smooth functioning. This energy consumption is so critical that it has its own indicator: PUE (Power Usage Effectiveness).

In DPCs with non-optimised PUEs, this additional energy can account for up to 50% of the total energy, giving us good room for improvement. According to minimum availability requirements and the options for investment in improvements, savings of up to 20% of the total energy consumed can be achieved (or between €8,000- €16,000 a year in an average 100 kW DPC).

As we have seen in this article, it is possible to study and measure possible improvements to data processing centres. The key phases are installing energy measuring units, analysing the data gathered and making decisions based on that analysis.

CIRCUTOR, with its decades of experience in energy efficiency solutions, offers a wide range of products that facilitate continuous data gathering for control, maintenance and energy efficiency management of DPCs.


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Consult our Success story in a Data Processing Centre


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How to avoid maximum demand penalties in your electricity bill

How to avoid maximum demand penalties in your electricity bill


Due to the constant increase of the electricity price, all types of customers must find new formulas to reduce their electricity bill. To succeed in this, we are presenting our new power management system to control the maximum demand: MDC series (MDC 4 and MDC 20).

How to understand the electricity bill

It is necessary to understand the different terms which appear in an electricity bill to identify where we can act to reduce it. Of all the concepts, the most important ones are: Active energy term, reactive energy term and, in some countries, the maximum demand term, being this one last the subject of this article.

As described below, an optimal management of the contracted power allows us to:

  • Adjust the installation to the real demand by reducing the contracted power
  • Avoid maximum demand penalties due to a power excess
Spanish bill simulation
Spanish bill simulation

Active energy term
Consumption of active energy (kWh), applying different tariffs and rates

Maximum demand term or Maximum demand indicator (MDI)
Maximum demand register (kW or kVA). This is the maximum power value, usually the average of 15 minutes, reached during the billing period (this average time may vary depending on the country). Once the value is higher than the contracted power, the customer will pay a penalty on the electricity bill.

Reactive energy term
Consumption of reactive energy (kVArh), applying different tariffs and rates. Depending on the cosϕ value, the user will pay a penalty (this penalty is not applied in all countries)

Maximum demand calculation

The maximum demand value is the average from the instantaneous power (in kW or kVA) during a defined time interval, usually every 15 minutes (this time interval will depend on each country). There are different methods to calculate this parameter:

Fixed window (Block window)

This is the maximum demand calculation during a defined interval (usually every 15 minutes). Once the data is obtained, the value is stored and it makes a reset to start a new calculation for the next 15 minutes. This 4 registers will be measured every hour.

Sliding Window

This is the maximum demand calculation during a defined interval (usually every 15 minutes). Once the data is obtained, it will wait one minute to start a new 15 minutes calculation (this time may vary depending on the country). This means that every minute (this time can depends on the meter) it will record one maximum demand value from the last 15-minute period. This 60 registers will be measured every hour.

What can we do to avoid maximum demand penalties on the electricity bill?

To avoid penalties for maximum demand we must ensure that this value will never exceed contracted power.

Usually in electricity bills, the highest maximum demand value recorded by the meter is compared to the contracted power. Whenever this value is higher than the contracted power, there will be an economic penalty. Therefore, if during the billing month the power exceeds the one contracted, during a period of 15 minutes, the customer will pay a penalty, even if it exceeds only once a month (one month has approximately 2880 fifteen-minute periods).

For the particular case of Spain, depending on the maximum demand value, the penalty can involve a very significant bill increase, as described in the following graph:

Maximum demand term increase depending on the Contracted power exceeds (Spain- for tariffs 3.0 and 3.1)
Maximum demand term increase depending on the Contracted power exceeds (Spain- for tariffs 3.0 and 3.1)

As shown in the graph, if the maximum demand value exceeds 10 % of the contracted power, the user will pay a 20% increase on the maximum demand term. However if the maximum demand value exceeds 20 % of the contracted power, the user will pay a 50% increase on the maximum demand term.

How to control the Maximum Demand value?

As we have been advancing, the goal to control the maximum demand is to not exceed the limit of the contracted power. To archive this goal, we advise to install a system able to disconnect non critical loads, on different time periods, and also avoid connecting loads simultaneously to reduce the instantaneous power.

Non-critical loads are those that do not affect the main production process or that are not essential, such as:

  • Lighting
  • Compressors
  • Air-conditioning systems
  • Pumps
  • Fans and extractors
  • Packaging machines
  • Shredders
  • others

Which devices help us avoid maximum demand penalties?

The main objective of the new CIRCUTOR MDC series is to manage and control the maximum demand of an installation. To achieve this objective, the device connects and disconnects some loads (non-critical ones) to ensure that the maximum demand will never be higher than the contracted power, avoiding electricity bill surprises. Moreover, the extended MDC 20 range, allows a tariff control to adjust the loads for being connected on periods with lower price, avoiding high consumptions due to loads simultaneity during high tariff price periods.

MDC 4 device
MDC 20
MDC 20 device

Small and medium-sized industries solution

MDC 4: Analyzer to control the maximum demand level

MDC 4 is perfect for those installations which need a basic maximum demand control. Following some easy configuration steps the user will define up to 4 maximum power levels to start disconnecting non-critical loads.

Furthermore, MDC 4 incorporates an internal power analyzer for the maximum demand calculation (it also records electrical parameters such as voltage, current and power). Every time MDC 4 detects a power excess, this will disconnect several lines with non-critical loads, reducing automatically the instantaneous power. This will ensure that the installation will not exceed the maximum demand limit, hence avoiding penalties on the next electricity bill.

Operation method of MDC 4

Operation method of MDC 4

  • Avoids maximum demand penalties
  • Avoids power peaks due to simultaneity while connecting loads
  • Helps to adjust the contracted power to the real situation
  • Manages up to 4 relay outputs
  • Built in power analyzer
  • Internal clock for power synchronization

Infrastructures and big-sized industries solution

MDC 20: Data logger to manage and control the maximum demand with integrated web server 

MDC 20 is a data logger with an integrated web server meant to manage and control the maximum demand. Its versatility allows the user to do basic or advanced configurations. MDC 20 manages non-critical loads to ensure that the maximum demand value will never exceed the contracted power, avoiding penalties for power excess.

MDC 20 has an Ethernet port and a RS-485 communication channel (Modbus RTU), 6 relay outputs for load management and 8 digital inputs for collecting pulses (from other meters) or for logical states (opened-closed). It is expandable up to 48 relay outputs and 48 digital inputs by connecting 12 LM 4I/O devices via RS-485 communications (with 4 inputs/outputs each one).

The device has an internal data base (more than one year of data) with an integrated web server with PowerStudio software for programming, configuring and monitoring the device status and the associated peripheral devices connected by RS-485. Furthermore, it graphically shows the simulation of the system behavior according to the programmed settings.

MDC 20 infrastructure

MDC 20 infrastructure

MDC 20
MDC 20
  • Avoids maximum demand penalties
  • Manages 6 relay outputs and 8 digital inputs
  • Expandable up to 48 inputs/outputs by RS-485 communications (installing LM 4 I/O devices)
  • Connection/disconnection of loads according to programmed priority
  • Versatile maximum demand control depending on conditions, using calendars, profiles, etc.
  • Simulation of system performance according to the device’s programming
  • Sends e-mails with customized messages
  • Stores more than one year of data
  • Compatible with any XML communication master
  • Creates and registers customized variables defined by the user (EnPI, %, Kg, CO2, Euros, …)

Click here to obtain more information about MDC 4 and MDC 20

New MDC series to manage and control the maximum demand

You can also follow our publications on CIRCUTOR's Twitter account, and on LinkedIn.

Audits in Energy Efficiency European Directive: an obligation for companies and an opportunity for the sector


European Union Directive 2012/27/EU of 25 October 2012 sets a deadline of 5 December 2015 for all companies in member countries to carry out independent energy audits by qualified and/or accredited experts. This Directive is binding in all member countries, and the administrative penalties for not performing energy audits on time can range from €300 to €100,000, in addition to other civil or criminal liabilities.

Specifically, the companies obliged to comply with the directive are:

  • Companies with more than 250 employees and more than €50 million in annual turnover.
  • And companies with a general annual balance sheet total of €43 million.

Furthermore, the Directive indicates that member states should promote energy audits among SMEs. It also lists funding and grant mechanisms for audits, training and energy efficiency improvements. The goal is for each member state to be aligned with the European Union's 2020 strategic plan.

How can we ensure our installations are in compliance with the Energy Efficiency Directive?

There are several steps that must be taken in order to comply with the law:

  • Carry out the audits in a timely manner. It is essential to have a key partner for this: Energy Service Companies play a vital role here, along with CIRCUTOR, offering open lines of collaboration that you can consult from our sales network.
  • Check that the recommended energy efficiency projects correspond to the reality of the installation by assessing the investment, the economic return and the quality of the proposal. Here you can see different energy efficiency improvement projects that have already been published.
  • Inform and train the installation's end users. User consumption habits play an important role in all energy efficiency projects and in proper compliance. This information and training should not be sporadic, but rather should be updated regularly to keep up with technological advances, staff turnover and changing habits and lifestyles. At CIRCUTOR we have an in both face-to-face and online formats.

Benefits of the European Directive for companies and the economy

The Directive will bring about economic benefits as a result of better efficiency in the companies performing the audits and improved energy efficiency overall. Other companies that will benefit directly are:

  • Energy service companies that do energy audits with properly trained and certified staff, as indicated by the law.
  • Engineering and installation companies that design, implement and monitor energy efficiency improvements to meet the targets.
  • Electrical equipment distribution companies with qualified staff that can offer value-added services in the field of energy efficiency.

Whether you are a company that must comply with the European Directive or an energy service company, installer or electrical equipment distributor, CIRCUTOR can partner with you to help you follow the law and obtain all the benefits of Energy Efficiency.

Contact us:
t. (+34) 93 745 29 00
CIRCUTOR Heavy Duty Capacitors

CIRCUTOR Heavy Duty Capacitors

One of the common solutions for improving energy efficiency is power factor correction, with the capacitor being the key element.

Consolidated strength

Rising costs of electrical energy and greater environmental awareness have led us to improve energy efficiency. One common solution for improving energy efficiency is power factor correction, with the capacitor being the key element.

Higher temperature strenght

For twenty years CIRCUTOR has been using gas impregnation technology, which together with other advances, provides capacitors with what are known in the market as Heavy Duty features.The capacitors permanently support 1.8 times the rated current (RC), reaching 2.5 times RC, for short time and can reach an inrush current of up to 400 times RC. Class D of the IEC-60831, the low voltage capacitor manufacturing standard, sets a maximum working value of 55ºC, but the strength of the CIRCUTOR Heavy Duty capacitor enables capacitors to work in extreme temperature conditions, occasionally supporting up to 65ºC, with this beings another key feature ensuring 150,000 h of useful life. All these features make CIRCUTOR Heavy Duty capacitors highly strenght and long lasting.

With CIRCUTOR Heavy Duty, the key material is metallized polypropylene, which is always of European origin with the very highest performance features.

European raw materials for greater durability

On this was these Heavy Duty capacitors can support more demanding work conditions, with extreme temperatures, and fluctuations in working voltage and current due to CIRCUTOR applies a policy of choosing high quality raw materials. In the case of CIRCUTOR Heavy Duty capacitors, the key material is metallized polypropylene, which always has European origin with the very highest performance features.

CIRCUTOR Heavy Duty capacitors impregnated by inert gas (DRY technology) are very safe against fire and toxic leakage, and are also biodegradable, in contrast to oil saturated foil, or solid or semi-solid resins which are flammable. Other advantages of inert gas impregnation are:

  • Lighter in weight compared to other capacitors of equal power, thus improving both transport costs and the cost of the batteries it is equipped with, and achieving greater cost efficiency and advantages for both the end user and for the whole supply chain.
  • Increased safety, due to the greater efficiency of the internal pressure relief valve protection system. In the absence of a liquid impregnant (oil) or solid impregnant (thermosetting resin), the gases of the capacitive elements emitted in the event of a fault act directly on this internal pressure relief safety valve.
  • The absence of leakages also enables different assembly options, adaptable to the various types of cabinets available, achieving optimal adaptation of the final solution to each user.
  • Environmentally friendly, since they are capacitors impregnated with harmless and inert gas, they are also free of oils or other impregnants with risk of leakage.

The optimised design of the CIRCUTOR Heavy Duty capacitor permits the achievement of this high level of performance, maintaining the necessary degree of cooling to achieve up to 150,000 hours of lifetime.

CIRCUTOR Heavy Duty capacitors saturated with inert gas (DRY technology) are very safe

Durability and safety as a key factor

Another advantage, besides the inert gas impregnant of these Heavy Duty capacitors, is the metallised selfhealing capacity (figure 1), which prevents leakages after a dielectric breakdown. This allows better withstand any network overvoltages, high working temperatures and the presence of harmonic currents in the network to be compensated, or even a high number of connection operations.

Self-healing process of the metalized polypropylene

Like with any other material, polypropylene chemically degrades over time, which here is coupled with the electrical stress factors of the capacitor. For this reasons, capacitors should be equipped with appropriate protection systems, so if necessary they can be disconnected without causing any damage to the neighboring elements (other capacitors, switching equipment, regulator etc.). In this regard, CIRCUTOR Heavy Duty capacitors are equipped with a pressure relief protection system, which acts in the event of an increase in its internal pressure simply a higher value than 506 hPa approximately (0.5 bar), disconnecting the capacitor from the mains as shown in the figure 2.

Figure.2  The CIRCUTOR Heavy Duty capacitors have an overpressure protection system which is activated in case of any increase in internal pressure, disconnecting the capacitor from the network.
The CIRCUTOR Heavy Duty capacitors have an overpressure protection system which is activated
in case of any increase in internal pressure, disconnecting the capacitor from the network.

Manufacturing: a vital step for quality

The figure 3 at the next page shows the main components of the capacitors filled with CIRCUTOR Heavy Duty gas.

Figure 3
Figure 3

Its manufacturing process includes the basic premise of any product manufactured by CIRCUTOR: maximum guarantees of quality and reliability. This means that the capacitor production process includes some aspects that are worthy of mention:

  1. Once the coils are mounted inside the aluminium tube, it is vital to ensure the total elimination of any possible humidity from their components, so each capacitor undergoes a long and exhaustive vacuum process in autoclaves. It is essential to ensure that there is no trace of humidity or oxygen left inside the capacitor to prevent oxidation of the metallic part of the polypropylene film. Preventing this oxidation also avoids rapid deterioration of the capacitor and therefore reduces its dielectric losses, lowering internal discharges and improving its capacity throughout its lifetime.
  2. After the vacuum process, the capacitors are filled with a mix of N2 (nitrogen) and He4 (helium gas isotope with an atomic mass of 4, a natural element which has a very low density and is colourless, odourless and flavourless) gases, once again under vacuum conditions, until achieving an internal pressure in the capacitor of slightly more than 1013 hPa (1atm). The figure shows this filling process.
  3. As can be seen in the figure, during the filling and sealing process of the capacitors, the cover is already equipped with the set of terminals for connection to the mains. These terminals already include the discharge resistors required to discharge the capacitor to a value of less than 75 V three minutes after it is disconnected from the mains (figure), as specified in the applicable standard IEC 60831-1.
  4. The production process ends with the performance of a basic test to guarantee the quality and reliability of each capacitor: checking the sealing process to ensure that there are no leakages of the internal gas. If any leakage is detected, that capacitor is removed from the production process.
Figure 4 Capacitor filling and sealing process
Figure 4. 
Capacitor filling and sealing process
Figure 5 Terminals for connection to the network
Figure 5. 
Terminals for connection to the network


In summary, we can highlight the strength of the Heavy Duty capacitors, a reliable unit that permanently supports 1.8 times the rated current and up to 2.5 times RC for short time, reaching an inrush current of up to 400 times RC, and guaranteeing a long lifetime of up to 150,000 hours. All these features make CIRCUTOR Heavy Duty capacitors highly resistant and long lasting. Aware also of market needs, CIRCUTOR has more than 15,000 Heavy Duty capacitors in stock, ready to be delivered upon customer request. CIRCUTOR is the ideal partner for power factor correction solutions, thanks to its Heavy Duty capacitors and its regulators.

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Energy control and Management

Energy control and Management

Example of energy savings at a Citroën car dealership

3SL Aplicaciones Integrales Eléctricas (Integral Power Applications), is a company that specialises in electrical installations. Major increases in electrical energy costs and the demand from the internal market have led us to specialise in energy consulting services to enable us to offer our clients greater returns from their installations.


Type of installation:

  • m2 of showroom space: 1.305
  • m2 of workshops: 4.085
  • m2 of offices: 330
  • m2 of warehouse: 500
  • Access tariff: 3.0 A
  • Utility company: Endesa
  • Contracted power: 175 kW
  • Annual consumption in kW-euros 2012: 260.000 kW – 55.000€ approx.

Since its creation some 5 years ago, our technical team has been constantly working on the development and implementation of an energy control system for electrical, gas, air, nitrogen and other energy sources that can make the maximum effective use of energy consumption at installations.

Installed units are provided with WEB-based remote control systems that enable us to store all the data on a secure server for subsequent processing; the data is then analysed to see what measures can be applied to the units to achieve the greatest possible efficiency. This process leads to sizeable energy savings, which in turn create savings in overall costs.

For example: an installation that operates as a car dealership, with a

  • Showroom of 1,305 m2
  • Workshop surface area of 4,085 m2
  • Office surface area of 330 m2
  • Warehouse surface area of 500 m2

To analyse the client's installation we install units manufactured by CIRCUTOR. A prior visual inspection of the installations is performed to establish the most critical points in terms of consumption. The car showroom area where customers are attended is the most complicated one to acclimatise because of the m2 and the solar orientation, and so we decided to control the area's air conditioning and lighting consumption.

 Based on the consumption of our installations we can determine the carbon footprint that we are leaving in the atmosphere
Based on the consumption of our installations we can determine the "carbon footprint" that we are leaving in the atmosphere

We then decided to control overall consumption by installing CIRCUTOR units in the general switchboard to compare real readings with those billed by the utility company, control reactive energy, power demand, etc.

The investment made in control and management units is approximately 4,000€, and consists of an EDS control unit and 4 CVM MINI analyzers in the air conditioning panel.

Example of a single screen of CIRCUTOR PowerStudio energy control software
Example of how on a single screen of CIRCUTOR PowerStudio energy control software we can control:
• General consumption
• Air-conditioning unit consumption
• Showroom lighting consumption
• Exterior and showroom temperature

An investment of approximately 5,000€ divided into three blocks has been made in the improvement section: firstly, improvements in air conditioning control with the physical installation of temperature probes and control relays for the start-up of the air conditioning units.

The second block consists of technical support for temperature programming and automatic operating schedules of the machinery, along with WEB-based control of every parameter and on-line alarm generation.

The third block consists of the installation of a power factor correction bank to eliminate unwanted generation. An investment return period of less than one year was calculated.

One of the major pluses of this system is that the user can consult the status of the installation any time, anywhere and can even take appropriate measures, he can also receive pre-defined alarm e-mails and so anticipate future breakdowns or excessive energy bills.

The results are really encouraging, a reduction of 11% to 24% is already being achieved; real data for 2012-2013.

The figures for the month of August are quite spectacular, the organisation obtained savings (compared to the same month in the previous year) of 28.74%, which represents 1,879.27€, at the same level of business activity as the year before.

 CIRCUTOR's EDS, CVM MINI and theOPTIM Series capacitor bank are theproducts used in the car dealership'sinstallation to improve efficiency andsave energy.

CIRCUTOR's EDS, CVM MINI and the OPTIM Series capacitor
bank are the products used in the car dealership's
installation to improve efficiency and save energy.

EDS / EDS 3G, New Data Logger with built-in Web Server Auditing 365 days a year

Is a simple, powerful industrial device, able to display, through its built-in Web and XML Server, all the electric variables from power analyzers or other field devices directly related to measuring consumption, electricity, water, gas, etc.

CVM MINI, Three-phase electrical power analyzer

The ONLY analyzer suitable for DIN rail distribution boards, only 3 modules

Measures, calculates and displays in true effective value (TRMS) the main electrical parameters for balanced and unbalanced, three-phase electrical systems.

OPTIM 1, Capacitor bank

The OPTIM series automatic capacitor banks are units designed for automatic reactive energy compensation in networks with fluctuating loads and power variations lasting seconds, through operations carried out by contactors.

Its simple installation, high technology and robustness make the OPTIM series the ideal units for compensating reactive energy in installations with fluctuating load levels.



New electrical parameter monitoring units can be used to check the following:

  • The distribution of consumption (what and how much is consumed)
  • The load profile (when consumption takes place)

The appropriate measures can be taken with this information, these reports and graphics to:

  • Permanently optimise and control installations, which facilitates their maintenance and improves their reliability
  • Achieve important savings and reduce the annual electrical energy bill
  • Forecast and check consumption and the electrical energy bill, i.e., general consumption and consumption distributed by use (lighting, air-conditioning, driving power, etc.)

However, the actions described in this report forecast savings of 11 to 24%, but we also have access to "Dossier-3SL-VEHICLE EXHIBITION AND SALE PLANT", from which we can calculate a 61% profitability (annual savings of 13,000 euros) of the investment, representing savings of 23.6% of the annual electricity bill over the total consumption of the plant..


Total reactive energy consumption in Euros

Total reactive energy consumption in Euros
To eliminate reactive energy generation and expense, a CIRCUTOR OPTIM series capacitor bank was installed for power factor correction.
An investment return period of less than one year was calculated.

Total electrical energy consumption in Euros

Total electrical energy consumption in Euros
Comparison of energy savings in euros for 2012 and 2013.
Reductions of 11% to 24% were achieved
We can see that electrical energy consumption in euros have decreased since June (installation date of the complete energy savings system); the same change can be seen in the reactive energy consumption graphic.
Reductions of 11% to 24% were achieved

pdf Download this article in PDF format


When monitoring becomes managing

New CEM series of multifunction energy meters for DIN rail connection

In an increasingly globalized world it is essential to manage efficiently the electrical consumption. In addition, the steady increase in the price of energy creates to the users the need to find new formulas to manage their installations.

The new CIRCUTOR's CEM series of multifunction energy meters provides all the essential information about the different consumption habits of an installation, helping to save money, resources and improving the installation's electrical energy efficiency.

The information is the key for an efficient management

The information is the key for an efficient management

Why install a CEM meter?

The objective of the new modular CEM meters is to allow the user to understand the electrical installation behavior by recording real energy patterns in order to take correct decisions to reduce and manage its electrical consumption. Thus, the user gets all the relevant information about how, when and where the energy is consumed. With all that information, it is possible to have all the billing data before receiving the utility's official bill, allowing the user to share out the costs with the different areas in the installation.

The task of identifying the individual consumptions, in one installation, is an almost impossible exercise if sectorized measurements are not taken. Therefore, to allocate costs to processes, devices or areas, it is completely necessary to implement a solution able to report detailed information about the electrical consumption by subdivisions and/or individually. In addition, CEM meters register the energy monetary cost (Euro, Dollars,..) and kgCO2 emissions for each tariff.

As an added value, it's reduced space and easy installation on DIN rail avoids high investments in modifying the current installation. This makes the new CEM's ideal to be installed in any switchboard or existing machinery.

The importance of the MID approval (EN 50470)

The new CEM energy meters are certified according to the European Directive MID (EN 50470). This allows the meters to be used for economic transactions (internal energy invoicing).

The EN 50470 standard declares the design and manufacturing process control by an external laboratory, ensuring the meters quality and transmitting the confidence to the different end users.


The new modular CEM meters are designed to be installed in any sector or application, always offering a wide range of advantages to the end user. Summarizing, three different areas of use can be defined:

  • Tertiary sector: Is common to find installations such as shopping malls, hotels, campsites, offices, airports or marinas where there is installed a single official utility meter which measures the total consumption of the installation. To allocate the real energy cost to the end users some formulas can be used but the most correct action would be to measure the real consumption, with high accuracy and individually.

Moreover, its reduced space with DIN rail connection makes its installation fast and easy in the existing switchboards.


Individual measurements allow a correct allocation of costs

Individual measurements allow a correct allocation of costs

  • Industrial sector: All industrial installations have an official billing meter installed on the main to measure and register the total energy consumption. However, this fact creates an ignorance of where, when and how this energy is consumed.

Registering the electrical consumption, the manager will be able to make the right decisions while connecting the different loads or starting processes, preventing simultaneous consumptions and maximum demand penalties. Moreover, the manager will have enough information to select the installation's most suitable electrical tariff.

As additional features, CEM meters register the energy cost (Euro, Dollar,...) and kgCO2 emissions for each tariff being key factors for understanding and improving the energy efficiency of the installation. Thus, by means of rigorous measurements, the operational manufacturing costs (OpEx) will improve.

The measurement requires precise knowledge, individually or sectorized, of each productive process

The measurement requires precise knowledge, individually
or sectorized, of each productive process

  • Condominium: There are some buildings where the neighbors share between them the total electricity bill without any control. In these cases, there is a meter installed on the main and the total consumption is paid by dividing the cost between the different tenants. Without an individualized measurement the distribution of costs may not be equal because it depends on the use of each tenant.

Installing the new modular CEM meters, the manager avoids possible complaints from the tenants. Therefore, installing individual meters together with the PowerStudio Scada software, the manager will be able to invoice customized bills to each tenant, even before receiving the official utility bill for the entire building.

Individual measurements transmit confidence to the different tenants

Individual measurements transmit confidence to the different tenants

The benefits for each sector can be summarized in the following table:

  • Equitable energy cost allocation through individualized measurements (processes/tenants).
  • Possibility to communicate the CEM meters with PowerStudio Scada to invoice customized bills to each tenant.
  • Reduced space in DIN rail connection with easy and fast installation.
  • MID approval (EN 50470) ensuring the safety and meter accuracy
  • Improvement on operational costs due to the measuring and monitoring of real energy data.
  • Operational costs registration via Modbus/RTU by using Scada software.
  • Displays the energy costs (Euro, Dollar,..) and kgCO2 emissions on each tariff.
  • Prevents simultaneous consumptions and maximum demand penalties.
  • Helps to select the most suitable electrical tariff.
  • Reduced space in DIN rail connection with easy and fast installation

CEM meters with OSC communications

In order to perform the different energy consumption analysis, CIRCUTOR launches the new CEM series of multifunction energy meters for DIN rail connection with OSC communication system. The new range consists of single (CEM-C10) and three phase direct (CEM-C20) and indirect (CEM-C30) meters. All the meters have a single pulse output to send pulses in relation to the consumed or generated energy.

To provide communications to the system it is as easy as coupling an additional CEM-M module which communicates directly with a CEM meter through OSC system. This system consists of an optical window that allows optical communications between the meter and the CEM-M module without the need of any extra wiring. Furthermore, the CEM-M module has a wired RS-485 output to send the meter's information to our PowerStudio Scada software via Modbus/RTU to register and monitor all the relevant data such as energy consumption, voltage, current, power, power factor and frequency.

OSC communication system

OSC communication system

The solution: New CEM multifunction energy meters

The new range of modular CEM meters allows obtaining all the relevant information about the different consumption habits of an installation, helping to save money, resources and improve the energy efficiency of an installation.

The CEM range consists on single and three phase static meters to measure the Active energy with Class B/1 (EN 50470/IEC 62053-21) and Reactive energy Class 2 (IEC 62053-23) with DIN rail connection. Each one has a 7-digit LCD display with scrolling screens and two buttons (1 sealable) to show all energy variables.

The CEM-M module provides RS-485 communications with Modbus/RTU protocol, connecting through optical interface (OSC) to any CEM-C meter.

cem-c10  cem-c20  cem-c30  cem-m 
 2 modules  4 modules  4 modules  2 modules





Single phase direct energy meter, up to 65 A Three phase direct energy meter, up to 65 A Three phase indirect energy meter .../5(10) A  Communication module for CEM energy meters
More information
More information
More information
More information
Medida de parámetros eléctricos  Electrical parameter measurement 
 V, A, kW, kW·h, kvar, cosφ
Sistema OSC    OSC System
Medida en 2 ó 4 cuadrantes Measurement in 2 or 4 quadrants Modbus/RTU (RS-485) Modbus/RTU (RS-485)
1 salida de impulsos Impulse output
Plug&play Plug&play     
Precintable Sealable  
Certificación MID    Clase B (IEC50470)  Clase 1 (IEC62053-21) MID Approval 
 Class B/1 (EN 50470/IEC 62053-21)


Contact us:
t. (+34)93 745 29 00
Cómo evitar penalizaciones por máxima demanda

The 3 essential rules for selectivity in earth leakage protection

A large part of unwanted tripping in an installation is caused by a lack of selectivity coordination between the earth leakage protections. With good installation practices, we can solve a large part of the earth leakage protection tripping.

Selectivity in earth leakage protection must be both horizontal and vertical. In this article, we will deal with the 3 essential rules for vertical selectivity

3 conditions must be met in order to guarantee correct vertical selectivity:

  • Amperometric selectivity
  • Chronometric selectivity
  • Type selectivity

Amperometric selectivity

 Amperometric selectivity


This condition must ensure that the sensitivity value of the earth leakage protection connected upstream (I∆1) is more than double the sensitivity of the protection connected downstream (I∆2).

For example, with an earth leakage protection with a sensitivity of 30 mA (I∆2) we might have a protection of 100 mA (I∆1) or higher upstream.

Only with amperometric selectivity would we meet one of the three conditions, so the selectivity would only be partial.

  Amperometric selectivity

Chronometric selectivity

 Chronometric selectivity


This condition must guarantee that an earth leakage protection connected upstream (t1) does not act before a protection downstream (t2) to avoid any current value.

The response times must be kept below the safety limit times.

We will achieve total selectivity along with amperometric selectivity.

  Chronometric selectivity

Type selectivity

 Type selectivity


To guarantee vertical selectivity, the type of class or earth leakage protection upstream must be the same as or higher than the protection installed downstream.

Due to the ever-larger demand in earth leakage protections in installations, more and more type A and type B protections are required, which makes it necessary to respect the vertical selectivity according to the type installed downstream.

  Type selectivity

Selectivity requirements

With CIRCUTOR's RGU-2, RGU-10, RGU-10B and CBS4 earth leakage protections, we can adapt to the selectivity requirements of any installation. We can therefore easily adapt both to the necessary parameters of sensitivity and time.

Earth leakage protection

With a single earth leakage protection, we are able to protect a single load, a sub-panel or a general supply. All of this added to their ultra-immunity and high performance (prealarm, display and communications), make CIRCUTOR earth leakage protections the ideal option for any installation.


Francesc Fornieles Castells

Responsable de Mercados - División Gestión Energética y Calidad de Red
Markets Manager - Energy Management and Power Quality Division

RGU-2 Earth Leakage Relay

1.- Summary:

Earth leakage protections are challenged, due to the continuing growth of complexity in electrical facilities and new regulations.
In this article a guest technical expert explains the new RGU-2 device, ready for these challenges, that increases productivity and saves in maintenance of facilities.


2.- Introduction:

The majority of electrical installations nowadays increasingly include loads that incorporate electronics.

Loads with electronics influence the electrical installation in various ways:

  • They generate harmonic distortion in the current they consume.
  • They generate current leakages at the mains frequency, 50 Hz, and at higher frequencies under normal operating conditions.
  • As soon as they are connected to the electrical power supply they generate a leakage current point.
  • During an insulation fault, the leakage current might not be sinusoidal, but rather pulsating, for example.

Examples of units incorporating electronics:

Computers, low consumption light bulbs, ceramic hobs, washing machines, dishwashers, microwaves, mobile phone chargers, air conditioning units, electric vehicle chargers, dryers, machine tools, etc.

Under normal conditions all these receivers generate leakage current in the electrical installation which makes the earth leakage protection more prone to trip.

3.- RGU-2 Earth leakage

The new RGU-2 unit provides the following technical details that help us maintain a protected installation and at the same time avoid unwanted tripping of the earth leakage protection, therefore supply has more guarantee.

Trip range:

The manufacturing standard for earth leakage establishes that the trip range must be between 50% and 100% of the sensitivity, for example, an earth leakage of 30 mA should trip between 15 and 30 mA.

What happens if we have an earth leakage with a trip sensitivity at 16 mA and another at 25 mA?

  • The two earth leakages comply with current legislation.
  • The first one will trip before the second.
  • If we also assert that there is always a leakage current in an installation without any malfunction, the first will always be much more prone to trip.
  • If at the moment the power supply connection is made we have a transient leakage current, it is much more likely that the more sensitive one will trip sooner.

What the RGU-2 provides:

  • It has a trip range of between 85% and 100% of its sensitivity.
  • Therefore, it guarantees a greater, more robust and reliable supply.
Trip range
Earth leakage
sensitivity [mA] 
Standard earth 
leakages [mA]
RGU-2 Earth
leakage [mA]
30 15 - 30 25 - 30
300  150 - 300 255 - 300
500 250 - 500 425 - 500
1000 500 - 1000 850 - 1000

Earth leakage type:

The most commonly installed earth leakages are type AC, but they only detect 50 Hz alternating leakage currents. Therefore they are not suitable when there are loads with electronics.

These units are marked with the symbol:

Class AC

The RGU-2 unit is capable of detecting pulsating and alternating leakage current, and it is classified as type A.

Type A units are marked with the following symbol:

Class A

Therefore, the RGU-2 provides our installation more security, and can detect both a pulsating and alternating leakage current.

Sensitivity with the frequency:

Another important detail is knowing how the earth leakage behaves with the frequency. Normal earth leakages are more sensitive to 50 Hz alternating current.

This would be enough if the facility did not have electronic loads.

The RGU-2, besides being sensitive to 50 Hz current, is less sensitive to higher frequency currents. Initially this might not appear as something good for electrical safety, but that is not entirely true.

We need to bear in mind that:

  • receivers that incorporate electronics generate high frequency leakages.
  • The human body is more sensitive to 50 Hz than 500 Hz. That means that the higher the frequency the more current is needed to produce the same effects.

International standard IEC 479-2 states the current values that a person can withstand depends on the current frequency. The RGU-2 earth leakage adjusts its sensitivity to the limits established by the safety standard.

Another important factor deduced from the response to high frequency is that it results in stronger immunity to inopportune trips. Plus, if it has less sensitivity at higher frequency, it means that in the end the earth leakage is more robust to any transient disturbances that could reach us through the electrical network itself.

Concept of Ultra-immunisation:

The RGU-2 is an ultra-immunised earth leakage!
But what does that mean and what does it add to our installation?

Ultra-immunised earth leakages protections are popularly known as ones that do not trip because of false alarms, or which are quite hard to trip inopportunely.

Where do these qualities come from? Well, basically from the data we have already described and which we summarise once more time:

  • Trip range between 85% and 100% of the sensitivity.
  • Frequency response, in particular reducing sensitivity when frequency increases.
  • Higher immunity to network transients

Other features of the RGU-2:

The new RGU-2 provides the following features:

  • Clear, simple display with a led bar graph or with an indicator of the exact leakage value on the LCD screen.
  • Wide range of external toroidals.
  • Sensitivity settings: 30, 100, 300, 500 mA, 1, 2, 3, 5 A.
  • Adjustable trip time: Instantaneous, Selective, 0.1, 0.2, 0.3, 0.5, 1, 2, 3, 5 Seconds.
  • 2 relay outputs for indicating pre-alarm and alarm.

RGU-2 wiring diagram

All these features make possible to use the RGU-2 earth leakage relay for a wide range of applications, both for installation at the main panel, on sub-panels, and in the final load protection, as well as being valid for VT, TN-S and IT network regimes, including single-phase and three-phase with and without neutral.


Joan Romans Artigas
Electronics Engineer
Telecommunications Technical Engineer

Francesc Fornieles Castells
Responsable de Mercados - División Calidad de Red
Markets Manager - Power Quality Division


More information

CIRCUTOR opens here a section for clients and Partners to send technical articles, about their experience with CIRCUTOR's equipment and software. 
Articles must be written on a right technical level, in order to be published.



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