Installer Guide to Compliance for Microgeneration Energy Management Devices
Product Compliance with EU Legislation
The letters ‘CE’ appear on many products that are traded on the single market in the European Economic Area (EEA).
CE marking is a key indicator of a product’s compliance with EU legislation and enables the free movement of products within the European market. By affixing the CE marking on a product, a manufacturer is declaring, on his sole responsibility, conformity with all of the legal requirements to achieve CE marking and therefore ensuring validity for that product to be sold throughout the EEA.
The Manufacturers Responsibilities
The manufacturer has sole and ultimate responsibility for the conformity of the product to the applicable Union harmonisation legislation, whether he designed and manufactured the product himself or is considered as a manufacturer because the product is placed on the market under his name or trademark
It means that the manufacturer has verified that the product complies with all relevant essential requirements of the applicable directive(s) or, if stipulated in the directive(s), had it examined by a notified conformity assessment body.
It is the manufacturer’s responsibility to:
•Carry out the conformity assessment, they must provide evidence of compliance with the essential requirements
•Set up the technical file (draw up technical documentation in accordance with the regulations)
•The manufacturer must then take all steps necessary to ensure that the apparatus is manufactured in accordance with the technical documentation
•Issue the EC Declaration of Conformity (DoC)
•Affix CE marking on a product
•The person responsible for placing the apparatus on the market must make available copies of the DoC and technical documentation, when requested to do so by an enforcement authority.
An investigation into an alleged non-conformity of a fixed installation may require the supply of documentation that relates to confidential details of performance or constructional details of apparatus. In such cases, it may be appropriate for the enforcement authority to obtain such evidence directly from the manufacturer of the apparatus or their authorised representative.
For the vast majority of apparatus, the following applies:
• Enforcement is carried out by the Trading Standards Departments of Local Authorities, or the Department of Enterprise, Trade and Investment in Northern Ireland
• Ofcom may enforce the Regulations where the action relates to the protection and management of the radio spectrum
• The Secretary of State for Business, Enterprise and Regulatory Reform may enforce the Regulations
Products sold in the EU that bear CE markings fall under one or more directives which determine the specific requirements that the product must meet in order to be CE marked. One of the most important directives for microgeneration energy management devices is Electromagnetic Compatibility (EMC).
The Electromagnetic Compatibility Regulations 2006, which implements into UK law the Electromagnetic Compatibility Directive 2004/108/EC of the European Parliament, defines the interaction of Equipment and Fixed Installations such that:
Regulation 4: “Equipment shall be designed and manufactured, having regard to the state of the art, so as to ensure that it has a level of immunity to the electromagnetic disturbance to be expected in its intended use which allows it to operate without unacceptable degradation of its intended use”
International standard EN 61000–3-2:2006 +A1+A2is applicable for electrical equipment that is supplied from mains network with voltage not less than 220V and current up to 16A (including) to limit the Harmonic Current Emissions.
Harmonic Current Emissions
With an increasing number of electronic power supplies used in a wide range of products the aim to limit the harmonic current emission has become more and more important. Most power systems can accommodate a certain level of harmonic currents but will experience problems when harmonics become a significant component of the overall load. As these higher frequency harmonic currents flow through the power system, they can cause communication errors, overheating and hardware damage, such as:
• Overheating of electrical distribution equipment, cables, transformers, standby generators, etc.
• High voltages and circulating currents caused by harmonic resonance
• Equipment malfunctions due to excessive voltage distortion
• Increased internal energy losses in connected equipment, causing component failure and shortened life span
• False tripping of branch circuit breakers
• Metering errors
• Fires in wiring and distribution systems
• Generator failures
• Crest factors and related problems
• Lower system power factor, resulting in penalties on monthly utility bills
It is a specific interest of the power distribution companies to keep the harmonic current emission to a considerable low level as harmonic current causes unnecessary loading of the power distribution infrastructure. This again may affect both quality and reliability of the power supply.
It forms part of the consumer’s agreement to connect, and it is the responsibility of the individual consumer to ensure that the appropriate procedures to agree connection of new loads are followed. It is also very important that the consumer understands the responsibilities placed on him by the supply utilities to avoid the possibility of having to implement costly remedial measures in the event of a problem. It is important to understand that Engineering Recommendations G5/4-1 is effectively an “Installation Standard” and applies to the total harmonic generating equipment installed by a consumer.
AC Power Control Methods
The varying of the power level to a load is often referred to as ‘proportional power control’. There are several known methods of providing proportional control of AC power. Simple control methods often use a TRIAC, this type of device acts like an AC switch that can be electronically controlled. There are serious limitations to consider when using TRIAC in AC power control, in addition EMC compliance can be almost impossible to achieve once power levels exceed a few hundred watts.
Burst-fire control is usually implemented by use of a TRIAC. With this method, the average power delivered to the load is adjusted by selectively switching in and out mains cycles.
• Simple and therefore cost effective
• Switching is done at the ‘zero-cross’ point, resulting in minimal RF interference
• Can cause current harmonics in mains supply
• Will cause voltage fluctuations on mains supply which can sometimes cause lights to flicker
• May not be compatible with some smart meters • Can cause measurement errors in some energy monitor devices
• Not able to be short-circuit protected
In this method of control, the output is turned on each half cycle after a delay period. By varying the delay the power level is adjusted. Again, a TRIAC is often used in this control method.
• Simple and therefore cost effective
• Will not cause voltage fluctuations
• Will cause severe current harmonics resulting in Harmonic Current Emissions (see below)
• Almost certain to cause RF interference
• May not be compatible with some smart meters
• Can cause measurement errors in some energy monitor devices
• Not able to be short-circuit protected
truSINE™ PWM Control
This is the power control technology implemented in the immerSUN®. It is basically immersuns's propriety control method. As the name suggests, the power being delivered to the load is kept as a true sine wave; only the voltage is varied. This control method cannot be achieved using TRIACs and so is much more difficult to design, requiring many more components which increases cost. However, the benefits far outweigh the initial cost.
• Compliant with EN 61000-3-3 (voltage fluctuation and flicker): Will never cause lights to flicker
• Compliant with EN 61000-3-2 (harmonic current emissions): Will never cause problems with inverters
• Fully short circuit protected in case of load fault • Over-load protection • Power factor correction
• Soft starting to avoid power surges
• Smart meter compatible / compatible with third-party energy monitors
• More expensive than TRIAC based technologies
Careful consideration needs to be given as to which controller is used. Choosing to save money on the initial cost of the unit may be false economy as problems could arise after installation. By choosing immerSUN with it’s truSINE™ power control technology, you can be assured of reliable, trouble free operation for many years.
The immerSUN is the only microgeneration energy management device that meets the legal requirements to comply with the limits for Harmonic Current Emissions.
References ;  Treating Harmonics in electrical distribution systems, Victor A. Ramos Jr.  Application notes from Controlled power company. Mirus Harmonics and Harmonic Mitigating Transformer.  An introduction to Power System Harmonics by Power System Engineering.  Application notes from Energy Vortex.  GOV.UK website.  Department for Business Enterprise (BERR) and Regulatory Reform