TE Connectivity - Energy Management / Power Control

Instrumentation Power Management - DMS - Digital Metering System - Energy Metering

The Cost

The annual energy consumption spend in the UK is approximately £55 billion, with an estimated 20%, or £11 billion, wasted every year. The advent of the climate change levy on industry, commerce, agriculture and the public sector dictates the need to reduce energy consumption and address methods for the better control of energy usage. ‘Energy Efficiency’ is not new to industry, we all understand the importance of energy efficient lighting, heating, ventilation, automation etc. and the benefits intelligent building management systems provide.

The control of facilities’ energy usage, however, has largely been overlooked. The average organisation can save 20% of its energy bill by installing simple energy management technology, which for energy intensive organisations can equate to savings of hundreds of thousands of pounds per year.

Knowing exactly where, when and how much energy a facility uses is fundamental to improving overall energy efficiency, and must therefore, be given the same consideration as the procurement of energy efficient plant and building services. An energy audit is the first step in the process of proactively managing energy, of which power measurement instrumentation plays a key role.

Power Instrumentation

Power instrumentation and ancillary equipment is specifically designed for the control and reduction of energy consumption, the monitoring of energy efficiency, and the protection of expensive power assets. All industrial and commercial applications including power utilities, distributed generation systems, UPS, AC or DC power supply and process manufacturing will benefit from effective instrumentation schemes and power monitoring solutions.

Power instrumentation equipment can be installed on individual circuits, onto production lines or specific machines, into building sand/or designated environments. Equipment can meter utilities, control energy consumption, measure power quality, display and communicate chosen measured electrical parameters, check and adjust protective relay conditions, control power factor, and monitor and control on site power generation.

L2 Building Regulations

The Building Regulations 2000 Part L2 states that reasonable provision shall be made for the conservation of fuel and power in buildings or parts of buildings by providing sufficient energy meters and sub-meters to enable owners or occupiers to measure their actual energy consumption. Reasonable provision for suitable energy consumption metering must provide sufficient information in a concise and understandable form, so that the building services can be operated and maintained, and they use no more energy than is reasonable. For buildings over 500m2 90% of the annual energy consumption must be accounted for.

Additional provision of sub metering equipment would be required for plant items with input powers greater than indicated on the table below.

Remote Monitoring

Remote monitoring of the data collected from many meters can be downloaded via communication interfaces using various protocols eg: Modbus, Profibus or Lonworks to a local PC, or integrated into building management systems for analysis.

The ability to manage metered readings automatically from data loggers simplifies the whole process of collecting, communicating and analysing energy usage, and provides an excellent energy management tool across single and multi site organisations. Analysis of power quality and energy data presents realistic opportunities to improve energy efficiency, extend equipment life, increase product yield, reduce costs and increase profit.

Power Quality

A perfect power supply would be one that is always available, always within voltage and frequency tolerances, and always free from distortion. However, power quality problems cost industry £ billions every year in downtime, and yet only 5% of this is spent on preventative equipment.

Power instrumentation equipment can help eliminate or reduce the effects of poor power quality by measuring, monitoring and analysing disruptions caused by voltage dips, transients, under or over voltage, harmonic distortion and total loss of supply. Each of these power disturbances has a different cause. A fault on the supply network may cause short voltage dips and consequent interruption to production processes, or a problem on one customers site may cause a transient which affects all others users on the same substation.

Longer breaks in supply are usually associated with the supplier, but can also be caused by the failure of on-site equipment, conductors and connections. Whilst the majority of power quality problems are the responsibility of the supplier, it is the consumers responsibility to implement simple energy management technologies which provide the power quality levels required by his facility.

Total Harmonic Distortion

Harmonic problems are almost always caused by the consumers’ equipment and installation practices. Harmonic distortion is caused by the high use of non-linear load equipment such as computer power supplies, electronic ballasts, and variable speed drives etc, which create high current flow with harmonic frequency components.

Harmonic distortion is caused by the introduction of waveforms at frequencies in multiplies of the fundamental ie: 3rd harmonic is 3x the fundamental frequency/150Hz. Total harmonic distortion is the ratio of true RMS values of the harmonic components to the total RMS of the waveform. The harmonic profiles of installed equipment can guide the system designer in determining practical harmonic range of a measurement instrument.

The economic effects of harmonic distortion to power quality are dramatically shorter equipment lifetimes, reduced energy efficiency and a susceptibility to nuisance tripping. The costs of supply interruption are high, however caused, resulting in costly data, disruption of process manufacturing and failure of telecommunications facilities etc. Therefore, continuous measurement and monitoring of power quality is critical to protect expensive power assets and avoidance of system shutdowns.

Conclusion

Statistics state that up to 20% energy savings can be achieved with accurate monitoring and awareness of energy usage profile and reduction of waste. To identify cost saving opportunities it is essential to build an accurate facilities’ energy profile and install appropriate measurement, control and protection instrumentation equipment. The use of power measurement and control instrumentation reduces energy costs, monitors energy efficiency, prolongs equipment lifetime, increases profitability and provides long term measurable performance improvement for business.