ELECTRIC.IE • The Magazine & Website for the Irish Electrical Industry • 29 NInadtuiosntrayl NRuelwes MDB Location using the Barycentre Method” is similar to the previous version. Annex 8.1B “Method to Assess the Energy Efficiency of an Electric Installation” provides multiple formulae throughout for this purpose. The objective of some of the calculations and the criteria given in the tables is in some cases vague or open to interpretation. It is worth noting that this Annex is classified as “normative” meaning it effectively forms part of the Standard and must be complied with. Carrying out an assessment of the energy efficiency of an electric installation using the prescribed methodology will, in my view, necessitate the development of dedicated software. PEI Concept (8.82.5) A prosumer's electrical Installation (PEI) is a set of electrical equipment having the following functions: • Supply - typically a connection to the DSOs LV system, • Local generators e.g. PV system, wind turbines and engine powered generator • Electrical energy storage system e.g. a battery • Distribution system e.g. distribution board and wiring systems • Consumption i.e. loads such as e.g. lighting, power and heating • Electrical Energy Management System (EEMS) Figure 3 here shows an example of a prosumer's electrical installation with a.c. electrical distribution within the PEI. This is based on Figure 8.82.1.in the Standard. The a.c. wiring is shown as black lines, d.c. as blue lines and EEMS wiring as red dashed lines. 1. DSO network /Transformer 2. Electrical Vehicle – V2G 3. Electric Heater 4. Domestic Appliances 5. Lighting 6. PC & other devices 7. EEM System 8. Battery and Rectifier 9. Solar PV & inverter 10. Wind turbine & inverter 11. Diesel generator & Grid PD 12. DSO POC / Cut out 13. Prosumer electrical installation 14. Local consumption 15. Local generation 16. EEM System signals 17. EV charging station Types of PEI (8.82.6) Section 8.82.6 is titled “Types of PEI” but mainly focusses on island mode operation. It opens up by saying there are different types of PEI including: Grid Connected PEI; Islandable PEI – Systems connected to the grid and Stand-alone PEI – Systems not connected to the grid. In grid-connected mode the PEI operates while connected to the utility grid. Energy can flow bidirectionally i.e. it will import when the PEI's energy demand exceeds local generation capacity and will export when it generates surplus energy. The use of locally generated energy is maximized so as to reduce reliance on the grid during peak demand periods when tariffs are typically higher. This generally necessitates the use batteries to balance supply and demand. It prioritizes on-site consumption over exporting energy to the grid. In Island Mode the PEI operates independently of the utility grid during planned or unplanned Figure 2 - Electrical Installation Energy Efficiency Classes EE0 to EE5 Figure 3 - Example of a Prosumer's Electrical Installation (a.c. only)
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