IEC 60364-8-1 standard : Energy Efficiency in low-voltage electrical installations
In the context of international regulation on Energy Efficiency, IEC 60364-8-1 standard ("Low voltage electrical installations – Energy efficiency") has been developed specifically for electrical installations.
The standard gives requirements and recommendations for the design of an electrical installation with an energy efficiency approach. This emphasizes the importance of Energy Efficiency in the design of electrical installations, in the same way as safety and implementation rules.
In manufacturing industry, Energy Efficiency can easily be defined by the quantity of energy (kWh) necessary to manufacture one product. For an electrical installation in a building particularly, Energy Efficiency is defined as a system approach, which objective is to optimize the use of electricity. This includes:
- Minimize energy losses,
- Use electricity at the right time and at the lower cost,
- Maintain the performance all along the installation life cycle.
Here are the main points to keep in mind while implementing Energy Efficiency approach in an electrical installation:
- There must be no conflict with the requirements relative to safety of people and property,
- There must be no deterioration of electrical energy availability,
- It is applicable to new and existing installations,
- It can be implemented anytime, the only point of consideration being the rhythm of investment,
- This is an iterative approach and improvements can be incremental. The ROI is the decision factor for implementation of new equipment dedicated to Energy Efficiency.
Technical guidance is provided on the design principles, taking into account the following aspects:
- Optimal location of the HV/LV substation and switchboard by using the barycenter method (see also chapter MV and LV architecture selection guide for buildings ),
- Reduction of the wiring losses, by increasing the c.s.a. of cables and by implementation of Power Factor Correction and Harmonic mitigation,
- Determination of meshes or zones with equipment having similar energy requirements,
- Load management techniques,
- Installation of control and monitoring equipment.
An example of assessment method is given with 5 levels of performance, considering different aspects such as:
- Monitoring of load profile,
- Location and efficiency or the transformer substation,
- Optimization of motor, lighting and HVAC equipment efficiency.
For example, Figure K8 gives the recommended assessment levels for determination of load profile in kWh (EM: Efficiency Measures). Other assessment levels are defined (for harmonics levels ...), and are specified per type of activity: Residential (dwellings), commercial, industrial or infrastructure.
|No consideration||Load profile onsumption of the installation for a day||Load profile consumption of the installation for each day of a week||Load profile consumption of the installation for each day of a year||Permanent data logging of the load profile consumption of the installation|
It is important to note that the objective of Energy Efficiency is not only making energy savings. Implementation of Energy Efficiency must keep the same level of service and safety, maintain performance, while saving energy and money, at present and in the future.
Figure K9 from IEC 60364-8-1 illustrates how to implement the electrical energy management system within the installation:
Step 1 = the inputs from the user shall be taken into account, such as the building temperature set point,
Step 2 = all sources of energy are considered, based on availability and real time price,
Step 3 = inputs from environmental data are taken into account to avoid inappropriate decisions, such as switch on the light during the day,
Step 4 = inputs from the load are extracted as they are key to verify the accuracy of the load profile,
Step 5 = detailed information on energy consumption are provided to the user,
Step 6 = decisions are taken relative to the loads such as load shedding,
Step 7 = decisions are taken relative to the sources of energy in order to deliver the service to the user at the lowest cost.