Measuring and managing – these two concepts go hand in hand. You can’t manage what you can’t measure, as the classic business adage says, and you also can’t see how well you’re managing without measuring on an ongoing basis. With power costs climbing, and the importance of good power quality on the rise, building owners and grid operators are seeing greater need for metering programs on both the supply and demand sides of electricity transactions.
As Figure 1 shows, meeting all these needs requires metering devices in a number of locations throughout a facility and the connected grid. Specifiers need to understand both the goals of each specific metering installation, along with any standards that might be relevant to the location and purpose of the device.
Specifically, today’s specifying engineers are being asked to address the major needs described below. In a series of posts, I’ll be going into each of these needs, in depth, describing goals and requirements. The following offers a brief overview of these applications.
- Billing. The process that allows energy suppliers or their representatives to invoice their customers according to a defined contract, for measured usages or services. (These applications may be covered by international standards or covered by regulations such as MID [Measuring Instruments Directive] in Europe or NMI [National Measurement Institute] in Australia, sometimes in addition to utility specifications.)
- Grid power-quality monitoring. The process that allows energy suppliers and/or their customers to verify the quality of energy delivered/received is in line with a defined contract or regulation. (Limits for European public networks are defined in EN 50160.)
- Cost allocation. The process that allows a facility manager to allocate energy expenses to their related internal departments or cost centers, such as manufacturing floors or data centers.
- Sub-billing (or tenant metering). The process that allows a landlord, property management firm, condominium association, homeowner association or other multi-tenant property to spread out invoice over tenants (assign portions of invoice to tenants), for measured usages or services. This fee is usually combined with other tenant’s facility fees. (These applications are sometimes covered by regulations, as they are in the UK, Canada and some U.S. states.)
- Bill checking. The process that allows customers to check if invoice sent by energy suppliers or their representatives is correct.
- Energy efficiency and cost savings, energy usage analysis. The process that allows a facility manager to assign energy consumption/costs to zones (e.g., plants, floors and workshops) and to specific usages (e.g., HVAC, lighting, appliances and processes) over time, in order to optimize energy consumption and energy costs.
- Network monitoring, power availability and reliability, facility planning. The process that allows a facility manager to monitor its electrical installation in order to ensure availability and reliability of energy as well as asset durability.
|Applications||Device||Regulations and/or product standards|
|Billing||Revenue meter, utility meter, electricity meter, billing meter (for legal metrology applications)||MID EN 50470||Local regulations ANSI C12.20||Local regulations NMI M6||Local regulations Standards|
|Sub-billing (tenant metering)||Legal tenant meter or legal sub-meter (for legal metrology applications)||If applicable: MID EN 50470||If applicable: ANSI C12.20||If applicable: NMI M6||If applicable: Local regulations & standards|
|Tenant meter or sub-meter||IEC 61557-12 (C-PMD1, i.e. with active energy independently certified, covered by manufacturing audits, meeting measurement durability requirements and providing an indication of manufacturing date for periodic verification)|
|Bill checking||Power meter||IEC 61557-12 (C-PMD1, i.e. with active energy independently certified, covered by manufacturing audits, meeting measurement durability requirements and providing an indication of manufacturing date for periodic verifications)
IEC 61557-12 (PMD1)
|Energy efficiency||Power meter||IEC 61557-12 (PMD1, PMD2, or PMD3)|
|Network Monitoring||Analog electrical measuring instruments||IEC 60051|
|Power meter||IEC 61557-12 (PMD2 or PMD3)|
|Class S power meter||IEC 61557-12 (PMD3) embedding IEC 61000-4-30 class S functions (tested according to IEC 62586-2)|
|Grid power quality monitoring||Power quality instrument||Relevant product embedding IEC 61000-4-30 class A functions (tested according to IEC 62586-2)|
|NOTE – Some devices are providing qualitative data, resulting from reduced acquisition performance or from simplified calculation algorithms. These approximate values are used for indication (e.g. current flowing or not), comparison (e.g. significant variation in consumption of an equipment between two time-periods) or estimation (e.g. low level of Power Factor) and cannot be compared to measurements provided by the above devices.|
If you are looking for more details, you can check out the following documents:
|IEC 61557-12||White paper||Guide to using IEC 61557-12 standard to simplify the setup of an energy measurement plan.|
|Measurement applications||White paper||Guide to energy measurement applications and standards|
Meeting today’s needs
Fortunately, the growing need for meters to address all these applications (except billing applications) can now be met with a new generation of PMDs (Power Metering and Monitoring Devices) is coming to market. Schneider Electric is leading the industry with its PowerLogic PM8000 Series, with models designed for key metering points throughout a facility’s energy infrastructure. We invite you to learn more about this versatile line-up on our website.