Glossary of Terms Relating to Smart Grid and Metering Advances Prepared for the WPUI Feed Back on Feed Back Workshop Hosted by: Wisconsin Public Service Corporation Resources used to develop these definitions: NERC, DOE, ITRON, Wikipedia, IEEE, EEI, EPRI Advanced Metering Infrastructure (AMI) Advanced Metering Infrastructure is a term denoting electricity meters that measure and record usage data at a minimum, in hourly intervals, and provide usage data to both consumers and energy companies at least once daily. It is a comprehensive utility metering and communications system built on bi-­‐
directional communications and open standards, offering functionality beyond AMR such as demand response and integrated turn on/off. AMI consists of four main components: •
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A smart meter able to collect and store electricity interval data for its own service type plus interface with and collect and store data from other devices such as other meters and home gateways. It can also initiate and respond to two-­‐way communications with the utility. A home gateway device able to collect data from, communicate with and control various energy-­‐
using appliances throughout the home such as air conditioners and hot water heaters. A home gateway also has two-­‐way communications with the utility. A data collection network that provides bi-­‐directional communication of data and commands between the home and the utility. The collection network can be publicly or privately owned and can operate using open and proprietary standards. An enterprise meter data management (MDM) system that provides a single, scalable repository for metering-­‐based data along with standard interfaces to other utility systems such as CIS, OMS, GIS, and workforce management. AMI systems also support advanced capabilities such as load control, Time-­‐of-­‐Use and Critical Peak Pricing, and outage and restoration reporting. Advanced Network Advanced networks possess the flexibility to communicate using multiple protocols and communications networks. These networks have standardizations of technologies to expand the capabilities of emerging communications standards. AMR (Automatic Meter Reading) Automated Meter Reading is a term denoting electricity meters that collect data for billing purposes only and transmit this data one way, usually from the customer to the distribution utility. Control Area Load The total amount of electricity being used at a given point in time by all consumers in a utility's service territory. Conservation Reducing electric, gas or water usage for the purpose of saving natural or scarce resources. Conservation limits peak usage or demand in order to ultimately reduce the capacity requirements for infrastructure and equipment DA (Distribution Automation) The ability to control and monitor a utility’s distribution feeders and equipment, i.e., switches, reclosers and capacitor bank controllers. Also referred to as DAS (Distribution Automation System). Demand charge: That portion of the consumer's bill for electric service based on the consumer's maximum electric capacity usage and calculated based on the billing demand charges under the applicable rate schedule. Demand charge credit: Compensation received by the buyer when the delivery terms of the contract cannot be met by the seller. Demand indicator: A measure of the number of energy-­‐consuming units, or the amount of service or output, for which energy inputs are required. Demand interval: The time period during which flow of electricity is measured (usually in 15-­‐, 30-­‐, or 60-­‐
minute increments.) Demand-­‐metered: Having a meter to measure peak demand (in addition to total consumption) during a billing period. Demand is not usually metered for other energy sources. Demand-­‐side management (DSM): The planning, implementation, and monitoring of utility activities designed to encourage consumers to modify patterns of electricity usage, including the timing and level of electricity demand. It refers to only energy and load-­‐shape modifying activities that are undertaken in response to utility-­‐administered programs. It does not refer to energy and load-­‐shaped changes arising from the normal operation of the marketplace or from government-­‐mandated energy-­‐efficiency standards. Demand-­‐Side Management covers the complete range of load-­‐shape objectives, including strategic conservation and load management, as well as strategic load growth. Demand-­‐side management costs: The costs incurred by the utility to achieve the capacity and energy savings from the Demand-­‐Side Management Program. Costs incurred by customers or third parties are to be excluded. The costs are to be reported in thousands of dollars (nominal) in the year in which they are incurred, regardless of when the savings occur. The utility costs are all the annual expenses (labor, administrative, equipment, incentives, marketing, monitoring and evaluation, and other incurred by the utility for operation of the DSM Program), regardless of whether the costs are expensed or capitalized. Lump sum capital costs (typically accrued over several years prior to start up) are not to be reported. Program costs associated with strategic load growth activities are also to be excluded. Distributed Generation A distributed generation system involves small amounts of generation or pieces of generation equipment applied to a utility's distribution system for the purpose of meeting local peak loads and/or displacing the need to build additional (or upgrade) local distribution lines and infrastructure. Distributed generation may be in the form of gas or propane generators, fuel cells, etc. Distribution The part of a power system that carries the lower, safer voltages, usually around 13-­‐7 kV. This system runs from the substation to customers’ homes. When the voltage is needed to provide service to a residence another transformer is needed to convert the voltage into 120/240V so appliances in the home can function properly. (See Transmission) Distribution Asset Optimization Applying data analysis to optimize the deployment, maintenance and reliability of electricity distribution assets such as transformers. Can be used to help identify transformers and switches that are degrading faster than planned and thus avoid an emergency outage. Distribution Line This is a line or system for distributing power from a transmission system to a customer. Distribution provider (electric): Provides and operates the wires between the transmission system and the end-­‐use customer. For those end-­‐use customers who are served at transmission voltages, the Transmission Owner also serves as the Distribution Provider. Thus, the Distribution Provider is not defined by a specific voltage, but rather as performing the Distribution function at any voltage. Distribution System A utility’s system that delivers electricity, gas or water to the end customers. In electric utilities, this consists of wires, switches, and transformers that serve neighborhoods and business. In electric systems the distribution system reduces (transformers) or “downgrades” power from high-­‐voltage transmission lines to a level that can be used in homes or businesses. DLMS (Device Language Message Specification): AMR (automatic meter reading) technology requires universal definitions and communication standards. DLMS/COSEM is a common international language used by many meters and meter reading equipment manufacturers to assure compatibility. DLMS COSEM: An international meter language used for viewing the functionality of meters, observed at their interface(s). It serves various purposes: •
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an identification system for all metering data a method of communicating with the model and converting the data into a series of bytes a method of carrying information between metering equipment and the data collection system Energy management and control system (EMCS): An energy conservation feature that uses mini/microcomputers, instrumentation, control equipment, and software to manage a building's use of energy for heating, ventilation, air conditioning, lighting, and/or business-­‐related processes. These systems can also manage fire control, safety, and security. Not included as EMCS are time-­‐clock thermostats. Energy management practices: Involvement, as a part of the building's normal operations, in energy efficiency programs that are designed to reduce the energy used by specific end-­‐use systems. This includes the following EMCS, DSM Program Participation, Energy Audit, and a Building Energy Manager. Fixed Network A permanent, non–mobile system typical composed of meters, transmitters/receivers, communication systems, and host system. Fixed networks can be used for automatic meter reading (AMR) plus other relevant applications. Data is collected from a given population of meters without dispatching meter readers or vehicles. Network communications technology varies between networks and network manufacturers. Gateway A device that handles communications between the utility and devices on the customer premise such as thermostats, water heaters, and pool pumps. Gateways offer two-­‐way communications, and often the ability for customer to override the utility’s load control signal. Gateways overcome the limitations of one-­‐
way load control by sending confirmation signals back to the utility. Web-­‐based software allows customers to see the status and effects of load control actions. Grid A system of synchronized power providers and consumers connected by transmission and distribution lines and operated by one or more control centers. In the continental United States, the electric power grid consists of three systems the Eastern Interconnect, the Western Interconnect, and the Texas Interconnect. In Alaska and Hawaii, several systems encompass areas smaller than the State (e.g., the interconnect serving Anchorage, Fairbanks, and the Kenai Peninsula; individual islands). The entity that oversees the delivery of electricity over the grid to the customer, while assuring consistently high levels of reliability, and public and worker safety. The grid operator potentially could be independent of the utilities and suppliers. Head-­‐end System The head-­‐end system receives the stream of meter data brought back to the utility by an AMR system. Head-­‐end systems may perform a limited amount of data validation before either making the data available for other systems to request or pushing the data out to other systems. Head-­‐end systems may also perform a limited set of data management functions for such activities as route management, outage detection, and on-­‐demand reads. Home Area Network (Home automation) A data communications system contained within a premise that can connect devices (smart devices) in the premise to the meter (the portal) or to a gateway between the meter and home devices. Home
automation may include centralized control of lighting, HVAC, appliances, and other systems, to provide improved
convenience, comfort, energy efficiency and security. Interval Data Collection For purposes including load research, demand response and on-­‐demand reads, meter data is frequently collected in hourly or even 15-­‐minute intervals. Short-­‐term storage of this interval data takes place before the system communicates the data to the utility. In general, interval data can be collected at the meter, or at an intermediary spot such as the fixed network collector unit that reads the meter’s output. Finer resolution of data in smaller time increments requires communications systems that can transmit the data without bogging down. Interruptible Load Energy loads that can be interrupted in the event of capacity or energy deficiencies on the supplying system. Interruptible Power Power that can be interrupted or curtailed by the supplier, usually under the guidelines of some sort of agreement by the parties involved. Interruptible Rates Interruptible rates provide power at a reduced rate to large industrial and commercial customers who agree to reduce their energy use in times of peak demand. Interval Reads Interval reads measure and store deltas of energy usage in regularly measured 15, 30, 60, or 120-­‐minute interval time periods. This interval data can then be used to determine block demand or load profile data. LAN Local Area Network. A data communications system that lies within a limited geographic area and has a specific user group; LANs are usually restricted to relatively small areas, such as rooms, buildings, small neighborhoods. Within AMI the LAN connects meters to collection points. Local area networking (LAN) offer solutions for different population densities. There are several good LAN technologies. For example, PLC, RF and RF-­‐
mesh are currently available and more, such as BPL, are coming. Each has different technology issues and costs to consider. PLC technology is great for rural and urban areas with large buildings. RF-­‐mesh solutions are extremely cost effective for suburban areas. Most utility companies will need to use a mix of these technologies in order to minimize the LAN networking costs. Load The amount of energy delivered or required at any specified point or points on a system at a particular time. Load originates from the equipment at the customer location. Load Control Having and exercising direct control over equipment at a customer’s premise for the purpose of lowering peak demand. When a utility has control over equipment, it typically does not receive a signal confirming that its load control command has been received and executed. Large customers can also have controls in their buildings to help control load. Load Forecast Load forecasting is the estimation of electricity or natural gas consumption at some future time. Forecasts can predict demand minutes ahead to years into the future. Load Following: Regulation of the power output of electric generators within a prescribed area in response to changes in system frequency, tie line loading, or the relation of these to each other, so as to maintain the scheduled system frequency and/or established interchange with other areas within predetermined limits. Load Leveling: Any load control technique that dampens the cyclical daily load flows and increases baseload generation. Peak load pricing and time-­‐of-­‐day charges are two techniques that electric utilities use to reduce peak load and to maximize efficient generation of electricity. Load Management Utility demand management practices directed at reducing the maximum kilowatt demand on an electric system and/or modifying the coincident peak demand of one or more classes of service to better meet the utility system capability for a given hour, day, week, season, or year. It includes technologies that shift all or part of a load from one time-­‐of-­‐day to another or may have an impact on energy consumption. Examples include load limiting devices or programs that aggressively promote time-­‐of-­‐use (TOU) rates, real time pricing or other innovative rates intended to reduce consumer bills and shift hours of operation of equipment from on-­‐peak to off-­‐peak periods. Mesh Network Full mesh topology occurs when every node has a circuit connecting it to every other node in a network. Full mesh is very expensive to implement but yields the greatest amount of redundancy, so in the event that one of those nodes fails, network traffic can be redirected to any of the other nodes. Metered Data: End-­‐use data obtained through the direct measurement of the total energy consumed for specific uses within the individual household. Individual appliances can be submetered by connecting the recording meters directly to individual appliances. Meter Data Management (MDM) Meter data management (MDM) is the ability to ensure the reliability of, and optimize the use of, available data. A full-­‐function MDM solution seamlessly combines data from multiple sources that use a variety of formats and collection schedules. •
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It supports incorporation of new data sources through creation of interfaces without requiring changes to the existing MDM application or data structure. It provides for safe and efficient storage and security-­‐controlled retrieval of data. It includes validation, editing, estimation, aggregation, and unit and interval conversion tools to ensure the reliability and manage the usability of data. It reports and tracks data sources and versions. It provides advanced calculation capabilities to support functions such as time-­‐of-­‐use and critical peak billing determinants. It enables interface to other utility systems such as customer information, outage management, work management, and geographical information. It provides flexible and comprehensive reporting. Metered Peak Demand: The presence of a device to measure the maximum rate of electricity consumption per unit of time. This device allows electric utility companies to bill their customers for maximum consumption, as well as for total consumption Mobile AMR Mobile AMR uses vehicles equipped with a radio transceiver to read communication module-­‐equipped electric, gas or water meters via radio without the need to access the meter. Mobile AMR dramatically improves meter reading efficiency. Net Metering Net metering applies to energy customers, such as commercial and industrial users, who both generate and purchase power. Utilities need to meter the power generated by customers to determine the credit the customer should receive. A net register calculates energy to be billed by subtracting power received from the customer from the power delivered to the customer. Net metering provides the technology to calculate this amount as a net amount within the meter. This saves the utility from needing to record multiple billing values during the data collection process and performing calculations to determine the net value. Neural Network Artificial neural networks, as they are used in forecasting, are flexible nonlinear models that can approximate a wide range of data generating processes. (See difference between SCADA and Smart Grid) Power Line Carrier (PLC) Power line communication or power line carrier (PLC), also known as Power line Digital Subscriber Line (PDSL), mains communication, power line telecom (PLT), power line networking (PLN), or Broadband over Power Lines (BPL) are systems for carrying data on a conductor also used for electric power transmission. Electrical power is transmitted over high voltage transmission lines, distributed over medium voltage, and used inside buildings at lower voltages. Powerline communications can be applied at each stage. Most PLC technologies limit themselves to one set of wires (for example, premises wiring), but some can cross between two levels (for example, both the distribution network and premises wiring). Typically the transformer prevents propagating the signal which allows multiple PLC technologies to be bridged to form very large networks. Power line communications technology can use the household electrical power wiring as a transmission medium. This is a technique used in home automation for remote control of lighting and appliances without installation of additional control wiring. Real Time Data Real or near-­‐real-­‐time data is the ability to collect data automatically on demand, and have the data delivered and analyzed quickly enough to effect monitoring and control decisions. This can be data directly collected from the meter (real-­‐time) or logically derived from data in the database (near-­‐real-­‐
time). Real-­‐time or near-­‐real-­‐time data collection would likely be a key component of “Smart Grid Technology.” Remote Disconnect Disconnecting and reconnecting a customer’s electrical service without accessing the customer’s premises or sending a service vehicle into the field. A hard disconnect — that is, cutting off power to a premise by throwing a physical switch — can be performed remotely, but requires additional specialized equipment at the meter. A virtual disconnect — that is, obtaining an on-­‐demand meter read at the time a premise is vacated or occupied — can be performed remotely through fixed network AMR systems. Virtual disconnect can also include monitoring of any consumption that should not be occurring after disconnect. In addition, some utilities are effectively utilizing mobile AMR systems to perform off-­‐cycle, final reads associated with move-­‐ins and move-­‐outs. SCADA (Supervisory Control and Data Acquisition) A computer system that supervises and controls the electric utility distribution and transmission system. A SCADA's System usually consists of the following subsystems: •
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A Human-­‐Machine Interface or HMI is the apparatus which presents process data to a human operator, and through this, the human operator monitors and controls the process. A supervisory (computer) system, gathering (acquiring) data on the process and sending commands (control) to the process. Remote Terminal Units (RTUs) connecting to sensors in the process, converting sensor signals to digital data and sending digital data to the supervisory system. Programmable Logic Controller (PLCs) used as field devices because they are more economical, versatile, flexible, and configurable than special-­‐purpose RTUs. Communication infrastructure connecting the supervisory system to the Remote Terminal Units. There is considerable confusion over the differences between SCADA systems and distributed control systems (DCS). Generally speaking, a SCADA system always refers to a system that coordinates, but does not control processes in real time. The discussion on real-­‐time control is muddied somewhat by newer telecommunications technology, enabling reliable, low latency, high speed communications over wide areas. Most differences between SCADA and DCS are culturally determined and can usually be ignored. As communication infrastructures with higher capacity become available, the difference between SCADA and DCS will fade. Smart Grid Smart Grid has come to encompass a number of desired characteristics and technologies for an enhanced power grid. Mainly, it would mean a grid that has the ability to be predictive and self-­‐healing, so that problems are automatically avoided. The function of an Electrical grid is not a single entity but an aggregate of multiple networks and multiple power generation companies with multiple operators employing varying levels of communication and coordination, most of which is manually controlled. Smart grids increase the connectivity, automation and coordination between these suppliers, consumers and networks that perform either long distance transmission or local distribution tasks. •
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Transmission networks move electricity in bulk over medium to long distances, are actively managed, and generally operate from 345kV to 800kV over AC and DC lines. Local networks traditionally moved power in one direction, "distributing" the bulk power to consumers and businesses via lines operating at 132kV and lower. This paradigm is changing as businesses and homes begin generating more wind and solar electricity, enabling them to sell surplus energy back to their utilities. Modernization is necessary for energy consumption efficiency, real time management of power flows and to provide the bi-­‐directional metering needed to compensate local producers of power. Although transmission networks are already controlled in real time, many in the US and European countries are antiquated by world standards, and unable to handle modern challenges such as those posed by the intermittent nature of alternative electricity generation, or continental scale bulk energy transmission. Smart Metering A smart meter is able to collect and store interval data for its own service type plus interface with and collect and store data from other devices such as other meters and home gateways. It can also initiate and respond to two-­‐way communications with the utility to automatically collect meter data frequently to support various applications beyond monthly billing. Solid State Meter Utility meters that rely on solid-­‐state circuitry, rather than mechanical and electromechanical technology, to measure energy usage and generate metering data more accurately and reliably. Two-­‐Way Networks The ability to send and receive signals in both directions between the head end and the endpoint of an automated meter-­‐reading system. In particular, the ability for either end of an automated meter-­‐reading system to respond to an unscheduled communication initiated from the other end. Wide Area Network (WAN) The communication solution between the Cell Relay and the Collection Engine for a wide area. Options may include GPRS, broadband over power line (BPL), Wi-­‐Fi or IP over Ethernet. WAN costs are commodities and should be treated as such. Utility companies should not get locked into long-­‐term contracts with communications companies. Prices will continue to drop. The concentrator technology chosen must have the ability to use different modems, including phone, cellular, even satellite, and be replaceable when the price is right. Also known as backhaul.