Smart Grid Technology Glossary

Balancing Systems

Phasor Measurement Unit (PMU): PMUs or synchrophasors are a key component of the smart grid.  They are devices that measure alternating current (AC) synchronization.  In order to achieve synchronization of electrical waves, synchrophasors use GPS synchronized time data.  Phasor measurement units make possible the balancing the power generated from multiple sources such as large hydroelectric plants, utility coal and gas plants, and smaller sources such as home solar and wind systems.

Phasor Data Concentrator (PDC): PDCs are stations that gather phasor data, or two-way information for several PMUs.  These stations process and retransmit these data.

End User Systems

Advanced Metering Infrastructure (AMI):  Are any end-user (commercial, industrial or residential) equipment and software that provide information eabout the status of the electricity grid such as hourly costs and demand.  AMIs also let end users monitor and analyze load control, maintenance needs, and other status of internal systems that can help improve energy efficiency.

Smart Meters: Are part of AMIs that provide two-way real time communications of electric ussage between end-users and utility companies.  The two way communication provides end-users with an opportunity to manage their electricity consumption, as well as simplification in the billing process to utility companies.

Home Area Network (HAN): Provide secure communication of smart devices and meters within a home.  It may use current technologies such as WiFi communications.

Neighborhood Area Network (NAN): Provide limited data communication between neighborhood homes for the purpose of real time electricity consumption and status.

Zigbee: Small wireless network communication devices specifically designed for sensor networks.  May be used to control power consumption within a HAN for the purposes of efficiency.

Automation Systems

Substation Automation System (SAS): Monitor, control, and logging systems for a substation that controls a finite portion of the grid.

Supervisory Control and Data Acquisition (SCADA): Are general industrial control systems which form part of the current grid, but will be transformed to act more independently.

Remote Terminal Unit (RTU): Are used to monitor digital data and transmit to central monitoring stations.

Intelligent Electronic Devices (IED): Are used to control power systems such as circuit breakers, transformers, and load balancing equipment.  IEDs use sensor data to make control decisions on other devices.