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PQube is a registered trademark [1] of Power Standards Lab for an electronic measuring instrument that records power quality and electric energy on the electric power grid.
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PQube is a registered trademark [1] of Power Standards Lab for an electronic measuring instrument that records power quality and electric energy on the electric power grid.
PQube instruments are widely used to gather data for academic research, [2] [3] [4] and at United States Department of Energy National Laboratories [5] and state energy regulators. [6] U.S. federal government agencies use PQubes to detect power quality issues – for example, the Federal Aviation Administration tracks disturbances at radar control centers. [7]
Each PQube instrument is traceable to the National Institute of Standards and Technology, so often these instruments are used in international academic and research environments. [8] [2]
PQubes are a key element in many smart grid projects, [9] [10] recording power disturbance and power flow data to examine efficiency and reliability effects.
Approximately 50 PQubes, located in approximately 40 countries, have been designated by their owners as free public sources of information at http://map.pqube.com . The site is updated approximately every 2 minutes with worldwide power quality and energy recordings.
Data from these PQubes can be used, for example, for developing and testing power quality algorithms. [11] [12] [13] Available data include daily, weekly, and monthly files in GIF and Microsoft Excel CSV format. Voltage and current oscillographs are recorded during every power disturbance and these worldwide locations, and are freely available. Data from each worldwide site is updated approximately once per minute.
Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines that facilitate this movement form a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is part of electricity delivery, known as the electrical grid.
In electrical engineering, the power factor of an AC power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit. Real power is the average of the instantaneous product of voltage and current and represents the capacity of the electricity for performing work. Apparent power is the product of RMS current and voltage. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power may be greater than the real power, so more current flows in the circuit than would be required to transfer real power alone. A power factor magnitude of less than one indicates the voltage and current are not in phase, reducing the average product of the two. A negative power factor occurs when the device generates real power, which then flows back towards the source.
Lawrence Berkeley National Laboratory (LBNL) is a federally funded research and development center in the hills of Berkeley, California, United States. Established in 1931 by the University of California (UC), the laboratory is sponsored by the United States Department of Energy and administrated by the UC system. Ernest Lawrence, who won the Nobel prize for inventing the cyclotron, founded the Lab and served as its Director until his death in 1958. Located in the hills of Berkeley, California, the lab overlooks the campus of the University of California, Berkeley.
Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to as distributed energy resources (DER).
A power outage is the loss of the electrical power network supply to an end user.
The utility frequency, (power) line frequency or mains frequency is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country.
Electric power quality is the degree to which the voltage, frequency, and waveform of a power supply system conform to established specifications. Good power quality can be defined as a steady supply voltage that stays within the prescribed range, steady AC frequency close to the rated value, and smooth voltage curve waveform. In general, it is useful to consider power quality as the compatibility between what comes out of an electric outlet and the load that is plugged into it. The term is used to describe electric power that drives an electrical load and the load's ability to function properly. Without the proper power, an electrical device may malfunction, fail prematurely or not operate at all. There are many ways in which electric power can be of poor quality, and many more causes of such poor quality power.
A microgrid is a local electrical grid with defined electrical boundaries, acting as a single and controllable entity. It is able to operate in grid-connected and in island mode. A 'Stand-alone microgrid' or 'isolated microgrid' only operates off-the-grid and cannot be connected to a wider electric power system.
Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Standard prefixes apply to watts as with other SI units: thousands, millions and billions of watts are called kilowatts, megawatts and gigawatts respectively.
A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that generate electrons when exposed to light. The electrons flow through a circuit and produce direct current (DC) electricity, which can be used to power various devices or be stored in batteries. Solar panels are also known as solar cell panels, solar electric panels, or PV modules.
Electrical devices are considered grid friendly if they operate in a manner that supports electrical grid reliability through demand response. Basic grid-friendly devices may incorporate features that work to offset short-term undesirable changes in line frequency or voltage; more sophisticated devices may alter their operating profile based on the current market price for electricity, reducing load when prices are at a peak. Grid-friendly devices can include major appliances found in homes, commercial building systems such as HVAC, and many industrial systems.
A phasor measurement unit (PMU) is a device used to estimate the magnitude and phase angle of an electrical phasor quantity in the electricity grid using a common time source for synchronization. Time synchronization is usually provided by GPS or IEEE 1588 Precision Time Protocol, which allows synchronized real-time measurements of multiple remote points on the grid. PMUs are capable of capturing samples from a waveform in quick succession and reconstructing the phasor quantity, made up of an angle measurement and a magnitude measurement. The resulting measurement is known as a synchrophasor. These time synchronized measurements are important because if the grid’s supply and demand are not perfectly matched, frequency imbalances can cause stress on the grid, which is a potential cause for power outages.
A grid-tie inverter converts direct current (DC) into an alternating current (AC) suitable for injecting into an electrical power grid, normally 120 V RMS at 60 Hz or 240 V RMS at 50 Hz. Grid-tie inverters are used between local electrical power generators: solar panel, wind turbine, hydro-electric, and the grid.
A smart grid is an electrical grid which includes a variety of operation and energy measures including:
An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:
A super grid or supergrid is a wide-area transmission network, generally trans-continental or multinational, that is intended to make possible the trade of high volumes of electricity across great distances. It is sometimes also referred to as a "mega grid". Super grids typically are proposed to use high-voltage direct current (HVDC) to transmit electricity long distances. The latest generation of HVDC power lines can transmit energy with losses of only 1.6% per 1,000 km.
FNET is a wide-area power system frequency measurement system. Using a type of phasor measurement unit (PMU) known as a frequency disturbance recorder (FDR), FNET/GridEye is able to measure the power system frequency, voltage, and angle very accurately. These measurements can then be used to study various power system phenomena, and may play an important role in the development of future smart grid technologies. The FNET/GridEye system is currently operated by the Power Information Technology Laboratory at the University of Tennessee (UTK) in Knoxville, Tennessee, and Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee.
Open Automated Demand Response (OpenADR) is a research and standards development effort for energy management led by North American research labs and companies. The typical use is to send information and signals to cause electrical power-using devices to be turned off during periods of high demand.
The UCLA Smart Grid Energy Research Center (SMERC), located on the University of California Los Angeles (UCLA) campus, is an organization focused on developing the next generation of technologies and innovation for SmartGrid. Partnerships with government, technology providers, DOE research labs and universities, utilities, policymakers, and electric vehicle and appliance manufacturers provide SMERC with diverse capabilities and exceptional, mature leadership.
This glossary of electrical and electronics engineering is a list of definitions of terms and concepts related specifically to electrical engineering and electronics engineering. For terms related to engineering in general, see Glossary of engineering.