AC/DC - Alternating Current/Direct Current
Baseload - The minimum amount of electric power delivered or required over a given period at a constant rate
Border Control Area - A Midwest ISO control area that is interconnected with a non-MISO control area.
Bulk Electric System - A term commonly applied to the portion of an electric utility system that encompasses the electrical generation resources and bulk transmission system.
Bundled Load - The aggregate usage of customers who purchase electric service as a single service rather than services, including transmission service, which may be purchased separately.
CIP - Critical Infrastructure Protection
Capacity - The rated continuous load-carrying ability, expressed in megawatts (MW) or megavolt-amperes (MVA) of generation, transmission, or other electrical equipment
Congestion Pricing - A system for pricing transmission service based in part on the instantaneous demand for transmission capacity.
Contingency - The unexpected failure or outage of a system component, such as a generator, transmission line, circuit breaker, switch, or other electrical element; a disturbance on the interconnected system.
DOE - Department of Energy - a cabinet-level, executive department of the federal government responsible for a variety of regulatory, research, and marketing programs related to energy production and use.
Direct Current- Electric current that flows in a single direction at a constant voltage.
Dynamic Schedule - A telemetered reading of value that is updated in real time and used as a schedule in the Automatic Generation Control/Area Control Error equation and the integrated value of which is treated as a schedule.
EPA - Environment Protection Agency
EPAct - National Energy Policy Act of 1992
Economic Dispatch - The distribution of total generation requirements among alternative sources for optimum system economy with consideration to both incremental generating costs and incremental transmission losses.
Electrical Systems Losses - Total electric energy losses in the electric system due to transmission, transformation, and distribution losses between supply sources and delivery points.
H-Frame Pole - This refers to a type of tower structure where the supporting members (wood or steel) look like the letter H. There are different ways the members may be braced but the basic structure forms an H.
HVDC - High Voltage Direct Current
High Voltage Underground Cables - Constructed in many different ways, but are usually shielded cables. They are made with a conductor, conductor-strand shielding, insulation, semi-conducting insulation shielding, metallic insulation shielding, and a sheath. The sheath can be metallic and may then serve as the metallic insulation shielding and be covered with a nonmetallic jacket to protect the sheath. This sheath helps to reduce or eliminate inductive reactance. Such cables are commonly used in circuits operating at 2400 volts or higher.
ISO - Independent System Operator - A neutral operator responsible for maintaining instaneous balance of the grid system. The ISO performs its function by controlling the dispatch of flexible plants to ensure that loads match resources available to the system.
Integrated Resource Planning (IRP) - A public planning process and framework within which the costs and benefits of both demand- and supply-side resources are evaluated to develop the least-total-cost mix of utility resource options. In many states, IRP includes a means for considering environmental damages caused by electricity supply/transmission and identifying cost-effective energy efficiency and renewable energy alternatives. IRP has become a formal process prescribed by law in some states and under some provisions of the Clean Air Act Amendments of 1992.
Interchange - Electric power or energy that flows from one entity to another.
Interconnection - The linkage of transmission lines between two utility, enabling power to be moved in either direction. Interconnections allow the utilities to help contain costs while enhancing system reliability.
Island - A portion of power system or several power systems that is electrically separated from the interconnection due to the disconnection of transmission system elements.
KETA - Kansas Electric Transmission Authority, a state agency formed in 2005 to promote the construction of new transmission lines in Kansas in order to facilitate wind development in the state. The Spearville-Axtell line was its first project that came to fruition, thus it came to be called the "KETA" project.
LMP - Locational Marginal Price
Lattice Tower - This refers to a type of tower where the members are made of a large number of relatively short individual steel pieces - much like an 'erector set' toy.
Load - An end-use device or customer that receives power from the electric system.
Load Centers - A geographical area where large amounts of power are drawn by end-users.
MPSC - Michigan Public Service Commission
MW - MegaWatt = 1000000 W
MWh - MegaWatthour = 1000000 Wh
Monopole - A transmission support structure that consists of a single tubular steel member to support the electrical conductors. It may support a single line of 3 conductors or a double circuit configuration with 6 electrical conductors, in addition to 1 or 2 grounded shield wires at the top.
NARUC - The National Association of Regulatory Utility Commissioners. A national association composed of governmental agencies of the fifty States, the District of Columbia, Puerto Rico and the Virgin Islands engaged in the regulation of utilities and carriers. The chief objective is to serve the consumer interest by seeking to improve the quality and effectiveness of public regulation in America.
NOPR - Notice of Proposed Rulemaking
Native Load Customers - Wholesale and retail customers that the transmission provider constructs and operates a system to provide electric needs.
Net Capacity Resource - The total owned capacity, plus capacity available from independent power producers, plus the net of total capacity purchases and sales, less the sum of inoperable capacity, and less planned outages.
Network Integration Transmission Service - Allows a transmission customer to integrate, plan, economically dispatch and regulate its network resources to serve its network load in a manner comparable to that of native load customers.
Non-Firm Transmission Service - Point-to-point transmission service that is reserved and/or scheduled on an as-available basis and is subject to interruption.
OASIS - Open Access Same-Time Information System
Overhead Transmission Lines - Overhead AC voltage transmission lines carry 3-phase current. The voltages vary according to the particular grid system they belong to. Transmission voltages vary from 69 kv up to 765 kv. The DC voltage transmission tower has lines in pairs rather than in threes (for 3-phase current) as in AC voltage lines. One line is the positive current line and the other is the negative current line.
PJM Interconnection - Pennsylvania, New Jersey, Maryland Independent System Operator
Parallel Path Flows - The difference between the scheduled and actual power flow, assuming zero inadvertent interchange, on a given transmission path.
Peak Load or Peak Demand - The electric load that corresponds to a maximum level of electric demand in a specified time period.
Point-to-Point Transmission Service - Reservation and/or transmission of energy from point(s) of receipt to point(s) of delivery.
RTO - Regional Transmission Organization. ITC is part of the RTO known as MISO.
SCADA - Reservation and/or transmission of energy from point(s) of receipt to point(s) of delivery.
SF6 Circuit Breakers - Switch electric circuits and equipment in and out of the system. These circuit breakers are filled with compressed sulfur-hexafluoride gas which acts to open and close the switch contacts. The gas also interrupts the current flow when the contacts are open.
Substation - A facility used for switching and/or changing or regulating the voltage of electricity. Service equipment, line transformer installations, or minor distribution or transmission equipment are not classified as substations.
Subtransmission lines - Subtransmission lines carry voltages reduced from the major transmission line system. Typically, 34.5 kv to 69 kv, this power is sent to regional distribution substations. Sometimes the subtransmission voltage is tapped along the way for use in industrial or large commercial operations. Some utilities categorize these as transmission lines.
Tariff - A document, approved by the responsible regulatory agency, listing the terms and conditions, including a schedule of prices, under which utility services will be provided.
Transformer - A device, which through electromagnetic induction but without the use of moving parts, transforms alternating or intermittent electric energy in one circuit into energy of similar type in another circuit, commonly with altered values of voltage and current.
Transmission - Transportation of bulk quantities of electric energy by means of electric conductors from generation sources to an electric distribution system, load center, or an interface with a neighboring control area.
Transmission Bus - Steel structure arrays of switches used to route power into a substation.
Transmission Distribution Center (TDC) - A substation that converts 138,000 transmission voltages to 69,000, 34,000 or 12,000 distribution voltages.
Transmission Substation (TSS) - A substation that converts 765,000 volts to 345,000 volts, and 345,000 volts to 138,000 volts on the transmission side. Some TSS's convert 138,000 volts to 69,000, 34,000 or 12,000 volts.
Underground transmission lines - These transmission lines are more common in populated areas. They may be buried with no protection, or placed in conduit, trenches, or tunnels.
Voltage - Measure of the force of moving energy.