AC current – Current going forward, then backward. It makes a wave. 4.4.1

ACE (Area Control Error) – Equation that yields a number representing how the footprint balances. 14.4.1

AGC (Automatic Generation Control) – Software that monitors ACE and deploys regulating reserve to maintain ACE at zero. 14.4.1

ASM (Ancillary Services Market) – Market for reserves. 16.4.5

ATC/AFC (Available Transfer Capability) – TSR verification to make sure a power line has enough room to support more energy. 11.5.4

AVR (Automatic Voltage Regulator) – Maintains voltage output on a generator. 9.2.1

BA (Balancing Authority) – Entity responsible for matching generation to load. They use reserves to restore ACE. 14.1.2

Black Start Units – Generators that can self start. Some of these get contracted out by the BA for black start services. 15.5.1

Breakers – Create open points. Designed to open under load. At substations, on distribution lines, in homes. 11.3.6

Bus Bar – Piece of metal other devices connect to. A hub for electricity. 11.2.1

Cap Banks – On distribution lines and in substations to raise voltage. 11.3.5

Capacitance – Resists a change in voltage. Two plates and a dielectric. Measured in Farads. 4.5.7

Cascading – One outage causing another outage which causes another outage etc. 15.2.1

Cold Load Pickup – Energizing load that has been without power for 20 minutes causes a much larger initial pick up than what was de-energized. 15.5.6

Contingency Reserve – Spinning reserve, non-spinning reserve 15.2.2

Contingency Event Recovery Period – 15 minutes to recover ACE 15.4.5

Contingency Reserve Restoration Period – 90 minutes to recover reserves after the 15 minute Contingency Event Recovery Period. 15.4.5

Counter Electromotive Force or Back EMF – Voltage in stator based on load that pushes back against EMF. 6.5.1

Cranking Path – TOs energize up to a sync point as part of their black start plan. 15.5.3

Current – Negative charge moving. Measured in Amps 2.4.2

DAM (Day Ahead Market) – Market that runs one day in advance and picks generation and tags based on offers. Creates DA LMP prices. 16.4.3

DC Current – Current only going one direction 4.2.2

Distribution Factor – Percentage of power going down different power lines. 11.5.3

Droop – Governor mode that targets a MW output for different Hz values. 13.2.6

EMF (Electromotive Force) – Voltage created by a generator that sends power into the stator and out into the world. 6.4.2

Enthalpy – Energy in steam. Used to get people thinking about energy. 7.2.2

Evan – Someone with good T-shirt ideas who invented the mayo chip. 9.1.1 , 13.4.6

Excited and Excitation Current – Current that goes to the rotor to provide a generator’s field. 6.3.2

Ferranti Rise – Open ended line has a higher voltage at the far end. 11.4.5

Fuse – Create open points, but get destroyed. Must be replaced to restore power. 11.3.8

Generation Shift Factor – Percentage of generator output going down different power lines. 11.5.3

Governor – Maintains generator frequency. 9.4.1

Headroom – Extra online generation above load, interchange, and reserves. 16.2.4

Impedance – Combination of resistance, capacitance, and inductance. 4.3.5

Inductance – Resists a change in current. Conductor, magnetic field, and relative motion can induce a current. Measured in Henrys. 4.5.3

IROL (Interconnection Reliability Operating Limit) – Facility ratings on facilities that can cause severe issues. IROLs defined by RC. 11.5.2

Isochronous – Governor mode that targets 60 Hz. 13.2.5

Kirchhoff’s Laws – The ins equals the outs. All voltages in a loop add to zero. All currents entering and exiting a node add to zero. 4.7.2

LMP (Locational Marginal Price) – Price for each specific location. 16.4.6

Load – Stuff using electricity. A toaster. A pump. 3.5.1

Market to Market – Two markets can agree to  help each other solve transmission issues instead of using TLRs. 16.4.9

MSSC, N-1 (Most Severe Single Contingency) – Biggest single loss a footprint could have. 15.2.1

Node – Electrical junction or intersection. 3.3.2

Non-spinning Reserve – Offline reserves that can get up to a certain MW value within 10 minutes. 15.2.2

OASIS (Open Access Same Time Information System) – Software that gives equal access to the transmission system. 14.2.2

Operating Reserve – Regulating reserve, spinning reserve, non-spinning reserve 15.2.2

Phase – One of three sine waves created by a generator, A, B, or C phase. 6.4.6

Power Factor – Percentage equaling real power over total power. 5.2.4

RBCE (Reportable Balancing Contingency Event) – Event that must be reported to NERC. DCS. 15.2.2

Reactance – Combination of Inductance and Capacitance. 4.6.1

Reactive Power – Power to make electrical fields. MVAR. 5.2.1

Reactors – Substation devices used to lower voltage. 11.2.2

Real Power – Power to make toast or perform work. MW. 5.2.2

Real-time Market – Energy market that runs every 5 minutes as part of the SCED process. 16.4.4

Regulating Reserve – Aggregate isochronous units. Pulse up and down to maintain ACE. 14.4.4

Regulators – Distribution equipment that lowers voltage. 11.3.5

Reclosers – Open up, let a fault clear, and close again. Line device and relays for substation breakers. 11.3.6

Resistance – Resists current flow. Measured in Ohms. 4.2.3

Rotational Energy – Inertia in the shaft. This value makes system frequency. 9.3.1

Rotor Winding/Field Winding – For a synchronous generator: Coiled wire in the shaft that receives excitation current and spins around to create relative motion. 6.3.2

RTCA (Real-time Contingency Analysis) – Software that looks for transmission constraints. 15.7.3

SCADA (Supervisory Control and Data Acquisition) – Computer program for monitoring and operating electrical equipment. 12.3.3

SCED (Security Constrained Economic Dispatch) – Dispatching units to a MW level starting with the cheapest units while also considering transmission congestion. 16.5.8

SCUC (Security Constrained Unit Commitment) – Committing the cheapest units while also considering transmission congestion. 16.5.4

SIL (Surge Impedance Load) – Goldilocks where a line is purely resistive. Below SIL, line has capacitive reactance and produces MVAR. Above SIL, line has inductive reactance and absorbs MVAR. 11.4.4

SOL (System Operating Limit) – Facility ratings that should not be exceeded. 11.5.2

Spinning Reserve – Online reserves. Used when something bad happens e.g., unit trip. 15.2.2

Stator Winding/Armature Winding – For a synchronous generator: Coiled wire that sits stationary around the shaft. Takes induced current and sends it to load. 6.3.5

Synchronizing – Getting two or more generators operating at the same speed with the same sine waves. Match voltage, frequency, and phase angle before connecting. 13.3.2

Synchronous Generator – Generator where the rotor field and stator field move at the same speed. 6.3.5

Tag – Receipt for an exchange of energy. Generally, needs a TSR. 14.3.1

TLR (Transmission Loading Relief) – Cutting tags in order to reduce load on a transmission line near a seam. Method for adjusting generation in another footprint. No price mechanism. Cuts tags pro rata. 15.7.5

Total Power – Real plus reactive power. MVA. 5.2.2

TSR (Transmission Service Request or Transmission Service Reservation) – Purchasing the right to use a power line path. 14.2.2

Voltage – Electrical push force. Measured in Volts. 3.4.1-4