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To help you understand the terminology we use in the electricity industry, we've listed a number of commonly used phrases and acronyms.
Embedded — any generation which is connected directly to the local distribution network, as well as combined heat and power schemes of any scale |
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Generator capacity — the total capacity of all generators |
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Interconnector — electric lines or other electrical plants based within Great Britain which convey electricity between Great Britain and another country or territory |
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Load — the energy demand experienced on a system |
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Margin — the difference between the level of demand and supply that is available to meet it |
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Maximum Generation Service — a facility that allows access to capacity which is outside of the generator's normal operating range in emergency circumstances for up to 2 hours |
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Peak — the maximum power requirement of a system at a given time, or the amount of power required to supply customers at times when need is greatest |
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Pumped Storage — used for converting large quantities of electrical energy to potential energy |
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Restricted — an estimate of the demand after any Customer Demand Management has occurred |
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Weekday Peak Demand — the highest electricity demand expected/observed during each week expected between Monday and Thursday |
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Winter Peak Demand — the highest electricity demand expected/observed during the winter |
A | Amperes |
AC | Alternating Current |
ACE | Advanced Commissioning Engineer |
ACER | Agency for the Cooperation of Energy Regulators |
AGI | Above Ground Installation |
AIS | Air Insulated Substation |
ANM | Active Network Management |
ASA | Ancillary Services Agreement |
AVCS | Automatic Voltage Control Schemes |
BCA | Bilateral Connection Agreement |
BEGA | Bilateral Embedded Generation Agreement |
BEIS | Department for Business, Energy and Industrial Strategy |
BELLA | Bilateral Embedded Licence Exemptible Large Power Station Agreement |
BETTA | British Electricity Transmission and Trading Arrangements |
BIL | Basic Impulse Level |
BM | Balancing Mechanism |
BMRS | Balancing Mechanism Reporting System |
BMU | Balancing Mechanism Unit |
BOA | Bid Offer Acceptance |
BS | Balancing Services |
BSC | Balancing and Settlement Code |
BSUoS | Balancing Services Use of System |
CB | Circuit Breaker |
CBA | Cost Benefit Analysis |
CC | Connection Conditions |
CCGT | Combined Cycle Gas Turbine |
CCS | Carbon Capture Storage |
CDM | Construction Design Management |
CEC | Connection Entry Capacity |
CEGB | Central Electricity Generation Board |
CfD | Contract for Difference |
CION | Connection and Infrastructure Options Note |
CM | Capacity Market |
CSAT | Customer Satisfaction |
CSM | Cable System Monitor |
CSS | Connection Site Specification |
CT | Current Transformer |
CTM | Circuit Thermal Monitor |
CUSC | Connection and Use of System Code |
CVA | Central Volume Allocation |
D Code | Distribution Code |
DAR | Delayed Auto Reclose |
DC | Direct Current |
DCUSA | Distribution Connection Use of System Agreement |
DN | Distribution Network |
DNO | Distribution Network Operator |
DPD | Detailed Planning Data |
DRC | Data Registration Code |
DSM | Dynamic System Monitor |
DSO | Distribution System Operator |
DSR | Demand Side Response |
E&R | Emergency and Restoration |
EDL | Electronic Dispatch Logging |
EDR | Environmental Discretionary Reward |
EDT | Electronic Data Transfer |
EMC | Electromagnetic Compatibility |
EMR | Electricity Market Reform |
EMT | Electromagnetic Transient |
ENA | Energy Networks Association |
ENCC | Electricity National Control Centre |
ENTSO-E | European Network of Transmission System Owners for Electricity |
EON | Energisation Operational Notification |
ESO | Electricity System Operator |
ETO | Electricity Transmission Owner |
ETYS | Electricity Ten Year Statement |
ETYS | Electricity Ten Year Statement |
EV | Electric Vehicles |
FACTS | Flexible alternating current transmission system |
FES | Future Energy Scenarios |
FFR | Firm Frequency Response |
FON | Final Operational Notification |
FR | Frequency Response |
GBSQSS | Great Britain Security and Quality of Supply Standard |
GC | Grid Code |
GEMA | Gas and Electricity Markets Authority |
GIS | Gas Insulated Substation |
GNCC | Gas National Control Centre |
GSP | Grid Supply Point |
GW | Gigawatt |
GWh | Gigawatt Hour |
HSE | Health and Safety Executive |
HV | High Voltage |
HVAC | High Voltage Alternating Current |
HVDC | High Voltage Direct Current |
Hz | Hertz |
IEC | International Electrotechnical Commission |
IET | The Institution of Engineering and Technology |
ION | Interim Operational Notification |
JPC | Joint Planning Committee |
kA | Kilo Amperes |
kV | Kilo Voltage |
kW | Kilowatt |
kWh | Kilowatt Hours |
LCPD | Large Combustion Plant Directive |
LDTEC | Limited Duration Transmission Entry Capacity |
LJRP | Local Joint Restoration Plan |
LV | Low Voltage |
LVAC | Low Voltage Alternating Current |
MEL | Maximum Export Limit |
MFR | Mandatory Frequency Response |
MIL | Maximum Import Limit |
MITS | Main Interconnected Transmission System |
MOA | Meter Operator Agent |
MSA | Mandatory Services Agreement |
MSC | Mechanical Switched Capacitors |
MVAr | Mega Volt Amperes Reactive |
MVArh | Mega Volt Reactive Hour |
MW | Megawatt |
MWh | Megawatt Hour |
NAP | Network Access Planning |
NBM | Non Balancing Mechanism Unit |
NDP | Network Development Policy |
NETS | National Electricity Transmission System |
NGET | National Grid Electricity Transmission |
NGP | National Grid Property |
NISM | Notification of Insufficient System Margin |
NOA | Network Options Assessment |
NPS | Negative Phase Sequence |
NTS | National Transmission System |
OCB | Oil Circuit Breaker |
OCGT | Open Cycle Gas Turbine |
OFGEM | Office of Gas and Electricity Markets |
OFTO | Offshore Transmission Owner |
OHL | Overhead Lines |
OTS | Operational Tripping System |
PAS | Platform for Ancillary Services |
PC | Planning Conditions |
PPE | Personal Protective Clothing |
PPS | Positive Phase Sequence |
PQM | Power Quality Monitor |
PTW | Permit to Work |
PV | Photovoltaic |
RDP | Regional Development Plan |
REMIT | Regulation of wholesale energy markets integrity and transparency |
RES | Renewable Energy Source |
RfG | Requirements for Generators |
RIIO | Revenue = Incentives + Innovation + Outputs Regulatory Framework |
SCS | Substation Control System |
SF6 | Sulphur Hexafluoride |
SGT | Supergrid Transformer |
SLD | Single Line Diagram |
SO | System Operator |
SOF | System Operability Framework |
SPD | Standard Planning Data |
SQSS | Security and Quality of Supply Standards |
SRS | Site Responsibility Schedule |
SSAT | Stakeholder Satisfaction |
STC | System Operator Transmission Owner Code |
STTEC | Short Term Transmission Entry Capacity |
SVC | Static VAR compensator |
TEC | Transmission Entry Capacity |
THD | Total Harmonic Distortion |
TISS | Transmission Interface Site Specification |
TNCC | Transmission National Control Centre |
TNUoS | Transmission Network Use of System |
TO | Transmission Owner |
TOCO | Transmission Owner Connection Offer |
TOGA | Transmission outage and generator availability |
TOV | Temporary Overvoltage |
TRW | Transmission Reinforcement Works |
TSO | Transmission System Operator |
TWh | Terawatt hour |
V | Voltage |
VIP | Visual Improvement Provision |
VT | Voltage Transformer |
W | Watt |
WVT | Wound Voltage Transformer |
ZPS | Zero Phase Sequence |