Glossary of terms and acronyms

To help you understand the terminology we use in the electricity industry, we've listed a number of commonly used phrases and acronyms.

 

Commonly used phrases

Embedded — any generation which is connected directly to the local distribution network, as well as combined heat and power schemes of any scale

   

Generator capacity — the total capacity of all generators

 

Interconnector — electric lines or other electrical plants based within Great Britain which convey electricity between Great Britain and another country or territory

 

Load — the energy demand experienced on a system

 

Margin — the difference between the level of demand and supply that is available to meet it

 

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

 

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

 

Pumped Storage — used for converting large quantities of electrical energy to potential energy

 

Restricted — an estimate of the demand after any Customer Demand Management has occurred

 

Weekday Peak Demand — the highest electricity demand expected/observed during each week expected between Monday and Thursday

 

Winter Peak Demand — the highest electricity demand expected/observed during the winter

 

 

Acronyms 

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