Definitions

Not a general electronics glossary — there are plenty of those, and nobody arrives here needing one. What catches people out on this side is the British acronym soup: which body issues what, which document is a standard and which is a contract condition, and which of them you can actually read.

Grid connection

ENA: The Energy Networks Association, the industry body for the companies that own and operate Britain's electricity and gas networks. It publishes the Engineering Recommendations that govern connecting generation to the distribution network.
EREC: Engineering Recommendation — the document class ENA publishes. G98 and G99 are both ERECs, which is why you see them written as 'ENA EREC G99'.
G98: The Engineering Recommendation covering the connection of fully type-tested micro-generation, up to and including 16 A per phase. Below that threshold the process is materially lighter than G99. ENA EREC G98 Issue 2
G99: The Engineering Recommendation covering generation above the G98 threshold. Issue 2 is dated 10 March 2025, and its requirements for modules incorporating electricity storage came into force on 1 March 2026. ENA EREC G99 Issue 2
DNO: Distribution Network Operator — the company that owns the local distribution network and to whom a connection application is made. Britain has several, by region.
Type verification: Proving a design once, by test, so individual installations do not each have to be proven. G99 sets out the procedures in its annexes, including the method for over- and under-voltage verification. ENA EREC G99 Issue 2
Power Generating Module: The G99 term for the generating unit being connected. Issue 2 extends explicit treatment to modules incorporating electricity storage. ENA EREC G99 Issue 2
Interface Protection: The protection that disconnects a generating module from the network when network conditions go outside defined limits. One of the functions G99 type verification exercises. ENA EREC G99 Issue 2
LFSM-O and LFSM-U: Limited Frequency Sensitive Mode — Overfrequency and Underfrequency. Required behaviours in which a module adjusts its output in response to network frequency moving outside a deadband. ENA EREC G99 Issue 2
RoCoF: Rate of Change of Frequency. A protection function that responds to how fast network frequency is moving rather than to the frequency itself, and a distinct item in a type-test programme. ENA EREC G99 Issue 2
Fault Ride Through: The requirement that a module stays connected through a network disturbance rather than tripping off, because a network that loses its generation during a fault has a worse problem than the fault. ENA EREC G99 Issue 2
Vector Shift: A protection function responding to a sudden change in voltage phase angle, historically used to detect loss of mains. Another separately verified item. ENA EREC G99 Issue 2
Grid simulator: A programmable AC source able to stand in for the distribution network, producing defined voltage and frequency conditions on demand. G99 states that a fully integrated package may be tested in a factory environment, for example on a grid simulator. ENA EREC G99 Issue 2

Market access

UKCA: UK Conformity Assessed — the British conformity marking. Since the 2024 amending regulations, it may also be applied where recognised EU requirements and conformity assessment have been met. SI 2024/696
CE marking: The European conformity marking. Great Britain continues to recognise it alongside or in place of UKCA, with no end date attached to that recognition. SI 2024/696
UKNI: The marking used where a Northern Ireland placement relies on a UK conformity assessment body. Equipment assessed under Module A never triggers it, because no notified body is involved. SI 2016/1091 and SI 2016/1101
Designated standard: The British counterpart to an EU harmonised standard. Great Britain publishes its own list — different list, different website, different update cycle — so check the one you are actually claiming against. SI 2024/696
Module A: Internal production control: the conformity assessment route in which the manufacturer declares conformity without a notified body. The usual route for EMC and Low Voltage on this class of equipment. SI 2016/1091 and SI 2016/1101
Economic operator: The party established in a market who is responsible for the declaration of conformity and the technical documentation. For the EU, that responsibility sits with the group's Irish entity. SI 2016/1091 and SI 2016/1101

Defence

Def Stan: Defence Standard — the MOD's own standard series. Def Stan 61-005 covers platform and vehicle electrical supplies; Def Stan 59-411 covers electromagnetic compatibility. Def Stan 61-005 Part 6 Issue 7
DEFCON: Defence Condition — a standard contract condition, not a standard. DEFCONs are incorporated into MOD contracts and flow down through the supply chain. DEFCON 658
DEFCON 658: The cyber security condition. It flows down to sub-tier suppliers, which means a delivered test system can be in scope even when the contract sits three tiers above you. DEFCON 658
Defence Gateway: The MOD's authentication portal. Several Def Stans sit behind it, which is why this site cites their designations and issue numbers rather than quoting clause text.
DE&S: Defence Equipment and Support — the MOD organisation that buys and supports equipment. Intepro UK Limited holds a current DE&S contract for in-service support of Power Supply Unit Automatic Test Equipment.
Design authority: The organisation holding technical responsibility for a design and authority to change it. It is why some support contracts can only be placed with one supplier, and DE&S names Intepro as the design authority for PSUATE.
In-service support: Keeping delivered equipment working for the life of the capability — maintenance, repair and obsolescence management — as distinct from supplying it in the first place.
JOSCAR: The Joint Supply Chain Accreditation Register, created by ADS and administered by Hellios, used across UK aerospace, defence and security supply chains as a common pre-qualification. Entries require revalidation.
Procurement organisation number: The identifier a supplier is registered under for UK public procurement under the Procurement Act 2023, and the number that appears against them on a published contract notice.

Instruments and method

Regenerative: Of a source or load: returns absorbed energy to the supply rather than dissipating it as heat. On a bench that runs for days the difference is a cooling problem and an electricity bill, not a specification line.
Four-quadrant: Able to source and sink, at either polarity — the full range of voltage and current sign combinations. What lets one instrument both drive and absorb.
Bidirectional: Sources and sinks from the same terminals. Turns a charge-discharge cycle into one instrument instead of a supply plus a load bank.
Load bank: A load that turns everything it absorbs into heat. The thing regeneration replaces, and the reason a room needs ventilating.
Auto-ranging: A source that delivers full power across more than one voltage band without reconfiguration, so a line running 115 V and 230 V product needs neither two sources nor a changeover.
DUT: Device Under Test — whatever is being tested, as opposed to the equipment doing the testing.
ATE: Automated Test Equipment. A configured system that runs a sequence and records the result, rather than a set of instruments somebody drives by hand.
Test executive: The software that sequences a test, controls the instruments, applies limits and produces the record. On a delivered system it is usually where the cyber requirement lands, and where repeatability is won or lost.
Open architecture: Building the executive against instrument interfaces rather than specific model numbers, so replacing an end-of-life supply is a configuration change instead of a rewritten test programme.
kVA and kW: Apparent power and real power. AC sources are rated in kVA because the load's power factor decides how much of it becomes real power; sizing a source in kW alone is how benches end up undersized.