Understand the term. Then see it in the system.

AC coupling

AC-coupled solar

Solar with its own inverter on the AC bus alongside the storage system. In an island it needs curtailment control.

Accuracy class (IEC and ANSI)

Electricity meter accuracy class

The permitted measurement error at reference conditions. IEC 62053-21 classes 0.5, 1 and 2 (and 0.1 S, 0.2 S and 0.5 S under IEC 62053-22 for transformer-operated meters) and ANSI C12.20 classes 0.2 and 0.5 are defined on different test bases and are not interchangeable. A TOR must name the standard whose class it means.

AMI

Advanced Metering Infrastructure

A complete system that connects meters, communications, collection platforms, data management, integrations, procedures and people so meter information can support utility operations.

AMR

Automated Meter Reading

One-way or limited remote collection of meter reads. AMR may reduce manual reading but does not necessarily provide the two-way control and operating architecture associated with AMI.

Anti-islanding

Anti-islanding protection

Protection that disconnects a converter when the grid is lost so it cannot energize a dead line. Required for grid-tied operation.

Basic and maximum current

Meter current rating, IEC notation

Written as 5(80) A: the meter is calibrated around a basic current of 5 A and can carry a maximum of 80 A continuously. The ANSI equivalent idea is the class, such as CL200; see the entry on class.

BESS

Battery Energy Storage System

An integrated system that stores electrical energy and releases it for a defined operating objective using batteries, controls, power conversion, protection and supporting equipment.

Billing integration

Billing or CIS integration

The controlled exchange of validated meter information with the utility system responsible for customer records, billing or related workflows.

Black start

Re-energizing a dead system from its own resources, with a written and tested sequence. Capability is confirmed per device.

BMS

Battery Management System

The control layer that monitors battery cells or modules and manages limits, balancing, protection and battery-state information.

Burden

Instrument-transformer burden

The load connected to the secondary circuit of a CT or PT/VT, including meters, relays and wiring. Burden above the rated value can move the transformer outside its stated accuracy class.

C-rate

Battery charge or discharge rate

Charge or discharge current expressed relative to battery capacity. At 1C, the rated capacity would be charged or discharged in about one hour; at 0.5C, in about two hours, under stated test conditions. Allowed C-rates affect power, heating, warranty and degradation.

CCS1

Combined Charging System Type 1

The North American DC charging family, built on the Type 1 inlet. It is not interchangeable with CCS2.

CCS2

Combined Charging System Type 2

A common connector arrangement used for AC and DC electric-vehicle charging. Vehicle compatibility and the selected charger configuration must still be confirmed.

CHAdeMO

The older Japanese DC charging standard, found on used Japanese imports.

CIS

Customer Information System

The utility system that holds customer accounts, service agreements and billing-related records. Validated meter data normally reaches billing through a defined MDMS-to-CIS interface.

CIU

Customer interface unit

A small display and keypad in the customer’s premises, paired to one meter over a short radio, Bluetooth or power line link. It shows remaining credit, warns when credit is low, accepts token entry and shows the meter’s acceptance or rejection. It is what makes split prepayment metering usable when the meter is sealed out of reach.

Class

Meter current class

In ANSI-based electricity metering, class is the maximum current rating of a meter, for example CL200 for 200 amperes. It is different from accuracy class, such as 0.2 or 0.5, which describes permitted measurement error. Both must be matched with form, voltage, service and utility requirements.

Climatic class

IEC 60721 climatic class

A code such as 3K6 or 3K7 that maps to a defined temperature and humidity band in IEC 60721. On a meter datasheet it states the range in which the meter stays within its accuracy class. Compare it with conditions inside a sealed outdoor meter box, not with shaded ambient.

Connected load

Connected charger capacity

The sum of equipment nameplate ratings connected to a site. Actual maximum demand may differ because of controls, diversity and operating conditions.

Corrosion class

ISO 12944 corrosivity category

A grade from C1 to C5 (and CX) for the atmosphere an enclosure’s finish is designed for. C5 covers coastal air with high salinity.

CSMS

Charging Station Management System

The central software platform that monitors and manages connected chargers, sessions, users, pricing and smart-charging limits, often through OCPP. Supported functions depend on the exact platform and charger versions.

CT

Current transformer

An instrument transformer that scales primary current to a level suitable for metering or protection. Ratio, burden, accuracy and installation must match the application.

DC coupling

DC-coupled solar

Solar connected through charge controllers to the battery’s DC bus, so solar and storage share one converter.

DC fast charging

Direct-current fast charging

Charging in which the charger itself converts AC to DC and delivers DC power directly to the vehicle battery, bypassing the vehicle’s onboard charger. Actual charging speed also depends on the vehicle.

DCU

Data concentrator unit

A field device that aggregates compatible meter communications and provides a path between groups of meters and central AMI systems.

Demand charge

Demand-based electricity charge

A tariff component based on the highest measured demand, or another defined demand value, during a defined period. It can materially affect EV-charging and BESS economics.

Dispenser

Charging dispenser

The bay-side unit of a split charger, carrying cable, screen and payment while the rectifiers sit in a separate power cabinet.

DLMS/COSEM

Device Language Message Specification and Companion Specification for Energy Metering

The IEC 62056 series standard that defines how a meter organizes its data (COSEM objects) and how a head-end system exchanges it (DLMS) over any link. Conformance, certified by the DLMS User Association for a specific model and firmware, is what lets one platform manage meters from several makers.

DMA

District metered area

A defined part of a water network where inflow and consumption can be compared to support leakage and network-performance analysis.

DOD

Depth of discharge

The fraction of capacity used in a cycle. A cycle-life figure means little unless the DOD behind it is stated.

Dual mode

Dual mode meter communications

A meter carrying both a power line and a radio module that falls back from one to the other when a link degrades. It adds resilience where neither path alone is dependable, at a higher unit cost.

Emergency credit

Prepayment emergency credit

A small negative balance a prepaid meter allows before disconnecting, recovered from the customer’s next purchase. It is a consumer-protection parameter set by utility policy under the regulator’s rules, not a meter default.

Empty pipe detection

An ultrasonic water meter event raised when air rather than water fills the measuring tube. A mechanical meter can register air movement as consumption; a static meter flags it instead.

EMS

Energy Management System

The control layer that dispatches a BESS or microgrid according to load, generation, tariff, resilience and operating rules.

Evidence status

Product evidence status

A label showing the level of source support currently available for a displayed product or claim. It does not replace project-specific compliance confirmation.

FAT/SAT

Factory and site acceptance tests

A factory acceptance test (FAT) checks equipment against agreed criteria before shipment. A site acceptance test (SAT) checks the installed equipment and its interfaces at site. The contract and approved test plan set the scope and pass criteria.

Form

Electric meter form

In ANSI-based metering, a standardized designation describing the meter’s electrical and terminal arrangement for a particular service configuration.

Friendly hours

Prepayment friendly hours

Defined periods, such as night hours, Sundays and holidays, during which a prepaid meter will not disconnect for zero credit. Usually a regulatory or social requirement; the meter enforces the policy the utility sets.

G3-PLC

G3 Power Line Communication

A power line communication standard that carries meter data over the electrical distribution network. Suitability depends on network and field conditions.

GB/T

GB/T charging standard

The Chinese national charging standard, carried by Chinese-built buses, trucks and many utility vehicles. A different connector and protocol from CCS2.

Grid-following

Grid-following converter control

A converter mode that synchronizes to an existing voltage and frequency and cannot operate without one. It is the usual mode for grid-tied operation.

Grid-forming

Grid-forming converter control

A converter control mode that sets and regulates voltage and frequency, so a BESS or other inverter-based resource can support an islanded system where designed. Capability, settings and transition behavior must be confirmed and tested for the exact equipment.

Grounding system

Grounding (earthing) arrangement: TN-S, TN-C-S or TT

The way a supply’s neutral and protective ground conductor are arranged. A charger is designed for a stated arrangement, which must match the site’s.

HES

Head-End System

The central AMI platform that communicates with field devices, schedules or requests reads, manages device interactions and passes data onward.

HPLC

High-speed power line carrier

A higher-data-rate form of power line carrier communication over the low-voltage conductors. Like G3-PLC it is bounded by the distribution transformer and sensitive to line condition; the higher rate supports more frequent reads and batch firmware upgrades where the lines allow.

Interconnection

Grid interconnection

The technical and procedural connection of a generating, storage or large-load system to the electrical network, including studies, protection and utility requirements.

Interval data

Interval load data

Energy or demand values recorded at regular time intervals. The interval length and data quality affect AMI, load and BESS analysis.

IP code

Ingress protection code

A rating under IEC 60529 in which the first digit states protection against solid objects and dust (5 protected, 6 tight) and the second against water (4 splashing, 5 jets, 6 powerful jets, 7 temporary immersion, 8 continuous immersion). IP54 suits an enclosure indoors; IP66 suits an exposed outdoor position; IP68 is required for a submerged pit. On storage cabinets, IP55 is dust-protected and jet-proof; IP67 is dust-tight and survives temporary immersion.

Isolation transformer

A transformer between the converter and the island’s loads that provides the island’s grounded neutral and separates the DC side from the load side. Whether one is needed is decided by the grounding study.

kW

Kilowatt

A unit of power describing the instantaneous rate of energy use, delivery or conversion. Compare kWh, the unit of energy.

kWh

Kilowatt-hour

A unit of energy describing power used or delivered over time. One kilowatt sustained for one hour equals one kilowatt-hour.

Last gasp

Last gasp message

A final message a meter or data concentrator sends when its supply fails, using stored energy, so that the outage is known to the head-end system before customers call. Useful only when the event has a route into outage assessment.

LFP

Lithium iron phosphate

The lithium battery chemistry used in the storage systems Metro Power supplies, as published by Bescore. It is thermally stable, offers long cycle life and has a nominal cell voltage of 3.2 V.

Liquid-cooled cable

Liquid-cooled charging cable

A charging cable with coolant circulated through it so that it can carry 400 A or more continuously; needed at the highest power tiers.

Load profile

Electric load profile

A time-based record of power or energy use that reveals peaks, operating patterns and variability.

LoRa

Long range radio modulation

The sub-gigahertz radio modulation used by some meters for point-to-point or multi-hop links. LoRaWAN is a separate network architecture built on the same modulation; a meter described as LoRa is not necessarily LoRaWAN compatible. Band, topology and gateway design must be confirmed for the exact model.

LoRaWAN

Long Range Wide Area Network

A low-power wide-area communications architecture that may be used for metering or sensing. Coverage, frequency, gateway and configuration must be validated.

MAP

Maximum admissible pressure

The pressure a water meter body is rated to withstand continuously. 1.6 MPa corresponds to the common PN16 rating. Confirm it against the network’s maximum, including surge.

MDMS

Meter Data Management System

A platform that stores, validates, estimates, edits and prepares meter data for billing, analytics and downstream utility use.

Microgrid

Microgrid system

A coordinated electrical system of loads and distributed resources that can be controlled as a defined unit and may support grid-connected or island operation.

Multiplier

Meter or billing multiplier

The factor applied to a meter register reading to obtain the primary quantity. For transformer-rated metering it normally combines the CT ratio, PT/VT ratio and any meter constant approved for the installation.

NB-IoT

Narrowband Internet of Things

A cellular low-power communications technology used by some connected meters and devices. Network coverage, band and operator support must be confirmed.

Neutral failure metering

A meter design that keeps measuring from the live-side current sensor when the neutral is cut or bypassed, so the classic single-phase bypass yields no unmetered energy. Meters with a second sensor on the neutral can also compare live and neutral current to detect a bypass directly.

NRW

Non-revenue water

Water that enters the distribution system but does not produce billed revenue. In a standard water balance it combines unbilled authorized consumption, apparent losses and real losses.

OBIS code

Object Identification System code

The standard address of one data item in a DLMS/COSEM meter, defined in IEC 62056-6-1. For example, 1-0:1.8.0 identifies total active energy imported on any conformant meter regardless of maker.

OCPP

Open Charge Point Protocol

A protocol used for communication between compatible EV chargers and central management platforms. Version and supported functions are configuration-specific.

P-rate

Power-to-energy rate

Rated power divided by rated energy, expressed per hour. 0.5P means a full charge or discharge in about two hours. It is a system design choice, not a battery property; compare C-rate.

PCS

Power Conversion System

The bidirectional power-electronics layer that converts between battery DC power and AC electrical systems and controls charge or discharge.

Peak shaving

Peak-demand reduction

Using controlled resources such as BESS or managed charging to reduce the site’s maximum demand during selected periods.

Pilot acceptance gate

Pilot success criteria

The measurable technical, operating and organizational conditions used to decide whether a pilot should proceed, change or stop.

POI

Point of interconnection

The defined electrical location where a project connects to another power system, such as the utility network. Ratings, metering, protection and performance guarantees are often stated at this point.

Power factor

The ratio of real power (kW) to apparent power (kVA) in an AC system. It affects current, equipment loading and electrical design.

PT/VT

Potential or voltage transformer

An instrument transformer that scales primary voltage to a level suitable for metering or protection. PT and VT name the same kind of device. Ratio, accuracy class, burden and connection must match the application.

Q1, Q2, Q3, Q4

OIML R49 flow points

Q3 is the permanent flow the meter is designed for, Q4 the overload flow it tolerates briefly, Q1 the minimum flow at which it still meets accuracy and Q2 the transitional flow between the lower and upper accuracy zones. R equals Q3 divided by Q1. See also the Q3/Q1 entry.

Q3/Q1

Water-meter turndown ratio (R)

The ratio R = Q3/Q1 between permanent flow rate (Q3) and minimum flow rate (Q1), as used in water-meter standards such as ISO 4064 and OIML R 49. A higher R indicates a wider measuring range. Exact definitions and claims must follow the selected standard and model evidence.

RCD Type B

Type B residual current device

A residual current device that can detect smooth DC as well as AC leakage current. Under IEC 60364-7-722, charging points need Type B, or Type A with a 6 mA DC detector; confirm against the Philippine Electrical Code and the charger’s own protection.

Reference frequency

Meter reference frequency

The system frequency at which a meter’s accuracy, clock and ratings were tested. The Philippine system operates at 60 Hz. Where a principal’s public datasheet shows 50 Hz, the 60 Hz variant and its model suffix are confirmed with the principal before a project offer.

RF mesh

Radio-frequency mesh network

A network in which compatible devices can relay data through multiple paths. Performance depends on density, terrain, interference, design and field validation.

Ride-through

Voltage ride-through

The ability of a converter to stay connected through a voltage dip or swell for a defined time instead of tripping. Requirements are set by the grid and distribution codes.

Simultaneity

Charging simultaneity

The proportion of connected chargers expected to operate at the same time and power level. It is an operating assumption, not a substitute for an electrical study.

Single-line diagram

Electrical single-line diagram

A simplified drawing showing the main electrical equipment, ratings and connections of a power system.

SOC

State of charge

An estimate of the energy remaining in a battery relative to its usable capacity under the applicable operating limits.

SOH

State of health

Present capacity compared with an agreed beginning-of-life reference; a cycle-life claim ends at a stated SOH such as 70 percent.

Split metering

Split prepayment metering

An arrangement in which the measuring unit is installed out of the customer’s reach, for example on a pole or in a shared sealed enclosure, and the customer operates the account through a customer interface unit. It is a revenue-protection design choice for dense or high-loss areas.

Starting current

Meter starting current

The smallest current at which a meter must register, set by the standard as a fraction of basic current for each accuracy class. It matters for low-consumption customers and standby loads.

STS (prepayment)

Standard Transfer Specification

The standard, published as the IEC 62055-41 family and administered by the STS Association, that defines the encrypted numeric tokens used to load credit and management instructions into prepaid electricity meters. On a meter datasheet, STS refers to this. On a storage datasheet, STS usually means a static transfer switch; see the separate entry.

STS (transfer switch)

Static transfer switch

A power-electronic transfer device used in some systems to transfer loads between sources according to the approved architecture. On an electricity meter datasheet the same abbreviation means the Standard Transfer Specification for prepayment; see that entry.

T class

Water temperature class

The maximum water temperature a meter is rated for under OIML R49, written T30, T50 and so on. Cold potable water meters are usually T30 or T50.

Token

Prepayment token

A numeric string, twenty digits under the Standard Transfer Specification, generated by a vending system and encrypted with a key unique to one meter. It loads credit or a management instruction into that meter, once. A token cannot be used on another meter or entered twice.

TOR

Terms of Reference

The controlling customer or procurement document that defines requirements, scope, evidence, deliverables and conditions for an opportunity.

Transformer area balance

Transformer area energy balance

The comparison of energy delivered by a distribution transformer with the sum recorded by the customer meters it serves over the same period. The difference is the area loss; trended over time and compared across areas it ranks where inspectors should go. It is the electrical equivalent of a district metered area (DMA) balance.

Type 1

IEC 62196-2 Type 1

The single-phase AC inlet on CCS1 vehicles.

Type 2

IEC 62196-2 Type 2

The AC inlet on CCS2 vehicles, used for single-phase or three-phase charging. The vehicle’s onboard charger sets the charging rate.

U and D class

Flow profile sensitivity class

Under OIML R49, the straight pipe a water meter needs, in pipe diameters upstream (U) and downstream (D). U10D5 means ten diameters upstream and five downstream; U0D0 means none. It is the nameplate answer to whether a meter fits an existing chamber.

Ultrasonic meter

Ultrasonic water meter

A static water meter that uses ultrasonic measurement principles rather than a mechanical measuring element. Correct sizing and installation remain essential.

VEE

Validation, estimation and editing

Rules applied to meter data to check quality, estimate missing or invalid values and record authorized edits before the data is used for billing or analysis.

Vending

Prepayment vending

The sale of prepaid electricity credit and the generation of the matching token by an authorized system, at an office, agent, kiosk or mobile channel. Vending integrates with billing and, where remote delivery is used, with the head-end system.

VSG

Virtual synchronous generator

A grid-forming converter mode that imitates the inertia and droop of a rotating generator so the converter can share load with a diesel generator set.

Wi-SUN

Wireless Smart Utility Network

An interoperable wireless communications family used in some utility networks. Supported profiles, frequency and device compatibility must be confirmed.