Electrical Energy Glossary

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Electrical Energy Glossary: a clear guide to quickly understand the main technical terms, concepts, and equipment in the electrical industry.

Digital Control System (CCN)

CCN refers to computerized systems used to control, monitor, and automate a substation.

• Data acquisition (sensors, measurements)
• Information processing
• Sending commands to circuit breakers, disconnectors
• Real-time process monitoring

Composition: industrial computer systems, IEC61850 network, HMI, bay connections, CCN software, IEC104 communication protocol compatible with SCADA
Summary: CCN is the “computer brain” that automatically controls and monitors substations.

EMS (Energy Management System)

An EMS is an Energy Management System that allows for:

• Measure and collect energy consumption (electricity, gas, water…)
• Analyze energy performance
• Optimize energy use to reduce costs and improve efficiency
• Control certain equipment to adjust consumption
• Monitor energy objectives and standards (e.g., ISO 50001)

Summary: It is a platform to monitor, analyze, and optimize the energy consumption of a site or facility.

IEC 60870-5-104 (IEC 104)

IEC 104 is an international standard that defines a communication protocol for the remote control and supervision of electrical systems via IP networks. It is part of the IEC 60870-5 family, used for electrical substations and SCADA systems.

Simple Definition

IEC 104 is a protocol that allows for:

• Transmit measurement information and device statuses from an electrical substation to a control center (SCADA)
• Remotely control electrical equipment (opening/closing of circuit breakers, relay commands…)
• Supervise the real-time operation of electrical installations
• Ensure reliable communication over TCP/IP networks

Main Features

• Based on TCP/IP for data transmission
• Supports remote control, remote signaling, remote measurements, and supervision functions
• Compatible with modern SCADA systems
• Mainly used in MV/HV electrical substations

Where is IEC 104 found?

• MV/LV substations
• SCADA control centers
• Industrial installations requiring remote control

What is it used for?

• Ensure remote control and supervision of electrical equipment
• Enable integration into a smart grid
• Guarantee reliable and secure communication between substations and the control center (dispatching)

In summary:
IEC 104 is a standardized communication protocol enabling the control, supervision, and remote management of electrical equipment over IP networks, essential in modern SCADA systems.

IEC 61850

IEC 61850 is an international standard that defines the communication and automation of electrical substations. It aims to standardize information exchange between equipment in modern substations.

Simple Definition

IEC 61850 is a protocol that allows for:

• Supervise and control electrical equipment (circuit breakers, transformers, protection relays)
• Exchange real-time data between devices via Ethernet networks
• Standardize data objects and services for interoperability
• Facilitate system integration in a SCADA and smart grid environment

Main Features

• Use of Ethernet for network communication
• Definition of standardized data objects for each device type
• Interoperability between equipment from different manufacturers
• Support for real-time protection, control, measurement, and monitoring

Where is IEC 61850 found?

• MV/HV electrical substations
• Smart grid projects and electrical network automation

What is it used for?

• Improve interoperability between equipment from different suppliers
• Ensure real-time supervision and protection
• Enable substation automation and smart grids
• Reduce engineering costs and facilitate maintenance

In summary:
IEC 61850 is an essential standard for the automation and standardized communication of electrical substations, enabling real-time supervision, protection, and control in modern networks.

OMT (Remote Control Operating Device)

An OMT cabinet stands for Remote Control Operating Device.
It is an electrical equipment used in MV to enable the control, protection, and communication of a substation or switchgear, often in distribution networks.

Simple Definition

An OMT cabinet is a remote control cabinet grouping all necessary devices to:

• Operate an MV switch or circuit breaker (opening/closing)
• Supervise statuses (position, voltage presence…)
• Transmit this information to a remote control system (SCADA)
• Ensure the safety and selectivity of operations

Typical contents of an OMT cabinet

• Operating control chain (motor, relays, converters)
• Low voltage protection devices
• Signaling and status feedback modules
• Backup power supply (battery, charger)
• RTU or remote control module depending on the installations

Where is an OMT cabinet found?

• MV/LV distribution substations
• Switching cabinets in public networks
• Underground or overhead structures requiring remote control

What is it used for?

• Enable local and remote control of MV switchgear
• Facilitate remote control in a smart grid
• Improve service continuity by enabling rapid operations
• Ensure the safety of operators and installations

Summary: The OMT cabinet is equipment dedicated to the operation, supervision, and remote control of MV switchgear, essential in modern electrical networks.

MV Protection (Medium Voltage level A)

MV protection refers to all devices designed to protect electrical networks and equipment operating between 1 kV and 50 kV.
Role:

• Detect faults (short-circuit, overload, insulation fault…)
• Quickly isolate the faulty area
• Ensure the safety of personnel and assets
• Guarantee service continuity

Typical equipment: circuit breakers, protection relays, disconnectors, surge arresters, current/voltage transformers
Summary: Ensures the rapid detection and elimination of faults to guarantee the safety and quality of the electrical supply.

RTU (Remote Terminal Unit)

An RTU is an industrial electronic equipment used to:

• Acquire data
• Monitor installations
• Remotely control equipment

Main functions:

• Read information from substation bays
• Transmit this data to a SCADA
• Receive and execute commands
• Ensure local monitoring

Summary: An RTU is a key device in SCADA systems, enabling the remote control and monitoring of field equipment.

SCADA (Supervisory Control And Data Acquisition)

A SCADA is an industrial computer system that allows for:

• Supervise technical installations (factories, energy, transport…)
• Acquire and centralize real-time data from substations
• Remotely control substations
• Analyze and archive data for monitoring, optimization, and maintenance

Summary: It is a centralized control station offering a global and controllable view of a complex industrial process.

Auxiliary Unit Panel (AU)

An auxiliary unit panel (often called AU) is an electrical panel dedicated to the power supply and management of auxiliary circuits of a substation, an MV/HV installation.

Simple Definition

The auxiliary unit panel groups all necessary equipment to provide auxiliary power supply(ies) essential for the operation of:

• the protections
• the PLCs / RTUs
• the switchgear operations
• the remote control / telecommunication
• the lighting
• and certain general services

It is the low voltage nerve center of the electrical substation.

What does an auxiliary unit panel contain?

It may include:

1. Power Supply

• AC power supply (230/400 V)
• DC backup power supply (48 V, 110 V, 220 V depending on substations)
• Charger + stationary batteries

2. Protection and Distribution

• LV circuit breakers and fuses
• Inverters (UPS)
• Busbars / terminal blocks

3. Control Equipment

• Power supply for protection relays
• Power supply for MV/HV operating motors
• Control circuits
• Reclosers, interface modules…

4. Auxiliary Services

• Safety lighting
• Substation ventilation / heating
• Service outlets
• Fire detection, pumps, etc.

Where is an auxiliary unit panel found?

• MV/HV electrical substations
• MV/LV transformer substations

What is an auxiliary unit panel used for?

• Ensure a reliable and secure power supply for critical substation equipment
• Guarantee operational continuity even in the event of a network outage
• Centralize and protect all auxiliary circuits
• Maintain control, operation, and protection functions

In summary:
An auxiliary unit panel is the low voltage panel that powers, protects, and distributes all essential auxiliary power for the operation of an electrical substation or industrial installation.