Cable hang off

Mechanical mounting of a cable system on offshore platforms (e.g. converter, collection or substation platforms).

Cable system

A system for transporting electrical energy, in which the electrical conductors are insulated from each other and against earth by material and also protected against mechanical damage with a shared or individual protective covering.

If the system is laid in the ground, it is known as a cable system. If the cable system is used to transport three-phase alternating current, it is known as an AC cable system. If the cable system is used to transport direct current, it is known as a DC cable system.


Indicates a group of offshore wind farms that are grouped close together.

Collection platform

Multiple AC connection lines are brought together on this offshore platform and joined together in such a way that should one of the AC connection lines malfunction between the collection platform and the mainland, the incoming energy from the offshore wind farms can be diverted to other AC connection lines if and where there is spare capacity.

Combined cycle gas turbine plant

A combined cycle gas turbine plant is an electricity generating unit, consisting of a gas turbine generator unit whose hot exhaust produces steam in a waste heat boiler, which is then used to generate electricity in a steam turbine generator unit.

Combined heat and power (CHP)

In the combined heat and power (CHP) process, both mechanical energy and heat energy are produced. The mechanical energy is generally converted into electricity and fed into the power grid. The resulting heat energy is used for heating purposes (district heating or process heat). Power plants using this approach may be referred to as CHP plants or cogeneration plants.

Common mode failure

A common mode failure is when one event causes multiple components (operating equipment and generation units) to fail due to the same cause.

Connection with HVDC technology

An undersea cable runs from every offshore wind farm to a platform with a rectifier station on it (usually referred to as a converter station). There, the three-phase alternating current produced by the wind turbines is converted into direct current (DC) and transported via high-voltage direct current transmission lines (HVDC) under the sea and over land to the nearest feed-in point – a converter station on land. This technology is currently only used for connecting offshore wind farms in the North Sea to the grid.


The term electrical consumer is used to refer to devices, equipment and facilities that consume and transform electrical energy (e.g. into heat, light or work).

Continuous output

The continuous output of a generation unit is the maximum power provided during normal operation without restriction to duration and which has no negative impact on the service life (operating time) or operational reliability of the generation unit. The continuous output may fluctuate over the course of the year, for example (e.g. due to cooling water conditions).

Control area

A transmission system operator (TSO) is legally obliged to constantly maintain the balance between electricity generation and electricity consumption within their control area to ensure grid stability (frequency stability of 50 Hertz and voltage stability). In order to do so, they use automatic power-frequency control, consisting of primary control and secondary control. The secondary control can also be supported by the manual activation of the tertiary control (minutes reserve).


A converter combines two functions: It converts alternating current into direct current and vice versa. This takes place in the frequency converter, the core element of a converter. Converters include transformers that adapt the input voltage to that of the grid into which the electricity is fed after conversion.

Converter platform

An offshore structure to house the converter and other offshore components of a HVDC transmission line, including all secondary installations. The converter platform itself is part of the HVDC transmission line.

Converter station

An onshore structure to house the converter and other onshore components of an HVDC transmission line, including all secondary installations.