Glossary

DC cable system
DC grid connection system
DC-Close Coupler

A DC close coupler (also known as a HVDC close coupler or direct current close coupler) is a controllable electrical power facility for the transmission of high voltage direct current in which both converters are situated on the same site or even in the same building, with the DC cable only a few metres long. Used within a synchronous area, a DC close coupler serves to manage power flow in a targeted manner, thereby making it possible to selectively influence other electronic resources such as AC overhead lines, in order to use them more effectively.

Direct current

Direct current indicates a flow of electrical current whose amount and direction is constant. In the literature, as in the GDP, the abbreviation ‘DC’ is commonly used.

Distribution network

The distribution network is used within a confined region for the distribution of electrical energy to supply facilities and consumer installations. The power flow throughout a distribution network is primarily dictated by the consumer load. In Germany, low-voltage, medium-high voltage and high-voltage (>110 kV) are used as distribution networks; in specific cases, a 380 and 220 kV power supply can also be regarded as a distribution network.

Distribution network operators (DNOs)

Operators of electricity distribution networks are natural persons, legal entities or legally dependent organisational units of an energy supply company, who are tasked with the distribution of electricity and are responsible for the safe and reliable operation, maintenance and any necessary expansion of the distribution network at the low-voltage, medium-high voltage or high-voltage level in a defined area as well as the connection lines to other networks where necessary.

Dumped Power

Dumped power, non-usable power, is the result of excess supply of power on the energy market. The total sum of dumped power over the year is known as ‘dumped energy’. The surplus power in a market area is the result of the sum of energy infeed, which cannot be reduced in spite of low energy prices (must-run generation, e.g. conventional combined heat and power or renewable energy infeed) minus the current load (including network losses) in the respective area. If this excess power cannot be stored or exported, the amount of power fed into the system must be reduced. In the model used in the GDP the infeed of energy from renewable sources is then reduced in addition to peak capping. Other options to reduce the amount of dumped energy is a reduction of conventional infeed, an increase in load, or the expansion of storage and export capacities.