The impedance, also known as AC resistance, is the ratio of the AC voltage to the AC current of an electrical load. This also corresponds to the Pythagorean sum of resistance and reactance.

Independent Power Producer (IPP)

An IPP is a power station operator without their own network and area of operation.

Induction (asynchronous) motor

A three-phase alternating current induction motor, also known as a three-phase alternating current asynchronous motor can be used either as a motor or as a generator. It has a passive rotor which is either permanently (squirrel-cage rotor) or intermittently (wound rotor) short-circuited. When being used as a generator, the rotor of the induction motor can also be activated with a different frequency from the grid frequency (double fed induction generator). Induction motors have a simple structure and can be used in a variety of different ways.

Initial grid

With respect to the Network Development Plan (NDP), the initial grid comprises the following grid projects: the actual grid, the measures from the Energy Line Expansion Act (Energieleitungsausbaugesetz or EnLAG), the grid expansion measures currently being implemented (planning approved or construction already in progress) and measures resulting from other obligations, such as the Regulation on Grid Connection of Power Plants (Kraftwerks-Netzanschlussverordnung or KraftNAV) or the obligation to connect industrial clients.

Interconnecting line

An interconnecting line is an electrical circuit (e.g. a transformer) that connects the busbars of various transmission grids.


An extra-high voltage transmission line running between two countries is known as an interconnector.