Protection and control technology

Previous centralised energy supply systems have a vertical network structure. This is characterized by a unidirectional distribution of electrical energy from the transmission grid level to the distribution grid level. The protection systems are adapted to the vertical network structure.

In the current transformation of electrical energy supply systems, two significant changes are to be mentioned that lead from a vertical to a "circular" network structure and have concrete changes to the structure and operation of electrical energy supply networks. These are:

Increasing distance of energy transmission between high performance power generation centres and load centres in transmission networks
Decentralised power generation structures in distribution networks

This results in new requirements for the network protection systems in order to be able to meet the basic requirements for the protection system, such as selectivity, speed and reliability, even in a "circular" network structure.

Due to the increased decentralized feed-in, the overload protection of equipment gains a new significance. In the case of the unidirectional distribution of electrical energy and power generation close to the load, it was possible to make a statement about the degree of utilisation of the entire supply chain from the feed-in to the consumer by dimensioning the equipment. Up to now, therefore, an overload of operating resources could be ruled out by appropriate network planning. However, decentralised feeds can also overload sections of a distribution network without causing significant load increases in the feed-in.

The increasing use of power electronic equipment (HVDC system, dynamic compensation systems, etc.) in all voltage levels of the electrical power supply leads to changes in the transient behaviour of the electrical networks, for example in the event of an error. Selective protection devices must and should react precisely in this time range.

The increased expansion of off-consumer generation (e. g. offshore wind farms) and the politically desired free electricity trading in Europe will increase the long-distance transport of electrical energy. As a result, the entire electrical energy system is increasingly being operated at the limits of stability. This applies to both angular and stress stability. The protective system has to evolve from the protection of equipment to that of the system. In addition, there are also special requirements for equipment protection, which must show a defined behaviour in the event of a loss of stability and must not lead to undesired cascade shutdown.

Projects

Basics:

Basics of the superordinate protection of electrical transport and distribution systems (system protection)

Influence of new equipment:

Effects of the increased integration of large wind farms into the transmission grid on the grid protection system
- Intermediate feed-in effect taking into account the specifications for the behaviour in the event of mains faults
Development and evaluation of protection concepts for new equipment

Development of new protection techniques:

Fast fault arc detection in the low voltage network using fast signal path analysis methods and modification of distance protection algorithms
Detection of unwanted island networks
Requirements for the detection of mains pendulums to stabilize or release distance protection devices
Adaptation of the AWE cycle by voltage monitoring during the AWE break and detection of the secondary arc
Exact fault location for hybrid lines (mixed transmission path with overhead line and cable components)

contact person

Research Assistant

Mr Dipl.-Ing. Carlo Liebermann

WG leader "Protection and Control"

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Contact Information

Chair of Electrical Power Supply

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Visiting address:

Toepler-Bau, Room 1040b Mommsenstraße 10

01069 Dresden

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Mitarbeiterfoto von Peter Schegner, IEEH

Institut director

Mr Prof. Dr.-Ing. Peter Schegner