Qualitative and quantitative statements about the wear of generators and their auxiliary equipment due to delivery of reactive power

Project Number 376

With the even more strict separation of power plants and grids, the delivery of reactive power as a system service becomes a financially assessed product. The demand of reactive power from the transmission network results from the network topology and has to ensure the voltage quality.

Besides the network topology, it depends on local power suppliers and consumers, and is therefore not available as a uniform market product in the entire network. Reactive power can be provided by network compensation and by power plant generators (mainly in connection with controlled unit transformers with tap changers).

For existing plants in Europe neither a standard for financial compensation of reactive power nor any other mechanism exists to ensure equal conditions for power plants providing reactive power or not.

In the course of the gradual implementation of the new European Network Codes by ENTSO-E a uniform procedure will be established.

In Germany evidence of expenditures and costs of reactive power delivery is requested already yet by the TSOs and the Federal Network Agency (Bundesnetzagentur). While the reimbursement of active power losses is not in doubt, reliable studies proving and financially assessing wear are not available.

The VGB-Technical Committee “Electrical Engineering, I&C and IT" initiated the research, carried out by Prof Paetzold (University of applied sciences Ruhr West, head of the project) and Sensoplan (generator part).

The research comprises the wear of electrical components of generation parts caused by delivering reactive power. In this project, typical wear of generators, which is caused or increased through delivery of reactive power, is identified and the effects are quantified. The additional stress is calculated on the basis of classified generators and load, which is subsequently broken down to company-specific data on expenditures and costs.

In addition, a VGB-statement was drafted, which includes an overview for the evaluation of plant-specific shares of investment, maintenance and operation. It includes the results of the research projects “Investigation of wear mechanism at reactive power load change to generators” (Sensoplan) and “Wear of electrical components at delivery of reactive power” (Hochschule Ruhr-West).