Detection and measurement of partial discharges
At our institute we develop and improve measurement techniques for the measurement of high amplitude impulse voltages and transient electromagnetic fields. In the last years one main topic in this field has become the detection and measurement of partial discharges. Here we basically deal with modern methods of noise reduction, with acoustic PD measurement techniques and with unconventional UHF partial discharge measurement and localisation techniques.
Particle motion in gas-insulated switchgear for high-voltage direct current transmission
Gas-insulated switchgears (GIS) are considered essential components of the power supply grid due to their high reliability and long operating experience in the AC grid. Therefore, this well-proven technology is also used increasingly in high voltage DC (HVDC) applications. However, the behavior of gaseous insulations in coaxial electrode arrangements differs significantly under DC field stress from the behavior under AC. An error state critical for breakdowns within HVDC GIS is the presence of free-moving particles in the gas volume, which are determined here.
Detailed monitoring of the operating conditions
The operation of electric power networks above their initial dimensioning levels and longer than their estimated lifespan requires a detailed monitoring of the operating conditions to ensure a safe supply with electric power also in the future (Life Cycle Management). For this task the diagnostic tools which are necessary for different apparatus are developed or improved (e. g. partial discharge measurement, Frequency Response Analysis, moisture determination, dissolved gas analysis, vibration measurement, on-line monitoring). These tools can be used to predict the overload capacity and residual life time of a H.V. apparatus. On the other side service and maintenance strategies for H.V. equipment are developed (asset management).
Regarding the design of high voltage equipment new materials (e. g. natural and synthetic esters) are investigated concerning their physical, chemical and electric properties. By means of modern software tools, e. g. finite element analysis (FEM) and Computational Fluid Dynamics (CFD), the oil flow distribution and the thermal behaviour of power transformers can be investigated and optimized. The research area Gaseous Dielectrics is characterized by topics like investigation of dielectric properties of pure SF6 and SF6-gas mixtures, the influence of atmospheric conditions on the dielectric strength of technical insulation designs and the investigation of generation and damping of very fast transients in gas-insulated switchgear.