Research topics (PhD)
Research Topics (Ph.D.)
Investigating the Properties and Applications of Noise Electromagnetic Field
Supervisor: Assoc. Prof. Petr Drexler
The measuring and diagnostic methods that exploit the irradiated electromagnetic field and its interactions with objects being tested are presently in wide use, having been thoroughly researched and refined. Most of the systems, however, follow a concept where an electromagnetic field with a defined frequency is generated and evaluated, namely, the frequency is swept in a controlled manner. In such a case, we need to consider the reactance relationships between the measuring and measured objects in the vicinity, as the measurement results may eventually be distorted. These effects, however, are potentially suppressible by applying wideband stochastic signals (noise signals). The study topic involves, above all, utilizing noise field-based diagnostics of materials and electromagnetic structures, especially in the radio-frequency and microwave domains, with the associated development and experimental verification completing the set of central tasks.
Advanced Methods for the Radiofrequency-Based Detection of Partial Discharges
Supervisor: Assoc. Prof. Petr Drexler
A major problem associated with the reliability of high voltage power transformers is the partial discharges generated in the oil. These discharges can be effectively monitored by means of radiofrequency-based techniques, whose successful application markedly depends on the UHF band detectability of the electromagnetic signal emitted by a discharge. The signal exhibits a relatively low level and occurs together with strong pulse interference from other relevant processes. By contrast, the signal possesses unique time and frequency relations that may allow its reliable detection and evaluation. The research topic is centered on designing a novel approach to detect partial discharge-emitted electromagnetic signals via their time and frequency characteristics. The aim of the thesis then generally rests in broadening the horizons of dependable detection and identification of partial discharges and in operating high voltage power transformers more reliably.