Radio frequency spectral characteristics of an HVDC converter station

The radio frequency (RF) energy levels in a DC converter switchyard and valve halls have been measured in order to gain insight into the RF performance of converter stations. Detailed extended spectral records were taken at selected points within the valve halls, and at selected points and traverses in the DC yard to establish the converter station characteristic or signature. The purpose of the study is the detection and absolute quantification of the electric and magnetic field strengths at the test locations. To obtain the maximum amount of information about a converter pole when it is considered as an RF source, swept frequency (broad band) noise measurements were selected as the prime records for the analysis of the performance. The principal source of the RF noise is clearly the igniting valve.Several observations were made based on the measurements related to the initial slope of the voltage collapse recorded within the valve hall, the role of the distant grounding electrode, and the ignition pulse that produces an ω^?2 spectral decay.The information will prove useful for (a) identification of the phenomena or station components shaping the station signature, (b) potential RF filtering applications in transmission line carrier bands, (c) the comparison of field and model tests performed by similar but scaled instrumentation systems.