As of today, various solutions to handle the dissipating heat of power electronics devices are available. These include the application of heatsinks, overmolding, embedding of components into substrates, use of substrates with embedded metal or ceramic heatsinks or liquid cooling approaches. When it comes to power electronics for high voltages and fast switching the parasitic capacity has to be considered. This parasitic capacity affects the electrical performance and may finally even lead to damage of the device. Embedding of metal heatsinks or mounting a substrate to a metal heatsink can even increase the parasitic capacity and hence, worsen the scenario. In this project a rectifier had to be built suitable for voltages of up to 20 kV and switching frequencies of 100 kHz while achieving a low parasitic capacity of max. 3 pF. High voltage diodes were selected to meet the electrical requirements. To fullfil both the thermal and capacitance demands the diodes were embedded into a substrate made from a highly thermal conductive FR4 material. In addition, the substrate is mounted to a ceramic heatsink to enable a superior cooling but to limit the parasitic capacity at the same time. This setup was characterised for its thermal management behaviour in the as build state. Though the lamination of the substrate to the ceramic heatsink showed some challenges its cooling performance could be assessed. Subsequently, the system without the ceramic heatsink was exposed to temperature shock cycles at -40/+125°C for up to 2,000 cycles to analyse the long term stability of the system behaviour. For the repeated investigation of the thermal behaviour and the structural integrity of the system a novel analysis approach using an infrared camera was applied. Cross sections were done in addition to verify the results from the novel thermal analysis approach. As of now no thermo-mechanical damage of the rectifier could be observed proving the ability of the embedding approach and the validity of the results gained with the novel non-destructive analysis approach.

In 2007 the German-Austrian-Swiss-Czech working group “D-A-CH-CZ EMC” published the 2nd edition of the “Technical Rules for the Assessment of Network Disturbances”. They are used in the 4 countries to assess the emission limits of large consuming and generating installations (in Germany consuming installations only). The rules define assessment methods and emission limits for LV and MV distribution networks. The HV distribution networks are not covered, because assessment methodologies are usually different to those used for LV and MV distribution networks. During the last 3 years the working group prepared an amendment document that is especially focused on HV distribution networks. The amendment has been published at the begin 2012. It describes methods for the assessment of emission limits for the following network disturbances: voltage changes and flicker, harmonics, unbalance, commutation notches, interharmonics and higher frequency components, ripple control systems. The paper gives an overview of the new amendment document and describes the assessment methods for selected network disturbances in detail. The application is illustrated by an example assessment for a distorting installation.

In public distribution networks the distribution network operator (DNO) is responsible for the voltage quality at all points of supply. In Europe the DNO have to guarantee specified values for voltage quality parameters according to EN 50160. Due to the wide use of electronics in electrical equipment and installations as well as the increase of dispersed generation, the disturbances on the supply network and their assessment is an important issue for the DNO. While the emissions of smaller equipment in LV networks (rated currents below 16A) are limited by appropriate standards (IEC 61000-3-x), the connection of larger installations (load and generation) or a bulk of small but identical devices has to be approved by the DNO as the case arises. The "Technical Rules for Assessment of Network Disturbances" (TR) contain guidelines for the approval of connection inquiries in low and medium voltage networks. Starting about 30 years ago different recommendations and principles for the assessment of network disturbances was developed in the four countries Austria (A), Switzerland (CH), Germany (D) and Czech Republic (CZ). In 2004, after 3 years of development, a joint version of the TR was released by the respective associations of the four countries based on corresponding resolutions. The TR is widely used by the DNO of the four countries. In December 2007 the second edition of the TR was published. The paper gives an overview of the contents of this revised edition. It describes the principles of the assessment procedures and the underlying philosophies. For the most important disturbances the assessment procedures are described in more detail. Several examples demonstrate the application of the TR.

Nowadays power quality, especially voltage quality becomes more and more important for utilities, manufacturers and customers as well as for the regulatory authorities. Therefore a growing number of voltage quality monitoring campaigns with continuously increasing measurement times, considerably longer than one week, are observed. The assessment of voltage quality according to common standards (e.g. IEC 61000-2-x or EN 50160) is usually based on an evaluation interval of one week while the handling of measurements lasting more than a week is not clearly specified. Furthermore the measurement data contain lots of information that is not used by the actual applied assessment methods in the most efficient way. Especially for internal planning purposes within the utilities the knowledge of medium- and long-term trends and variations as well as information about the typical time-dependent customer behavior can be very useful. The paper presents a method that includes medium- and long- term variations (e.g. seasonal variations) of continuous voltage quality parameters (e.g. harmonics) into the calculation of actual levels. The method is based on statistical tolerance bounds and produces more reliable values that can be compared with limits given by actual standards or used for further analyses. After a description of actual assessment methods the paper gives a systematical overview on the variations of voltage quality parameters and typical reasons for that. Next the statistical basics are explained on several examples. Based on the experiences of the authors finally some recommendations for practical application of the suggested method are given.