Methods for the assessment of network disturbances in distribution networks

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.