Study On The EMC Problems And Application In The Secondary System Of High Voltage Substation

With the concept of intelligent substation increasingly promotion in the power industry in China, the growing number of the low-voltage secondary components are used in the switchgear field in high-voltage substation of 66kV and above. And as the complex electromagnetic environment nearby the switchgear, the secondary components may not work properly caused by the electromagnetic interference, and it even leads to some accidents. This article focuses on how to build high reliability systems, and how to improve the ability of the secondary components to against the electromagnetic interference. And according to the features of the intelligent 8D series GIS products from Siemens, the author re-design and optimize its secondary digital control system, so as to improve its EMC performance. The main research works are listed as below.1. According to the composition structure of the high-voltage substation, combining with the theoretical analysis and engineering measurement, find out the EMC problems that may arise in the secondary system of the high-voltage switchgear. The author indicates that the main sources of interference combined with two parts to affect the secondary system working, by analysis for the sources of interference and the coupling path. The external interference sources are caused by switching, lightning and short circuit fault etc. And the internal interference sources are caused by the secondary parts installation, selection and other factors from the equipments themselves. And the author analyzed in detail for those main interference sources and their coupling ways.2. After analysis the EMC technical standards in the process level, bay level and station level, proposed solutions are advanced by the author to increase the EMC characteristics.3. With the real examples, analysis the EMC levels of the current common equipments. Pointed out the weakness during design and installation, and analysis the results caused by such problems. Proposals are suggested as well. The mentioned improving measures are proved by the relevant tests.Through the above measures, the author do believes that to enhance the whole anti-electromagnetic interference capability of the high-voltage switch secondary system, it must aim at a variety of conditions in the primary system, then carefully consider the working principle of the secondary components. Through a rational layout and installation methods, try to shield the sensitive components in the secondary systems. After that, it cuts the coupling path between the source of interference and the sensitive equipments. Finally, the author hopes this article could play a guiding role in the secondary system design, device selection and on-site installation, etc.