Yüksek gerilim teçhizatlarında dış etken kaynaklı arızaların analizi ve azaltılması

Abstract

Bu çalışmada, yüksek gerilim güç sistemlerinde arızaların en çok yaşandığı teçhizatlar olan izolatörler ve porselen dış yüzeye sahip şalt ekipmanları incelenmiştir. Bu teçhizatlarda arızalara neden olan dış ortam etkileri belirlenmiştir. Dış ortam etkilerinin teçhizatlar üzerinde meydana getirdiği arızalar aşama aşama incelenmiştir. Kirlilik etmenlerinin ortamın nemli ve yağışlı yapısıyla birleşerek izolatör yüzeylerinde yüzey kaçak akımları oluşturduğu, oluşan kaçak akımların kuru band bölgelerini meydana getirdiği bilinmektedir. İzolatör yüzeyinde oluşan kısmi arkların tüm yüzeye yayılarak atlamaya neden olması sonucu izolatörde deformasyon oluştuğu saptanmıştır. Bu arızaların sonucunda elektrik kesintileri ve maddi kayıplar oluşmaktadır. Bu çalışmada, meydana gelen bu arızaların azaltılması için porselen izolatörlerin silikon kaplama materyalleriyle kaplanması ya da silikon izolatörlerle değiştirilmesi gerekliliği ortaya konulmuştur. Yüksek gerilim şalt ekipmanlarının da silikon kaplamayla kaplanması gerekmektedir. Bu yöntem ile porselen izolatörlerin hidrofobikliğinin arttırılması ve bu sayede yüzey kaçak akımlarının bastırılması amaçlanmıştır.

Keywords

• Porselen izolatör, Yüksek gerilim arızaları, Kuru band, Silikon kaplama

Analysis and mitigation of external factors induced failures in high voltage equipment

Abstract

In this study, insulators and switchyard equipment with porcelain outer surface with the most experienced equipment failures in high voltage power systems have been investigated. The effects of the external environment cause malfunctions in these equipments are determined. Due to the external environment effects failures occurring in equipment were examined. Firstly, high-voltage switchgear equipments which are the subject of study are explained. These include circuit breakers, disconnectors, current transformers, voltage transformers, surge arresters and insulators, which have porcelain outer surface are counted. External environment pollution which is exposure of these devices is determined. Beach and industrial dirt, the dirt is separated into two parts. How caused pollution effects and dry dirt layer on the insulator surface by pollution factors explained. Then it was determined, the dry dirt layer combined with the moist and rainy environment, creates surface leakage current on insulator surface and leakage current is forming a dry band arcs. After, on the entire surface has been found to occur in the insulator deformation with seen flashover. As a result of these failures it was determined that the formation of power outages and financial loss. Different methods to reduce these defects occurring have been proposed. These include porcelain surface periodic manual cleaning, cleaning with abrasive spray, washing with water, heating the insulator surface, design changes, use surface covering materials. The most effective among these methods the porcelain surface is coated with the silicone coating material. Also, porcelain insulators to be replaced with silicon insulators necessity were laid. The surface coating material impact and implementation are described. With this method the surface of the porcelain insulator to increase the hydrophobicity and whereby the surface leakage currents was intended the suppression. In order to emphasize the benefits of the proposed method within the scope of this article, operating within the Turkey national electricity transmission system in the Kaş district of Antalya province TEIAŞ 154 / 31.5 kV Kaş substation and 154 kV Kaş- Fethiye power transmission lines was investigated. Kaş substation switchgear equipment (circuit breakers, disconnectors, current transformers, voltage transformers, surge arresters, insulators) coated with a silicone coating material in june in 2011 year and Kaş-Fethiye 154 kV power transmission line porcelain insulators were replaced with silicon insulators in the same year. The power of transformer center which selected 50 MVA. The length of the transmission line 82 km and conductor grade 477 MCM. Number of 154 kV line failures when before and after the maintenance works occurring has been compared with 48 in 2010, the work was completed in 2011 which fell to 5, the number of failures has been determined to occur among 3 to 5 in subsequent years. If additional table 1 and additional table 2 analyzed, distance protection relays of a large proportion of the fault has been found to be phase ground fault. This shows that due to the loading line overcurrent fault or phase-to-phase fault originating from the conductives contact to each other are not seen. The equipment was contaminated under the influence of environmental conditions and due to the coastal region moisture has led to formation of discharge in the transmission line which selected. Failure count becomes low, interruption time has decreased. After each failure occurred, transmission line not becomes active. Because it needs to be replaced damaged equipment during fault. Obtained results, the proposed method in this article method shows that the implementation and performance plays an important role in preventing power outages that may occur in the transmission lines.

Keywords

• Porcelain insulators, High-voltage failures, Dry band, Silicone coating