Summary
This paper deals with measures to alleviate overvoltages (lightning and switching) that occur in positions of cable-overhead line and cable-gas insulated switchgear connections. The reason for the emergence of excessively high transient overvoltages is mostly the alteration of surge impedance in these interconnecting points. In reported cases the metal oxide arresters (MOA) embedded sensors are installed, and grounding connections may contribute to the protection level increment and harm the protection efficiency. A thorough analysis by a series of computer simulation was carried out to assess and select the most suitable arrester location, arresters and cable-screen grounding conductor cross section and placement. Surge impedance of overhead line tower and grounding resistance also significantly impacts the level of overvoltages which can occur in main insulation of cable as well on screen of cable. Especially switching operations in gas insulated switchgear can cause on screen a very high over voltages with extreme high frequency which may damage the outer sheet of cable. Based on the obtained analysis results a proposal for improving of some existing cases and design suggestions for future projects was presented to the interested transmission system operator (TSO). The proposed solutions meet the safety criteria and facilitate the execution of periodic maintenance works of the installed equipment.
Additional informations
| Publication type | ISH Collection |
|---|---|
| Reference | ISH2017_187 |
| Publication year | |
| Publisher | ISH |
| File size | 699 KB |
| Pages number | 6 |
| Price for non member | Free |
| Price for member | Free |
Authors
GOMES, DE CARVALHO CARNEIRO, SAKSENA
