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Mobile QR Code QR CODE : Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

Journal of the Korean Institute of Illuminating and Electrical Installation Engineers

ISO Journal TitleJ Korean Inst. IIIum. Electr. Install. Eng.

  1. (Master course, Dept. of Electrical Eng., Korea National University of Transportation, Korea)



Corona ring, DC insulator, Electric field mitigation, Grade ring, HVDC

1. ์„œ ๋ก 

1.1 ์—ฐ๊ตฌ์˜ ๋ฐฐ๊ฒฝ

HVDC (high voltage direct current) ๊ธฐ์ˆ ์€ ๋ฐœ์ „์†Œ์—์„œ ๊ต๋ฅ˜๋กœ ์ƒ์‚ฐํ•œ ์ „๊ธฐ๋ฅผ ์ง๋ฅ˜๋กœ ๋ณ€ํ™˜ํ•˜์—ฌ ์†ก์ „ํ•œ ๋’ค ๋‹ค์‹œ ๊ต๋ฅ˜๋กœ ๋ณ€ํ™˜ํ•˜๋Š” ๊ธฐ์ˆ ๋กœ์„œ 1954๋…„, ์Šค์›จ๋ด์—์„œ ์ตœ์ดˆ๋กœ ์ ์šฉ๋˜์–ด ๋ฏธ๊ตญ, ์œ ๋Ÿฝ ๋“ฑ์˜ ์„ ์ง„๊ตญ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ์ค‘๊ตญ๊ณผ ๋ธŒ๋ผ์งˆ, ์ธ๋„ ๋“ฑ ์„ธ๊ณ„ ์—ฌ๋Ÿฌ ๋‚˜๋ผ์—์„œ ์ ์šฉํ•˜๊ณ  ์žˆ๋Š” ์†ก์ „๋ฐฉ์‹์ด๋‹ค[1]. HVDC์˜ ์žฅ์ ์€ ์ „์žํŒŒ ํ”ผํ•ด์— ๋Œ€ํ•œ ์ด์Šˆ๊ฐ€ ์—†๊ณ , ์žฅ๊ฑฐ๋ฆฌ ์†ก์ „์‹œ HVAC (high voltage alternative current)์— ๋น„ํ•˜์—ฌ ์ „๋ ฅ์†์‹ค์ด ํš๊ธฐ์ ์œผ๋กœ ๊ฐ์†Œํ•˜๋ฉฐ, ์ฃผํŒŒ์ˆ˜๊ฐ€ ์„œ๋กœ ๋‹ค๋ฅธ ๊ณ„ํ†ต๊ณผ ๋น„๋™๊ธฐ ์—ฐ๊ณ„๊ฐ€ ๊ฐ€๋Šฅํ•˜๋ฏ€๋กœ ๊ตญ๊ฐ€ ๊ฐ„ ์ „๋ ฅ๊ณ„ํ†ต์˜ ์ƒํ˜ธ ์—ฐ๊ณ„๊ฐ€ ๊ฐ€๋Šฅํ•˜๋‹ค[2, 3].

HVDC์šฉ ์• ์ž์˜ ์„ค๊ณ„๊ธฐ์ˆ ์€ HVDC ์ ˆ์—ฐ์„ค๊ณ„์˜ ํ•ต์‹ฌ๊ธฐ์ˆ ๋กœ์„œ ํ•„์š”ํ•˜์ง€๋งŒ, ํ˜„์žฌ๊นŒ์ง€ ๊ทธ์™€ ๊ด€๋ จ๋œ ์ž์„ธํ•œ ๊ธฐ์ˆ ์  ์ •๋ณด๋Š” ๊ณต๊ฐœ๋˜๊ณ  ์žˆ์ง€ ์•Š์€ ์‹ค์ •์ด๋‹ค. ๊ทธ๋Ÿฌ๋ฏ€๋กœ HVDC ์ „๋ ฅ๊ณ„ํ†ต์˜ ๊ธฐ์ˆ  ํ™•๋ฆฝ์„ ์œ„ํ•ด์„œ๋Š” DC ์ „๊ณ„ํ•ด์„์„ ๊ธฐ๋ฐ˜์œผ๋กœ ํ•˜๋Š” ์ ˆ์—ฐ์„ค๊ณ„ ๊ธฐ์ˆ  ํ™•๋ณด๊ฐ€ ํ•„์š”ํ•˜๋‹ค.

์ „๋ ฅ์šฉ ์• ์ž๋Š” ์ „์„ ์„ ์ฒ ํƒ‘ ๋˜๋Š” ์ „์ฃผ์— ๊ณ ์ •ํ•˜๊ณ  ์ •๊ฒฉ์ „์••์˜ ์ ˆ์—ฐ๋‚ด๋ ฅ์„ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์‚ฌ์šฉ๋˜๋Š” ์ง€์ง€๋ฌผ๋กœ์„œ ์šฐ์ˆ˜ํ•œ ์ ˆ์—ฐ๋‚ด๋ ฅ๊ณผ ๊ธฐ๊ณ„์  ๊ฐ•๋„, ๋ฐœ์ˆ˜์„ฑ, ๊ทธ๋ฆฌ๊ณ  ๋‚ฎ์€ ์ถฉ์ „์šฉ๋Ÿ‰ ํŠน์„ฑ์„ ๊ฐ€์ ธ์•ผ ํ•œ๋‹ค. ๊ณผ๊ฑฐ์—๋Š” ์ œ์ž‘์˜ ์šฉ์ด์„ฑ์œผ๋กœ ์ธํ•˜์—ฌ ์œ ๋ฆฌ ๋˜๋Š” ์ž๊ธฐ ์†Œ์žฌ๋กœ ์ œ์ž‘๋œ ์• ์ž๋ฅผ ์‚ฌ์šฉํ•˜์˜€๋‹ค[4]. ๊ทธ๋Ÿฌ๋‚˜ ์œ ๋ฆฌ ์• ์ž์™€ ์ž๊ธฐ ์• ์ž๋Š” ์ถฉ๊ฒฉ์— ์•ฝํ•˜๊ณ  ๋ฌด๊ฑฐ์šธ ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ๊ณ ๊ฐ€์ธ ๋‹จ์ ์„ ๊ฐ€์ง€๊ณ  ์žˆ์œผ๋ฏ€๋กœ ์ตœ๊ทผ์—๋Š” ์ด์™€ ๊ฐ™์€ ๋‹จ์ ์„ ๊ทน๋ณตํ•œ ํด๋ฆฌ๋จธ ์• ์ž๋ฅผ ๊ฐœ๋ฐœํ•˜์—ฌ ํญ๋„“์€ ๋ถ„์•ผ๋กœ ์ ์šฉํ•˜๊ณ  ์žˆ๋‹ค[5]. ํŠนํžˆ HVDC์šฉ ์• ์ž๋Š” ์ง๋ฅ˜ ํŠน์œ ์˜ ์ •์ „ํ˜„์ƒ์œผ๋กœ ์ธํ•˜์—ฌ ๊ธฐ์กด์˜ HVAC์šฉ ์• ์ž์— ๋น„ํ•˜์—ฌ ์˜ค์†๋ฌผ์„ ๋งŽ์ด ํก์ฐฉํ•˜๋Š” ํŠน์„ฑ์„ ๊ฐ€์ง€๋ฏ€๋กœ ๋ฐœ์ˆ˜์„ฑ์ด ์šฐ์ˆ˜ํ•˜์—ฌ ๋‚ด์˜ค์† ํŠน์„ฑ์ด ์šฐ์ˆ˜ํ•˜๋‹ค๊ณ  ํ‰๊ฐ€๋˜๊ณ  ์žˆ๋Š” ํด๋ฆฌ๋จธ ์žฌ์งˆ์˜ ์• ์ž ์ ์šฉ์ด ํ•„์ˆ˜์ ์ด๋‹ค[6]. ๋”ฐ๋ผ์„œ ๊ด€๋ จ ์ „๋ ฅ๊ธฐ๊ธฐ ๋ฐ ์‹œ์Šคํ…œ ๊ฐœ๋ฐœ์„ ์œ„ํ•œ ๊ณตํ†ต๊ธฐ์ˆ ๋กœ์„œ HVDC ํŠน์„ฑ์— ๊ธฐ๋ฐ˜ํ•œ DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ์ ˆ์—ฐ์„ค๊ณ„ ๊ธฐ์ˆ ์˜ ํ™•๋ณด๊ฐ€ ํ•„์š”ํ•œ ์‹ค์ •์ด๋‹ค.

AC ์ „๋ ฅ์šฉ ์• ์ž์—์„œ๋Š” ๊ณต๊ธฐ์— ๋…ธ์ถœ๋˜๋Š” ๊ธˆ๊ตฌ๋ฅ˜์™€ ์ฝ”์–ด์™€ shed, ๊ทธ๋ฆฌ๊ณ  ๊ธˆ๊ตฌ๋ฅ˜๊ฐ€ ๋งŒ๋‚˜๋Š” ์‚ผ์ค‘์ ์—์„œ ์ „๊ณ„๊ฐ€ ์ง‘์ค‘๋˜์–ด ์ ˆ์—ฐํŒŒ๊ดด๊ฐ€ ๋ฐœ์ƒํ•œ๋‹ค๊ณ  ์•Œ๋ ค์ ธ ์žˆ์œผ๋ฉฐ, ์ด๋ฅผ ๋ฐฉ์ง€ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์ฝ”๋กœ๋‚˜๋ง (corona ring)์„ ์„ค์น˜ํ•˜๊ณ  ์žˆ๋‹ค[7]. ์ด์— ๋ฐ˜ํ•˜์—ฌ DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ๊ฒฝ์šฐ์—๋Š” ํ˜„์žฌ๊นŒ์ง€ ์ฝ”๋กœ๋‚˜๋ง ๊ฐœ๋ฐœ์„ ์œ„ํ•œ ์„ค๊ณ„ ๊ธฐ์ค€์•ˆ์ด ์กด์žฌํ•˜์ง€ ์•Š์œผ๋ฉฐ, ๋‹จ์ˆœํžˆ AC ์ „๋ ฅ์šฉ ์• ์ž๋ฅผ ๊ธฐ์ค€์œผ๋กœ ์ผ์ • ํฌ๊ธฐ์˜ ์—ฌ์œ ๋ฅผ ๋‘๊ณ  ์„ค๊ณ„๋ฅผ ์ง„ํ–‰ํ•˜๊ณ  ์žˆ๋‹ค[8]. ๊ทธ๋Ÿฌ๋‚˜ AC ์ „๊ณ„ํŠน์„ฑ์€ ์œ ์ „์œจ์— ์˜์กดํ•˜์ง€๋งŒ, DC์˜ ์ „๊ณ„ ํŠน์„ฑ์€ ๋„์ „์œจ์— ์˜์กดํ•˜๋Š” ๋“ฑ ๊ทผ๋ณธ์ ์œผ๋กœ ์„œ๋กœ ๋‹ค๋ฅธ ๋ฉ”์ปค๋‹ˆ์ฆ˜์„ ๊ฐ€์ง€๊ณ  ์žˆ์œผ๋ฏ€๋กœ DC ์ ˆ์—ฐํŠน์„ฑ์— ๊ด€ํ•œ ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•˜์—ฌ ์„ค๊ณ„๊ธฐ์ค€์„ ์„ ์ •ํ•˜๋Š” ์—ฐ๊ตฌ๊ฐ€ ํ•„์š”ํ•˜๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” HVDC์šฉ ์• ์ž์˜ ์ ˆ์—ฐ์„ค๊ณ„๊ธฐ์ˆ  ํ™•๋ณด๋ฅผ ์œ„ํ•˜์—ฌ AC ์ „๋ ฅ์šฉ ์• ์ž์™€ DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ์ „๊ณ„๋ถ„ํฌํŠน์„ฑ์„ ์œ ํ•œ์š”์†Œํ•ด์„๋ฒ•์„ ์ด์šฉํ•˜์—ฌ ๋ถ„์„ํ•˜๊ณ  ๋น„๊ตํ•˜์˜€์œผ๋ฉฐ, ๊ทธ ๊ฒฐ๊ณผ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ 500kV๊ธ‰ HVDC ์• ์ž์˜ ์ „๊ณ„๋ถ„ํฌ ์™„ํ™”๋ฅผ ์œ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง ์„ค๊ณ„๋ฅผ ์ง„ํ–‰ํ•˜์˜€๋‹ค.

2. ๋ณธ ๋ก 

2.1 AC์™€ DC์˜ ์ „๊ณ„๋ถ„ํฌํŠน์„ฑ ๋น„๊ต

DC ์ „๊ณ„ํŠน์„ฑ์€ ๊ณต๊ฐ„์ „ํ•˜์˜ ์กด์žฌ์™€ ๋„์ „์œจ์˜ ์˜จ๋„ ์˜์กด์„ฑ ๋“ฑ์œผ๋กœ ์ธํ•˜์—ฌ AC ์ „๊ณ„ํŠน์„ฑ๊ณผ ์ƒ์ดํ•˜๋ฏ€๋กœ, ๊ธฐ์กด์˜ AC ์ ˆ์—ฐ์„ค๊ณ„ ๊ธฐ์ˆ ์„ ์ง์ ‘์ ์œผ๋กœ ์ ์šฉํ•  ์ˆ˜ ์—†๋‹ค. ๋”ฐ๋ผ์„œ ๊ณ ์‹ ๋ขฐ์„ฑ์˜ DC ์ ˆ์—ฐ์„ค๊ณ„ ๊ธฐ์ˆ ์„ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” DC ์ „๊ณ„ํŠน์„ฑ์— ๋Œ€ํ•œ ์ดํ•ด๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ํ•œ DC ์ ˆ์—ฐ์„ค๊ณ„๊ธฐ์ˆ  ๊ฐœ๋ฐœ ์—ฐ๊ตฌ๊ฐ€ ํ•„์š”ํ•˜๋‹ค. DC๋Š” ์œ ์ „์ฒด์˜ ์œ ์ „์œจ์— ์˜์กดํ•˜๋Š” AC ์ „๊ณ„๋ถ„ํฌํŠน์„ฑ๊ณผ ๋‹ค๋ฅด๊ฒŒ ์œ ์ „์ฒด์˜ ๋„์ „์œจ์— ์˜ํ•˜์—ฌ ์ „๊ณ„๋ถ„ํฌ๊ฐ€ ํ˜•์„ฑ๋œ๋‹ค. ๋˜ํ•œ AC ์ ˆ์—ฐ์„ค๊ณ„์—์„œ๋Š” ์ •์ƒ์ƒํƒœ์—์„œ์˜ ์ „๊ณ„ํŠน์„ฑ๋งŒ์„ ๊ณ ๋ คํ•˜์ง€๋งŒ, DC ์ ˆ์—ฐ์„ค๊ณ„์—์„œ๋Š” ์Šค์œ„์นญ ์ „์••์˜ ON/OFF, ์ •์ƒ์ƒํƒœ, ๊ทน์„ฑ๋ฐ˜์ „ ๋ฐ ์ถฉ๊ฒฉ์ „์••์˜ ์ค‘์ฒฉ๊ณผ ๊ฐ™์€ ํŠน์„ฑ์„ ์ข…ํ•ฉ์ ์œผ๋กœ ๊ณ ๋ คํ•ด์•ผ ํ•œ๋‹ค. ํŠนํžˆ ํ‘œ๋ฉด์ „ํ•˜๋‚˜ ๊ณต๊ฐ„์ „ํ•˜์˜ ์กด์žฌ๋กœ ์ธํ•˜์—ฌ ์ „๊ณ„์™œ๊ณก ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ, ๊ทน์„ฑ๋ฐ˜์ „ ์‹œ ๊ณต๊ฐ„์ „ํ•˜์™€ ์—ญ์ „๊ณ„์˜ ์ค‘์ฒฉ์œผ๋กœ ์ธํ•˜์—ฌ ๋งค์šฐ ์‹ฌ๊ฐํ•œ ์ „๊ณ„์ง‘์ค‘์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค[9].

๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” DC ์ ˆ์—ฐ์„ค๊ณ„๊ธฐ์ˆ  ํ™•๋ณด๋ฅผ ์œ„ํ•œ ์„ ํ–‰์—ฐ๊ตฌ๋กœ์„œ AC์™€ DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ์ „๊ณ„๋ถ„ํฌํŠน์„ฑ์„ ๋น„๊ตํ•˜๊ณ  ์ •์ƒ์ƒํƒœ๋ฅผ ๊ธฐ์ค€์œผ๋กœ ํ•œ 500kV๊ธ‰ HVDC ํด๋ฆฌ๋จธ ์• ์ž์˜ ์ „๊ณ„์™„ํ™”๋ฅผ ์œ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค๊ณ„ํ•˜์˜€๋‹ค. HVDC ํด๋ฆฌ๋จธ ์• ์ž์˜ ์ „๊ณ„ํ•ด์„์„ ์œ„ํ•˜์—ฌ ์œ ํ•œ์š”์†Œํ•ด์„ ํ”„๋กœ๊ทธ๋žจ์ธ COMSOL Multiphysics๋ฅผ ์ด์šฉํ•˜์˜€๋‹ค. 500kV๊ธ‰ HVDC ํด๋ฆฌ๋จธ ์• ์ž์˜ ์ „๊ณ„ํ•ด์„์— ์‚ฌ์šฉ๋œ ๋ชจ๋ธ์˜ ์ด๊ธธ์ด๋Š” 6,828mm๋กœ Fig. 1์— ๊ฐœ๋žต๋„๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. Fig. 1์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ์• ์ž์˜ ์ฝ”์–ด๋Š” GFRP (glass fiber reinforced plastic)์ด๊ณ  ํ•˜์šฐ์ง•์€ ์‹ค๋ฆฌ์ฝ˜์ด๋ฉฐ, ์–‘๋‹จ์˜ ๊ธˆ๊ตฌ๋ฅ˜๋Š” ์•Œ๋ฃจ๋ฏธ๋Š„์œผ๋กœ ์„ค์ •ํ•˜์˜€์œผ๋ฉฐ ์ด์— ํ•ด๋‹นํ•˜๋Š” ์ƒ์„ธ ๋ฌผ์„ฑ์€ Table 1์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. Table 1์—์„œ t๋Š” ์˜จ๋„๋ฅผ ์˜๋ฏธํ•œ๋‹ค. ์ด๋•Œ ์• ์ž์˜ DC์˜ ๋ˆ„์„ค๊ฑฐ๋ฆฌ๋Š” AC ์ „์•• ๊ทœ๊ฒฉ์ธ IEC 60815์˜ ์ค‘์˜ค์† ์ง€์—ญ ๋ˆ„์„ค๊ฑฐ๋ฆฌ์ธ 31mm/kV์˜ 1.7๋ฐฐ์ธ 52.7mm/kV๋กœ ์ ์šฉํ•˜์˜€์œผ๋ฉฐ, ์ด ๊ฐ’์„ ํ™•๋ณดํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์ด๋ˆ„์„ค๊ธธ์ด๋Š” 26,890mm๋กœ ์„ค์ •ํ•˜์˜€๋‹ค. ๋˜ํ•œ shed์˜ ์ง๊ฒฝ์€ 230mm์™€ 195mm ์˜ ๋‘ ๊ฐ€์ง€๋กœ ์ด 125๊ฐœ์˜ shed๊ฐ€ ๋ฒˆ๊ฐˆ์•„ ์œ„์น˜ํ•˜๋„๋ก ์„ค์ •ํ•˜์˜€๋‹ค. Fig. 3๊ณผ 4์—๋Š” AC์™€ DC ์ „์••์„ ์ธ๊ฐ€ํ•  ๊ฒฝ์šฐ, ์• ์ž์˜ ์ ‘์ง€๋ถ€์™€ ๊ณ ์ „์•• ์ธ๊ฐ€๋ถ€์— ํ˜•์„ฑ๋˜๋Š” ์ „๊ณ„๋ถ„ํฌ๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. Fig. 2์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด AC ์ „์••์„ ์ธ๊ฐ€ํ•œ ๊ฒฝ์šฐ์—๋Š” ์ ‘์ง€์ธก๊ณผ ๊ณ ์ „์•• ์ธ๊ฐ€์ธก์˜ ๊ธˆ๊ตฌ๋ฅ˜์—์„œ ๊ฐ๊ฐ 9.32kV/mm์™€ 8.25kV/mm์˜ ์ตœ๋Œ€์ „๊ณ„๊ฐ€ ์ง‘์ค‘๋˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋ฐ˜๋ฉด์— DC ์ „์••์„ ์ธ๊ฐ€ํ•œ ๊ฒฝ์šฐ์—๋Š” Fig. 3์—์„œ ๋ณด๋“ฏ์ด ์ ‘์ง€์ธก๊ณผ ๊ณ ์ „์•• ์ธ๊ฐ€์ธก ๊ธˆ๊ตฌ๋ฅ˜์— ๊ฐ๊ฐ 6.65kV/mm์™€ 6.20kV/mm์˜

Fig. 1. Schematics of 500kV HVDC insulator

../../Resources/kiiee/JIEIE.2022.36.12.017/fig1.png

Table 1. Electrical properties of materials

์žฌ์งˆ

๋„์ „์œจ[S/m]

๋น„์œ ์ „์œจ

Aluminum

4.032ร—106

1

GFRP

5ร—10โˆ’15

4.8

Silicon

4.08ร—10โˆ’21ร—e0.0425t

3.8

Air

3.33ร—10โˆ’13

1

Fig. 2. Electric field distribution under AC voltage

../../Resources/kiiee/JIEIE.2022.36.12.017/fig2.png

์ตœ๋Œ€์ „๊ณ„๊ฐ€ ๋ถ„ํฌํ•˜์˜€์œผ๋ฉฐ, AC ์ „์••์„ ์ธ๊ฐ€ํ•œ ๊ฒฝ์šฐ์™€ ๋‹ค๋ฅด๊ฒŒ ํ‘œ๋ฉด์ „ํ•˜์˜ ์˜ํ–ฅ์œผ๋กœ ๊ธˆ๊ตฌ๋ฅ˜์™€ ์ธ์ ‘ํ•œ ์ ‘์ง€์ธก๊ณผ ๊ณ ์ „์•• ์ธ๊ฐ€์ธก shed ๋‚ด๋ถ€์—๋„ ๊ฐ๊ฐ 12.08kV/mm์™€ 23.53kV/mm์˜ ๋†’์€ ์ „๊ณ„๊ฐ€ ์ง‘์ค‘๋˜๋Š” ์‚ฌ์‹ค์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋”ฐ๋ผ์„œ DC ์ „๋ ฅ์šฉ ์• ์ž๋Š” ๊ณต๊ธฐ์™€ ๋งž๋‹ฟ๋Š” ๊ธˆ๊ตฌ๋ฅ˜์—์„œ ์ ˆ์—ฐํŒŒ๊ดด๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ์„ ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ shed ๋‚ด๋ถ€์˜ ๋†’์€ ์ตœ๋Œ€์ „๊ณ„๊ฐ’์œผ๋กœ ์ธํ•˜์—ฌ ๋น ๋ฅธ ์‹œ๊ฐ„ ๋‚ด์— ๋ถ€๋ถ„๋ฐฉ์ „๊ณผ ๊ฐ™์€ ์—ดํ™”ํ˜„์ƒ์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค๊ณ  ์ง์ž‘ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ ๊ธˆ๊ตฌ๋ฅ˜์™€ shed ๋‚ด๋ถ€์˜ ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ์™„ํ™”ํ•˜๊ธฐ ์œ„ํ•œ ์ ˆ์—ฐ์„ค๊ณ„๊ฐ€ ํ•„์š”ํ•˜๋‹ค๋Š” ์‚ฌ์‹ค์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค.

Fig. 3. Electric field distribution under DC voltage without corona ring

../../Resources/kiiee/JIEIE.2022.36.12.017/fig3.png

2.2 ๊ธˆ๊ตฌ๋ฅ˜ ์ธก ์ „๊ณ„์™„ํ™”

์ผ๋ฐ˜์ ์œผ๋กœ ์ฝ”๋กœ๋‚˜๋ง์ด๋ž€ ๊ธฐ์ฒด์™€ ๋งž๋‹ฟ๋Š” ๊ธˆ๊ตฌ๋ฅ˜์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ์™„ํ™”ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์„ค์น˜ํ•˜๋Š” ๊ธˆ์†์˜ ๊ตฌ์กฐ๋ฌผ์„ ์˜๋ฏธํ•œ๋‹ค. ๋ณธ ์ ˆ์—์„œ๋Š” 2.1์ ˆ์˜ ์œ ํ•œ์š”์†Œํ•ด์„ ๊ฒฐ๊ณผ์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ์ ‘์ง€์ธก๊ณผ ๊ณ ์ „์•• ์ธ๊ฐ€์ธก ๊ธˆ๊ตฌ๋ฅ˜์— ๋ถ„ํฌํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ์™„ํ™”์‹œํ‚ค๊ธฐ ์œ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง ์„ค๊ณ„๋ฅผ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. Fig. 4์—๋Š” ๋ฐ˜๊ฒฝ์ด 80mm์ธ ์ฝ”๋กœ๋‚˜๋ง์„ ์ž„์˜์˜ ์œ„์น˜์— ์„ค์น˜ํ•œ ๊ฒฝ์šฐ์— ๋ถ„ํฌํ•˜๋Š” ์ „๊ณ„๊ฐ’์„ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. Fig. 4์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ์ž„์˜์˜ ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค์น˜ํ•จ์œผ๋กœ์„œ ์ ‘์ง€์ธก ๊ธˆ๊ตฌ๋ฅ˜์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์ด 6.65kV/mm์—์„œ 2.88kV/mm๋กœ, ๊ณ ์ „์•• ์ธ๊ฐ€์ธก ๊ธˆ๊ตฌ๋ฅ˜์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์€ 6.20kV/mm์—์„œ 2.84kV/mm๋กœ ์ฝ”๋กœ๋‚˜๋ง์ด ์„ค์น˜๋˜์ง€ ์•Š์•˜์„ ๋•Œ์™€ ๋น„๊ตํ•˜์—ฌ ๊ฐ๊ฐ 56.7%์™€ 54.2%์˜ ์ „๊ณ„์™„ํ™” ํšจ๊ณผ๊ฐ€ ์žˆ๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.

๊ธˆ๊ตฌ๋ฅ˜์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ์™„ํ™”ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๊ธˆ๊ตฌ๋ฅ˜ ๋๋‹จ์—์„œ ์ฝ”๋กœ๋‚˜๋ง ์ค‘์‹ฌ๊นŒ์ง€์˜ ๋†’์ด (h), ์• ์ž์˜ ์ค‘์‹ฌ์ถ•์œผ๋กœ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ๊ฑฐ๋ฆฌ (d), ๊ทธ๋ฆฌ๊ณ  ์ฝ”๋กœ๋‚˜๋ง์˜ ๋ฐ˜๊ฒฝ (r)์„ ๋ณ€ํ™”์‹œํ‚ค๋ฉด์„œ ์ „๊ณ„์™„ํ™” ํšจ๊ณผ๊ฐ€ ์šฐ์ˆ˜ํ•œ ์ฝ”๋กœ๋‚˜๋ง์˜ ์„ค๊ณ„์•ˆ์„ ๋„์ถœํ•˜์˜€๋‹ค. Fig. 5์—๋Š” DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ์ฝ”๋กœ๋‚˜๋ง ์„ค๊ณ„๋ฅผ ์œ„ํ•œ ๊ฐœ๋…๋„๋ฅผ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค.

Fig. 4. Electric field mitigation under AC voltage by corona ring

../../Resources/kiiee/JIEIE.2022.36.12.017/fig4.png

Fig. 5. Configuration of corona ring for DC insulator

../../Resources/kiiee/JIEIE.2022.36.12.017/fig5.png

๋จผ์ € ์ ‘์ง€์ธก ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค๊ณ„ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ๋ฐ˜๊ฒฝ์ด 30mm์ด๊ณ  ๊ธˆ๊ตฌ๋ฅ˜ ๋๋‹จ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง ๋๊นŒ์ง€์˜ ๋†’์ด์ธ h๊ฐ€ 150mm์ธ ์•Œ๋ฃจ๋ฏธ๋Š„ ์žฌ์งˆ์˜ ์ฝ”๋กœ๋‚˜๋ง์„ ๊ฐ€์ •ํ•˜๊ณ  ์• ์ž์˜ ์ค‘์‹ฌ์ถ•์œผ๋กœ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ๊ฑฐ๋ฆฌ d๋ฅผ 100mm์—์„œ 400mm๊นŒ์ง€ ๋ณ€ํ™”์‹œ์ผฐ์„ ๋•Œ ๋ฐœ์ƒ๋˜๋Š” ๊ธˆ๊ตฌ๋ฅ˜์ธก์˜ ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ํ™•์ธํ•˜์˜€๋‹ค. Fig. 6(a)์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ์• ์ž์˜ ์ค‘์‹ฌ์ถ•์—์„œ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ๊ฑฐ๋ฆฌ d๊ฐ€ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ์„œ ๊ธˆ๊ตฌ๋ฅ˜์ธก์˜ ์ตœ๋Œ€์ „๊ณ„๋Š” ๊ฐ์†Œํ•˜๋Š”๋ฐ d๊ฐ€ 370mm ์ด์ƒ์ด ๋  ๋•Œ ํฌํ™”ํ•˜๋Š” ๊ฒฝํ–ฅ์„ ๋ณด์ด๋ฏ€๋กœ d๋Š” 370mm๋กœ ๊ฒฐ์ •ํ•˜์˜€๋‹ค. ๋˜ํ•œ ๊ธˆ๊ตฌ๋ฅ˜ ๋๋‹จ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ๋†’์ด์ธ h๋Š” Fig. 6(b)๋กœ๋ถ€ํ„ฐ ์ตœ๋Œ€์ „๊ณ„๊ฐ€ ๊ฐ€์žฅ ์ž‘๊ฒŒ ๋ถ„ํฌํ•˜๊ฒŒ ๋˜๋Š” 150mm๋กœ ๊ฒฐ์ •ํ•˜์˜€๋‹ค. ์ฝ”๋กœ๋‚˜๋ง์˜ ๋ฐ˜๊ฒฝ r์€ Fig. 6(c)์™€ ๊ฐ™์ด ์ฆ๊ฐ€ํ• ์ˆ˜๋ก ์ „๊ณ„๊ฐ€ ๊ฐ์†Œํ•˜๋Š” ๊ฒฝํ–ฅ์„ ํ™•์ธํ•˜์˜€์œผ๋ฉฐ, ์•ˆ์ „์œจ์„ ๊ณ ๋ คํ•˜์—ฌ 40mm๋กœ ๊ฒฐ์ •ํ•˜์˜€๋‹ค.

Fig. 6. Maximum electric field intensity according to specifications of corona ring under DC voltage

../../Resources/kiiee/JIEIE.2022.36.12.017/fig6.png

๊ณ ์••์ธก ์ฝ”๋กœ๋‚˜๋ง ๋˜ํ•œ ๋™์ผํ•œ ๊ณผ์ •์œผ๋กœ ์„ค๊ณ„๋ฅผ ์ง„ํ–‰ํ•˜์˜€๋‹ค. ๊ณ ์••์ธก์˜ ๊ฒฝ์šฐ ์ ‘์ง€์ธก์— ๋น„ํ•ด ์ „๊ณ„๊ฐ€ ๋†’์€ ๊ฒƒ์„ ๊ณ ๋ คํ•˜์—ฌ ๋ฐ˜๊ฒฝ์„ 40mm, ๊ธˆ๊ตฌ๋ฅ˜ ๋๋‹จ์œผ๋กœ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ์ด๊ฒฉ๊ฑฐ๋ฆฌ์ธ ๋†’์ด h๊ฐ€ 150mm์ธ ์•Œ๋ฃจ๋ฏธ๋Š„ ์žฌ์งˆ์˜ ์ฝ”๋กœ๋‚˜๋ง์„ ๊ฐ€์ •ํ•œ ํ›„์— d์˜ ๊ฐ’์„ 100mm์—์„œ 400mm๊นŒ์ง€ ๋ณ€ํ™”์‹œ์ผฐ์„ ๋•Œ ๋ฐœ์ƒ๋˜๋Š” ๊ธˆ๊ตฌ๋ฅ˜์ธก์˜ ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ํ™•์ธํ•˜์˜€๋‹ค. ๊ฒฐ๊ณผ์ ์œผ๋กœ ๊ณ ์••์ธก ์ฝ”๋กœ๋‚˜๋ง์˜ ์„ค๊ณ„๊ฐ’์€ ๊ธˆ๊ตฌ๋ฅ˜ ๋๋‹จ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ๋†’์ด h๋Š” 150mm, ์• ์ž์˜ ์ค‘์‹ฌ์ถ•์œผ๋กœ๋ถ€ํ„ฐ ์ฝ”๋กœ๋‚˜๋ง๊นŒ์ง€์˜ ๊ฑฐ๋ฆฌ d๋Š” 300mm, ๊ทธ๋ฆฌ๊ณ  ์ฝ”๋กœ๋‚˜๋ง์˜ ๋ฐ˜๊ฒฝ์€ 50mm๋กœ ๊ฒฐ์ •ํ•˜์˜€๋‹ค.

2.3 Shed์ธก ์ „๊ณ„์™„ํ™”

๊ณ ์ฒด ์œ ์ „์ฒด ๋‚ด๋ถ€์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ์™„ํ™”ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์„ค์น˜ํ•˜๋Š” ๊ตฌ์กฐ๋ฌผ์€ ๊ทธ๋ ˆ์ด๋“œ๋ง (grade ring)์ด๋ผ๊ณ  ํ•œ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ๊ธˆ๊ตฌ์ธก์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ์™„ํ™”ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค๊ณ„ํ•˜์˜€์œผ๋ฉฐ, ์„ค๊ณ„๋œ ์ฝ”๋กœ๋‚˜๋ง์„ ํ†ตํ•˜์—ฌ ์• ์ž์˜ shed์ธก์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์„ ๋™์‹œ์— ์™„ํ™”ํ•  ์ˆ˜ ์žˆ์Œ์„ ํ™•์ธํ•˜์˜€๋‹ค. Fig. 3์— ๋‚˜ํƒ€๋‚ธ ๋ฐ”์™€ ๊ฐ™์ด ์ฝ”๋กœ๋‚˜๋ง์ด ์„ค์น˜๋˜์ง€ ์•Š์€ DC ์• ์ž์—์„œ๋Š” shed ๋‚ด๋ถ€์— ์•ฝ 23.53kV/mm์˜ ๋†’์€ ์ „๊ณ„๊ฐ€ ์œ ๋„๋˜์–ด ์žฅ์‹œ๊ฐ„ ์šด์ „ํ•  ๊ฒฝ์šฐ์— ๋ถ€๋ถ„๋ฐฉ์ „์ด ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋‹ค๋Š” ์‚ฌ์‹ค์„ ํ™•์ธํ•˜์˜€๋‹ค. ๋ฐ˜๋ฉด์— 2.2์ ˆ์—์„œ ์„ค๊ณ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง์„ ํ†ตํ•˜์—ฌ shed ๋‚ด๋ถ€์˜ ์ตœ๋Œ€์ „๊ณ„๊ฐ€ 23.53kV/mm์—์„œ 4.10kV/mm๋กœ ์•ฝ 83%์˜ ์ „๊ณ„์™„ํ™”ํšจ๊ณผ๊ฐ€ ์žˆ๋‹ค๋Š” ์‚ฌ์‹ค์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ด์™€ ๊ฐ™์€ ์ฝ”๋กœ๋‚˜๋ง์˜ ์„ค์น˜๋กœ ์ธํ•œ shed์ธก์—์„œ์˜ ์ „๊ณ„ ๊ฐ์†Œํšจ๊ณผ๋ฅผ Fig. 7์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ ๊ณ ์ฒด ์œ ์ „์ฒด๋Š” ์ˆ˜์‹ญ kV/mm์—์„œ ์ ˆ์—ฐํŒŒ๊ดด๊ฐ€ ๋ฐœ์ƒํ•˜๋Š” ๊ฒƒ์œผ๋กœ ์•Œ๋ ค์ ธ ์žˆ๋Š”๋ฐ, ์ฝ”๋กœ๋‚˜๋ง์˜ ์„ค์น˜๋ฅผ ํ†ตํ•˜์—ฌ shed ๋‚ด๋ถ€์˜ ์ „๊ณ„๊ฐ’์„ ์™„ํ™”์‹œ์ผœ ์ „๊ธฐ์  ์ ˆ์—ฐ ์•ˆ์ •์„ฑ์„ ํ™•๋ณดํ•  ์ˆ˜ ์žˆ์Œ์„ ํ™•์ธํ•˜์˜€๋‹ค.

Fig. 7. Electric field analysis result by installation of corona ring under DC voltage

../../Resources/kiiee/JIEIE.2022.36.12.017/fig7.png

3. ์ฝ”๋กœ๋‚˜๋ง ์„ค๊ณ„์•ˆ ๋ฐ ์•ˆ์ „์œจ ๊ฒ€ํ† 

์ ˆ์—ฐํŒŒ๊ดด ๊ธฐ์ค€์ „๊ณ„์™€ ์ „๊ณ„ํ•ด์„์„ ํ†ตํ•˜์—ฌ ๊ณ„์‚ฐ๋œ ์ „๊ณ„๊ฐ’์„ ์ด์šฉํ•˜์—ฌ ์•ˆ์ „์œจ์„ ๊ณ„์‚ฐํ•  ์ˆ˜ ์žˆ๋‹ค. ์•ˆ์ „์œจ์ด๋ž€ ์ „๋ ฅ์„ค๋น„๊ฐ€ ์ •๊ฒฉ์œผ๋กœ ์šด์ „๋  ๋•Œ ์ ˆ์—ฐํŒŒ๊ดด ๊ธฐ์ค€์ „๊ณ„๋ฅผ ๊ณ ๋ คํ–ˆ์„ ๋•Œ ์ ˆ์—ฐ์ ์œผ๋กœ ์•ˆ์ „ํ•œ ์ •๋„๋ฅผ ์ •๋Ÿ‰์ ์œผ๋กœ ํ‘œํ˜„ํ•˜๋Š” ๋ฐฉ๋ฒ•์œผ๋กœ์„œ ๋‹ค์Œ์˜ (1)๊ณผ ๊ฐ™์ด ํ‘œํ˜„ํ•  ์ˆ˜ ์žˆ๋‹ค.

(1)
safetyfactor=์ ˆ์—ฐํŒŒ๊ดด๊ธฐ์ค€์ „๊ณ„์ „๊ณ„ํ•ด์„๊ฒฐ๊ณผ

์ผ๋ฐ˜์ ์œผ๋กœ ๊ธฐ์ค‘์—์„œ DC ์ „์••์— ์˜ํ•œ ์ ˆ์—ฐํŒŒ๊ดด ๊ธฐ์ค€์ „๊ณ„๋Š” ์•ฝ 3kV/mm๋กœ ์•Œ๋ ค์ ธ ์žˆ๋‹ค. ๋˜ํ•œ ๋ณธ ์—ฐ๊ตฌ์—์„œ ๊ณ„์‚ฐ๋œ 500kV๊ธ‰ HVDC์šฉ ์• ์ž์˜ ์ ‘์ง€์ธก ๊ธˆ๊ตฌ๋ฅ˜์—์„œ์˜ ์ตœ๋Œ€์ „๊ณ„๊ฐ’์ด 2.27kV/mm๋กœ ๊ณ„์‚ฐ๋จ์„ ๊ณ ๋ คํ•œ๋‹ค๋ฉด (1)์„ ์ด์šฉํ•˜์—ฌ ๋„์ถœ๋œ ์„ค๊ณ„์•ˆ์˜ ์•ˆ์ „์œจ์€ 1.32๋กœ ๊ณ„์‚ฐ๋œ๋‹ค. ๋˜ํ•œ ํด๋ฆฌ๋จธ๋Š” ์ˆ˜์‹ญ kV/mm์˜ ์ ˆ์—ฐํŒŒ๊ดด ๊ธฐ์ค€์ „๊ณ„๋ฅผ ๊ฐ€์ง€๊ณ  ์žˆ๋Š” ๊ฒƒ์— ๋ฐ˜ํ•˜์—ฌ ๋„์ถœ๋œ ์„ค๊ณ„์•ˆ์˜ ๊ฒฝ์šฐ์—๋Š” ํด๋ฆฌ๋จธ shed ๋‚ด๋ถ€์— ์œ ๋„๋˜๋Š” ์ตœ๋Œ€์ „๊ณ„๊ฐ’์ด 4.10kV/mm๋กœ ํ‰๊ท ์ „๊ณ„๋Š” ๊ทธ ์ดํ•˜๊ฐ€ ๋  ๊ฒƒ์ด๋ฏ€๋กœ ์ „๊ธฐ์  ์ ˆ์—ฐ ์•ˆ์ „์„ฑ์ด ๋” ๋†’์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

๊ฒฐ๊ณผ์ ์œผ๋กœ ๋ณธ ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•˜์—ฌ ๋„์ถœ๋œ 500kV๊ธ‰ HVDC์šฉ ์• ์ž์˜ ์ „๊ณ„์™„ํ™”๋ฅผ ์œ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง์˜ ์„ค๊ณ„ ํŒŒ๋ผ๋ฏธํ„ฐ๋Š” Table 2์™€ ๊ฐ™๋‹ค. ๋˜ํ•œ ์ด์™€ ๊ฐ™์€ ์‚ฌ์–‘์˜ ์ฝ”๋กœ๋‚˜๋ง์œผ๋กœ ์ธํ•œ ์ „๊ณ„์™„ํ™” ํšจ๊ณผ๋ฅผ Table 3์— ์ •๋ฆฌํ•˜์—ฌ ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ๊ณ„์‚ฐ๋œ ์•ˆ์ „์œจ์€ Table 4์— ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค. ์ฝ”๋กœ๋‚˜๋ง ์„ค์น˜ ์ „ ์•ˆ์ „์œจ์€ ๊ณ ์••๋ถ€์™€ ์ ‘์ง€๋ถ€ ๊ฐ๊ฐ 0.48, 0.45์ธ๊ฒƒ์— ๋น„ํ•ด ์ฝ”๋กœ๋‚˜๋ง ์„ค์น˜ ํ›„ 1.19, 1.32๋กœ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ์ด๋ฅผ ํ†ตํ•ด ์„ค๊ณ„๋œ ์ฝ”๋กœ๋‚˜๋ง์ด ํšจ๊ณผ์ ์œผ๋กœ ์ „๊ณ„์ง‘์ค‘์„ ์™„ํ™”์‹œํ‚จ๋‹ค๋Š” ์‚ฌ์‹ค์„ ํ™•์ธํ•  ์ˆ˜ ์žˆ๋‹ค.

Table 2. Specidfications of corona ring for 500kV DC insulators

ground corona ring

high voltage corona ring

height[mm]

150

150

distance[mm]

370

300

radius[mm]

40

50

Table 3. Mitigation of maximum electric field intensity by proposed corona ring

condition

EMAX[kV/mm]

without corona ring

with corona ring

metal fitting

(high voltage)

6.20

2.52

metal fitting

(ground)

6.65

2.27

shed (high voltage)

23.53

4.95

shed (ground)

12.08

4.10

Table 4. Safety factor calculated by the proposed corona ring

condition

Safety factor

without corona ring

with corona ring

metal fitting

(high voltage)

0.48

1.19

metal fitting

(ground)

0.45

1.32

4. ๊ฒฐ ๋ก 

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” 500kV๊ธ‰ DC ์• ์ž์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์ตœ๋Œ€์ „๊ณ„๋ฅผ ์™„ํ™”ํ•˜๊ธฐ ์œ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค๊ณ„ํ•˜์˜€๋‹ค. AC ์ „๋ ฅ์šฉ ์• ์ž์™€ DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ์ „๊ณ„ํŠน์„ฑ์„ ๋ถ„์„ํ•˜์—ฌ ๋น„๊ตํ•˜์˜€์œผ๋ฉฐ, DC ์ „๋ ฅ์šฉ ์• ์ž์˜ ๊ฒฝ์šฐ์—๋Š” ์ „๊ณ„๊ฐ€ ์ง‘์ค‘๋˜๋Š” ํŠน์„ฑ์ด AC ์ „๋ ฅ์šฉ ์• ์ž์™€ ์ƒ์ดํ•˜๋‹ค๋Š” ์‚ฌ์‹ค์„ ํ™•์ธํ•˜์˜€๋‹ค. ํŠนํžˆ ๊ธˆ๊ตฌ๋ฅ˜์˜ ๋๋‹จ๋ถ€ ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ํ‘œ๋ฉด์ „ํ•˜์˜ ์˜ํ–ฅ์œผ๋กœ ์ธํ•˜์—ฌ shed ๋‚ด๋ถ€์—๋„ ๋†’์€ ์ „๊ณ„๊ฐ€ ์ง‘์ค‘๋˜๋ฏ€๋กœ ์ด๋ฅผ ์™„ํ™”์‹œํ‚ค๊ธฐ ์œ„ํ•œ ์ฝ”๋กœ๋‚˜๋ง์˜ ์„ค๊ณ„์•ˆ์„ ์ œ์‹œํ•˜์˜€๋‹ค. ์„ค๊ณ„๋œ ์ฝ”๋กœ๋‚˜๋ง์˜ ๋ฐ˜์ง€๋ฆ„์€ ๊ณ ์••๋ถ€์™€ ์ €์••๋ถ€ ๊ฐ๊ฐ 50mm, 40mm ์ด๋ฉฐ, ๊ฑฐ๋ฆฌ๋Š” 300mm, 370mm ์ด๊ณ , ๋†’์ด๋Š” ๋™์ผํ•˜๊ฒŒ 150mm์ด๋‹ค. DC ์ „๊ณ„ํŠน์„ฑ์€ ์œ ํ•œ์š”์†Œํ•ด์„ ํ”„๋กœ๊ทธ๋žจ์ธ COMSOL Multiphysics๋ฅผ ์ด์šฉํ•˜์—ฌ ๋ถ„์„ํ•˜์˜€์œผ๋ฉฐ, ์ ‘์ง€์ธก๊ณผ ๊ณ ์ „์•• ์ธ๊ฐ€์ธก์— ๊ฐ๊ฐ์˜ ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค๊ณ„ํ•จ์œผ๋กœ์„œ ๊ธˆ๊ตฌ๋ฅ˜ ๊ธฐ์ค€ ์•ˆ์ „์œจ์€ ๊ณ ์••๋ถ€์˜ ๊ฒฝ์šฐ 1.19, ์ ‘์ง€๋ถ€์˜ ๊ฒฝ์šฐ 1.32๋กœ ์„ค๊ณ„ํ•˜์—ฌ ๊ธˆ๊ตฌ๋ฅ˜์™€ shed ๋‚ด๋ถ€์— ์ง‘์ค‘๋˜๋Š” ์ตœ๋Œ€์ „๊ณ„ ์™„ํ™” ํšจ๊ณผ๋ฅผ ํ™•์ธํ•˜์˜€๋‹ค.

๋ณธ ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•˜์—ฌ ์ •์ƒ์ƒํƒœ์—์„œ์˜ ์ „๊ณ„ํŠน์„ฑ์„ ๊ณ ๋ คํ•œ 500kV๊ธ‰ HVDC ํด๋ฆฌ๋จธ ์• ์ž์šฉ ์ฝ”๋กœ๋‚˜๋ง์„ ์„ค๊ณ„ํ•˜์˜€์œผ๋ฉฐ, ํ–ฅํ›„์—๋Š” ๊ทน์„ฑ๋ฐ˜์ „์ด๋‚˜ ์ •์ƒ์ƒํƒœ์—์„œ ์ถฉ๊ฒฉํŒŒ๊ฐ€ ์ค‘์ฒฉ๋˜๋Š” ๊ทนํ•œ์˜ ์กฐ๊ฑด์„ ๋ชจ์˜ํ•œ ์ฝ”๋กœ๋‚˜๋ง ์„ค๊ณ„๋ฅผ ์ˆ˜ํ–‰ํ•  ๊ณ„ํš์ด๋‹ค.

Acknowledgement

์ด ๋…ผ๋ฌธ์€ 2022๋…„๋„ ์ •๋ถ€(์‚ฐ์—…ํ†ต์ƒ์ž์›๋ถ€)์˜ ์žฌ์›์œผ๋กœ ํ•œ๊ตญ์—๋„ˆ์ง€๊ธฐ์ˆ ํ‰๊ฐ€์›์˜ ์ง€์›์„ ๋ฐ›์•„ ์ˆ˜ํ–‰๋œ ์—ฐ๊ตฌ์ž„. (20222A10100020, ์†กยท๋ฐฐ์ „ ์ „๋ ฅ๊ธฐ๊ธฐ์šฉ ์นœํ™˜๊ฒฝ ๋ฐ ์ง๋ฅ˜ ์ ˆ์—ฐ์†Œ์žฌยท๋ถ€ํ’ˆ์˜ ์„ฑ๋Šฅํ‰๊ฐ€ ์‹œํ—˜๊ธฐ์ˆ  ๋ฐ ํ‘œ์ค€ ๊ฐœ๋ฐœ)

References

1 
Hingorani N. G., 1996, High-voltage DC Transmission: A Power Electronics Workhorse, in IEEE Spectrum, Vol. 33, No. 4, pp. 63-72DOI
2 
Hwang J. S., 2016., A Study on the DC Electric Field Analysis Based on the Measurement of Electrical Conductivity and the Optimum Insulation Design of HVDC Power Cable Accessories, Ph.D. Thesis, Department of Electronic Systems Engineering, Hanyang University, pp. 242Google Search
3 
Wang Hualei, Redfern M. A., 2010, The Advantages and Disadvantages of Using HVDC to Interconnect AC networks, Proc. of 45th International Universities Power Engineering Conference UPEC2010URL
4 
Jang J. T., 2000, A Study on The Market Overview of Polymer Insulator in Power Systems at The Two Americans, a Collection of Essays 6.1, pp. 429-443Google Search
5 
Yeo S. H., 2016., A Study on Economic Analysis of VSC-HVDC Technologies, M.Sc. Thesis, Department of Electrical Engineering, Chonnam National University, pp. 89Google Search
6 
Kalimurugan M. S., Sankar S. A., Iruthayarajan M. W., 2014, Investigation of Electric Field Distribution on AC Composite 230kV Insulator Using Corona Ring, 2014 International Conference on Circuits, Power and Computing Technologies [ICCPCT-2014], pp. 142-147DOI
7 
Kwon I. S., et al. , 2015, DC Electric Field Characteristics considering Thermal Effect for HVDC Slip-on Type Outdoor Termination, KEPCO Journal on Electric Power and Energy, Vol. 1, No. 1, pp. 39-46DOI
8 
Kreuger F. H., 1995, Industrial High DC Voltage, Delft University PressGoogle Search

Biography

Seunghee O
../../Resources/kiiee/JIEIE.2022.36.12.017/au1.png

She received a masterโ€™s degree in electrical engineering from Korea National University of Transportation in 2022. Currently, attending a Ph.D. course in electrical engineering, Korea National University of Transportation. Her research interests are high voltage engineering, power asset management, and applied superconductivity.

Minkyung Jeong
../../Resources/kiiee/JIEIE.2022.36.12.017/au2.png

She received a masterโ€™s degree in electrical engineering from Korea National University of Transportation in 2020. Currently, attending a Ph.D. course in electrical engineering, Korea National University of Transportation. Her research interests are high voltage engineering, power asset.

Bonhyuk Ku
../../Resources/kiiee/JIEIE.2022.36.12.017/au3.png

He is currently a bachelorโ€™s course in Dept. of electrical engineering, Korea National University of Transportation. His research interests are high voltage engineering, power asset management, and applied superconductivity.

Hobin Lee
../../Resources/kiiee/JIEIE.2022.36.12.017/au4.png

He is currently a bachelorโ€™s course in Dept. of electrical engineering, Korea National University of Transportation. His research interests are superconducting magnet, High voltage insulation design.

Hyoungku Kang
../../Resources/kiiee/JIEIE.2022.36.12.017/au5.png

He received doctorโ€™s degree in electrical engineering from Yonsei University in 2005. He is currently a professor in Dept. of electrical engineering, Korea National University of Transportation. His research interests are high voltage engineering, power asset management, and applied superconductivity.