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  1. (Dept. of Electrical Engineering, Korea Polytechnics University, Korea.)



Partial Discharge, Ultrasonic Signal, Phase Resolved Partial Discharge, Insulator, XLPE(Cross Linking-Polyethylene)

1. ์„œ ๋ก 

์ „๋ ฅ์˜ ์•ˆ์ „ํ•œ ๊ณต๊ธ‰์€ ์‹œ๋Œ€ ํ๋ฆ„์— ๋”ฐ๋ผ ๊ทธ ์ค‘์š”์„ฑ์ด ๋”์šฑ ๊ฐ•์กฐ๋˜๊ณ  ์žˆ๋‹ค. ํŠนํžˆ ์ „๋ ฅ์‚ฌ๊ณ ์˜ ์ „์กฐ์ฆ์ƒ์„ ํŒŒ์•…ํ•˜์—ฌ ์˜ˆ๋ฐฉํ•˜๋Š” ์˜ˆ๋ฐฉ ์ •๋น„๋ถ€๋ถ„์€ ๊ทธ ์ค‘์š”์„ฑ์ด ์ง€์†์ ์œผ๋กœ ๊ฐ•์กฐ๋˜๊ณ  ์žˆ๋‹ค.

๋ฐœ์ „์†Œ์—์„œ ์†ก์ „ํƒ‘ ๋ฐ ๋ณ€์ „์†Œ ๋“ฑ์„ ๊ฑฐ์ฒ˜ ์‚ฐ์—…์ฒด๋‚˜ ๊ฐ€์ •์—๊นŒ์ง€ ์ „๊ธฐ๊ฐ€ ๊ณต๊ธ‰๋˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์—ฌ๋Ÿฌ ๊ณผ์ •์„ ๊ฑฐ์น˜๊ฒŒ ๋˜๊ณ  ์ด ์ „์ฒด์˜ ๊ณผ์ •์—์„œ ์ ˆ์—ฐ ๋“ฑ์— ์ด์ƒ์ด ์ƒ๊ฒผ์„ ๋•Œ ๋ถ€๋ถ„๋ฐฉ์ „(PD, Partial Discharge)์ด ๋ฐœ์ƒํ•˜๊ฒŒ ๋œ๋‹ค. ์ฆ‰ ๋ถ€๋ถ„๋ฐฉ์ „์€ ๊ณ ์ „์•• ์ „๋ฐ˜์— ๊ฑธ์ณ ์ ์šฉํ•  ์ˆ˜ ์žˆ๋Š” ๋ฐฉ๋ฒ•์ด๋ฉฐ ๋ถ€๋ถ„๋ฐฉ์ „์˜ ์ง€์†์  ๊ฒ€์ถœ์„ ํ†ตํ•˜์—ฌ ์„ค๋น„ ๋ฐ ์žฅ๋น„์˜ ๋…ธํ›„ํ™”๋กœ ์ธํ•˜์—ฌ ์ƒ๊ธฐ๋Š” ์ ˆ์—ฐํŒŒ๊ดด์˜ ํŠธ๋ Œ๋“œ๋ฅผ ๋ถ„์„ํ•˜๊ณ  ์ด๋ฅผ ํ†ตํ•˜์—ฌ ์‚ฌ๊ณ  ์ด์ „์— ๋ถ€ํ’ˆ๊ต์ฒด๋‚˜ ์ˆ˜๋ฆฌ๋ฅผ ์‹œํ–‰ํ•˜์—ฌ ์‚ฌ๊ณ ๋ฅผ ์˜ˆ๋ฐฉํ•  ์ˆ˜ ์žˆ๋‹ค.

๋ถ€๋ถ„๋ฐฉ์ „ ๋ฐœ์ƒ ์‹œ ์—ฌ๋Ÿฌ ๊ฐ€์ง€ ์‹ ํ˜ธ๊ฐ€ ๋‚˜ํƒ€๋‚˜๋ฏ€๋กœ, ๋ถ€๋ถ„๋ฐฉ์ „ ์‹œ ๋ฐœ์ƒํ•˜๋Š” ์‹ ํ˜ธ์˜ ๊ฒ€์ถœ์— ๋”ฐ๋ผ ๋ถ€๋ถ„๋ฐฉ์ „ ๋ฐœ์ƒ ์—ฌ๋ถ€๋ฅผ ํŒ๋‹จํ•˜๊ฒŒ ๋œ๋‹ค. ๋ณดํŽธ์ ์œผ๋กœ UHF์‹ ํ˜ธ ๋Œ€์—ญ๊ณผ ์ดˆ์ŒํŒŒ ์‹ ํ˜ธ๋ฅผ ๊ฒ€์ถœํ•˜์—ฌ ํŒ๋‹จํ•œ๋‹ค. ์ผ๋ฐ˜์ ์ธ ๊ฒฝ์šฐ ์ผ€์ด๋ธ” ๋“ฑ์— ์ง์ ‘ ์„ผ์„œ๋ฅผ ๋ถ€์ฐฉํ•˜์—ฌ UHF์‹ ํ˜ธ๋ฅผ ๊ฒ€์ถœํ•˜๋Š” ๋ฐฉ์‹์„ ๋งŽ์ด ์‚ฌ์šฉํ•˜๊ณ  ์žˆ์œผ๋ฉฐ, ๋˜ํ•œ ์ดˆ์ŒํŒŒ๋ฅผ ์ด์šฉํ•œ ์ผ€์ด๋ธ” ์˜ˆ๋ฐฉ์ง„๋‹จ์— ๋Œ€ํ•œ ์—ฐ๊ตฌ๋„ ๊พธ์ค€ํžˆ ์ง„ํ–‰๋˜๊ณ  ์žˆ๋‹ค. ๊ทผ๋ž˜์—๋Š” ์ดˆ์ŒํŒŒ๋ฅผ ์ด๋ฏธ์ง€ํ™”ํ•˜์—ฌ ํ™”์ƒ์œผ๋กœ ํ‘œํ˜„ํ•˜๋Š” ์—ฐ๊ตฌ๋„ ํ™œ๋ฐœํžˆ ์ง„ํ–‰๋˜๊ณ  ์žˆ์œผ๋ฉฐ, ์ด๋Š” ์ดˆ์ŒํŒŒ ์‹ ํ˜ธ๋ฅผ ์ด์šฉํ•˜๋ฉด ์ง€ํ–ฅ์„ฑ์œผ๋กœ ์ธํ•œ ๊ณ ์žฅ๋ถ€๋ถ„์˜ ๊ฒ€์ถœ์ด UHF์‹ ๋กœ๋ฅผ ์ด์šฉํ•œ ์ง„๋‹จ๋ณด๋‹ค ์œ ๋ฆฌํ•œ ์ธก๋ฉด์ด ์žˆ๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค. ๋˜ํ•œ, ์‹ ํ˜ธ๋ฅผ ๊ฐ€๊ณตํ•˜์—ฌ ๋ถ„์„ํ•˜๋Š” ๋ฐฉ๋ฒ•์œผ๋กœ๋Š” PRPD(Phase Resolved Partial Discharge)๋ฐฉ๋ฒ•์„ ๊ฐ€์žฅ ๋งŽ์ด ์‚ฌ์šฉํ•˜๊ณ  ์žˆ์œผ๋ฉฐ PRPS(Phase Resolved Pulse Sequence)๋ฅผ ์ด์šฉํ•œ ๋ฐฉ๋ฒ•๋„ ํ•จ๊ป˜ ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋‹ค(1).

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ดˆ์ŒํŒŒ์„ผ์„œ๋ฅผ ์ด์šฉํ•˜์—ฌ ๋ถ€๋ถ„๋ฐฉ์ „ ์‹œ ์ผ์–ด๋‚˜๋Š” ์ดˆ์ŒํŒŒ๋ฅผ PRPD๋ฐฉ๋ฒ•์œผ๋กœ ๋ถ„์„ํ•˜์—ฌ ์ ˆ์—ฐ๋ฌผ์ด ์—†๋Š” ์ฝ”๋กœ๋‚˜ ๋ฐฉ์ „๊ณผ ๊ฐ€๊ตํด๋ฆฌ์—ํ‹ธ๋ Œ ์ฆ‰ XLPE(Cross Linking-Polyethylene)์ ˆ์—ฐ๋ฌผ์ด ์žˆ๋Š” ๋ถ€๋ถ„๋ฐฉ์ „์˜ PRPD์ƒ์— ๋‚˜ํƒ€๋‚˜๋Š” ๋ฐฉ์ „ ์‹ ํ˜ธ์˜ ์œ„์ƒ ์ฐจ์ด๋ฅผ ๋น„๊ต ๋ถ„์„ํ•˜์˜€๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ PRPD์ƒ์— ๋‚˜ํƒ€๋‚˜๋Š” ์‹ ํ˜ธ์˜ ๊ตฐ์ง‘ ํ˜•ํƒœ๋ฅผ ๋‰ด๋Ÿด ๋„คํŠธ์›Œํฌ(Neural Network)์„ ์ด์šฉํ•˜์—ฌ ๋ถ„์„ ๋ฐ ํŒ์ •์„ ํ•˜๋Š” ๋ฐฉ๋ฒ•๊ณผ ๋”๋ถˆ์–ด ์ตœ๊ทผ์—๋Š” ๋”ฅ๋Ÿฌ๋‹(Deep Learning)์„ ์ด์šฉํ•œ ๋ถ„์„๊ณผ ํŒ์ •์— ๊ด€ํ•œ ์—ฐ๊ตฌ๊ฐ€ ํ™œ๋ฐœํ•˜๊ฒŒ ์ง„ํ–‰๋˜๊ณ  ์žˆ๋‹ค(2).

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ด๋Ÿฌํ•œ ํŒ์ • ๋ฐ ๋ถ„์„ ๋ฐฉ๋ฒ•์— ์žˆ์–ด ์ค‘์š”ํ•œ ์š”์†Œ์ธ ๊ตฐ์ง‘์˜ ์œ„์ƒ๋ณ€ํ™”๊ฐ€ ์ ˆ์—ฐ๋ฌผ ์œ ๋ฌด์— ๋”ฐ๋ผ ์–ด๋–ป๊ฒŒ ๋‹ฌ๋ผ์ง€๋Š”์ง€ ํ™•์ธํ•˜๋Š” ๋ฐ ๊ทธ ๋ชฉ์ ์ด ์žˆ๋‹ค.

2. ๋ณธ ๋ก 

2.1 ๋ถ€๋ถ„ ๋ฐฉ์ „ ๋ชจ๋ธ

1930๋…„๋Œ€๋ถ€ํ„ฐ ๋ถ€๋ถ„๋ฐฉ์ „์„ ๋‚˜ํƒ€๋‚ด๊ธฐ ์œ„ํ•ด ์—ฌ๋Ÿฌ ๋ชจ๋ธ์ด ๊ฐœ๋ฐœ๋˜์—ˆ๋‹ค(3). ๊ทธ์ค‘ ๊ฐ€์žฅ ๋นˆ๋„์ˆ˜๊ฐ€ ๋†’๊ฒŒ ์‚ฌ์šฉํ•˜๋Š” ๋ชจ๋ธ์€ a-b-c๋ชจ๋ธ์ด๋ผ๊ณ  ํ•˜๋Š” 3-capacitor๋ชจ๋ธ ์ด๋‹ค. ๊ฐ„๋‹จํ•˜๊ฒŒ ํ‘œ์‹œ๋œ ๋ฐฉ๋ฒ•์œผ๋กœ ๋ฐฉ์ „์‹œ๋‚˜๋ฆฌ์˜ค๋ฅผ ์‰ฝ๊ฒŒ ์ดํ•ด ํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. 1960๋…„๋Œ€์— ๊ฐœ๋ฐœ๋œ 5-capacitor๋ชจ๋ธ(4)๊ณผ 1980๋…„๋Œ€์— ๊ฐœ๋ฐœ๋œ ์Œ๊ทน์ž ๋ชจ๋ธ(5)์ด ์žˆ์—ˆ์ง€๋งŒ a-b-c๋ชจ๋ธ์ด ๊พธ์ค€ํ•˜๊ฒŒ ์‚ฌ์šฉ๋˜์–ด ์™”์œผ๋ฉฐ ์ด๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ IEC 60270์€ ํ…Œ์ŠคํŠธ ๋Œ€์ƒ ๋‹จ์ž์—์„œ ์ธก์ •ํ•  ์ˆ˜ ์žˆ๋Š” ์ „ํ•˜์ธ โ€˜ํ”ผ์ƒ ์ „ํ•˜โ€™(Apparent charge)๋ผ๋Š” ์šฉ์–ด๋ฅผ ์ •์˜ํ•œ๋‹ค. IEC๊ฐ€ ํ”ผ์ƒ์ „ํ•˜๋ผ๋Š” ์šฉ์–ด๋ฅผ ํ†ตํ•ด ์ธก์ •๋œ ์ „ํ•˜์˜ ๊ฐ’์ด ๋ฐฉ์ „์—์„œ์˜ ์ „ํ•˜์™€ ์ •ํ™•ํ•˜๊ฒŒ ๊ฐ™์ง€ ์•Š๋‹ค๋Š” ๊ฒƒ์ด๋‹ค. ์ฆ‰ $C_{\begin{aligned}c\\ \end{aligned}}$๊ฐ€ ์ „ํ•˜ ๋ถ€์กฑ๋ถ„ ์ปคํŒจ์‹œํ„ด์Šค, $C_{b}$๊ฐ€ ๋ถ€์กฑ๋ถ„๊ณผ ์ง๋ ฌ๋กœ ์—ฐ๊ฒฐ๋œ ์œ ์ „์ฒด์˜ ์ปคํŒจ์‹œํ„ด์Šค, $q_{c}$๊ฐ€ ๊ฒฐํ•จ ์œ„์น˜์˜ ์ „ํ•˜๋‹จ์ž($q_{a}$)์—์„œ ์ธก์ •๋œ ์ „ํ•˜๋ผ๊ณ  ํ•˜๋ฉด, ์‹ (1)๊ณผ ๊ฐ™์ด ๋‚˜ํƒ€๋‚ผ ์ˆ˜ ์žˆ๋‹ค.

(1)
$q_{a}=q_{c}(C_{b}/C_{c})$

$q_{a}$ : ๋‹จ์ž์—์„œ ๋ฐœ์ƒ๋œ ์ „ํ•˜ $q_{c}$ : ์ธก์ •๋œ ์ „ํ•˜ $C_{b}$ : ์ง๋ ฌ๋กœ ์—ฐ๊ฒฐ๋œ ์œ ์ „์ฒด ์ปคํŒจ์‹œํ„ด์Šค $C_{\begin{aligned}c\\ \end{aligned}}$ : ์ „ํ•˜๋ถ€์กฑ๋ถ„ ์ปคํŒจ์‹œํ„ด์Šค

๊ทธ๋Ÿฌ๋‚˜ $C_{\begin{aligned}c\\ \end{aligned}}$๊ฐ€ $C_{b}$์— ๋น„ํ•˜์—ฌ ํฌ๋‹ค๊ณ  ๊ฐ€์ •ํ•  ๋•Œ $q_{c}$๋Š” $q_{a}$๋ณด๋‹ค ํฌ๊ฒŒ ๋˜๊ณ  ์ด๋Ÿฌํ•œ ์ด์œ ๋กœ ์‹ค์ œ ๋ฐฉ์ „ ๊ฐ’๊ณผ ๊ด€๋ จ ์—†๋Š” ์ž„์˜์˜ ๊ฐ’์œผ๋กœ ์ž˜๋ชป ํ•ด์„๋˜์—ˆ๋‹ค. 2010๋…„์—๋Š” ์Œ๊ทน์ž ๋ชจ๋ธ์„ ๊ธฐ๋ฐ˜์œผ๋กœ โ€˜์œ ๋„ ์ „ํ•˜โ€™(Induced charge)๋ผ๋Š” ์šฉ์–ด๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ๋ถ€๋ถ„๋ฐฉ์ „์„ ์ธก์ •ํ•˜์˜€๊ณ  ์ด๋Š” IEC 60270์— ์˜ํ–ฅ์„ ์ค€ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” IEC ๋ชจ๋ธ์„ ์ฐธ๊ณ ํ•˜์˜€์œผ๋‚˜ ๋ฐฉ์ „๋Ÿ‰ ์ค‘์‹ฌ์ด ์•„๋‹Œ ๋ฐฉ์ „ ์‹œ ๋‚˜ํƒ€๋‚˜๋Š” ์œ„์ƒ์˜ ๋ณ€ํ™”๋ฅผ PRPD ๋ฐฉ๋ฒ•์œผ๋กœ ๊ณ ์ฐฐํ•˜์˜€๋‹ค.

2.2 ์‹คํ—˜๋ฐฉ๋ฒ•

2.2.1 ๋ฐฉ์ „ ์‹คํ—˜์žฅ์น˜ ๊ตฌ์„ฑ

๋ณธ ์—ฐ๊ตฌ๋ฅผ ์œ„ํ•˜์—ฌ ๋ถ€๋ถ„๋ฐฉ์ „์„ ๋งŒ๋“ค์–ด๋‚ด๋Š” ์‹คํ—˜์žฅ์น˜์™€ ๋ถ€๋ถ„๋ฐฉ์ „์„ ์ธ์‹ํ•˜๊ณ  ๋ฌผ๋ฆฌ์  ์‹ ํ˜ธ๋ฅผ ๋ถ„์„ํ•˜๋Š” ์‹คํ—˜์žฅ์น˜๊ฐ€ ํ•„์š”ํ•˜๋‹ค. ๋จผ์ € ๋ถ€๋ถ„๋ฐฉ์ „์„ ๋งŒ๋“ค์–ด๋‚ด๊ธฐ ์œ„ํ•˜์—ฌ ๊ตญ๋‚ด์—์„œ ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋Š” AC๊ณ ์ „์••๊ณผ ๊ฐ™์€ ์ „์••๊ณผ ์œ„์ƒ์ด ํ•„์š”ํ•˜๋‹ค. ์ด๋ฅผ ์œ„ํ•˜์—ฌ ๊ทธ๋ฆผ 1๊ณผ ๊ฐ™์€ ์‹คํ—˜์žฅ์น˜๋ฅผ ๋งŒ๋“ค์–ด ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์‹คํ—˜์˜ ์ •ํ™•์„ฑ์„ ์œ„ํ•˜์—ฌ ๊ธฐ์กด์— ์‚ฌ์šฉํ•˜๋Š” ๋ฐฉ์ „์žฅ์น˜์ธ DC ๊ณ ์ „์•• ๋ฐฉ์ „์ด๋‚˜ Tesla Coil๊ณผ ๊ฐ™์ด ์ฃผํŒŒ์ˆ˜ ๋ณ€ํ˜•์„ ์ผ์œผํ‚ค๋Š” ์žฅ๋น„๋Š” ์‚ฌ์šฉํ•˜์ง€ ์•Š์•˜์œผ๋ฉฐ ์šฐ๋ฆฌ๊ฐ€ ์‚ฌ์šฉํ•˜๊ณ ์ž ํ•˜๋Š” ์ƒ์šฉ์ฃผํŒŒ์ˆ˜(60 Hz)๋ฅผ ํ•˜๋Š” ์‹คํ—˜ ์žฅ๋น„๋ฅผ ์ œ์ž‘ํ•˜์—ฌ ์‹คํ—˜์„ ์ง„ํ–‰ํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ 1 ๊ณ ์ „์•• ๋ฐฉ์ „ ์‹คํ—˜์žฅ์น˜์˜ ์™ธ๊ด€

Fig. 1 High Voltage Discharge Experimental Apparatus

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๋ถ€๋ถ„๋ฐฉ์ „์€ ์ ˆ์—ฐ์ฒด๊ฐ€ ์ž์‹ ์˜ ์ ˆ์—ฐ์„ฑ์„ ์žƒ์–ด ์ „๋ฅ˜๋ฅผ ํ˜๋ฆฌ๋Š” ํ˜„์ƒ์œผ๋กœ ์ ˆ์—ฐ์ด ํŒŒ๊ดด๋˜๋Š” ์กฐ๊ฑด์— ์ „์••๋ฟ ๋งŒ ์•„๋‹ˆ๋ผ ์ฃผํŒŒ์ˆ˜์˜ ์˜ํ–ฅ์ด ํฌ๊ธฐ ๋•Œ๋ฌธ์— ๋ณธ ์žฅ๋น„๋ฅผ ํ†ตํ•˜์—ฌ ์ƒ์šฉ์ „์••์ธ 220 V๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ „์••๋งŒ์„ ์ƒ์Šน์‹œ์ผœ ์ฃผํŒŒ์ˆ˜ ๋ณ€๋™ ์—†์ด ๋ฐฉ์ „ํ•˜๋Š” ๊ฒƒ์ด ํŠน์ง•์ด๋‹ค.

๋˜ํ•œ, ๊ทธ๋ฆผ 2์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ๋ณธ ์‹คํ—˜ ์žฅ์น˜์— ์Šฌ๋ผ์ด๋‹ฅ์Šค๋ฅผ ์ด์šฉํ•˜์—ฌ ์ „์••์„ ์กฐ์ •ํ•˜๊ณ , ์กฐ์ • ์ „์••์„ ์•Œ ์ˆ˜ ์žˆ๋„๋ก ๋””์Šคํ”Œ๋ ˆ์ด๋ฅผ ํ†ตํ•ด ํ‘œ์‹œํ–ˆ์œผ๋ฉฐ, ๋Œ€์ „๋ฅ˜๊ฐ€ ํ๋ฅด์ง€ ์•Š๋„๋ก ๊ณ ์ „์••์šฉ ์ €ํ•ญ์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๋˜ํ•œ ๋ˆ„์„ค๋ณ€์••๊ธฐ๋ฅผ ์ด์šฉํ•˜์—ฌ ๋ˆ„์„ค ๋ฆฌ์•กํ„ด์Šค๋ฅผ ํฌ๊ฒŒ ์ฆ๊ฐ€์‹œ์ผœ ๋ถ€ํ•˜ ์ž„ํ”ผ๋˜์Šค์˜ ๋ณ€๋™์—๋„ ์ผ์ •ํ•œ 2์ฐจ ์ „๋ฅ˜๊ฐ€ ํ๋ฅด๋„๋ก ํ•˜์—ฌ ๋‚ด๊ตฌ์„ฑ ๋ฐ ์•ˆ์ „์„ฑ์„ ๋„๋ชจํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ 2 AC๋ฐฉ์ „๊ธฐ์˜ ๊ตฌ์„ฑ๋„

Fig. 2 Configuration diagram of AC discharger

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2.2.2 ์ดˆ์ŒํŒŒ ์„ผ์„œ๋ฅผ ํ†ตํ•œ ์‹ ํ˜ธ ์ˆ˜์ง‘ ์žฅ์น˜ ๊ตฌ์„ฑ

์ดˆ์ŒํŒŒ ์‹ ํ˜ธ ์ˆ˜์ง‘ ์žฅ์น˜ ๊ตฌ์„ฑ ์ค‘ ๊ฐ€์žฅ ์ค‘์š”ํ•œ ์ดˆ์ŒํŒŒ ์„ผ์„œ์˜ ์ŠคํŽ™์€ ํ‘œ 1๊ณผ ๊ฐ™๋‹ค. ์ผ๋ฐ˜์ ์œผ๋กœ ์ดˆ์ŒํŒŒ๋Š” 20kHz ์ด์ƒ์„ ์˜๋ฏธํ•˜์ง€๋งŒ ๋ณธ ์‹คํ—˜์— ์‚ฌ์šฉํ•œ ์„ผ์„œ๋Š” 40 kHz ์ด์ƒ ์‹ ํ˜ธ๋ฅผ ๊ฐ์ง€ํ•˜๋Š” ์„ผ์„œ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์ƒํ™œ ์žก์Œ์œผ๋กœ ์ธํ•œ Noise์˜ ์˜ํ–ฅ์„ ์ตœ์†Œํ™”ํ•˜์˜€๋‹ค.

๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” ์ผ๋ฐ˜์ ์œผ๋กœ ๋ถ€๋ถ„๋ฐฉ์ „์— ๋„๋ฆฌ ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋Š” UHF(ultra-high frequency) ๊ทน์ดˆ๋‹จํŒŒ ์„ผ์„œ๊ฐ€ ์•„๋‹Œ ์ดˆ์ŒํŒŒ ์„ผ์„œ๋ฅผ ์‚ฌ์šฉํ•œ ์ด์œ ๋Š” UHF ์‹ ํ˜ธ๋ฅผ ๊ฒ€์ถœํ•˜๋Š” ๊ฒƒ์ด ์‹ ํ˜ธ ๋ฏผ๊ฐ๋„๋Š” ์œ ๋ฆฌํ•˜์ง€๋งŒ ์‚ฌ๊ณ ์ง€์ ์„ ํŒŒ์•…ํ•  ์ˆ˜ ์žˆ๋Š” ์ง€ํ–ฅ์„ฑ์—์„œ๋Š” ์ดˆ์ŒํŒŒ ์‹ ํ˜ธ๋ฅผ ํ™œ์šฉํ•˜๋Š” ๊ฒƒ์ด ์œ ๋ฆฌํ•˜๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค. ์ฆ‰, ๊ฐœ๋ฐฉ๋œ ๊ณต๊ฐ„์—์„œ ์‚ฌ๊ณ ์ง€์ ์„ ์ฐพ๋Š” ๋ถ€๋ถ„์— ์žˆ์–ด์„œ๋Š” ์ดˆ์ŒํŒŒ ์„ผ์„œ๋ฅผ ์ด์šฉํ•œ ๋ฐฉ๋ฒ•์ด ์œ ๋ฆฌํ•˜๋‹ค๊ณ  ๋ณผ ์ˆ˜ ์žˆ๊ธฐ ๋•Œ๋ฌธ์ด๋‹ค.

ํ‘œ 1 ์ดˆ์ŒํŒŒ ์„ผ์„œ ์ŠคํŽ™

Table 1 Ultrasonic sensor specifications

Field

Value or Performance

Center frequency[kHz]

40/48/58ยฑ1.5

Capacitance[pF]

2000ยฑ15%

Sound pressure level[dB]

โ‰ฅ100ยฑ5

Sensitivity[dB]

-73ยฑ5

Directivityยฐ]

X=100ยฑ5 Y=60ยฑ10

Resistance[ฮฉ]

500

Ring time[ms]

โ‰ค

Max. input voltage

150Vp-p

Operating temperature rangeยฐC]

-35 ~ +80

Storage temperature rangeยฐC]

-40 ~ +85

Weight[g]

3.8

๊ทธ๋ฆผ 3์—์„œ์™€ ๊ฐ™์ด ์ดˆ์ŒํŒŒ ์„ผ์„œ๋Š” ์ง€ํ–ฅ์„ฑ ๋ฐ ์‹ ํ˜ธ ์ฆํญ์„ ์œ„ํ•˜์—ฌ ํ”Œ๋ผ์Šคํ‹ฑ ์žฌ์งˆ์˜ ํ˜ผ(horn)์„ ์ด์šฉํ•˜์˜€๊ณ  Lan ํ†ต์‹ ์„ ์ด์šฉํ•˜์—ฌ PD Analysisํ”„๋กœ๊ทธ๋žจ๊ณผ ์—ฐ๋™ํ•˜์—ฌ ๋ถ„์„ํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ 3 ์ดˆ์ŒํŒŒ ์‹ ํ˜ธ ์ˆ˜์ง‘ ์žฅ์น˜ ๊ตฌ์„ฑ๋„

Fig. 3 Configuration diagram of ultrasonic signal acquisition device

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2.2.3 ์‹คํ—˜์‹ค ๋‚ด๋ถ€์˜ ๋…ธ์ด์ฆˆ ์ธก์ •

์‹คํ—˜์‹ค ๋‚ด๋ถ€์˜ ๋…ธ์ด์ฆˆ๋ฅผ ์ธก์ •ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ AC๋ฐฉ์ „๊ธฐ๋ฅผ ์ผœ์ง€ ์•Š์€ ์ƒํƒœ์—์„œ ๋…ธ์ด์ฆˆ๋ฅผ ์ธก์ •ํ•˜์˜€์œผ๋ฉฐ ๊ธฐ๋ณธ ๋…ธ์ด์ฆˆ์˜ PRPS, PRPD ํŒจํ„ด์€ ๊ทธ๋ฆผ 4์™€ ๊ฐ™๋‹ค ๋…ธ์ด์ฆˆ๋Š” PRPD ๋ถ„ํฌ์—์„œ ๋ณด๋Š” ๋ฐ”์™€ ๊ฐ™์ด ์ƒ์šฉ์ฃผํŒŒ์ˆ˜ 60 Hz์™€ ๋ฌด๊ด€ํ•˜๊ฒŒ ์ผ์ •ํ•œ ํŒจํ„ด์„ ๋ณด์ด๊ณ  ์žˆ์œผ๋ฏ€๋กœ ์‹คํ—˜์‹ค์˜ ๋…ธ์ด์ฆˆ๊ฐ€ ์‹คํ—˜์— ํฐ ์˜ํ–ฅ์ด ์—†์Œ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

๊ทธ๋ฆผ 4 ์‹คํ—˜์‹ค ๋‚ด๋ถ€ ๋…ธ์ด์ฆˆ์— ๋Œ€ํ•œ PRPD, PRPS์ธก์ •

Fig. 4 PRPD, PRPS measurement for laboratory noise

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2.2.4 ๊ธฐ์ค‘ ์ ˆ์—ฐํŒŒ๊ดด PD ์‹œํ—˜

๋ณธ ์—ฐ๊ตฌ์—์„œ ์‚ฌ์šฉํ•œ AC์ง€์† ๋ฐฉ์ „์žฅ์น˜์˜ ์ „์••์„ 18 kV๋กœ ์ผ์ •ํ•˜๊ฒŒ ์œ ์ง€ํ•˜๊ณ  ๋ฐฉ์ „ ํƒญ์˜ ๊ทน๊ฐ„ ๊ฐ„๊ฒฉ์„ 5mm๋กœ ๊ณ ์ •์‹œ์ผœ ์‹คํ—˜ํ•˜์˜€์œผ๋ฉฐ ์ „์ฒด์ ์ธ ์‹คํ—˜๋ฐฉ๋ฒ•์€ IEC 60270์„ ์ฐธ๊ณ ํ•˜์˜€๋‹ค.

๋ฐฉ์ „ ํƒญ๊ณผ ์ดˆ์ŒํŒŒ ์„ผ์„œ๊ฐ„์˜ ์ธก์ •๊ฑฐ๋ฆฌ๋Š” 2.5m๋ฅผ ์œ ์ง€ํ•˜์—ฌ ์‹คํ—˜ ํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ 5 ๊ธฐ์ค‘ ์ „์—ฐํŒŒ๊ดด ์ฝ”๋กœ๋‚˜ ๋ฐฉ์ „ ์ธก์ •

Fig. 5 Insulation breakdown corona discharge measurement in air

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๊ธฐ์ค‘ ์ ˆ์—ฐํŒŒ๊ดด์—์„œ ๋‚˜ํƒ€๋‚˜๋Š” ์ฝ”๋กœ๋‚˜๋Š” ๋ถ€๋ถ„๋ฐฉ์ „์— ์žˆ์–ด์„œ๋Š” ๋Œ€ํ‘œ์ ์ด๊ณ  ๊ฐ€์žฅ ๊ฒ€์ถœํ•˜๊ธฐ ์‰ฌ์šด ํŒจํ„ด์„ ๊ฐ€์ง€๊ณ  ์žˆ์œผ๋ฉฐ PRPD๋ถ„์„์— ์žˆ์–ด ํ‘œ๋ณธ์ด ๋˜๋Š” ์ง€ํ‘œ๋กœ ํ™œ์šฉ ํ•  ์ˆ˜ ์žˆ๋‹ค.

๊ทธ๋ฆผ 6 ๊ธฐ์ค‘ ์ ˆ์—ฐํŒŒ๊ดด ์ฝ”๋กœ๋‚˜ PRPS, PRPD

Fig. 6 Insulation breakdown corona in air PRPS, PRPD

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๊ทธ๋ฆผ 6์€ ๊ทธ๋ฆผ 5์™€ ๊ฐ™์ด ๊ธฐ์ค‘ ์ ˆ์—ฐํŒŒ๊ดด ์ƒํƒœ์—์„œ PRPS, PRPD๋ฅผ ๋‚˜ํƒ€๋‚ด๋ฉฐ PRPDํ™”๋ฉด์€ 10์ดˆ๊ฐ„ ์ ์‚ฐํ•˜์˜€์œผ๋ฉฐ 1์ดˆ๋‹น 60๋ฒˆ ์ด600ํšŒ ์ ์‚ฐํ•˜์˜€์œผ๋ฉฐ ์ƒ˜ํ”Œ๋ง์€ ์ดˆ๋‹น 7680ํšŒ ์ƒ˜ํ”Œ๋ง ํ•˜์˜€๋‹ค.

2.2.5 XLPE ์ ˆ์—ฐ๋ฌผ์ด ์žˆ๋Š” ์ƒํƒœ์—์„œ์˜ PDํŒจํ„ด

ํ˜„์žฌ 22.9 kV ๊ณ„ํ†ต์—์„œ ๊ฐ€์žฅ ๋งŽ์ด ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋Š” ์ผ€์ด๋ธ”์€ CNCV ๊ณ„์—ด๋กœ ์ด ์ผ€์ด๋ธ”์˜ ์ฃผ ์ ˆ์—ฐ์žฌ๋Š” XLPE์ด๋ฉฐ ์ผ€์ด๋ธ”์˜ ๋ง๋‹จ๋ถ€ ์ด์™ธ์˜ ๋ถ€๋ถ„๋ฐฉ์ „์—์„œ๋Š” XLPE์˜ ์ƒํƒœ๊ฐ€ ๋ถ€๋ถ„๋ฐฉ์ „์— ๊ฐ€์žฅ ํฐ ์˜ํ–ฅ์„ ๋ฏธ์นœ๋‹ค. XLPE์˜ ์ ˆ์—ฐํŒŒ๊ดด๋Š” ๋ฌผ๋ฆฌ์ ์ธ ์†Œ์† ์ด์™ธ์—๋„ ํŠธ๋ฆฌ์— ์˜ํ•œ ์†Œ์†๊ณผ ํ™”ํ•™์  ๋ณ€ํ™”์— ์˜ํ•œ ์†Œ์† ๋“ฑ์ด ์žˆ์„ ์ˆ˜ ์žˆ๋‹ค.

๋ณธ ์‹คํ—˜์—์„œ๋Š” ๊ทธ๋ฆผ 7๊ณผ ๊ฐ™์ด ๋ฌผ๋ฆฌ์  ์†Œ์†์ด ์žˆ๋Š” CNCV ์ผ€์ด๋ธ”์— ์ „์••์„ ๊ฐ€์••ํ•˜์—ฌ ์‹คํ—˜ํ•˜์˜€์œผ๋ฉฐ ๋ฐฉ์ „์ „์••์€ ๊ธฐ์ค‘๊ณผ ๋™์ผํ•˜๊ฒŒ 18 kV๋กœ ์ผ์ •ํ•˜๊ฒŒ ์œ ์ง€์‹œ์ผœ ์‹คํ—˜ ํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ 7 ์‹œํ—˜์— ์‚ฌ์šฉํ•œ ๋ฌผ๋ฆฌ์  ๊ฒฐํ•จ์ด ์žˆ๋Š” CNCV์ผ€์ด๋ธ”

Fig. 7 CNCV cable used for testing

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๊ทธ๋ฆผ 8 XLPE ๋ฌผ๋ฆฌ์  ํŒŒ๊ดด๋กœ ์ธํ•œ ๋ฐฉ์ „ PRPS, PRPD

Fig. 8 Discharge due to XLPE physical destruction PRPS, PRPD

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2.3 ๋ถ„์„๋ฐฉ๋ฒ•

๋ณธ ์—ฐ๊ตฌ์—์„œ ์‚ฌ์šฉํ•œ ์ดˆ์ŒํŒŒ ์‹ ํ˜ธ๋Š” 60 Hz ์ „์šฉ PD Analysis ์†Œํ”„ํŠธ์›จ์–ด๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ๊ทธ๋ฆผ 8๊ณผ ๊ฐ™์ด PRPS, PRPD ๋ฐ์ดํ„ฐ๋ฅผ ์ƒ์„ฑํ•  ์ˆ˜ ์žˆ์œผ๋ฉฐ ์ƒ์„ฑ๋œ ๋ฐ์ดํ„ฐ๋ฅผ CSV(Comma Separated Value)ํŒŒ์ผ์„ Excelํ”„๋กœ๊ทธ๋žจ์„ ํ†ตํ•˜์—ฌ ๊ฐ€๊ณตํ•˜์—ฌ ๋ถ„์„ํ•˜์˜€๋‹ค.

2.3.1 ์‹คํ—˜์‹ค ๋‚ด๋ถ€ ๋…ธ์ด์ฆˆ ๋ถ„์„

๊ทธ๋ฆผ 9๋Š” PD Analysis ์†Œํ”„ํŠธ์›จ์–ด์—์„œ ์‹คํ—˜์‹ค ๋‚ด๋ถ€๋…ธ์ด์ฆˆ ๋ฐ์ดํ„ฐ๋ฅผ CSV ํŒŒ์ผ๋กœ ๋ณ€ํ™˜ํ•˜์—ฌ Excel ํ”„๋กœ๊ทธ๋žจ์œผ๋กœ ๊ฐ€๊ณตํ•˜์—ฌ ๊ฐ ์ฃผํŒŒ์ˆ˜๋ณ„ ๋…ธ์ด์ฆˆ์˜ ํŒจํ„ด์„ ๋ถ„์„ํ•˜์˜€์œผ๋ฉฐ ์„ธ๋กœ์ถ•์€ ๋ฐฉ์ „์˜ ์„ธ๊ธฐ๋ฅผ ๊ฐ€๋กœ์ถ•์€ ์‹œ๊ฐ„ ์ถ•์œผ๋กœ 60 Hz ํ•œ์ฃผ๊ธฐ์˜ 360ยบ์œ„์ƒ์„ 128๊ฐœ๋กœ ๋‚˜๋ˆ„์–ด ์•ฝ 2.8ยบ๋‹น ํ‰๊ท  ๋ฐฉ์ „ํšŸ์ˆ˜๋Š” 576.34ํšŒ ์ตœ๋Œ“๊ฐ’ 600ํšŒ ์ตœ์†Ÿ๊ฐ’ 555ํšŒ ํ‘œ์ค€ํŽธ์ฐจ 8.4๋กœ ํ‰๊ท ๋Œ€๋น„ ์•ฝ1.45% ํŽธ์ฐจ๋กœ ์ผ์ •ํ•˜๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. PD Analysis ํ”„๋กœ๊ทธ๋žจ์—์„œ์˜ ๋…ธ์ด์ฆˆ ๊ฐ•๋„ ๋‹จ์œ„๋Š” dBm์œผ๋กœ ๋‚˜ํƒ€๋‚ด์ง€๋งŒ, ์ƒ๊ธฐ ์ˆ˜์น˜๋Š” ์ธก์ • ํšŸ์ˆ˜๋ฅผ ์ ์šฉํ•˜์—ฌ ๋…ธ์ด์ฆˆ์—๋Š” 60 Hz์— ๋Œ€ํ•œ ์ฃผ๊ธฐ์„ฑ์ด ์—†๋Š” ๊ฒƒ์œผ๋กœ ํŒ๋‹จ ํ•  ์ˆ˜ ์žˆ๋‹ค.

๊ทธ๋ฆผ 9 ๋…ธ์ด์ฆˆ PRPD์˜ Excel๊ฐ€๊ณต ๋ฐ์ดํ„ฐ

Fig. 9 Excel Processing Data for Noise PRPD

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(2)
$F_{nosie}=\sqrt{\dfrac{\sum_{k=1}^{k}(N_{k}-N_{av})^{2}}{k}}$

2.3.2 ๊ธฐ์ค‘ ์ฝ”๋กœ๋‚˜ ๋ฐฉ์ „ ์‹œ ์ค‘์‹ฌ ์œ„์ƒ ์ธก์ •

๊ทธ๋ฆผ 5์™€ ๊ฐ™์ด ๋ฐฉ์ „๊ทน ์‚ฌ์ด์— ๊ณต๊ธฐ๋งŒ์ด ์กด์žฌํ•˜๋Š” ์ž์—ฐ๋ฐฉ์ „์—์„œ PD(๋ถ€๋ถ„๋ฐฉ์ „)์„ ์ธก์ •ํ•˜๊ณ  PD Analysis ์†Œํ”„ํŠธ์›จ์–ด์—์„œ ์–ป์–ด์ง„ CSV ๋ฐ์ดํ„ฐ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ Excel ํ”„๋กœ๊ทธ๋žจ์œผ๋กœ ๊ฐ€๊ณตํ•˜์—ฌ ๊ธฐ์ค‘๋ฐฉ์ „ ์ฝ”๋กœ๋‚˜์˜ ์ค‘์‹ฌ์œ„์ƒ์„ ์‚ฐ์ถœํ–ˆ๋‹ค. ๋ณธ ์—ฐ๊ตฌ์—์„œ ์ค‘์‹ฌ์œ„์ƒ์ด๋ž€ ์ผ๋ฐ˜์ ์ธ sin ํŒŒํ˜•์—์„œ ์ „์••์ด ๊ฐ€์žฅ ๋†’์€ 90ยบ๋ฅผ ์˜๋ฏธํ•˜๋ฉฐ ๋ฐฉ์ „ ๋ถ„ํฌ๊ฐ€ ๊ฐ€์žฅ ํ™œ๋ฐœํ•˜๊ฒŒ ์ผ์–ด๋‚˜๋Š” ๊ตฐ์ง‘์˜ ์ค‘์‹ฌ์œ„์ƒ์„ ๋งํ•œ๋‹ค. ์ฆ‰ ๊ต๋ฅ˜ํŒŒํ˜•์—์„œ ์ „์••์ด ๊ฐ€์žฅ ๋†’์€ ์œ„์ƒ(90ยบ)์—์„œ ๋ฐฉ์ „์ด ๊ฐ€์žฅ ๋งŽ์ด ์ผ์–ด๋‚œ๋‹ค๊ณ  ๊ฐ€์ •ํ•˜๊ณ  ์ด ์ค‘์‹ฌ์ด ๋ฐฉ์ „๊ธฐ์˜ ์œ ๋„์„ฑ ๋ฆฌ์•กํ„ด์Šค(Inductive Reactance)์— ์˜ํ•œ ์œ„์ƒ ๋ณ€ํ™”๋ฅผ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

์ค‘์‹ฌ์œ„์ƒ์„ ์ธก์ •ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ Excel์˜ ์ค‘์‹ฌ์œ„์ƒ์„ ์•Œ๊ธฐ ์œ„ํ•ด์„œ๋Š” ๊ฐ ์œ„์ƒ๋ณ„ ํฌ๊ธฐ๋Š” ๋ฌด์‹œํ•˜๊ณ  ๋ฐฉ์ „ํšŸ์ˆ˜๋กœ ์‹ (3)๊ณผ ๊ฐ™์ด ์ค‘์‹ฌ์œ„์ƒ์„ ๋„์ถœํ•˜์˜€๋‹ค.

(3)
$P_{mid}=\dfrac{\sum_{k=1}^{64}(2.8k\times PD_{k})}{\sum_{k=1}^{64}PD_{k}}$

$P_{mid}$ : ์ค‘์‹ฌ์œ„์ƒ

$PD_{k}$ : k๋ฒˆ์งธ ์œ„์ƒ์˜ ๋ฐฉ์ „ํšŸ์ˆ˜

๊ทธ๋ฆผ 10๋Š” ์—‘์…€๋กœ ๋ณ€ํ™˜ํ•œ ์‹คํ—˜ ํŒŒ์ผ์„ ์ˆซ์ž์— ๋น„๋ก€ํ•œ ์กฐ๊ฑด๋ถ€ ์„œ์‹์œผ๋กœ ์ˆซ์ž์˜ ํฌ๊ธฐ์— ๋น„๋ก€ํ•˜์—ฌ ์ƒ‰์กฐ๋ฅผ ๋ฐ˜์˜ํ•˜์˜€๋‹ค.

์œก์•ˆ์œผ๋กœ ๋ณด์•˜์„ ๋•Œ ๋ฐฉ์ „์œ„์ƒ์ด ์•ฝ๊ฐ„ ์•ž์„œ์žˆ๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ์œผ๋ฉฐ ์ด๋ฅผ ์‹ (3)์œผ๋กœ ์ค‘์‹ฌ์ถ•์„ ๊ณ„์‚ฐํ–ˆ์„ ๋•Œ ์•ฝ 88.071๋กœ ์‚ฐ์ถœํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค.

๊ทธ๋ฆผ 10 ์ฝ”๋กœ๋‚˜ ๋ฐฉ์ „์˜ Excel ๊ฐ€๊ณต ๋ฐ์ดํ„ฐ

Fig. 10 Excel Processing Data for corona Discharge

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2.3.3 XLPE ์ ˆ์—ฐ๋ฌผ ๋ฐฉ์ „ ์‹œ ์ค‘์‹ฌ ์œ„์ƒ ์ธก์ •

์ผ€์ด๋ธ”์˜ ํ‘œ์ ์ธ XLPE ์ ˆ์—ฐ๋ฌผ์ด ์žˆ๋Š” ์ƒํƒœ์—์„œ์˜ ๋ฐฉ์ „ ์‹คํ—˜์—์„œ๋Š” ๊ทธ๋ฆผ 11์—์„œ์™€ ๊ฐ™์€ ํŒจํ„ด์œผ๋กœ ๋‚˜ํƒ€๋‚ฌ์œผ๋ฉฐ ์ด๋Š” ๋ถ„์„ํ”„๋กœ๊ทธ๋žจ์„ ์‚ฌ์šฉํ•˜์˜€์„ ๊ฒฝ์šฐ์™€ ์œ ์‚ฌํ•œ ๋ชจํ˜•์ž„์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๊ทธ๋ฆผ 11์˜ ์—‘์…€ ํŒŒ์ผ์„ ๋™์ผํ•˜๊ฒŒ ์‹ (3)์œผ๋กœ ์ค‘์‹ฌ์ถ•์„ ๊ณ„์‚ฐํ–ˆ์„ ๋•Œ ์•ฝ 92.055ใ€ฌ ๋กœ ์‚ฐ์ถœ๋˜์—ˆ์œผ๋ฉฐ ์ด๋Š” ์œก์•ˆ์œผ๋กœ ๋ณด์•˜์„ ๋•Œ๋„ ์ „์••์ด ๊ฐ€์žฅ ๋†’์€ ์ฒซ ๋ฒˆ์งธ ์œ„์ƒ์ธ 90ยบ์— ๋Œ€๋น„ ๋’ค์ฒ˜์ง„ ์œ„์ƒ์ž„์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ฆ‰ ์ ˆ์—ฐ์ฒด๊ฐ€ ์—†๋Š” ๊ธฐ์ค‘ ์ฝ”๋กœ๋‚˜์™€ ์ ˆ์—ฐ์ฒด ์žˆ๋Š” ์ฝ”๋กœ๋‚˜์˜ ์œ„์ƒ ์ฐจ์ด๋Š” ๋ถ„๋ช…ํ–ˆ์œผ๋‚˜ ๊ทธ ์ •๋„์™€ ์œ„์ƒ๊ฐ์€ ๋ฐ˜๋ณต ์‹คํ—˜์„ ํ†ตํ•ด ๋ณ€ํ™”ํ•จ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์œ„์ƒ๊ฐ์˜ ๋ณ€ํ™”๋Š” ๋จผ์ € ๋ฐฉ์ „๊ธฐ์— ์œ ๋„์„ฑ ๋ฆฌ์•กํ„ด์Šค ์„ฑ๋ถ„์ด ์žˆ์–ด ํ•œ์ „ ์œ„์ƒ๊ณผ ์ •ํ™•ํ•˜๊ฒŒ ์ผ์น˜ํ•œ๋‹ค๊ณ  ๋ณผ ์ˆ˜ ์—†๋‹ค. ๋ณธ ์‹คํ—˜์—์„œ๋Š” ๋ถ€๋ถ„๋ฐฉ์ „์„ ์ƒ์‹œ ๋ชจ๋‹ˆํ„ฐ๋ง ํ•˜๋Š” ๋ณ€์ „์†Œ์—์„œ ์ ˆ์—ฐ์— ์ด์ƒ์ด ์žˆ์„ ๊ฒฝ์šฐ ์ค‘์‹ฌ์œ„์ƒ ๋ณ€ํ™”๊ฐ€ ๋‚˜ํƒ€๋‚  ์ˆ˜ ์žˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ๋‹ค.

๊ทธ๋ฆผ 11 XLPE์ ˆ์—ฐ๋ฌผ ๋ฐฉ์ „์˜ Excel๊ฐ€๊ณต ๋ฐ์ดํ„ฐ

Fig. 11 Excel Processing Data for XLPE Insulation Discharge

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3. ๊ฒฐ ๋ก 

ํ˜„์žฌ ๋ถ€๋ถ„๋ฐฉ์ „์€ ๋ณ€์ „์‹œ์„ค ํ˜น์€ ์ผ€์ด๋ธ”์— ์˜ˆ๋ฐฉ์ง„๋‹จ ๋ชฉ์ ์œผ๋กœ ๋„๋ฆฌ ์‚ฌ์šฉํ•˜๊ณ  ์žˆ๋‹ค. ํŠนํžˆ ์ผ€์ด๋ธ”์˜ ๋ถ€๋ถ„๋ฐฉ์ „์€ PRPD๋ฅผ ์ด์šฉํ•œ ๋ถ„์„๋ฟ๋งŒ ์•„๋‹ˆ๋ผ ๋ฐฉ์ „๋Ÿ‰๊ณผ ๋ฐฉ์ „ํŠน์„ฑ(ํ‘œ๋ฉด๋ฐฉ์ „, ๋‚ด๋ถ€๋ฐฉ์ „, ์ฝ”๋กœ๋‚˜๋ฐฉ์ „ ๋“ฑ)์— ๊ด€ํ•œ ์—ฐ๊ตฌ๋กœ ํ™œ๋ฐœํ•˜๊ฒŒ ์ง„ํ–‰๋˜๊ณ  ์žˆ๋‹ค(11). ๋ณธ ์—ฐ๊ตฌ์—์„œ๋Š” PD ๋ชจ๋‹ˆํ„ฐ๋ง ๋„์ค‘ ์ผ€์ด๋ธ”์ด ๋ฌผ๋ฆฌ์ ์œผ๋กœ ์†Œ์†๋˜์–ด ์ ˆ์—ฐํŒŒ๊ดด๊ฐ€ ๋ฐœ์ƒํ–ˆ์„ ๋•Œ PD์˜ ์œ„์ƒ๋ณ€ํ™”๋ฅผ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•˜์—ฌ ์‹คํ—˜ํ•˜์˜€์œผ๋ฉฐ ๋‹ค์Œ๊ณผ ๊ฐ™์€ ๋‚ด์šฉ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค.

๋ณธ ์‹คํ—˜์€ ์ผ€์ด๋ธ”์˜ ๋ถ€๋ถ„ ๋ฐฉ์ „ ์‹œ ์œ„์ƒ๋ณ€ํ™”๋ฅผ ์‹ค์ฆํ•œ ๊ฒƒ์— ์˜๋ฏธ๊ฐ€ ์žˆ์œผ๋ฉฐ, PD Analysisํ”„๋กœ๊ทธ๋žจ์—์„œ ์ถœ๋ ฅ๋˜์ง€ ์•Š๋Š” ์ค‘์‹ฌ์œ„์ƒ์„ Excel ํ”„๋กœ๊ทธ๋žจ์„ ํ†ตํ•˜์—ฌ ์‰ฝ๊ฒŒ ์ฐพ์•„๋‚ผ ์ˆ˜ ์žˆ๊ฒŒ ์‹ (3)์„ ๋„์ถœํ•˜์˜€๋‹ค. ์ด๋ฅผ ํ†ตํ•˜์—ฌ ๊ธฐ์ค‘ ์ฝ”๋กœ๋‚˜์˜ ์œ„์ƒ๊ณผ XLPE ์ ˆ์—ฐ๋ฌผ์„ ํ†ต๊ณผํ•˜๋Š” ์ฝ”๋กœ๋‚˜ ์œ„์ƒ์˜ ๋ณ€ํ™”๋ฅผ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค.

์ƒ์šฉ์ฃผํŒŒ์ˆ˜ ๋™๊ธฐํ™”์™€ ๊ฐ™์€ ๋‹จ์ ๋„ ์žˆ์ง€๋งŒ, ๊ธฐ์กด์— ํŒ๋ณ„์˜ ๊ธฐ์ค€์ด ๋˜์—ˆ๋˜ ๋‰ด๋Ÿด ๋„คํŠธ์›Œํฌ(Neural Network) ๋ฐฉ์‹์— ์†Œํ”„ํŠธ์›จ์–ด ์ˆ˜์ • ์—†์ด Excelํ”„๋กœ๊ทธ๋žจ์„ ์ด์šฉํ•˜์—ฌ ์ค‘์‹ฌ์ถ•์˜ ๋ณ€ํ™”๋ฅผ ์‚ดํŽด๋ณด๊ณ  ์ด๋ฅผ ํ†ตํ•˜์—ฌ ์ด์ƒ ์—ฌ๋ถ€๋ฅผ ํŒ๋ณ„ํ•  ์ˆ˜ ์žˆ๋Š” ์žฅ์ ์ด ์žˆ๋‹ค.

๋ณธ ์‹คํ—˜์€ ์ฝ”๋กœ๋‚˜ ๋ฐฉ์ „์— ๊ด€ํ•œ ํ•œ์ •๋œ ์‹คํ—˜์œผ๋กœ, ๊ด‘๋ฒ”์œ„ํ•˜๊ฒŒ ์‚ฌ์šฉ๋  ์ˆ˜๋Š” ์—†์œผ๋‚˜ ํ–ฅํ›„ ํ‘œ๋ฉด(surface) ๋ฐฉ์ „์ด๋‚˜ ๋ณด์ด๋“œ(void) ๋ฐฉ์ „์˜ ์œ„์ƒ ๋ณ€ํ™”์— ๋Œ€ํ•œ ์ถ”๊ฐ€์ ์ธ ์‹คํ—˜์ด ํ•„์š”ํ•˜๋‹ค. ๋˜ํ•œ, ๋ณธ ์‹คํ—˜์—์„œ ์‚ฌ์šฉํ•œ AC์ง€์† ๋ฐฉ์ „ ์‹คํ—˜ ์žฅ์น˜๋ฅผ ํ†ตํ•˜์—ฌ ํ˜„์žฅ์—์„œ ์ผ์–ด๋‚  ์ˆ˜ ์žˆ๋Š” ์—ฌ๋Ÿฌ ๊ฐ€์ง€ ๋ถ€๋ถ„๋ฐฉ์ „์˜ ํ˜•ํƒœ๋ฅผ ๋งŒ๋“ค์–ด ๊ณ ์ „์•• ๋ถ€๋ถ„๋ฐฉ์ „์— ๋Œ€ํ•œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ์‹œํ—˜์„ ์ง€์†์ ์œผ๋กœ ํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ํŒ๋‹จ๋œ๋‹ค.

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์ €์ž์†Œ๊ฐœ

๊น€์ง„ํ˜• (Jin-Hyung Kim)
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Jin-Hyung Kim received the B.S from Jeonju University in Electrical and Electronic Engineering in 2005, and Received a M.D from the University of Seoul 2013, and Completion Ph.D. from Hankyong National University in 2021.

He is a Professor in the Department of Electrical Engineering at Korea polytechnics.

His research interests are high voltage partial discharge and maintenance of solar power generation facilities.

๊น€๊ทœํ˜ธ (Kyu-Ho Kim)
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Kyu-Ho Kim received the B.S., M.S. and Ph.D. degrees from Hanyang University, South Korea, in 1988, 1990 and 1996, respectively.

He is a Professor in the Department of Electrical Engineering at Hankyong National University, South Korea. He was a Visiting Scholar at Baylor University for 2011.9-2012.8 and University of Colorado Denver for 2020.2-2021.1.

His research interests include power system control and operation, optimal power flow and the development of control techniques for wind power plants.

๊น€๊ฒฝ์‹  (Kyoung-Shin Kim)
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Kyoung-Shin Kim received the B.S., M.S. and Ph.D. degrees in electrical engineering from Chung-Ang University, South Korea, in 1997, 2000 and 2011, respectively.

He is currently a Professor in the Department of Electrical Engineering at Korea polytechnics.

His research interests include optimal power flow of power system and microwave electrodeless lamp discharge.