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  1. (Department of Electrical Engineering, Soongsil University, Korea.)



Grounding System, Large-Scale, Photovoltaic, PV Plant, Safety Voltage, Step Voltage, Touch Voltage

1. ์„œ ๋ก 

์ตœ๊ทผ ํ™”์„์—ฐ๋ฃŒ ๊ณ ๊ฐˆ ๋ฐ ๊ธฐ์กด ๋ฐœ์ „์†Œ(ํ™”์„์—ฐ๋ฃŒ๋ฅผ ์‚ฌ์šฉํ•˜๋Š” ๋ฐœ์ „์†Œ)์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์˜จ์‹ค๊ฐ€์Šค ๋ฐฐ์ถœ๋Ÿ‰์ด ์ง€์†์ ์œผ๋กœ ๋น ๋ฅด๊ฒŒ ์ฆ๊ฐ€ํ•˜๋ฉด์„œ ์ง€๊ตฌ์˜จ๋‚œํ™” ๋“ฑ ์‹ฌ๊ฐํ•œ ํ™˜๊ฒฝ๋ฌธ์ œ๊ฐ€ ๊ตญ์ œ์ ์œผ๋กœ ์ด์Šˆํ™”๋˜๊ณ  ์žˆ๋‹ค(1).

์˜จ์‹ค๊ฐ€์Šค ๊ฐ์ถ•์„ ์œ„ํ•ด ๊ตญ๋‚ด์˜ ๊ฒฝ์šฐ โ€˜์žฌ์ƒ์—๋„ˆ์ง€ 3020 ์ดํ–‰๊ณ„ํš(์•ˆ)โ€™์„ ๋ฐœํ‘œํ•˜์—ฌ 2030๋…„๊นŒ์ง€ ์ „์ฒด ๋ฐœ์ „๋Ÿ‰์˜ 20%๋ฅผ ์žฌ์ƒ์—๋„ˆ์ง€๋กœ ๋Œ€์ฒดํ•˜๋Š” ๊ณ„ํš์„ ์ˆ˜๋ฆฝํ•˜์˜€๋‹ค. 2018๋…„~2030๋…„๊นŒ์ง€ ๊ณ„ํšํ•œ ์žฌ์ƒ์—๋„ˆ์ง€ ์‹ ๊ทœ ์„ค๋น„์šฉ๋Ÿ‰(48.7GW)์ค‘ 95% ์ด์ƒ์„ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ(PV Plat) ๋“ฑ ์žฌ์ƒ์—๋„ˆ์ง€๋กœ ๋Œ€์ฒดํ•  ์˜ˆ์ •์ด๋‹ค(2).

ํ•ด์™ธ์˜ ๊ฒฝ์šฐ 2017๋…„ ํ•œํ•ด ์žฌ์ƒ์—๋„ˆ์ง€ ์‹ ๊ทœ ์„ค๋น„์šฉ๋Ÿ‰์€ ์ด 178GW์ด๋ฉฐ, ๊ทธ ์ค‘์—์„œ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์˜ ์‹ ๊ทœ ์„ค๋น„์šฉ๋Ÿ‰์€ 98GW(55%)๋กœ ๊ฐ€์žฅ ๋†’์•˜๋‹ค. ๋˜ํ•œ 1990๋…„~2017๋…„๊นŒ์ง€ ๊ฒฝ์ œํ˜‘๋ ฅ๊ฐœ๋ฐœ๊ธฐ๊ตฌ(OECD) ๊ตญ๊ฐ€์˜ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์—ฐํ‰๊ท  ์„ฑ์žฅ๋ฅ ์€ 34.8%๋กœ ์žฌ์ƒ์—๋„ˆ์ง€์› ์ค‘ ๊ฐ€์žฅ ๋†’์•˜๋‹ค(3).

์ด์™€ ๊ฐ™์ด ์ „ ์„ธ๊ณ„์ ์œผ๋กœ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ๊ณต๊ธ‰๋Ÿ‰์ด ์ง€์†์ ์œผ๋กœ ์ฆ๊ฐ€ํ•จ์— ๋”ฐ๋ผ ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ(MWp๊ธ‰)๋„ ์ฆ๊ฐ€ํ•˜๊ณ  ์žˆ๋‹ค. ์ด์— ๋”ฐ๋ผ ์ง€๋ฝ์‚ฌ๊ณ ์— ์˜ํ•œ ์ธ์ฒด๊ฐ์ „์‚ฌ๊ณ  ๋ฐ ์„ค๋น„์˜ ์†์ƒ ๋“ฑ์„ ์˜ˆ๋ฐฉํ•˜๊ธฐ ์œ„ํ•œ ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ์„ค๊ณ„์˜ ์ค‘์š”์„ฑ์ด ๊ฐ•์กฐ๋˜๊ณ  ์žˆ๋‹ค. ์ฆ‰ ์ธ์ฒด๊ฐ์ „์‚ฌ๊ณ  ๋ฐ ์„ค๋น„์˜ ์†์ƒ์„ ์˜ˆ๋ฐฉํ•˜๊ธฐ ์œ„ํ•ด์„œ๋Š” ์ง€๋ฝ์‚ฌ๊ณ ๊ฐ€ ๋ฐœ์ƒํ•˜์˜€์„ ๋•Œ ์•ˆ์ „์ „์••(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••)์„ ์ œํ•œํ•˜๋„๋ก ์ ‘์ง€์‹œ์Šคํ…œ์ด ์„ค๊ณ„๋˜์–ด์•ผ ํ•œ๋‹ค(4).

ํŠนํžˆ, ์ง€๋ฝ์ „๋ฅ˜ ์œ ์ž… ์‹œ ๋ฐœ์ƒํ•˜๋Š” ๊ณ ์žฅ์ „๋ฅ˜๋กœ ์ธํ•˜์—ฌ ์ธ์ฒด ๊ฐ์ „์‚ฌ๊ณ  ํ™•๋ฅ ์ด ๋†’์œผ๋ฉฐ, ์†์ƒ๋  ๊ฒฝ์šฐ ๋งŽ์€ ๋ณต๊ตฌ ์‹œ๊ฐ„ ๋ฐ ๋น„์šฉ์ด ๋ฐœ์ƒํ•˜๋Š” ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„(๋ณ€์••๊ธฐ, ์ธ๋ฒ„ํ„ฐ, ๋ถ„๋ฐฐ์ „๋ฐ˜ ๋“ฑ) ๋ถ€๋ถ„์˜ ์•ˆ์ „์ „์••์„ ๊ณ ๋ คํ•œ ์ ‘์ง€์‹œ์Šคํ…œ ์„ค๊ณ„๊ฐ€ ์ค‘์š”ํ•˜๋‹ค(5).

๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์— ์ ์šฉ๋˜๋Š” ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹๋ณ„(๊ฐœ๋ณ„์ ‘์ง€, ํ†ตํ•ฉ์ ‘์ง€)์— ๋”ฐ๋ฅธ ๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„ ๋ถ€๋ถ„์˜ ์•ˆ์ „์ „์••์„ ๊ฒ€ํ† ํ•˜๊ณ ์ž ํ•œ๋‹ค. ์ด๋ฅผ ์œ„ํ•ด ๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••์„ CDEGS๋ฅผ ํ™œ์šฉํ•œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜์œผ๋กœ ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹๋ณ„๋กœ ๋น„๊ตํ•˜์˜€๋‹ค.

2. ์ด ๋ก 

2.1 ๋ณดํญ์ „์••(step voltage)

์ ‘์ง€์‹œ์Šคํ…œ์— ๊ณ ์žฅ์ „๋ฅ˜๊ฐ€ ์œ ์ž…ํ•˜๋ฉด ์ ‘์ง€์‹œ์Šคํ…œ ๋ถ€๊ทผ์˜ ๋Œ€์ง€์ „์œ„๊ฐ€ ์ƒ์Šนํ•˜๊ฒŒ ๋œ๋‹ค. ์ด๋•Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ถ€๊ทผ์— ์„œ ์žˆ๋Š” ์ธ์ฒด์˜ ์–‘๋ฐœ ์‚ฌ์ด์— ์ธ๊ฐ€๋˜๋Š” ์ „์••์„ ๋ณดํญ์ „์••์ด๋ผ ํ•œ๋‹ค.

IEEE Std 80-2000์— ์˜ํ•˜๋ฉด ๋ณดํญ์ „์••์€ ์ธ์ฒด๊ฐ€ ์„œ ์žˆ๋Š” ์ƒํƒœ์—์„œ ์–‘๋ฐœ์„ 1m ๊ฐ„๊ฒฉ์œผ๋กœ ๋ฒŒ๋ ธ์„ ๋•Œ ์ง€ํ‘œ๋ฉด ์œ„์˜ ์–‘๋ฐœ ์‚ฌ์ด์˜ ์ „์œ„์ฐจ๋กœ ์ •์˜ํ•˜๊ณ  ์žˆ๋‹ค(6-8).

๊ทธ๋ฆผ 1์€ ๋ณดํญ์ „์••์— ๋Œ€ํ•œ ๊ฐœ๋…๋„์ด๋ฉฐ, ์—ฌ๊ธฐ์„œ $I$๋Š” ์ ‘์ง€์‹œ์Šคํ…œ์— ์œ ์ž…๋œ ๊ณ ์žฅ ์ „๋ฅ˜์ด๋‹ค.

๊ทธ๋ฆผ. 1. ๋ณดํญ์ „์••์˜ ๊ฐœ๋…๋„

Fig. 1. The basic scheme of step voltage

../../Resources/kiee/KIEE.2019.68.11.1458/fig1.png

์ตœ๋Œ€ํ—ˆ์šฉ๋ณดํญ์ „์•• $E_{step}$์€ (1)๊ณผ ๊ฐ™๋‹ค.

(1)
$E_{step}= I_{B}\bullet(R_{B}+ 2R_{F})$

์—ฌ๊ธฐ์„œ $I_{B}$๋Š” ์ธ์ฒด์— ํ๋ฅด๋Š” ์ „๋ฅ˜, $R_{B}$๋Š” ์–‘๋ฐœ ์‚ฌ์ด์˜ ์ธ์ฒด์ €ํ•ญ ๊ทธ๋ฆฌ๊ณ  $R_{F}$๋Š” ํ•œ์ชฝ ๋ฐœ์˜ ๋Œ€์ง€์ ‘์ด‰์ €ํ•ญ์ด๋‹ค.

IEEE Std 80-2000์—์„œ๋Š” ์–‘๋ฐœ ์‚ฌ์ด์˜ ์ธ์ฒด์ €ํ•ญ(1000โ„ฆ)์„ ์ ์šฉํ•˜์—ฌ ์ฒด์ค‘์ด 50kg์ธ ์‚ฌ๋žŒ๊ณผ ์ฒด์ค‘์ด 70kg์ธ ์‚ฌ๋žŒ์— ๊ด€ํ•˜์—ฌ ๊ณ ์žฅ์ „๋ฅ˜ ์‹œ๊ฐ„์— ๋Œ€ํ•œ ํ—ˆ์šฉ๋ณดํญ์ „์••์„ (2)์™€ ๊ฐ™์ด ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค(6-9).

(2)
\begin{align*} E_{step50}=(1000 + 6C_{s}\bullet\rho_{s})\dfrac{0.116}{\sqrt{t_{s}}}\\ \\ E_{step70}=(1000 + 6C_{s}\bullet\rho_{s})\dfrac{0.157}{\sqrt{t_{s}}} \end{align*}

์—ฌ๊ธฐ์„œ $C_{s}$๋Š” ํ‘œ๋ฉด์ธต์˜ ๊ฐ์†Œ๊ณ„์ˆ˜, $\rho_{s}$๋Š” ํ‘œ๋ฉด์ธต์˜ ๋Œ€์ง€์ €ํ•ญ๋ฅ  ๊ทธ๋ฆฌ๊ณ  $t_{s}$๋Š” ๊ณ ์žฅ์˜ ์ง€์†์‹œ๊ฐ„์ด๋‹ค.

2.2 ์ ‘์ด‰์ „์••(touch voltage)

์ ‘์ง€์‹œ์Šคํ…œ์— ๊ณ ์žฅ์ „๋ฅ˜ ์œ ์ž… ์‹œ ์ธ์ฒด๊ฐ€ ์ ‘์ง€์‹œ์Šคํ…œ ๋ถ€๊ทผ์˜ ๊ตฌ์กฐ๋ฌผ์— ์ ‘์ด‰ํ•˜๊ฒŒ ๋˜๋ฉด, ๊ตฌ์กฐ๋ฌผ์˜ ์ „์œ„์™€ ์ธ์ฒด๊ฐ€ ์„œ ์žˆ๋Š” ์ง€์ ์˜ ๋Œ€์ง€ํ‘œ๋ฉด ์‚ฌ์ด์— ์ „์œ„์ฐจ๊ฐ€ ๋ฐœ์ƒํ•˜๊ฒŒ ๋˜๋Š”๋ฐ ์ด๊ฒƒ์ด ์ ‘์ด‰์ „์••์ด๋ผ ํ•œ๋‹ค.

IEEE Std 80-2000์— ์˜ํ•˜๋ฉด ์ ‘์ด‰์ „์••์€ ์ ‘์ง€๋˜์–ด ์žˆ๋Š” ๊ตฌ์กฐ๋ฌผ๊ณผ ๋Œ€์ง€ํ‘œ๋ฉด์ƒ์˜ ๊ฑฐ๋ฆฌ 1m์ธ ์ง€์ ์‚ฌ์ด์˜ ์ „์œ„์ฐจ๋กœ ์ •์˜ํ•˜๊ณ  ์žˆ๋‹ค(6-8).

๊ทธ๋ฆผ 2๋Š” ์ ‘์ด‰์ „์••์— ๋Œ€ํ•œ ๊ฐœ๋…๋„์ด๋‹ค.

๊ทธ๋ฆผ. 2. ์ ‘์ด‰์ „์••์˜ ๊ฐœ๋…๋„

Fig. 2. The basic scheme of touch voltage

../../Resources/kiee/KIEE.2019.68.11.1458/fig2.png

์ตœ๋Œ€ํ—ˆ์šฉ์ ‘์ด‰์ „์•• $E_{touch}$์€ (3)๊ณผ ๊ฐ™๋‹ค.

(3)
$E_{touch}= I_{B}\bullet(R_{B}+\dfrac{R_{F}}{2})$

IEEE Std 80-2000์—์„œ๋Š” ์–‘๋ฐœ ์‚ฌ์ด์˜ ์ธ์ฒด์ €ํ•ญ(1000โ„ฆ)์„ ์ ์šฉํ•˜์—ฌ ์ฒด์ค‘์ด 50kg์ธ ์‚ฌ๋žŒ๊ณผ ์ฒด์ค‘์ด 70kg์ธ ์‚ฌ๋žŒ์— ๊ด€ํ•˜์—ฌ ๊ณ ์žฅ์ „๋ฅ˜ ์‹œ๊ฐ„์— ๋Œ€ํ•œ ํ—ˆ์šฉ์ ‘์ด‰์ „์••์„ (4)์™€ ๊ฐ™์ด ๋‚˜ํƒ€๋‚ด์—ˆ๋‹ค(6-9).

(4)
\begin{align*} E_{touch50}=(1000 + 1.5C_{s}\bullet\rho_{s})\dfrac{0.116}{\sqrt{t_{s}}}\\ \\ E_{touch70}=(1000 + 1.5C_{s}\bullet\rho_{s})\dfrac{0.157}{\sqrt{t_{s}}} \end{align*}

3. ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ํ˜„ํ™ฉ ๋ฐ ๋ชจ๋ธ๋ง

ํ˜„์žฌ ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ์€ ๊ฐœ๋ณ„์ ‘์ง€ ๋˜๋Š” ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•˜๊ณ  ์žˆ์œผ๋ฉฐ, ์ˆ˜์ „์„ค๋น„๋Š” ๋Œ€๋ถ€๋ถ„ ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ธ์ž…๊ตฌ ๋ถ€๋ถ„์— 1๊ฐœ์†Œ๋ฅผ ์„ค์น˜ํ•˜์—ฌ ์šด์šฉํ•˜๊ณ  ์žˆ๋‹ค(11-12).

3.1 ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง

๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์— ์ ์šฉ๋˜๋Š” ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹(๊ฐœ๋ณ„์ ‘์ง€ ๋ฐ ํ†ตํ•ฉ์ ‘์ง€)์— ๋”ฐ๋ฅธ ๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„์— ๋ฏธ์น˜๋Š” ์˜ํ–ฅ์„ ๊ฒ€ํ† ํ•˜๊ณ ์ž ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹๋ณ„๋กœ ๋ชจ๋ธ๋งํ•˜์˜€๋‹ค. ๋˜ํ•œ ํ†ตํ•ฉ์ ‘์ง€๋Š” Mesh ์ ‘์ง€๊ทน ๊ตฌ์„ฑ์— ๋”ฐ๋ฅธ ์˜ํ–ฅ์„ ๊ฒ€ํ† ํ•˜๊ณ ์ž ์ด 3๊ฐ€์ง€(ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ, ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ, ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ)๋กœ ๊ตฌ์„ฑํ•˜์˜€๋‹ค. ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง์€ CDEGS ํ”„๋กœ๊ทธ๋žจ์˜ HIFREQ ๋ชจ๋“ˆ์„ ์ด์šฉํ•˜์—ฌ ๊ตฌ์„ฑํ•˜์˜€๋‹ค.

๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์„ค์น˜ ๋ฉด์ ์€ 31,500m2, ์šฉ๋Ÿ‰์€ 2MWp๋กœ ๊ตฌ์„ฑํ•˜์˜€์œผ๋ฉฐ, ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ๊ฐ€ ์„ค์น˜๋œ ๊ณณ์˜ ๋Œ€์ง€์ €ํ•ญ๋ฅ ์€ 135ฮฉ โ€ค m๋กœ ์„ค์ •ํ•˜์˜€๋‹ค(10).

ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„ ๋ถ€๋ถ„์˜ ์•ˆ์ „์ „์••์€ IEEE Std 80-2000์˜ ๊ณ„์‚ฐ์‹์„ ๊ธฐ๋ฐ˜์œผ๋กœ ์–‘๋ฐœ ์‚ฌ์ด์˜ ์ธ์ฒด์ €ํ•ญ์€ 1000โ„ฆ, ์ฒด์ค‘์ด 50kg์ธ ์‚ฌ๋žŒ์„ ๊ธฐ์ค€์œผ๋กœ ํ•˜์˜€๋‹ค. ์‹œ๋ฎฌ๋ ˆ์ด์…˜์€ CDEGS ํ”„๋กœ๊ทธ๋žจ์˜ MALT ๋ชจ๋ฅ ์„ ์ด์šฉํ•˜์˜€๋‹ค.

์—ฌ๊ธฐ์„œ ๊ณ ์žฅ์ „๋ฅ˜๋Š” 825A(1์„  ์ง€๋ฝ ์ „๋ฅ˜์˜ 20%), ๊ณ ์žฅ ์ง€์†์‹œ๊ฐ„์€ ๋ฐฐ์„ ์šฉ์ฐจ๋‹จ๊ธฐ(MCCB)์˜ ์ฐจ๋‹จ์‹œ๊ฐ„์„ ๊ฐ์•ˆํ•œ ์ตœ๋Œ€ 0.5sec๋กœ ์„ค์ •ํ•˜์˜€์œผ๋ฉฐ, ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ๊ฐ€ ์„ค์น˜๋œ ๊ธฐ์ดˆ ๋ถ€๋ถ„์˜ ๋น„์ €ํ•ญ ๋ฐ ๊นŠ์ด๋Š” 3,000ฮฉ โ€ค m, 0.1m๋กœ ์„ค์ •ํ•˜์˜€๋‹ค(6,8,10).

3.1.1 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์˜ ๊ฐœ๋ณ„์ ‘์ง€ ๋ชจ๋ธ๋ง

๊ทธ๋ฆผ 3์€ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง์ด๋ฉฐ, ์ผ๋ฐ˜์ ์œผ๋กœ ํ˜„์žฌ ์„ค์น˜ํ•˜์—ฌ ์šด์šฉ์ค‘์ธ ์ˆ˜์ „์„ค๋น„๊ฐ€ 1๊ฐœ์†Œ์ธ ๊ฒฝ์šฐ๋กœ ๊ตฌ์„ฑํ•˜์˜€๋‹ค. ์ˆ˜์ „์„ค๋น„๋Š” ์ „๋ ฅ์ด ๊ณต๊ธ‰๋˜๋Š” ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ธ์ž…๊ตฌ ๋ถ€๋ถ„์— 1๊ฐœ์†Œ๋ฅผ ์ ์šฉํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ. 3. ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง

Fig. 3. Modeling of 2MWp PV Plant grounding system applied with isolation grounding

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ํ‘œ 1์€ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๊ตฌ์„ฑ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค.

ํ‘œ 1. ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๊ตฌ์„ฑ

Table 1. Grounding system configuration of 2MWp PV Plant with isolation grounding

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์ ‘์ง€์‹œ์Šคํ…œ ๊ตฌ์„ฑ์€ ์ ‘์ง€์„ (๋‚˜๋™์„  50mm2) ๋ฐ ์ ‘์ง€๋ด‰(๋™๋ด‰, ร˜19ร—2400mm) ์ด 381๊ฐœ๋กœ ๊ตฌ์„ฑํ•˜์˜€์œผ๋ฉฐ, ์ ‘์ง€์‹œ์Šคํ…œ์˜ ์ ‘์ง€์ €ํ•ญ๊ฐ’์€ ์•ฝ 2.5ฮฉ์ด๋‹ค.

๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„์— ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••์„ ๊ฒ€ํ† ํ•˜๊ณ ์ž ํ•œ๋‹ค.

3.2.2 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์˜ ํ†ตํ•ฉ์ ‘์ง€ ๋ชจ๋ธ๋ง

๊ทธ๋ฆผ 4~๊ทธ๋ฆผ 6์€ ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง์ด๋‹ค. Mesh ์ ‘์ง€๊ทน ๊ตฌ์„ฑ์— ๋”ฐ๋ฅธ ์˜ํ–ฅ์„ ๊ฒ€ํ† ํ•˜๊ณ ์ž ์ด 3๊ฐ€์ง€(ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ, ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ, ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ)๋กœ ๊ตฌ์„ฑํ•˜์˜€๋‹ค.

๊ฐœ๋ณ„์ ‘์ง€์™€ ๋™์ผํ•˜๊ฒŒ ์ˆ˜์ „์„ค๋น„๋Š” ์ „๋ ฅ์ด ๊ณต๊ธ‰๋˜๋Š” ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ธ์ž…๊ตฌ ๋ถ€๋ถ„์— 1๊ฐœ์†Œ๋ฅผ ์„ค์น˜ํ•˜์˜€๋‹ค. ์ ‘์ง€์‹œ์Šคํ…œ ๊ตฌ์„ฑ์€ Mesh ์ ‘์ง€๊ทน(๋‚˜๋™์„  50mm2) ๋ฐ ์ ‘์ง€๋ด‰(ํผ๋ผ์ดํŠธ ์ ‘์ง€๋ชจ๋“ˆ, ร˜260ร—1000mm) ์ด 8๊ฐœ๋กœ ๊ตฌ์„ฑํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ 4๋Š” ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋ฉฐ, Mesh ์ ‘์ง€๊ทน ๊ตฌ์„ฑ์€ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์™ธ๊ณฝ ๋ถ€๋ถ„ ๋ฟ๋งŒ์•„๋‹ˆ๋ผ ์ˆ˜์ „์„ค๋น„์— ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••์„ ๋‚ฎ์ถ”๊ธฐ ์œ„ํ•ด์„œ ์ˆ˜์ „์„ค๋น„ ๋ถ€๋ถ„์— ๊ฐ„๊ฒฉ 10mร—10m๋กœ ์ง‘์ค‘์ ์œผ๋กœ ์ ์šฉํ•˜์˜€๋‹ค. ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ์œผ๋กœ ๊ตฌ์„ฑํ•˜์˜€์„ ๋•Œ ์ ‘์ง€์‹œ์Šคํ…œ์˜ ์ ‘์ง€์ €ํ•ญ๊ฐ’์€ ์•ฝ 0.39ฮฉ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

๊ทธ๋ฆผ. 4. ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง

Fig. 4. Modeling of 2MWp PV Plant grounding system applied with common grounding 1

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๊ทธ๋ฆผ 5๋Š” ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋ฉฐ, Mesh ์ ‘์ง€๊ทน ๊ตฌ์„ฑ์€ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์™ธ๊ณฝ ๋ถ€๋ถ„ ๋ฟ๋งŒ์•„๋‹ˆ๋ผ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์„ค์น˜ ๋ฉด์ ์— ๊ท ๋“ฑํ•˜๊ฒŒ ๊ฐ„๊ฒฉ 50mร—50m์œผ๋กœ ์ ์šฉํ•˜์˜€๋‹ค.

๊ทธ๋ฆผ. 5. ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง

Fig. 5. Modeling of 2MWp PV Plant groundign system applied with Common Grounding 2

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ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ์œผ๋กœ ๊ตฌ์„ฑํ•˜์˜€์„ ๋•Œ ์ ‘์ง€์‹œ์Šคํ…œ์˜ ์ ‘์ง€์ €ํ•ญ๊ฐ’์€ ์•ฝ 0.34ฮฉ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

๊ทธ๋ฆผ 6์€ ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋ฉฐ, Mesh ์ ‘์ง€๊ทน ๊ตฌ์„ฑ์€ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์™ธ๊ณฝ ๋ถ€๋ถ„์—๋งŒ ๊ฐ„๊ฒฉ 150mร—210m์œผ๋กœ ์ ์šฉํ•˜์˜€๋‹ค. ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ์œผ๋กœ ๊ตฌ์„ฑํ•˜์˜€์„ ๋•Œ ์ ‘์ง€์‹œ์Šคํ…œ์˜ ์ ‘์ง€์ €ํ•ญ๊ฐ’์€ ์•ฝ 0.40ฮฉ์œผ๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

๊ทธ๋ฆผ. 6. ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง

Fig. 6. Modeling of 2MWp PV Plant groundign system applied with Common Grounding 3

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ํ‘œ 2๋Š” ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๊ตฌ์„ฑ์„ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค.

ํ‘œ 2. ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๊ตฌ์„ฑ

Table 2. Grounding system configuration of 2MWp PV Plant with common grounding

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๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„์— ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••์„ ๊ฒ€ํ† ํ•˜๊ณ ์ž ํ•œ๋‹ค.

4. ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ

4.1 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์˜ ๊ฐœ๋ณ„์ ‘์ง€ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ

๊ทธ๋ฆผ 7์€ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์ˆ˜์ „์„ค๋น„์˜ ๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์•• ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ์ด๋‹ค.

๊ทธ๋ฆผ. 7. ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••)

Fig. 7. Simulation results of 2MWp PV Plant applied with isolation grounding (step voltage and touch voltage)

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๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•œ ๋ณดํญ์ „์••์€ 1900V์ด๋ฉฐ, ์ ‘์ด‰์ „์••์€ 1727.2V๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์— ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•  ๊ฒฝ์šฐ ๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋†’์€ ๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••์ด ๋ฐœ์ƒํ•˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.

4.2 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์˜ ํ†ตํ•ฉ์ ‘์ง€ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ

๊ทธ๋ฆผ 8~๊ทธ๋ฆผ 10์€ ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ์ด๋‹ค.

๊ทธ๋ฆผ 8์€ ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์ˆ˜์ „์„ค๋น„์˜ ๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์•• ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ์ด๋‹ค.

๊ณ ์žฅ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•œ ๋ณดํญ์ „์••์€ 5.4V์ด๋ฉฐ, ์ ‘์ด‰์ „์••์€ 16.3V๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

๊ทธ๋ฆผ. 8. ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ (๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••)

Fig. 8. Simulation results of 2MWp PV Plant applied with common grounding 1(step voltage and touch voltage)

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๊ทธ๋ฆผ 9๋Š” ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์ˆ˜์ „์„ค๋น„์˜ ๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์•• ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ์ด๋‹ค.

๊ณ ์žฅ ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•œ ๋ณดํญ์ „์••์€ 7.3V์ด๋ฉฐ, ์ ‘์ด‰์ „์••์€ 12.4V๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

๊ทธ๋ฆผ 10์€ ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์ˆ˜์ „์„ค๋น„์˜ ๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์•• ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ์ด๋‹ค. ๊ณ ์žฅ ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•œ ๋ณดํญ์ „์••์€ 5.1V์ด๋ฉฐ, ์ ‘์ด‰์ „์••์€ 16.5V๋กœ ํ™•์ธ๋˜์—ˆ๋‹ค.

ํ†ตํ•ฉ์ ‘์ง€(1์•ˆ, 2์•ˆ, 3์•ˆ)๋ฅผ ์ ์šฉํ•  ๊ฒฝ์šฐ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•  ๊ฒฝ์šฐ๋ณด๋‹ค ๋งค์šฐ ๋‚ฎ์€ ์•ˆ์ „์ „์••์ด ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.

4.3 ์•ˆ์ „์ „์••(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••) ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ

ํ‘œ 3์€ IEEE Std 80-2000์˜ ๊ณ„์‚ฐ์‹์„ ๊ธฐ๋ฐ˜์œผ๋กœ CDEGS ํ”„๋กœ๊ทธ๋žจ์˜ MALT ๋ชจ๋“ˆ์„ ์ด์šฉํ•˜์—ฌ ๊ณ ์žฅ ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ชจ๋ธ๋ง์— ๋Œ€ํ•œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••) ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ๋ฅผ ๋‚˜ํƒ€๋‚ธ ๊ฒƒ์ด๋‹ค.

๊ทธ๋ฆผ. 9. ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ (๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••)

Fig. 9. Simulation results of 2MWp PV Plant applied with common grounding 2 (step voltage and touch voltage)

../../Resources/kiee/KIEE.2019.68.11.1458/fig9.png

ํ‘œ 3์—์„œ ๋ณด๋Š”๋ฐ”์™€ ๊ฐ™์ด ํ†ตํ•ฉ์ ‘์ง€(1์•ˆ, 2์•ˆ, 3์•ˆ)๋Š” ๋ชจ๋‘ ํ—ˆ์šฉ ์ „์•– ๊ธฐ์ค€๊ฐ’์— ์ ํ•ฉํ•˜์˜€์ง€๋งŒ ๊ฐœ๋ณ„์ ‘์ง€๋Š” ์ ‘์ด‰์ „์••์ด ํ—ˆ์šฉ ์ „์•• ๊ธฐ์ค€๊ฐ’์— ๋ถ€์ ํ•ฉํ•˜๋‹ค๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.

ํ‘œ 3. ์•ˆ์ „์ „์••(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••) ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ

Table 3. Simulation results of safety voltage(step voltage and touch voltage)

๊ตฌ๋ถ„

๊ฐœ๋ณ„์ ‘์ง€

ํ†ตํ•ฉ์ ‘์ง€

ํ—ˆ์šฉ ์ „์•• ๊ธฐ์ค€๊ฐ’

1์•ˆ

2์•ˆ

3์•ˆ

๋ณดํญ์ „์••

2441.9V

1900.0V

5.4V

7.3V

5.1V

์ ‘์ด‰์ „์••

727.5V

1727.2V

16.3V

12.4V

16.5V

5. ๊ฒฝ์ œ์„ฑ ๋ถ„์„

ํ‘œ 4๋Š” 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹๋ณ„(๊ฐœ๋ณ„์ ‘์ง€ ๋ฐ ํ†ตํ•ฉ์ ‘์ง€)๋กœ ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„๋ฅผ ๋น„๊ตํ•œ ๊ฒƒ์ด๋‹ค.

2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„ ์‚ฐ์ถœ์€ ์‹ค์ œ ํ˜„์žฅ์— ์ ์šฉ๊ฐ€๋Šฅํ•œ ์‹ค์‹œ ์„ค๊ณ„ ๊ธฐ์ค€์œผ๋กœ ์‚ฐ์ถœํ•œ ๊ฒƒ์ด๋‹ค.

๋‹จ, 22.kV-Y ์ธ์ž… ๋ฐฐ์ „์„ ๋กœ ๋น„์šฉ์„ ์ œ์™ธํ•œ ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„๋ฅผ ์‚ฐ์ถœํ•œ ๊ฒƒ์ด๋‹ค.

๊ทธ๋ฆผ. 10. ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ์„ ์ ์šฉํ•œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••)

Fig. 10. Simulation results of 2MWp PV Plant applied with common grounding 3 (step voltage and touch voltage)

../../Resources/kiee/KIEE.2019.68.11.1458/fig10.png

% ๋น„๊ต๋Š” ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„๊ฐ€ ๊ฐ€์žฅ ๋†’์€ ๊ฐœ๋ณ„์ ‘์ง€(100%)๋ฅผ ๊ธฐ์ค€์œผ๋กœ %๋กœ ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„๋ฅผ ๋น„๊ตํ•œ ๊ฒƒ์ด๋‹ค. ํ†ตํ•ฉ์ ‘์ง€ 1์•ˆ์„ ์ ์šฉํ•œ ๊ฒฝ์šฐ ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„๋Š” ๊ฐœ๋ณ„์ ‘์ง€๋ณด๋‹ค ์•ฝ 68% ๊ฐ์†Œ, ํ†ตํ•ฉ์ ‘์ง€ 2์•ˆ์„ ์ ์šฉํ•œ ๊ฒฝ์šฐ๋Š” ๊ฐœ๋ณ„์ ‘์ง€๋ณด๋‹ค ์•ฝ 62% ๊ฐ์†Œ, ํ†ตํ•ฉ์ ‘์ง€ 3์•ˆ์„ ์ ์šฉํ•œ ๊ฒฝ์šฐ๋Š” ๊ฐœ๋ณ„์ ‘์ง€๋ณด๋‹ค ์•ฝ 71% ๊ฐ์†Œํ•œ ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.

๋”ฐ๋ผ์„œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์— ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•  ๊ฒฝ์šฐ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ ๊ฒฝ์šฐ๋ณด๋‹ค ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„๊ฐ€ ํ‰๊ท  ์•ฝ 67% ๊ฐ์†Œํ•˜๋Š” ๊ฒƒ์„ ํ™•์ธํ•˜์˜€๋‹ค.

ํ‘œ 4. 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ์˜ ์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„

Table 4. Grounding system construction total cost of 2MWp PV Plant

๊ตฌ๋ถ„

์ ‘์ง€์‹œ์Šคํ…œ ์ด ๊ณต์‚ฌ๋น„

% ๋น„๊ต

๊ฐœ๋ณ„์ ‘์ง€

์•ฝ 87,500์ฒœ์›

100%

ํ†ตํ•ฉ์ ‘์ง€

1์•ˆ

์•ฝ 27,900์ฒœ์›

์•ฝ 32%

2์•ˆ

์•ฝ 33,600์ฒœ์›

์•ฝ 38%

3์•ˆ

์•ฝ 25,000์ฒœ์›

์•ฝ 29%

6. ๊ฒฐ ๋ก 

๋ณธ ์—ฐ๊ตฌ๋Š” ๊ณ ์žฅ ์ „๋ฅ˜ ์ธ๊ฐ€ ์‹œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„์—์„œ ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••(๋ณดํญ์ „์•• ๋ฐ ์ ‘์ด‰์ „์••)์„ CDEGS๋ฅผ ํ™œ์šฉํ•œ ์‹œ๋ฎฌ๋ ˆ์ด์…˜์œผ๋กœ ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹๋ณ„(๊ฐœ๋ณ„์ ‘์ง€ ๋ฐ ํ†ตํ•ฉ์ ‘์ง€)๋กœ ๋น„๊ตํ•˜์—ฌ ๋‹ค์Œ๊ณผ ๊ฐ™์€ ๊ฒฐ๋ก ์„ ์–ป์—ˆ๋‹ค.

(1) ์•ˆ์ „์ „์•• ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๊ฒฐ๊ณผ ๊ฐœ๋ณ„์ ‘์ง€๋ฅผ ์ ์šฉํ•œ ๊ฒฝ์šฐ ๋ณดํญ์ „์••์€ ํ—ˆ์šฉ ์ „์•• ๊ธฐ์ค€๊ฐ’์— ์ ํ•ฉํ•˜์˜€์ง€๋งŒ, ์ ‘์ด‰์ „์••์€ ํ—ˆ์šฉ ์ „์•• ๊ธฐ์ค€๊ฐ’์— ๋ถ€์ ํ•ฉํ•˜์˜€๋‹ค.

(2) ํ†ตํ•ฉ์ ‘์ง€์˜ Mesh ์ ‘์ง€๊ทน ๊ตฌ์„ฑ์— ๋”ฐ๋ฅธ ์˜ํ–ฅ์„ ๊ฒ€ํ† ํ•œ ๊ฒฐ๊ณผ ์•ˆ์ „์ „์••์€ ํ†ตํ•ฉ์ ‘์ง€(1์•ˆ, 2์•ˆ, 3์•ˆ) ๋ชจ๋‘ ํ—ˆ์šฉ ์ „์•• ๊ธฐ์ค€๊ฐ’์— ์ ํ•ฉํ•˜์˜€๋‹ค.

(3) ์ ‘์ง€์‹œ์Šคํ…œ ๊ณต์‚ฌ๋น„๋Š” ๊ฐœ๋ณ„์ ‘์ง€๋ณด๋‹ค ํ†ตํ•ฉ์ ‘์ง€๋ฅผ ์ ์šฉํ•  ๊ฒฝ์šฐ ํ‰๊ท  ์•ฝ 67% ๊ฐ์†Œํ•˜์˜€๋‹ค.

๋ณธ ์—ฐ๊ตฌ๋ฅผ ํ†ตํ•ด ๋‚™๋ขฐ ์‹œ 2MWp ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ ์ˆ˜์ „์„ค๋น„์— ๋ฐœ์ƒํ•˜๋Š” ์•ˆ์ „์ „์••์„ ๊ฐ์†Œํ•˜๊ธฐ ์œ„ํ•œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹์€ ๊ฐœ๋ณ„์ ‘์ง€๋ณด๋‹ค ํ†ตํ•ฉ์ ‘์ง€๊ฐ€ ์ ํ•ฉํ•˜๋‹ค๊ณ  ํŒ๋‹จ๋œ๋‹ค.

๋”ฐ๋ผ์„œ ๋ณธ ์—ฐ๊ตฌ์—์„œ ์ œ์•ˆํ•œ ์ ‘์ง€์‹œ์Šคํ…œ ๋ฐฉ์‹์€ ์•ˆ์ „์ „์••์„ ๊ณ ๋ คํ•œ ๋Œ€๊ทœ๋ชจ ํƒœ์–‘๊ด‘๋ฐœ์ „์†Œ(MWp๊ธ‰) ์ ‘์‹œ์‹œ์Šคํ…œ ์„ค๊ณ„ ์‹œ ๊ธฐ์ดˆ์ž๋ฃŒ๋กœ ํ™œ์šฉํ•  ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ๊ธฐ๋Œ€ํ•œ๋‹ค.

References

1 
2009, Meteorological Technology & Policy, Vol. 2, No. 3, pp. 19-42Google Search
2 
Ministry of Trade Industry and Energy, 2017, Renewable Energy 3020 Implementation Plan, pp. 2-3Google Search
3 
Korea Energy Economics Institute, 2018, International Renewable Energy Policy Change and Market Analysis, pp. 11-19Google Search
4 
D. W. Kim, Y. B. Lim, S. I. Lee, M. I. Choi, H. W. Moon, 2015, Study on Measurement Error Reduction Technique when Measuring Touch and Step Voltage of Grounding System, The Transactions of the Korean Institute of Electrical Engineers, Vol. 64, No. 1, pp. 188-195DOI
5 
C. U. Lee, J. C. Kim, 2019, An Analysis and comparison of Lightning Induced Overvoltage According to Isolation and Common Grounding System of Large-Scale Photovoltaic Power Plant in Lightning Strikes, The Transactions of the Korean Institute of Electrical Engineers, Vol. 68, No. 8, pp. 1017-1024Google Search
6 
Y. S. Sim, 2011, A Study on the Diagonal Unequally Spaced Mesh Grounding for the Decreasing of the Touch Voltage, Ph.D. Thesis, School of Electrical Engineering, Hongik University, pp. 18-23Google Search
7 
H. K. Kim, B. D. Moon, D. W. Park, G. S. Kil, J. S. Han, 2008, Comparative Measurement of Touch and Step Voltages in Ground Systems, The Korean Society For Railway, pp. 309-313Google Search
8 
IEEE Std 80-2000, 2000, IEEE Guide for Safety in AC Sub- station Grounding, pp. 8-118Google Search
9 
D. W. Kim, H. J. Gil, D. O. Kim, K. Y. Lee, H. W. Moon, H. K. Kim, 2011, Measurement Standard Analysis of Touch and Step Voltage of Grounding System, The Korean Institute of Illuminating and electrical Installation Engineers, pp. 237-238Google Search
10 
H. J. Kim, 2013, A Study on the Solar Power Distribution Grid and the Protection Relay, M.Sc. Thesis, School of Electrical Engineering, Hanyang University, pp. 47-55Google Search
11 
C. U. Lee, J. C. Kim, Aug 2019, An Analysis and comparison of Lightning Induced Overvoltage According to Isolation and Common Grounding System of Large-Scale Photovoltaic Power Plant in Lightning Strikes, KIEE, Vol. 68, No. 8, pp. 1017-1024Google Search
12 
R. Araneo, M. Park, J. H. Kim, Jul 2017, Analysis of the Lightning Transient Response of the Earthing System of Large-Scale Ground-Mounted PV Plants, in Proc. of IEEE Manchester PowerTech, pp. 1550-1555DOI

์ €์ž์†Œ๊ฐœ

์ด์ฐฝ์šฑ(Chang-Uk Lee)
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He received his B.S. and M.S. degree from Yeungnam University, korea in 2006 and 2008.

He is currently pursuing a Ph.D. degree with the Department of electrical engineering at Soongsil University, korea. He is now an engineer of OMNI LPS from 2009.

๊น€์žฌ์ฒ (Jae-Chul Kim)
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He received his B.S. degree in the electrical engineering from Soongsil University, korea in 1979 and his M.S. and Ph. D. degrees in the electrical engineering from Seoul National University, korea in 1983 and 1987, respectively.

He is now a professor of electrical engineering of Soongsil University.