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Accident Prevention Solution for Voltage Sag - "Smart POWER Vaccine®"
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Sag Accident Case

  • Semiconductor Factory located in Cheonan Tangjeong
    87% voltage drop based on 3-phase R,S,T 154000V, 48mSec. Instantaneous voltage drop accident

  • Chemical Factory in Yeosu Chemical Complex
    98% instantaneous voltage drop accident based on 3-phase R,S,T 154000V

  • Electronic Smartphone Factory in Gumi
    70% instantaneous voltage drop accident based on 3-phase R,S,T 154000V

  • Display Factory in Giheung, Gyeonggido
    Instantaneous Voltage Drop Accident in 2000

    • Date Voltage-Dip Reasons
    Voltage Level(%) Time(msec) R
    APR,2000 04.05 15:16 18,387 12% 183 3.36 Yongin↔Bundang Cogeneration Transmission Line TRIP
    04.21 19:47 12,800 8% 288 3.69 Yongin#1, 2 (re-closing circuit operation due to lightning strike on power transmission line)
    04.28 02:45 34,000 22% 84 2.86 KEPCO Singal~New Yongin Singal #1T/L re-closing circuit operation
    May,2000 05.04 05:23 13,820 9% 100 1.38 Yangju~Uijeongbu 345KV Yangju#2 T/LA re-closing circuit operation (5Cycle) due to ground fault
    05.19 21:11 19,700 13% 100 1.97 Uijeongbu 345KV#1T/L Lightning Strike
    05.21 15:15 14,000 9% 500 7.00 Accident Impact on Suwon Home Appliances Business
    05.23 09:02 18,500 12% 116 2.15 East Seoul Substation DS FLASH OVER
    05.31 12:30 24,000 16% 100 2.40 Western Incheon Thermal Power Plant MAIN Transformer Failure
    05.31 13:12 24,000 16% 120 2.88 Western Incheon Thermal Power Plant MAIN Transformer Reinstallation Failure
    Jun,2000 06.04 17:05 53,000 34% 217 11.50 GIS accident in Western Incheon Thermal Power Plant
    06.11 14:03 32,000 21% 250 8.00 New Siheung Substation 345KV system failure due to lightning strike
    06.29 18:51 27,800 18% 83 2.31 Uman T/L re-closing circuit operation due to lightning strike
    Jul,2000 07.19 18:49 14,200 9% 136 1.93 Cheongpyeong~Yangsu 154KVT/L re-closing circuit operation due to lightning strike
    07.22 12:23 8,100 5% 80 0.65 Icheon T/L re-closing circuit operation due to lightning strike
    Aug,2000 08.07 13:51 17,700 11% 150 2.66 Seoul T/L lightning
    08.27 04:01 24,000 16% 116 2.78 Seongnam ↔ Bundang 154KVT/L re-closing circuit operation due to lightning strike
    08.28 00:05 18,000 12% 180 3.24 Yangji 154KVT/L re-closing circuit operation due to lightning strike
    08.28 01:12 8,656 6% 133 1.15 New Young-seo 345KVT/L re-closing circuit operation due to lightning strike
    08.28 03:41 22,000 14% 132 2.90 Uljin 154KVT/L re-closing circuit operation due to lightning strike
    Sep,2000 09.11 17:57 20,000 13% 250 5.00 Incheon Thermal Power~Incheon Steel Transmission Line Failure
    Oct,2000 10.29 05:15 17,700 11% 150 2.66 Yangji ~ Sadang #1T/L line accident
    Nov,2000 11.05 12:25 15,600 10% 67 1.05 Internal line (GIS) BUS failure in Wangsimni Substation
    11.17 01:30 18,000 12% 116 2.09 Eastern Seoul MAIN T/L TRIP
    Dec,2000 12.14 17:39 13,600 9% 67 0.91 Dangjin Power Plant Generator #1.2.3 TRIP
    12.27 07:52 10,000 6% 68 0.68 KEPCO system failure (Anseong~Songtan)
    12.30 06:18 13,300 9% 184 2.45 Western Seoul S/S#61BUS TRIP- -(Reference) Bucheon Fairchild:87,000V

  • Note: in early 2004 - 70% voltage drop occurred for 0.7 seconds
  • Semiconductor factory in Singal, Gyeonggi-do
    2015 instantaneous voltage drop accident

    • 2005 occurrence order date and time of occurrence voltage-sag accident details cause of occurrence
    degree of voltage drop voltage drop duration
    (V) (%) mSec Cycle(s) classification details
    1 01/16 08:30 6,000 4 150 9 ground fault accident in Uljin nuclear power plant
    2 02/16 1:19 78,000 51 66 4 galloping Galloping phenomenon caused by heavy snowstorm (KEPCO)
    : KEPCO transmission line re-closer operation
    ‣345kV T/L: Dong Seoul NO 1,2      New Suwon NO 1,2
    ‣345kV T/L: New Yongin No. 1,2      Shinyeon (New Sungnam~Yeongok) NO 1,2
    3 01:30 108,000 70 66 4
    4 01:39 38,000 25 83 5
    5 01:43 114,000 74 100 6
    6 01:57 79,000 51 66 4
    7 02:34 76,000 49 83 5
    8 02:51 16,000 10 66 4
    9 03:01 20,000 13 66 4
    10 03:34 22,000 14 66 4
    11 05:26 97,000 63 66 4
  • US Semiconductor Factory Group Survey
    Instantaneous voltage drop accident and SEMI F47 Standard


  • You can see the occurrence frequency of Sag is the highest when the size of Sag is less than 50% and the duration of Sag is less than 3Cycles (50msec).



  • • Task Force that created SEMI F47 Studied 16 Plants, 14 in US
    • 30.5 Monitor years
    • Total events = 1064
    • Average number of Events below SEMI F47 per site per year is 3.1