• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.2216-2217
• /
• 2008

This paper write about earth system for the prevention electric shock and a protection of equipment in england. The IEC60364 and BSI(British Standards Institution) define earthing method(IT, TT, TN-C, TN-S, TN-C-S)-BSI is british standards and in case of england almost use the TN system. TN system can classify TN-S & TN-C-S(PME). The findings on survey in england are used the TN-S system and TN-C-S system about 70% and residue 30% are used TT system and IT system from the exiting state of things.

• 조명전기설비학회논문지
• /
• 제24권1호
• /
• pp.56-62
• /
• 2010

본 논문에서는 IEC 60364에서 제시하고 있는 접지계통(TT접지계통, TN-S 접지계통 및 TN-C)의 누전차단기 동작특성 및 보호도체의 임피던스변화에 따른 Loop Impedance 특성분석을 실시하였다. 분석결과 Loop Impedance의 경우 저항성분과 인턱턴스성분에 영향을 받는 것으로 나타났다. 접지계통별 전류 전압특성은 TN-S 접지계통 및 TN-C 접지계통의 경우 사고전류가 높고 접촉전압이 낮은 특성을 나타낸 반면 TT 접지계통의 경우 사고전류는 낮고 접촉전압이 높게 나타남을 확인하였다.

• 조명전기설비학회논문지
• /
• 제24권6호
• /
• pp.67-74
• /
• 2010

국내의 저압수용가 대부분은 한국전력공사의 TN-C접지방식으로부터 공급받고 있으나 부하설비는 TT 접지방식을 위주로 한 전기설비기술기준에 따라 시설되어 있다. 본 연구에서는 정보기술설비를 뇌서지로부터 보호할 수 있는 적절한 전원계통접지방식을 제안하기 위해서 TT, TN계통의 뇌서지에 대한 보호성능을 연구하였다. 그 결과, 뇌서지가 배전계통의 중성선에 입사한 때 TT계통의 기기접지단자와 전원선의 중성점 사이에 높은 전위차가 발생하였으며, 예민한 컴퓨터설비가 손상될 위험성이 있으므로 TT계통은 적합하지 않다. 뇌서지로부터 저압 설비를 보호하기 위해서는 등전위본딩이 중요한 요건이며, TN계통이 중성선을 통하여 입사하는 뇌서지의 저감에 가장 우수하였으며, 수용가 인입구에서의 추가접지도 바람직한 방법이다.

• 조명전기설비학회논문지
• /
• 제21권8호
• /
• pp.113-120
• /
• 2007

본 논문은 TN-C-S계통에서 중성선 겸용 보호도체(PEN도체)의 단선고장시 감전의 위험성 및 보호대책에 관한 것으로 PEN도체의 단선고장시 노출도전성 부분의 접촉전압을 줄이기 위하여 전원측 접지저항과 수용가 추가접지 저항에 따른 PEN도체 단선시 노출도전성 부분에 나타나는 접촉전압을 실험적으로 조사하였다. 그 결과 TN-C-S 계통으로 공급되는 설비에 대하여 등전위본딩은 중요한 요건이다. 수용가의 인입구에 추가접지를 하는 것은 PEN 도체의 단선시 노출도전성 부분에 나타나는 접촉전압을 저감시키는 방법 중의 하나이다. 접촉전압을 안전전압 50[V]이하로 제한하는데 필요한 추가접지의 접지저항은 부하용량과 고장회로정수에 의하여 정해진다. 또한 부족전압계전기는 TN-C-S계통에서 PEN도체의 단선고장을 검출할 수 있는 적절한 해결방안이 될 수 있다.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 추계학술대회 논문집
• /
• pp.315-318
• /
• 2009

Electric shock is the accident caused by the current through a person or animal's body. That is characterized by the physiological effects. In this paper, we evaluate performance of protection against electric shocks for TT and TN grounding systems which are used by a low voltage consumer nowadays. The performance of protection against electric shocks for TT grounding system is very excellent in equipotential area of the third class grounding, but the performance is poor outside the equipotential area. The performance of protection against electric shocks for TN grounding system is excellent because the potential difference is less than 50V. Accordingly, the performance of protection for TN grounding system is good as compared with that for TT grounding System.

• 조명전기설비학회논문지
• /
• 제26권5호
• /
• pp.58-64
• /
• 2012

In electric power supply systems, an earthing system determines the electric potential of the conductors related to that of the Earth's surface. The choice of earthing system has implications for the safety of the power supply systems. There are considerably different regulations for earthing (grounding) systems in each country. A protective earth(PE) conductor ensures that all exposed conductive surfaces are at the same electric potential as the earth surface. This paper deals with that when PEN conductor of TN-C-S system is disconnected, dangerous touch voltage causes personnel body to be harmed and human being's property to be damaged seriously. For this reason, this paper explains how serious problems can occur when the fault current flows. As a consequence, we can understand how we can design earthing system properly to ensure the personnel safety against earth faults. The result shows the way that TN-C-S system can be applied safely in Korea.

• 한국전기전자재료학회논문지
• /
• 제27권2호
• /
• pp.110-114
• /
• 2014

In this study, we report the doping effect of graphene quantum dots (QDs) in nematic liquid crystal (NLC) system on rubbed polyimide (PI) surface. The good LC alignment and high thermal stability in QD-LC cell system on rubbed PI surfaces can be measured. Also, the low threshold voltage of QD-TN cell was observed about 2.77 V. The fast response time of 13.2 ms for QD-TN cell can be achieved. Finally, the good voltage holding ratio of QD-TN cell on rubbed PI surface was measured.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 추계학술대회 논문집
• /
• pp.59-62
• /
• 2009

In electrical power supply systems, an earthing system determines the electrical potential of the conductors relative to that of the Earth's conductive surface. The choice of earthing system has implications for the safety of the power supply. Note that regulations for earthing (grounding) systems vary considerably among different countries. A protective earth(PE) connection ensures that all exposed conductive surfaces are at the same electrical potential as the surface of the Earth, This paper investigates that when PEN conductor of TN-C-S system is disconnected, dangerous touch voltage is caused at personnel body. According to this paper, we can understand that when TN-C-S system is applied in Korea, what we should set up to ensure the personnel safety from fault current.

• 한국환경복원기술학회지
• /
• 제11권6호
• /
• pp.120-129
• /
• 2008

Removal rate of $NO_3-N$ and TN in a free water surface wetland system with litter layer on its bottom was compared with that without one. The system was established on floodplain in the down reach of the Gwangju Stream in 2001. Its dimensions were 31 meters in length and 12 meters in width. Water of the stream was funneled into it and its effluent was discharged back into the channel. Average litter layer of 9.6 cm was formed on its bottom in 2007. The layer and above-ground parts of reeds and cattails on the system were eliminated in Spring 2008. Volumes and water quality of inflow and outflow of the system were analyzed from May to November in 2007 and 2008, respectively. Inflow into the system both in 2007 and 2008 averaged approximately $40m^3/day$ and hydraulic residence time both in 2007 and 2008 was about 1.5 days. Average influent $NO_3-N$ concentration in 2007 and 2008 was 2.16 and 2.05 mg/L, respectively and influent TN concentration in 2007 and 2008 averaged 3.98 and 3.89 mg/L, respectively. With a 0.05 significance level, effluent temperatures, influent concentrations of $NO_3-N$ and TN, and stem numbers per square meter and height of the emergent plants showed no difference between the system with litter layer and without one. $NO_3-N$ removal in the system with litter layer and without it averaged 55.59 and 46.06%, respectively and TN retention averaged 57.24 and 48.97%, respectively. Both $NO_3-N$ and TN abatement rates in the system with litter layer were significantly high (p < 0.001) when compared with those without one. The wetland system having litter layer on its bottom was more efficient for $NO_3-N$ and TN retention than that without one.

• 상하수도학회지
• /
• 제24권4호
• /
• pp.407-412
• /
• 2010

The purpose of this study was to investigate removal efficiencies of contaminants in night soil treatment plant using the B3 system. The samples were collected from retaining tank and settlement tank in Yechon night soil plant. We experimented concentrations of BOD, COD, SS, TN and TP. Concentration data were processed using removal efficiencies by season and correlation analysis with pilot running parameters. Removal efficiencies of total organic carbon was over 96%, TN was 98% during summer, 80.9% during winter. In the case of TP, the highest removal efficiencies was 94.1% during fall and the lowest removal efficiencies was 82% during spring. Results of correlation analysis showed two positive correlation groups and one negative group. Positive correlations were among temperature, BOD and TN. The others were pH, BOD, COD, SS, TN and TP. Negative correlation were among MLSS, BOD, COD, SS, TN, TP.