• 대한전기학회논문지:전력기술부문A
• /
• 제53권12호
• /
• pp.678-684
• /
• 2004

Automatic reclosing is a typical protection method in power distribution systems for clearing the temporary faults. However, it has a fatal weakness in regards to voltage sags because it produces successive voltage sags. In this paper, we explored successive impact of voltage sag due to the automatic reclosing of power distribution systems. The actual tests of low voltage loads were accomplished for obtaining the susceptibility of voltage sags. The final results of the test yielded power acceptability curves of voltage sag, and the curves were transformed the 3-dimensional CBEMA(Computer Business Equipment Manufacturer Association) format. For the quantitative evaluation of the impact of successive voltage sags, an assessment formulation using the voltage sag contour was proposed. The proposed formulation was tested by using the voltage sag contour data of IEEE standard and the results of the test. Through the case studies, we verified that the proposed method can be effectively used to evaluate the actual impact of successive voltage sans.

• KIEE International Transactions on Power Engineering
• /
• 제5A권3호
• /
• pp.293-299
• /
• 2005

Automatic reclosing is a typical protection method in power distribution systems for the clearing of temporary faults. However, it has a fatal weakness in regards to voltage sags because it produces repetitive voltage sags. In this paper, we explored the repetitive impact of voltage sag due to the automatic reclosing of power distribution systems. The actual tests of low voltage loads were carried out for obtaining the susceptibility of voltage sags. The final results of the tests yielded power acceptability curves of voltage sag, and the curves transformed the 3-dimensional CBEMA (Computer Business Equipment Manufacturer Association) format. For the quantitative evaluation of the impact of repetitive voltage sags, an assessment formulation using the voltage sag contour was proposed. The proposed formulation was tested by using the voltage sag contour data of IEEE standard and the results of the test. Through the case studies, we verified that the proposed method can be effectively used to evaluate the actual impact of repetitive voltage sags.

• 전기학회논문지
• /
• 제59권8호
• /
• pp.1347-1352
• /
• 2010

This paper presents a new adaptive single-phase auto reclosure (SPAR) algorithm to discriminate between a permanent fault and a transient fault and to minimize a protection dead time. The algorithm precisely detects the extinction of the secondary arc, based on THD's profiles on the faulted phase voltage waveform. The EMTP/ATPDraw program was used to simulate the single phase grounding fault for evaluating the proposed algorithm. And the simulation results show that the proposed algorithm is performing well.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2002년도 하계학술대회 논문집 A
• /
• pp.166-168
• /
• 2002

This paper presents a new numerical algorithm suitable for defining recloser reclaims time and blocking automatic reclosing during permanent faults on overhead lines. It is based on terminal voltage input data processing. The decision if it is safe or not to reclose is determined from the voltage signal of faulted and tripped line phase using Total Harmonic Distortion factor calculated by Discrete Fourier Transform. The algorithm was successfully tested using signals recorded on the real power system. The tests demonstrate the ability of presented algorithm to determine the secondary arc extinction time and to block unsuccessful automatic reclosing of HV lines with permanent fault.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 C
• /
• pp.1130-1132
• /
• 1999

This paper presents the feature extraction of fault current related to the multi-shot reclosing scheme in the power distribution system. Fourier transform is used to extract the feature of the fault current waveform in the case of the temporary fault and the permanent fault. After the waveform is analyzed using Fourier transform, the magnitude spectrum and the relative variation of THD are calculated. These results are that the relative variation of THD is great in the temporary fault and is little in the permanent fault.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.592-593
• /
• 2015

Recently, the fault current has increased to exceed the rated breaking capacity of protective device due to the growth of the power demand on the power system where is changed into the loop-, mesh-, network grid. To limit fault current, the superconducting fault current limiter (SFCL) is announced with various methods. In many researches, the current limiting effect with the SFCL has been analyzed considering the rated breaking capacity of the CB with one fault condition. However, the power system has various short circuit and operation conditions. In order to select the capacity of the SFCL with reclosing operation and burden of the fault current on the protective device, the characteristics of the power system were investigated. Through the analysis, the evaluation method of the current rate was improved.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1995년도 하계학술대회 논문집 B
• /
• pp.613-615
• /
• 1995

KEPCO is now going on upgrading the highest system voltage from 345kV to 765kV since 1992. The main reason of this 765kV project is the bulk power transmission from the power generation sites at the East and West coasts to the Kyeong-in area. The first 765kV transmission lines will be constructed by 1998 and operated as 345kV level until 2001. This system needs a detailed evaluation of the 2nd arc in case of 765kV transmission line outages and the countermeasures for the fast arc reduction for the successful high speed reclosing. So, this paper deals with the simulation results of the 2nd arc characteristics using EMTP and comparison of Sh.R and HSGS for the reduction methods.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 하계학술대회 논문집 A
• /
• pp.36-38
• /
• 2003

In this paper, It was evaluated that the customer's effects of momentary voltage sag in power distribution system considering reclosing interval. Above all, power quality problems were discussed widely, various international standards about power quality were compared to each other. after the continuous voltage sag waves of power distribution system on fault were induced, the experimentation about voltage sag for critical load was performed using source simulator. The results of experimentation were displayed as the form of 2 and 3-dimensional CBEMA Curve.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
• /
• pp.106-108
• /
• 1996

This paper presents the Implementation and performance simulation of HSGS(High Speed Ground Switch)-Adaptive scheme for EHV transmission. EMTP/TACS(Transient Analysis of Control System) functions are combined and used for the implementation and simulation. The simulation results are compared with those for the conventional reclosing scheme and discussed.

• 한국전자통신학회논문지
• /
• 제17권3호
• /
• pp.417-422
• /
• 2022

선로를 따라 흐르는 전력흐름은 장기간에 걸쳐서 차단되지 않는 연속성을 갖는 것이 바람직하다. 배전선로에서 재폐로기의 최적 기준은 전력계통의 신뢰성을 개선하는 것으로 알려져 있으며, 배전계통에서 보호기능은 이러한 재폐로기의 수량과 위치가 매우 중요하다. 본 연구에서는 배전망 사고 동안 발생되는 손실을 줄이기 위하여 재폐로 동작 횟수를 포함한 보호기법의 사용 효과를 검토한다. 본 연구의 최종 목적은 표준 배전망에 대한 PSCAD/EMTDC의 모의데이터를 기반으로 사고전류 조건과 재폐로 동작 횟수를 결정하는 것이다. 피더의 보호기능인 재폐로기에서 동작횟수 결정은 배전망의 최적 운영과 신뢰성 확보에 도움이 된다.