IEC 61850 기반 후비보호계전시스템 보호협조 개선방안

김형규(Hyung-Kyu Kim),강상희(Sang-Hee Kang) 대한전기학회 2011 전기학회논문지 Vol.60 No.1

A distance relay scheme is commonly used for backup protection. This scheme, called a step distance protection, is comprised of 3 steps for graded zones having different operating time. As for the conventional step distance protection scheme, Zone 2 can exceed the ordinary coverage excessively in case of a transformer protection relay especially. In this case, there can be overlapped protection area from a backup protection relay and, therefore, malfunctions can occur when any fault occurs in the overlapped protection area. Distance relays and overcurrent relays are used for backup protection generally, and both relays have normally this problem, the maloperation, caused by a fault in the overlapped protection area. Corresponding to an IEEE standard, this problem can be solved with the modification of the operating time. On the other hand, in Korea, zones are modified to cope with this problem in some specific conditions. These two methods may not be obvious to handle this problem correctly because these methods, modifying the common rules, can cause another coordination problem. To overcome this problem clearly, this paper describes an improved backup protection coordination scheme using an IEC 61850-based distance relay for transformer backup protection. IEC 61850-based IED(Intelligent Electronic Device) and the network system based on the kernel 2.6 LINUX are realized to verify the proposed method. And laboratory tests to estimate the communication time show that the proposed coordination method is reliable enough for the improved backup protection scheme.

The impact of density, distance and division on intellectual property rights protection: the case of Huaihai Economic Zone, China

Xing Gao 서울시립대학교 도시과학연구원 2021 도시과학국제저널 Vol.25 No.2

Although intellectual property rights (IPRs) protection is often discussed at national level, it may also present spatial difference at sub-national level due to regional economic development inequality in geographic space. The paper explores the empirical impact of 3Ds (Density, Distances and Division) framework of the 2009 World Development Report on spatial heterogeneity of IPRs protection within 20 cities in Huaihai Economic Zone (HEZ), China. Endogeneity and spatial effect issues are discussed in the study. This study not only employs OLS to examine the effects of spatial heterogeneity on IPRs protection, but also uses two-stage least squares regression (2SLS) and spatial effects to address endogeneity and neighbour issues respectively. Econometric results indicate that distance plays an important role in disparities of IPRs protection, especially distances to provincial capitals. However, the role of Xuzhou, the central city of HEZ, is not highlighted. The positive effect of density can help us understand IPRs protection and its significant role proves the existence of agglomeration, but due to the small sample size, we have to treat its effect carefully. Meanwhile, the results on division demonstrate the negative impact of foreign direct investment (FDI) and the existence of low quality FDI in Huaihai Economic Zone. In addition, the above conclusions continue to be held by interaction variables, and time dummies indicate that HEZ has been committed to the development of IPRs protection in recent years. Finally, these results have a strong policy implication for economic agglomeration, economic integration and central city development in HEZ.

3차원 가상착의를 활용한 방호복 평가

이옥경,이희란 한국염색가공학회 2023 韓國染色加工學會誌 Vol.35 No.2

The purpose of this study was to analyze the patterns of D level protective clothing, improve their ease of movement by modifying the patterns, and validate the effectiveness of the improvements through 3D virtual fitting and subjective wearing evaluations. Based on previous studies that identified numerous complaints, the patterns of the neck, armpit, and waist areas were modified, resulting in the development of new patterns. To compare and analyze the improved protective clothing with the basic protective clothing, stress and strain were examined after 3D virtual fitting. Additionally, to assess the clothing`s allowance, the overall distance between the avatar and the protective clothing, as well as the sectional circumference length and distance of each avatar body part, were measured. Furthermore, the improved protective clothing was manufactured, and a subjective wearing evaluation was conducted with ten males in their twenties as participants. The results showed that the improved protective clothing had evenly distributed stress, larger sectional circumference, and lower average cavity distance. The subjective wearing evaluation also revealed that the suit with improved patterns exhibited superior size suitability, reduced pulling sensation in different body parts, and increased ease of movement. In conclusion, this study confirmed that even minimal pattern modifications can enhance the functionality of protective clothing, alleviating discomfort for wearers.

보호거리와 부하 유형에 따른 SPD의 보호효과에 대한 실험적 고찰

이복희(Bok-Hee Lee),김유하(You-Ha Kim),안창환(Chang-Hwan Ahn) 한국조명·전기설비학회 2012 조명·전기설비학회논문지 Vol.26 No.10

Surge protective devices(SPDs) are widely used as a most effective means protecting the electrical and electronic equipment against overvoltages such as lightning and switching surges. When installing SPDs, it is essential that the voltage protection level provided by SPDs should be lower than the withstand voltage of the equipment being protected. But even the proper selection of SPDs are achieved, the voltage at the equipment terminal may be higher than the residual voltage of SPD due to the reflection and oscillation phenomena. This paper was focused on the investigations of the conditions for which the equipment is protected by an SPD taking into account the influences of the protective distance and type of load. The protective effects of SPD with voltage-limiting component were analyzed as functions of types of load and protective distance between the SPD and load. As a result, in the cases of long protective distances, capacitive loads and loads with high resistance, the voltage at the load terminal was significantly higher than the residual voltage of SPD. It was found that the proper installation of SPDs should be carried out by taking into account the protective distance and type of load to achieve reliable protection of electronic equipments against surges.

종속 접속된 전압제한형 서지방호장치의 에너지협조

이복희(Bok-Hee Lee),신희경(Hee-Kyung Shin) 한국조명·전기설비학회 2013 조명·전기설비학회논문지 Vol.27 No.2

For the purpose of designing and applying optimum surge protection, one of the essential points is to take into account the energy coordination between cascaded surge protective devices(SPDs) and it is important to obtain an acceptable sharing of the energy stress between two cascaded SPDs. In this paper, in case of two voltage-limiting SPDs connected in parallel, the amount of splitting impulse current and energy that flow through each SPDs is investigated as a function of the protective distance. As a result, the energetic coordination between cascaded SPDs is strongly dependent on the voltage protection level of SPDs and the protective distance. It was confirmed that the sharing of the energy between two cascaded SPDs and the limited voltage levels are appropriate when the voltage protection levels of both upstream and downstream SPDs are the same.

보호거리에 따른 전압제한형 SPD의 보호효과에 대한 시뮬레이션기법

이복희(Bok-Hee Lee),김유하(You-Ha Kim),안창환(Chang-Hwan Ahn) 한국조명·전기설비학회 2013 조명·전기설비학회논문지 Vol.27 No.7

This paper presents a method of simulating the protection effects of surge protective devices(SPDs) depending on the protective distance and types of input impedance of load to be protected. In order to analyze the protective performances of voltage-limiting type SPDs associated with the reflection and oscillation phenomena, the terminal voltage across load being protected and the residual voltage of SPDs were simulated by using EMTP model as functions of the protective distance and types of input impedance of loads. As a consequence, SPDs should be installed by taking into account the protective distance and input impedance of loads to achieve reliable protection of electrical and electronic equipment from lightning and switching surges. It is expected that the simulation method proposed in this paper could be practically used in design for installing SPDs in low-voltage distribution systems.

ISM 기기에 의한 디지털 방송 서비스 간섭 영향 분석

심용섭(Yong-Sup Shim),이일규(Il-Kyoo Lee),박승근(Seung-Keun Park),민경일(Kyoung-Il Min) 한국정보기술학회 2011 한국정보기술학회논문지 Vol.9 No.2

This paper analyzes the interference effect of ISM(Industrial Scientific Medical) equipment on Digital Broadcasting Service in ISM frequency band. For setting up interference power of ISM equipment, CISPR(International Special Committee on Radio Interference) 11 radiation limit standard was used. Then, MCL(Minimum Coupling Loss) which is for worst case and MC(Monte Carlo) which is for statistic analysis considering mobility of digital broadcasting receiver are used to get protection distance. Finally, according to each channel number 14, 40, 60, protection distance of 184.97m, 104.67m, 73.79m were calculated separately for the worst case. The protection distance of 29m to meet 5% of interference probability was calculated for statistic analysis regardless of channels. As a result, this protection distance was suggested to protect digital broadcasting service from ISM devices.

화학사고의 일차 대응을 위한 피해영향범위 산정 개선 방안

이덕재 ( Deok Jae Lee ),안재현 ( Jae-hyun Ahn ),송창근 ( Chang Geun Song ) 한국안전학회 2017 한국안전학회지 Vol.32 No.2

Calculation of the damage impact of chemical accidents is an important element in site, and the initial isolation distance and the protective action distances are significant factors in coping the chemical accident. In this study, three major cities that represent each Province were selected, and the safety distances were calculated considering regional climate conditions. The results were compared with the prescribed values in Emergency Response Guidebook. It is concluded that the regional meteorological conditions such as temperature, vapour pressure, relative humidity, wind speed, and cloud cover should be reflected in estimating the initial isolation distance and the protective action distance.

Setting Considerations of Distance Relay for Transmission Line with STATCOM

Wen-Hao Zhang,Seung-Jae Lee,Myeon-Song Choi 대한전기학회 2010 Journal of Electrical Engineering & Technology Vol.5 No.4

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.

Setting Considerations of Distance Relay for Transmission Line with STATCOM

Zhang, Wen-Hao,Lee, Seung-Jae,Choi, Myeon-Song The Korean Institute of Electrical Engineers 2010 Journal of Electrical Engineering & Technology Vol.5 No.4

Distance relay plays an important role in the protection of transmission lines. The application of flexible AC transmission systems (FACTS) devices, such as the static synchronous compensator (STATCOM), could affect the performance of the distance relay because of compensation effect. This paper analyzes the application of distance relay on the protection of a transmission line containing STATCOM. New setting principles for different protection zones are proposed based on this analysis. A typical 500 kV transmission system employing STATCOM is modeled using Matlab/Simulink. The impact of STATCOM on distance protection scheme is studied for different fault types, fault locations, and system configurations. Based on simulation results, the performance of distance relay is evaluated. The setting principle can be verified for the transmission line with STATCOM.