PSCAD/EMTDC를 이용한 ESS의 누설전류 모델링에 관한 연구

김지명(Ji-Myung Kim),태동현(Dong-Hyun Tae),이일무(Il-Moo Lee),임건표(Geon-Pyo Lim),노대석(Dae-Seok Rho) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.2

ESS의 누설전류는 PCS(Power Control System)측 누설전류와 계통불평형 전류로 인한 누설전류로 구분되는데, PCS측의 누설전류는 정상 상태 운전 시, IGBT(Insulated Gate Bipolar Transistor) 스위칭의 전압 변화량과 IGBT와 방열판 사이에 존재하는 기생 커패시턴스에 의해 발생한다. 또한, 계통불평형 전류에 의한 누설전류는 불평형 부하로 인해 발생한 불평형 전류가 Yg-Δ 결선방식의 3각 철심이 적용된 태양광전원 연계형 변압기의 중성선을 통해 ESS로 유입된다. 따라서, 본 논문에서는 방열판 유도공식을 통해 산정한 기생 커패시턴스에 의하여 PCS측의 누설전류 발생메커니즘을 제시하고 또한, 계통불평형에 의한 ESS측의 누설전류 발생 메커니즘을 제안한다. 이를 바탕으로, 배전계통 상용해석 프로그램인 PSCAD/EMTDC를 이용하여 배터리부, PCS부, AC전원부로 이루어진 PCS측의 누설전류 발생 메커니즘과 배전 계통부, 불평형 부하부, ESS부로 이루어진 계통불평형에 의한 ESS측의 누설전류 발생 메커니즘을 모델링하고, 누설전류의 특성을 평가한다. 상기의 모델링을 바탕으로 시뮬레이션을 수행한 결과, 외함의 저항과 접지저항의 크기에 따라 PCS측의 누설전류는 7[mA]에서 34[mA]로, 계통불평형에 의한 배터리 외함으로 흐르는 누설전류는 3.96[mA]에서 10.76[mA]로 증가하여 배터리측에 큰 영향을 미침을 알 수 있었다. A leakage current of ESS is classified mainly by the occurrence from a PCS(Power Conditioning System) section and an unbalanced grid current. The reason for the leakage current from the PCS section is a voltage change by IGBT (Insulated Gate Bipolar Transistor) switching and stray capacitance between the IGBT and heatsink. The leakage current caused by the grid unbalanced current flows to the ESS through the neutral line of grid-connected transformer for the ESS with a three limb iron type of Yg-wire connection. This paper proposes a mechanism for the occurrence of leakage current caused by stray capacitance, which is calculated using the heatsink formula, from the aspect of the PCS section and grid unbalance current. Based on the proposed mechanisms, this study presents the modeling of the leakage current occurrence using PSCAD/EMTDC S/W and evaluates the characteristics of leakage currents from the PCS section and grid unbalanced current. From the simulation result, the leakage current has a large influence on the battery side by confirming that the leakage current from the PCS is increased from 7[mA] to 34[mA], and the leakage current from an unbalanced load to battery housing is increased from 3.96[mA] to 10.76[mA] according to the resistance of the housings and the magnitude of the ground resistance.

저항성 누설전류(Igr) 검출 콘센트의 개발 및 안전성 평가

김창성(Chang-Soung Kim),한송엽(Song-Yop Hanh),최충석(Chung-Seog Choi) 대한전기학회 2009 전기학회논문지 P Vol.58 No.2

In this paper, we analyzed form of flowing leakage current in electrical installation. Leakage current (I<SUP>g</SUP>) is consisted of resistive leakage current (I<SUP>gr</SUP>), capacitive leakage current (I<SUP>gc</SUP>), and inductive leakage current (I<SUP>gl</SUP>). Resistive leakage current (I<SUP>gr</SUP>) is big occasion than capacitive leakage current (I<SUP>gc</SUP>) in system, Residual Current Protective Device(RCD) detects correctly leakage current. But, (I<SUP>gc</SUP>) is big occasion than (I<SUP>gr</SUP>), RCD is malfunctioned. It is resistance to lead to electric fire in electrical device. We manufactured outlet that resistive leakage current detecting circuit is had. Manufactured outlet displayed performance exactly in leakage current of 5 mA. Therefore, this product estimates that contribute on electric fire courtesy call.

저항성 누전전류에 의하여 동작하는 새로운 누전차단기

咸承珍(Seung Jin Ham),韓松曄(Song Yop Hahn),高彰燮(Chang Seop Koh) 대한전기학회 2008 전기학회논문지 Vol.57 No.2

The conventional Residual Current Protective Devices (RCD, or earth leakage circuit breaker, ELB) operates depending on the total leakage current which is the vector-sum of resistive and capacitive components of a leakage current. However, the electric disaster such as electric shock or fire is mainly caused by the resistive component. Therefore, in this view point, the RCD is more realistic when it operates by the resistive component of the leakage current. In this paper, a new algorithm for measuring the resistive leakage current from the total leakage current is suggested, and is realized to an actual circuit. According to the suggested algorithm, the resistive component of the leakage current can be found by integrating the total leakage current over only a half cycle of the Line voltage, and it is realized by using analog switches and resettable integrators. It is confirmed through experiments that the suggested algorithm detects, within maximum average error of 6.74%, the resistive leakage current from the total leakage current, and the RCD employing the suggested algorithm brakes the circuit within the regular interrupt time (30msec).

Leakage flux, Leaked voltage, Leaked current, Magnetic flux density, Surface leakage

Chung Hyeok Kim,Tag-Yong Kim,Yong-Cheul Oh 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.3

Current research about voltage leakage involves investigation of the effects of leaked voltage and current on humans through simulated environments and dummies. Electrocution results from leaked current when electricity flows through the body as a result of potential difference. Research that analyzes actual electrocution is insufficient because of the danger from leaked voltage present in the leakage area. This thesis analyzes magnetic flux density from current around a leak to investigate the distribution of current. The authors used a simulated environment to investigate electrocution accidents that frequently occur during floods through leakage along metal surfaces, and evaluated the distribution of leaked magnetic flux. Current research about voltage leakage involves investigation of the effects of leaked voltage and current on humans through simulated environments and dummies. Electrocution results from leaked current when electricity flows through the body as a result of potential difference. Research that analyzes actual electrocution is insufficient because of the danger from leaked voltage present in the leakage area. This thesis analyzes magnetic flux density from current around a leak to investigate the distribution of current. The authors used a simulated environment to investigate electrocution accidents that frequently occur during floods through leakage along metal surfaces, and evaluated the distribution of leaked magnetic flux.

새로운 저항성 누전전류 측정 방법

咸承珍(Seung Jin Ham),韓松曄(Song Yop Hahn),高彰燮(Chang Seop Koh) 대한전기학회 2007 전기학회논문지 Vol.56 No.8

It is important to measure the resistive component separately from the total leakage current at power distribution line. It is because electric disasters such as electric shock and fire are caused mainly by the resistive component of the total leakage current. In this paper, a new theory for measuring the resistive component separately from the total leakage current is suggested, and is embodied to an actual circuit using operational amplifiers, analog switch and R-C low pass filter. Through experiments for various cases containing both the resistive and capacitive leakage currents, the suggested algorithm is confirmed to be able to measure the resistive leakage current within 4.1% of error even when the capacitive leakage current is much bigger than the resistive one. The suggested method is expected to lower the total cost because it can be realized using simple and cheap devices, and implies the measuring time can be possibly reduced because the resistive leakage current is computed exactly from the signals during only a half period of power voltage.

Characterization of Leakage Current Mechanisms for Aerosol-deposited BaTiO3 Thin Films at Room Temperature

오종민,김형준,남송민 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.41

BaTiO3 thin films having different thickness of 0.2-2.2 μm were fabricated on flat Cu and stainlesssteel (SUS) substrates by using aerosol deposition (AD) at room temperature. The dependence of the leakage current on the thickness of the BaTiO3 thin films was measured, and the leakage current mechanisms were investigated to clarify the origins of the leakage currents. As a result of the measurements and examination, the leakage currents are highest for the thinnest BaTiO3films, and by decreasing the thickness of the films, the leakage current mechanism was changed from Poole-Frenkel emission to a modified-Schottky (M-S) emission. In particular, in the case of BaTiO3thin films with 0.2 μm-thick which is minimum thickness on SUS substrates, the dominant leakage current mechanism was M-S emission at low electric fields, the Fowler-Nordheim tunneling appeared as the primary leakage current mechanism at high electric fields due to electric-field concentration. Consequently, the origins of leakage current are suggested to be microscopic defects, such as oxygen vacancies, acting as donors in the BaTiO3 films and the ununiform electric-field concentration at the rough interfaces between the BaTiO3 films and the metal substrates at high electric fields.

Measurement Method of the Resistive Leakage Current for Lightning Arrester Diagnosis

길경석,Ju-Seop Han,Jae-Yong Song,Hwang-Dong Seo 한국전기전자재료학회 2005 Transactions on Electrical and Electronic Material Vol.6 No.2

Several ways for monitoring the soundness of ZnO lightning arresters have been suggested, and all of which are based on the measurement of leakage current since it is well known that the resistive leakage current is a main indicator of arrester deterioration. In this paper, we proposed an algorithm to measure the resistive leakage current, which is quite different from the conventional method that eliminates capacitive current from the total leakage current. The proposed algorithm is based on that the magnitudes of the resistive leakage current are equal at the same applied voltage levels. To confirm the reliability of the algorithm, we fabricated a leakage current detector and designed an analysis program. Experimental results showed that the method does not need a complex circuitry and is useful to analyze the resistive leakage current.

리튬이온전지를 사용하는 ESS에서 CMV 및 누설전류의 발생원인과 저감방법에 관한 연구

김승호(Seung-Ho Kim),최형석(Hyoung-Seok Choi),김진용(Jin-Yong Kim),한아(Ah Han) 대한전기학회 2021 전기학회논문지 Vol.70 No.1

ESS(Energy Storage Systems) using lithium ion battery are rapidly increasing their capacity because they can efficiently store electrical energy in a small area with high energy density. However, 29 fire accidents have been reported in Korea for last 4 years. Up to now, the root cause of ESS fire has not been clearly defined, but some lithium ion battery manufacturer assert that the reason of fire may be caused by CMV(Common Mode Voltage) and leakage current. This study investigated the mechanism, measuring, acceptable level, and mitigation of CMV and leakage current through experimental field analysis with its corresponding simulation. The stray capacitance of IGBT module and lithium-ion battery are investigated as the cause of CMV and leakage current, and the magnitude variation of CMV and leakage current by the type of system earthing of the AC side is investigated too, then this paper suggested the use of an isolation transformer as a mitigation method. In addition, it was analyzed how the use of an isolation transformer can reduce CMV and this study proved that the installation of an isolation transformer is a complete and fundamental solution to reduce both CMV and leakage current by simulation and field measurement results. On the other hand, this study found the shape and period of the waveform of CMV and leakage current are completely identical, and prove that these two are produced by the same cause and the leakage current was also demonstrated to be lowered when the CMV was lowered. On the other hand, based on the analyzing the path of the leakage current flow in the grounded system and the non-ground systems, this study found that it was reasonable to measure CMV and leakage current on the DC side of PCS, and this was proved by P-Sim simulation and field experiments.

부하종류에 따른 회로의 누설전류 및 절연저항 특성 연구

한경철,최용성 한국전기전자학회 2019 전기전자학회논문지 Vol.23 No.2

The ratios of compliant branch circuit of leakage current and insulation resistance were 68.4% and 90.8%, respectivelyat the lamp load, 64.6% and 96.5% at the heat load, 86.7% and 88.9% at the power load. Limit of residual current of thezero phase secondary current value at the zero phase primary current was 100 A when rated primary current 400 A morethan. The reason why the ratio of branch circuit of the leakage current was less than the ratio of compliant branchcircuit of the insulation resistance might be that the leakage current includes the capacitive leakage current and the zerophase current. 본 논문에서는 전기재해를 일으킬 수 있는 요소를 미리 제거하기 위해 전등부하, 전열부하, 동력부하를 대상으로 누설전류와 절연저항을 측정하여 분포비율과 누적비율을 비교하고 분석하여 보다 효과적이고 신뢰성 있는 누설전류 검출방법을 찾고자 하였다. 누설전류와 절연저항의 적합 비율 차이는 전열부하 32.5%, 전등부하 22.8%, 동력부하 2.2%의 순으로 나타났으며,누설전류계가 낮은 적합 비율을 나타내었으며, 누설전류계는 측정방법에 따른 오차와 용량성 누설전류 및 영상전류가 포함되어 있기 때문으로 생각되었다.

The Effect of Transformer Leakage Inductance on the Steady State Performance of Push-pull based Converter with Continuous Current

Chen, Qian,Zheng, Trillion Q.,Li, Yan,Shao, Tiancong The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.3

As a result of the advantages such as high efficiency, continuous current and high stability margin, push-pull converter with continuous current (PPCWCC) is competitive for battery discharge regulator (BDR) which plays an important role in power conditioning unit (PCU). Leakage inductance yields current spike in low-ripple current of PPCWCCs. The operating modes are added due to leakage inductance. Therefore the steady state performance is affected, which is embodied in the spike of low-ripple current. PPCWCCs which are suitable for BDR can be separated into three types by current spike characteristics. Three representative topologies IIs1, IIcb2 and Is3 are analyzed in order to investigate the factors on the magnitude and duration of spike. Equivalent current sampling method (ECSM) which eliminates the sampling time delay and achieves excellent dynamic performance is adopted to prevent the spike disturbance on current sampling. However, ECSM reduces the sampling accuracy and telemetry accuracy due to neglecting the spike. In this paper, ECSM used in PPCWCCs is summarized. The current sampling error is analyzed in quality and quantity, which provides the foundation for offsetting and enhancing the telemetry accuracy. Finally, current sampling error rate of three topologies is compared by experiment results, which verify the theoretical analysis.