Al₂O₃ 첨가에 따른 송전용 현수애자의 전기적 성능 평가 연구

최인혁,최장현,이동일,최연규,조한구,한세원,박영창,Choi, In-Hyuk,Choi, Jang-Hyun,Lee, Dong-Il,Choi, Yeon-Gyu,Cho, Han-Goo,Han, Se-Won,Park, Young-Chang 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.1

To analyze the reason of aging deterioration in transmission line insulators, we performed a various kind of test and investigated mechanical and electrical characteristics of insulators. Test samples consisted of K-1989(36,000lbs), K-1995(36,000lbs) and K-2001(36,000lbs) type insulators which have been used in domestic 154 kV transmission lines. As a result of this test, the facts turned out K-2001 insulator which contain 17 wt.% alumina has better physical characteristics than K-1989 insulator which contain 8 wt% alumina. Relativity density and fracture toughness of K-1989 porcelain are 94.2 % and 1.4 MPa\ulcornerm$^{1}$2// but relativity density and fracture toughness of K-2001 porcelain are 96 % and 1.7 MPa\ulcornerm$^{1}$2//. K-2001 insulators show a good performance not only in a physical property test but also in power arc test and steep front of wave flashover test which is performed to evaluate electrical characteristics.

Recovery of the Vanadium and Tungsten from Spent SCR Catalyst Leach Solutions by Hydrometallurgical Methods

최인혁,문경혜,전종혁,이진영,라제쉬 쿠마 죠티,Choi, In-Hyeok,Moon, Gyeonghye,Jeon, Jong-Hyuk,Lee, Jin-Young,Jyothi, Rajesh Kumar The Korean Institute of Resources Recycling 2020 資源 리싸이클링 Vol.29 No.2

In new millennium, wide-reaching demands for selective catalytic reduction (SCR) catalyst have been increased gradually in new millennium. SCR catalyst can prevent the NO_x emission to protect the environment. In SCR catalyst the main composition of the catalyst is typically TiO₂ (70~80%), WO₃ (7~10%), V₂O₅ (~1%) and others. When the SCR catalysts are used up and disposed to landfills, it is problematic that those should exist in the landfill site permanently due to their extremely low degradability. A new advanced technology needs to be developed primarily to protect environment and then recover the valuable metals. Hydrometallurgical techniques such as leaching and liquid-liquid extraction was designed and developed for the spent SCR catalyst processing. In a first stage, V and W selectively leached from spent SCR catalyst, then both the metals were processed by liquid-liquid extraction process. Various commercial extractants such as D2EHPA, PC 88A, TBP, Cyanex 272, Aliquat 336 were tested for selective extraction of title metals. Scrubbing and stripping studies were tested and optimized for vanadium and tungsten extraction and possible separation. 3^rd phase studies were optimized by using iso-decanol reagent.

얕은 심도 V_S주상도를 활용한 V_S30 예측 방법론 비교 및 최적 계수 제시

최인혁,곽동엽,Choi, Inhyeok,Kwak, Dongyoup 한국지반공학회 2020 한국지반공학회논문집 Vol.36 No.3

Ground motion models predicting intensity measures on surface use a time-averaged shear wave velocity, V_S30, as a key variable simulating site effect. The V_S30 can be directly estimated from V_S profiles if the profile depth (z) is greater than or equal to 30 m. However, some sites have V_S profiles with z < 30 m. In this case V_S30 can be predicted using extension models. This study proposes new coefficient sets for existing prediction equations using 297 Korea V_S profiles. We have collected V_S profiles from KMA and Geoinfo database. Fitting six existing methods to data, we suggest new coefficients for each method and evaluate their performance. It turns out that if z ≥ 15 m, the standard deviation (σ) of residual in log₁₀ is 0.061, which indicates that the estimated V_S30 is nearly accurate. If z < 15 m, the σ keeps increasing up to 0.1 for z = 5 m, so we caution the use of models at very low z. Nonetheless, we recommend investigating up to 30 m depth for V_S30 calculation if possible. 지표면에서의 지반운동을 예측하는 지반운동예측모델은 30m까지의 평균전단파속도인 V_S30을 부지효과를 나타내는 주요한 변수로 사용한다. V_S30은 만약 V_S주상도 깊이(z)가 30m 이상이면 주상도로부터 바로 계산할 수 있다. 하지만, 모든 부지에서 z가 30m 까지 있는 것은 아니다. 따라서, z < 30m일 경우 30m까지 연장하는 모델로부터 V_S30을 예측할 필요가 있다. 이번 연구에서는 국내 지반 환경에 맞게 z가 30m 미만인 부지에서 V_S30을 추정하는 예측 모델에 대한 새로운 계수를 제안하였다. 분석 자료로 기상청과 국토지반정보 통합DB센터에서 획득한 297개의 V_S주상도를 활용하였고, 선행연구에서 제안한 식의 계수들을 회귀분석을 통해 새롭게 제시하였다. 분석 결과, z ≥ 15m 일 경우 대수로그 잔차의 표준편차가 약 0.061이내이므로 신뢰성 높은 V_S30를 예측하는 것으로 확인하였다. z < 15m 일 경우 σ가 계속 증가하며, z = 5m일 경우 σ = 0.1으로 나타났다. 따라서, 매우 얕은 심도의 V_S주상도를 모델에 적용하는 경우 주의를 요하며, 가능하다면 30m깊이까지 지반조사를 실시하여 V_S30을 계산하는 것을 추천한다.

베이지안 방법론을 적용한 154 kV 송전용 자기애자의 수명 평가 개발

최인혁,김태균,윤용범,이준신,김성욱,Choi, In-Hyuk,Kim, Tae-Kyun,Yoon, Yong-Beum,Yi, Junsin,Kim, Seong Wook 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.9

It is extremely important to improve methodologies for the lifetime assessment of porcelain insulators. While there has been a considerable amount of work regarding the phenomena of lifetime distributions, most of the studies assume that aging distributions follow the Weibull distribution. However, the true underlying distribution is unknown, giving rise to unrealistic inferences, such as parameter estimations. In this article, we review several distributions that are commonly used in reliability and survival analysis, such as the exponential, Weibull, log-normal, and gamma distributions. Some properties, including the characteristics of failure rates of these distributions, are presented. We use a Bayesian approach for model selection and parameter estimation procedures. A well-known measure, called the Bayes factor, is used to find the most plausible model among several contending models. The posterior mean can be used as a parameter estimate for unknown parameters, once a model with the highest posterior probability is selected. Extensive simulation studies are performed to demonstrate our methodologies.

정상적(正常的)인 한우(韓牛)의 심전도(心電圖)에 관(關)한 연구(硏究) I. 표준지유도(標準肢誘導)

최인혁,정인성,김남수,서두석,Choi, In-hyuk,Jung, In-sung,Kim, Nam-soo,Suh, Doo-seok 대한수의학회 1993 大韓獸醫學會誌 Vol.33 No.4

The electrocardiographic(ECG) parameters on the standard limb leads in the normal Korean native cattle have been measured with a 3 channel Electrocardiograph built in a computed analysis. The study was conducted on the animals 98 heads of mean age of 17.7 months. Conduction parameters, waves, intervals and segments have been recorded. The recordings were analyzed as to shape and amplitude of the P and T waves and the components of the QRS complex. Heart rate was recorded by the Electrocardiogram which were a mean of $80.4{\pm}11.6beats/min$. And the younger had a higher heart rate than the older one. Average conduction times in the RP, the QRS complex and the QTc interval recorded $166.7{\pm}23.1msec.$, $79.7{\pm}8.8msec.$ and $395.5{\pm}30.4msec.$, in the P and T wave duration recorded $70.1{\pm}13.5msec.$ and $97.6{\pm}16.9msec.$, and in the PR and ST segment duration recorded $97.9{\pm}23.5msec.$ and $173.9{\pm}40.3msec.$, respectively. The wave forms in each lead observed various types. The amplitudes of wave type showed the highest frequency in each lead that were analyzed as follow : 1. In P wave, amplitudes of the positive type showed the frequency of 65.3%, 82.7% and 52.0% in leads I, II and III that were $103.1{\pm}47.8{\mu}V$, $115.2{\pm}37.3{\mu}V$ and $67.4{\pm}26.9{\mu}V$, and it showed the frequency of 54.1% and 85.7% in the leads aVL and aVF that were $63.7{\pm}23.0{\mu}V$, $88.0{\pm}83.6{\mu}V$, respectively. Average amplitude of the negative type showed the frequency of 78.6% in lead aVR which was $99.3{\pm}38.0{\mu}V$. 2. Average amplitude of the QRS complex were from $362.8{\pm}177.7{\mu}V$ to $532.8{\pm}253.9{\mu}V$(mean of $449.1{\pm}57.2{\mu}V$) that in all leads except lead I were manifested the Low-Voltage QRS complex(below 0.5mV). Average amplitudes of each wave type in the QRS complex aere $-50.2.4{\pm}258.2{\mu}V$ and $-428.6{\pm}195.1{\mu}V$ in the QS groups type that showed a frequency of 66.3%, 70.4% in the leads I and aVL, were $451.1{\pm}20.4.0{\mu}V$, $387.6{\pm}175.8{\mu}V$ and $299.3{\pm}146.5{\mu}V$ in the R groups type that showed a frequency of 48.0%, 53.1% and 34.7% in the leads III, aVR and aVF, and were $-307.5{\pm}180.3{\mu}V$, $201.4{\pm}77.2{\mu}V$ in the QR wave type which showed a frequency of 39.8% in lead II, respectively. 3. In T wave, amplitude of the positive type showed the frequency of 50.0%, 82.7%, 51.0% and 57.1% in leads II, III aVR and aVF which were $214.9{\pm}115.6{\mu}V$, $188.5{\pm}119.3{\mu}V$, $191.0{\pm}93.7{\mu}V$ and $165.7{\pm}91.9{\mu}V$, and the negative type showed a frequecny of 66.3% and 72.5% in leads I and aVL. that were $221.3{\pm}112.5{\mu}V$, $-173.6{\pm}86.7{\mu}V$, respectively. 4. Amplitude of ST segment in leads I, II and III were a mean of $-12.2{\pm}37.2{\mu}V$, $17.5{\pm}42.6{\mu}V$ and $28.3{\pm}40.4{\mu}V$, in leads aVR, aVL and aVF were $-3.9{\pm}32.5{\mu}V$, $-15.9{\pm}35.6{\mu}V$ and $26.2{\pm}37.5{\mu}V$, respectively.

AE기법을 이용한 자기애자의 손상 분석

최인혁,신구용,임윤석,구자빈,손주암,임대연,오태근,윤영근,Choi, In-Hyuk,Shin, Koo-Yong,Lim, Yun-seog,Koo, Ja-Bin,Son, Ju-Am,Lim, Dae-Yeon,Oh, Tae-Keun,Yoon, Young-Geun 한국전기전자재료학회 2020 전기전자재료학회논문지 Vol.33 No.3

This paper investigates the soundness of porcelain insulators associated with the acoustic emission (AE) technique. The AE technique is a popular non-destructive method that measures and analyzes the burst energy that occurs mainly when a crack occurs in a high-frequency region. Typical AE methods require continuous monitoring with frequent sensor calibration. However, in this study, the AE technique excites a porcelain insulator using only an impact hammer, and it applies a high-pass filter to the signal frequency range measured only in the AE sensor by comparing the AE and the acceleration sensors. Next, the extracted time-domain signal is analyzed for the damage assessment. In normal signals, the duration is about 2ms, the area of the envelope is about 1,000, and the number of counts is about 20. In the damage signal, the duration exceeds 5ms, the area of the envelope is about 2,000, and the number of counts exceeds 40. In addition, various characteristics in the time and frequency domain for normal and damage cases are analyzed using the short-time Fourier transform (STFT). Based on the results of the STFT analysis, the maximum energy of a normal specimen is less than 0.02, while in the case of the damage specimen, it exceeds 0.02. The extracted high-frequency components can present dynamic behavior of crack regions and eigenmodes of the isolated insulator parts, but the presence, size, and distribution of cracks can be predicted indirectly. In this regard, the characteristics of the surface crack region were derived in this study.

정상적(正常的)인 한우(韓牛)의 심전도(心電圖)에 관(關)한 연구(硏究) II. 흉부단극유도(胸部單極誘導)의 파형(波形)과 전위(電位)

최인혁,김수용,김남수,서두석,Choi, In-hyuk,Kim, Soo-young,Kim, Nam-soo,Suh, Doo-seok 대한수의학회 1993 大韓獸醫學會誌 Vol.33 No.4

Electrocardiographic parameters of amplitude and the shape of waves on the unipolar precordial chest leads in the normal Korean native cattles have been measured with a 3 channel electrocardiograph built in a computed and analysis. The study was conducted on 98 heads of mean age of 17.6 months. The wave forms of P, T and QRS complex wave in all leads showed various types. The parameters of the amplitude in the wave types showed the most frequency in each lead that were analyzed as follow : 1. In P wave, amplitudes of positive type showed a frequency of 92.9% and 93.9% in leads $CV_6LU$ and $CV_6LL$ that were $83.8{\pm}31.0{\mu}V$ and $76.0{\pm}30.7{\mu}V$, and negative type showed a frequency of 97.9% in lead V 10 that were $-80.2{\pm}29.4{\mu}V$, respectively. But the plate type in leads $CV_6RU$ and $CV_6RL$ showed frequency of 48% and 58.3%, respectively. 2. Average amplitude of the QRS complex were in a range of $277.0{\pm}154.0{\mu}V$ to $648.2{\pm}146.2{\mu}V$(mean of $418.8{\pm}139.4{\mu}V$) in all leads that were manifested the Low-Voltage QRS complex(below 1 mV in unipolar precordial leads). Average amplitudes of each wave type in the QRS complex were $-250.0{\pm}139.8{\mu}V$ and $-399.2{\pm}226.8{\mu}V$ in the QS group types that showed a frequency of 50.0% and 82.5% in the leads $CV_6LU$ and $CV_6LL$, respectively. And average amplitudes of the R group types showed a frequency of 85.6%, 56.1% and 75.8% in the $CV_6RU$, $CV_6RL$ and $V_{10}$ that were $321.5{\pm}142.1{\mu}V$, $271.6{\pm}139.9{\mu}V$ and $552.4{\pm}132.7{\mu}V$, respectively. 3. In T waves, Amplitudes of the positive type showed a frequency of 60.2%, 46.9% and 83.7% in leads of $CV_6LL$, $CV_6RU$ and $CV_6RL$ that were respectively $184.7{\pm}93.7{\mu}V$ $103.7{\pm}64.43{\mu}V$ and $111.8{\pm}39.3{\mu}V$, the negative type showed a frequency of 62.2% and 93.7% in leads $CV_6LU$ and $V_{10}$ that were $142.2{\pm}82.1{\mu}V$ and $-280.3{\pm}107.2{\mu}V$, respectively. 4. Average amplitude of ST segment were $3.7{\pm}33.1{\mu}V$, $0.9{\pm}23.1{\mu}V$, $10.9{\pm}28.6{\mu}V$, $5.8{\pm}28.3{\mu}V$ and $-34.7{\pm}48.4{\mu}V$ in leads $CV_6LL$, $CV_6RU$, $CV_6RL$, $CV_6LU$ and $V_{10}$ respectively.

개의 비유합(非癒合) 골절(骨折) model에 있어서 동결건조골이식(凍結乾燥骨移植)의 효과(效果)

최인혁,김현경,김남수,사사키 노부오,Choi, In-hyuk,Kim, Hyeon-gyeong,Kim, Nam-soo,Sasaki, Nobuo 대한수의학회 1996 大韓獸醫學會誌 Vol.36 No.2

To investigate the effectiveness of the freeze-dried allografts and fibrin glue in bone grafts, the status of new bone formation and union of the grafted bone were observed in three types of grafting bones; autogenic bone(AT), allogenic bone(AL), and allogenic bone particles mixed with fibrin glue(FG). These were transplanted into non-union fracture model of 7 adult dogs with 2cm defect made in the proximal metaphysis of both fibulae. The autogenic and allogenic grafting bones had been treated by a modified freeze-dried method. The serial radiogram were observed the repair process of grafted bones biweekly until 17 or 21 weeks after transplantation and the observation of histological aspects, tetracycline double labeling and microradiography in the grafted bones were undertaken at 17 or 21 weeks after transplantation. The incorporation of bone minerals to the non-union fracture models were accomplished in 4 of 5 cases grafted with AL and in 2 of 4 cases grafted with AT. None of 5 cases grafted with FG were incorporated. The process of new bone formation and resorption in the grafted bones were observed three types; resorption of the grafted bones after newbone formation(type A) in 4 cases, new bone formation after resorption(type B) in 2 cases and complete or incomplete resorption without new bone formation(type C) in 8 cases. The modified freeze-dried method used in this study contributed to inhibite the rejection in allogenic grafts but the union period of the grafted freeze-dried bone was more prolonged than that of fresh autografts. Fibrin glue did not contribute to induce a new bone formation ofbone grafts.

자기애자의 유지 관리를 위한 CNN 기법을 이용한 이미지 분석

최인혁,신구용,구자빈,손주암,임대연,오태근,윤영근,Choi, In-Hyuk,Shin, Koo-Yong,Koo, Ja-Bin,Son, Ju-Am,Lim, Dae-Yeon,Oh, Tae-Keun,Yoon, Young-Geun 한국전기전자재료학회 2020 전기전자재료학회논문지 Vol.33 No.3

This study examines the feasibility of the image deep learning method using convolution neural networks (CNNs) to maintain a porcelain insulator. Data augmentation is performed to prevent over-fitting, and the classification performance is evaluated by training the age, material, region, and pollution level of the insulator using image data in which the background and labelling are removed. Based on the results, it was difficult to predict the age, but it was possible to classify 76% of the materials, 60% of the pollution level, and more than 90% of the regions. From the results of this study, we identified the potential and limitations of the CNN classification for the four groups currently classified. However, it was possible to detect discoloration of the porcelain insulator resulting from physical, chemical, and climatic factors. Based on this, it will be possible to estimate the corrosion of the cap and discoloration of the porcelain caused by environmental deterioration, abnormal voltage, and lightning.

송전용 폴리머 애자에 대한 산불 영향 평가

최인혁,이동일,이철호,강병규,이원교,박준호,Choi, In-Hyuk,Lee, Dong-Il,Lee, Chul-Ho,Kang, Byoung-Kyu,Lee, Won-Kyo,Park, Jun-Ho 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.9

To understand the effects of forest fires on polymer insulators for transmission lines, the forest fire simulation tests were performed with polymer and porcelain insulators at Gochang testing center. These tests consisted of energizing 90 kV at line-to-ground voltage of 154 kV lines and open flame rising up to $600-630^{\circ}C$ as being measured at insulator surface. Mechanical and electrical characteristics such as specific mechanical load, leakage current, low frequency dry flashover voltage and impulse flashover voltage were analyzed for the polymer insulators before, during and after simulation tests compared with porcelain insulators. At the end of fire simulation tests, there was no detrimental deterioration of any insulators. All insulators passed the criteria of KEPCO specification. This study showed that forest fire simulation had no impact on polymer insulators.