• The Transactions of The Korean Institute of Electrical Engineers
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• 제58권4호
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• pp.655-664
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• 2009

This paper, Part 1, describes the effective dual-input PSS parameter design procedure for the IEEE Type PSS2A against the Dangjin 612 MVA thermal plant's EX2000 excitation system. The suggested tuning technique used the model-based PSS tuning method and consisted of three steps: 1) generation system modeling; 2) determination of PSS2A model parameters using linear, time-domain transient and 3-phase simultaneous analyses, and 3) field testing and verification, which are described in Part 2. The effective PSS2A model parameters of EX2000 system in the Dangjin T/P #4 were designed according to the suggested procedure, and verified by using three analyses.

• Proceedings of the KIEE Conference
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.240-242
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• 2005

전력계통안정화장치(PSS)는 전력안정화를 위하여 발전기의 여자기에 보조신호를 주입하여 전력계통의 진동문제를 해결할 수 있는 장치이다. 본 논문은 기존의 비실시간 툴 (PSS/E, EMTDC/PCAD.,)을 사용한 경우와 달리 실시간 시뮬레이션 툴을 사용하여 전력계통안정화장치(Power System Stabilizer : PSS)의 영향 및 효과를 검토하였다. 이에 사용된 실시간 툴은 RTDS의 PC 버전인 RSCAD를 이용하여 분석하였다. 모의에 사용된 선로는 3상 3회선 송전선로이며 무한모선에 연결하였다. 사고는 3회선 중의 1회선 중앙에 3상 지락 상정사고를 발생시켜 선로 차단 및 재투입을 고려하여 실시하였다. 본 연구에서 RSCAD에 대한 기존의 전통적인 형태인 IEEE의 PSS1A type과 보다 정교한 이중구조를 가진 PSS2A type을 사용하여 검토하였다. IEEE의 PSS1A type은 각속도 ${\omega}$를 측정하여 사용하고 PSS2A type은 각속도 ${\omega}$와 유효전력 P를 측정하여 사용할 수 있는 형태이다. 그리고 실시간 시뮬레이션 결과는 각속도 ${\omega}$와 유효전력 P를 측정하여 PSS의 입력에 주입하고 이에 대한 효과를 비교하였다.

• Proceedings of the KIEE Conference
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.87-89
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• 2005

This paper proposes new series and parallel Sin+Cos PSS(power system stabilizer) for the purpose to improve the existing PSS1A's performance. The purpose of PSS is used to enhance damping of power system oscillations through injection of auxiliary signal for an excitation control terminal. The Proposed series and Parallel Sin+Cos PSS is connected adding the Sin+Cos terms additionally with serial and with parallel connection in a conventional PSS1A. The proposed controller is aim to considering of a damping of oscillation when it changes parameter fluctuations or operational load variations in a power system. The object of electric power system is KEPCO system and the voltage of power transmission line is a 154kV and a 345kV. The PSCAD/EMTDC package is used to authorize the effect of the proposed controller. Simulations were shown by and compared with the waveforms for frequency, voltage and electric power.

• Journal of Electrical Engineering and Technology
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• 제1권3호
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• pp.271-278
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• 2006

This paper scrutinized the damping effects of installing the prototype PSSs by a transient analysis for eight buses of faults in the South Korean power system. The PSSs used have the co-PSS blocks for IEEEST model with a single input and the co+power PSS blocks for PSS2A model with dual inputs. The simulation tool was a TSAT(Transient Security Assessment Tool) developed by Powertech Labs Inc. The voltages of the transmission line for simulations were 765kV and 345kV, and the faults for eight cases were sequenced by considering the open state and the close state of the lines. In the simulations, the three-phase line to ground (L-G) fault generated different points for each region. The simulations were compared to the cases of no PSS, partial IEEEST and PSS2A, absolute IEEEST, and absolute PSS2A to show that the power system oscillation can be effectively damped by PSS modules. Simulations were conducted to confirm the effectiveness for the KEPCO (Korea Electric Power Corporation) power system.

• KIEE International Transactions on Power Engineering
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• 제5A권4호
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• pp.378-384
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• 2005

This paper proposes a new series and parallel Sin+Cos PSS (power system stabilizer) for the purpose of improving the existing PSS1A's performance. The purpose of the PSS is to enhance the damping of power system oscillations through injection of auxiliary signals for an excitation control terminal. The proposed series and parallel Sin+Cos PSS is connected adding the Sin+Cos terms additionally with the serial and parallel connection in a conventional PSS1A. The proposed controller is aimed at considering the damping of oscillation when it changes parameter fluctuations or operational load variations in a power system. The electric power system used is the KEPCO system and the voltage of the power transmission line is 154kV and 345kV. The PSCAD/EMTDC package is used to authorize the effect of the proposed controller. Simulations were shown by and compared with the waveforms for frequency, voltage and electric power.

• Industrial Engineering and Management Systems
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• 제15권2호
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• pp.181-195
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• 2016

In a product environment where various product-service systems (PSSs) are already being provided, the provision of a different type of PSS is difficult for second movers but necessary for their sustainability and differentiation. Despite the importance of providing distinguishing PSSs to market, prior PSS studies have not effectively considered the influence of existing PSSs in their methods. In response, we suggest an approach to generate new PSS concepts by employing general needs (GNs) and business system evolution patterns (BSEPs). Our approach 1) identifies customer GNs fulfilled by existing PSSs, 2) generates advanced PSS ideas from an evolutionary perspective by mapping the existing PSSs onto BSEPs, and 3) selects PSS ideas that can meet the unfulfilled or insufficiently considered GNs using a GN-PSS linking matrix, thereby generating new PSS concepts based on the selected ideas. The workings and practicability of this approach are illustrated using a PSS case study of furniture industry. This approach would provide PSS planners with an ability to generate the differentiated PSS concepts that handle the customer needs that have been untapped throughout a product's lifecycle. In addition, this approach as a module will have a synergetic effect when incorporated with other PSS methodologies.

• Korean Journal of Animal Reproduction
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• 제27권2호
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• pp.97-102
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• 2003

This study was carried out to find out PSS(Porcine Stress Syndrome) with the PSE(Pale, Soft, Exudative) in different piglets. These experiments were accomplished with the aid of PCR-RFLP(Polymerase Chain Reaction-Restriction Fragment Length Polymorphism). The samples were collected and examined from umbilical cord blood of piglets of Yorkshire, Landrace and Crossbred. And then, the PCR products were digested by restriction enzyme, Hha I. The results obtained were as follows; The PCR products of the blood genomic DNA of ryanodine receptor gene were length of 1 .8kb in umbilical cord blood. Normal type(NN), heterozygous type(Nn) and recessively homozygous type(nn, PSS) as a result of digestion of restriction enzyme, Hha 1, were 90.0%, 10.0% and 0.0% in Yorkshire piglets, 76.2%, 19.0% and 4.8% in Landrace, 69.1%, 23.8% and 7.1% in crossbred, respectively. As already showing the above results, the blood from piglets umbilical cord can be availably used for the determination of genotypes of PSS because of easiness of blood collection without stress in live piglets.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.146-146
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• 2015

We report the enhanced performance of poly(N-vinylcarbozole) (PVK)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based quantum-dot light-emitting diodes by inserting the polyaniline:poly (p-styrenesulfonic acid) (PANI:PSS) interlayer. The QD-LED with PANI:PSS interlayer exhibited a higher luminance and luminous current efficiency than that without PANI:PSS. Ultraviolet photoelectron spectroscopy results exhibited different electronic energy alignments of QD-LEDs with/without the PANI:PSS interlayer. By inserting the PANI:PSS interlayer, the hole-injection barrier at the QD layer/PVK interface was reduced from 1.45 to 1.23 eV via the energy level down-shift of the PVK layer. The reduced barrier height alleviated the interface carrier charging responsible for the deterioration of the current and luminance efficiency. This suggests that the insertion of PANI:PSS interlayer in QD-LEDs contributed to (i) increase the p-type conductivity and (ii) reduce the hole barrier height of QDs/PVK, which are critical factors leading to improve the efficiency of QD-LEDs.

• Journal of Veterinary Science
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• 제21권3호
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• pp.44.1-44.10
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• 2020

Background: Congenital portosystemic shunt (cPSS) is one of the most common congenital disorders diagnosed in dogs. Hepatic encephalopathy (HE) is a frequent complication in dogs with a cPSS and is a major cause of morbidity and mortality. Despite HE been a major cause of morbidity in dogs with a cPSS, little is known about the cellular changes that occur in the central nervous system of dogs with a cPSS. Objectives: The objective of this study was to characterise the histological changes in the cerebral cortex and cerebellum of dogs with cPSS with particular emphasis on astrocyte morphology. Methods: Eight dogs with a confirmed cPSS were included in the study. Results: Six dogs had substantial numbers of Alzheimer type II astrocytes and all cases had increased immunoreactivity for glial fibrillary acidic protein in the cerebral cortex, even if there were minimal other morphological changes. Conclusions: This study demonstrates that dogs with a cPSS have marked cellular changes in the cerebral cortex and cerebellum. The cellular changes that occur in the cerebral cortex and cerebellum of dogs with spontaneously arising HE are similar to changes which occur in humans with HE, further validating dogs with a cPSS as a good model for human HE.

• Journal of Electrochemical Science and Technology
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• 제11권1호
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• pp.50-59
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• 2020

Birnessite-type manganese dioxide (δ-MnO₂) with hierarchical micro-/mesoporosity was synthesized via sacrificial graphene template approach under mild hydrothermal conditions for the first time. Graphene template was obtained by a surfactant (cetyltrimethylammonium bromide, CTAB) assisted liquid phase exfoliation (LPE) in water. A thin PEDOT:PSS (poly (3,4-ethylene dioxythiophene): poly (styrene sulfonate)) layer was applied to improve electrical conductivity and rate capability of MnO₂. The MnO₂ (535 F g^-1 at 1 A g^-1 and 45 F g^-1 at 10 A g^-1) and MnO₂/PEDOT:PSS nanocomposite (550 F g^-1 at 1 A g^-1 and 141 F g^-1 at 10 A g^-1) delivered electrochemical performances superior to their previously reported counterparts. An asymmetric supercapacitor, composed of MnO₂/PEDOT:PSS (positive) and Fe₃O₄/Carbon (negative) electrodes, provided a maximum specific energy of 18 Wh kg^-1 and a maximum specific power of 4.5 kW kg^-1 (ΔV= 2 V, 1M Na₂SO₄) with 85% capacitance retention after 1000 cycles. The graphene-templated MnO₂/PEDOT:PSS nanocomposite obtained by a simple and green approach promises for future energy storage applications with its remarkable capacitance, rate performance and cycling stability