• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.12
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• pp.2196-2201
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• 2011

According to the 5th national plan for electric power demand and supply, the 3rd HVDC link will be installed between KEPCO and Jeju Island system and go into operation in June, 2016. However, if it adopt LCC HVDC, Jeju power system could be in voltage instable condition. In order to solve the problem, we propose the application of VSC HVDC to the 3rd HVDC project. In the past, VSC HVDC has many disadvantages such as, inefficiency in conversion, size limit, and expensiveness, compared to LCC HVDC. Recently, the new technologies and the demand for renewable energy interconnection are leading a large growth in VSC HVDC market. In this paper, we will introduce the technical and market trends of VSC HVDC and power system stability analysis results for Jeju power system having LCC and VSC HVDCs.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.982-983
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• 2015

본 논문은 CIGRE 492 보고서를 따른 것으로 최근 해외 선도 기업 및 미국, 유럽, 중국 등에서 도입하고 있는 LCC-HVDC, VSC-HVDC와 기존 송전시스템인 HVAC의 기술 및 경제적 효율성을 비교분석하였다. 분석 방법은 동일한 조건을 설정하여 각 시스템에 모의 적용하였으며, (1) HVAC와 VSC-HVDC와의 비교 (2) LCC-HVDC와 VSC-HVDC와의 비교를 진행하였다. 그 결과 시간 흐름에 따라 AC보다 DC에서의 경제적 효율성을 확인하였고, 또한 HVDC의 전류형과 전압형의 비용 분석에서는 오차범위, 추가적 편익 등을 고려할 시 전압형의 경제성에 대한 긍정적 측면을 확인할 수 있었다. 본 연구에서는 일반적인 PWM 방식을 택하였으나, 추후 연구에서는 최근 선도 기술이라 평가받는 MMC 방식의 전압형 HVDC를 적용하여 연구하고자 한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.153-154
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• 2015

Voltage Source Converter HVDC (VSC-HVDC) are a better alternative than conventional thyristor based HVDC systems. Unfortunately, VSC-HVDC's full potential cannot be utilized up till now due to absence of suitable HVDC protection. Recently, hybrid HVDC circuit breakers (HDCCB) have been developed and successfully lab tested. However, their application and feasibility in VSC-HVDC needs to be investigated. In this research paper we have modelled an existing HDCCB and evaluated its impact on fault reduction and interruption in VSC-HVDC systems. The HDCCB was applied in Korean Jeju-Haenam VSC-HVDC system model and its impact was analyzed for HVDC line-to-ground and line-to-line faults. HDCCB successfully interrupted the fault current and prevented the damages to costly IGBTs and converter transformers.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.1
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• pp.65-71
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• 2020

Recently, interest in the DC transmission is rapidly increasing worldwide. In many countries and leading companies are prior to the aggressive development of HVDC technology and application. Especially, VSC-HVDC system has been widely applied to transfer power at long distance between power plant and power consumption area. Therefore in this paper, we analyzed the benefit-cost of VSC-HVDC system which has more advantages than existing transmission system. The proposed system is MMC(Modular Multilevel Converter) VSC-HVDC system that have stability of Power Grid, interconnect Large-scale New Power Generation Plants by prevents Blackout. And MMC VSC-HVDC system Reduced the loss importing foreign systems. And the benefits were calculated in four stages, and the costs were applied to the actual project. By evaluating the various avoidance costs compared to the benefit-cost, it was confirmed that MMC VSC-HVDC system was advantageous in system stability and economic and social benefits.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.3
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• pp.343-348
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• 2014

Recently, applications of VSC-HVDC systems to power systems are growing because of their control ability of reactive power. Meanwhile, the hardware-in-the-loop simulation (HILS) based on the real-time digital simulator has been applying to develop and test imbedded controllers and systems in the power industry to decrease costs and to save time. In this paper, a 3-level neutral point clamped (NPC) VSC-HVDC system is modeled and the embedded controllers of the NPC VSC-HVDC system are designed. The designed controllers are implemented by TMS320F28335. The TMS320F28335-based controllers of the NPC VSC-HVDC system are tested using the HILS.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.6
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• pp.236-241
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• 2006

This paper presents a transfer capability enhancement process using VSC HVDC system which can control active power as well as reactive power. The transfer capability is constrained by stability like voltage stability as well as thermal rating of power system components. Transfer capability of the power system limited by these constraints may be enhanced by reactive power control ability and active power flow control ability of the VSC HVDC system. To enhance the transfer capability of the system using VSC HVDC, selection of the HVDC installation site is performed. In this work, power zones which consist of major power plants and their sinks are identified using power tracing and distribution factor. Alternative route of major AC transmission line in the power zone is identified as VSC HVDC system.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.161-162
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• 2015

최근 세계적으로 전력계통의 대륙 간 연계나 신재생에너지, 분산전원의 계통 연계를 위해 HVDC(High voltage Direct Current)에 대한 연구가 활발히 진행되고 있다. 대용량, 장거리 송전이 필요한 경우 HVAC에서의 전력손실과 송전거리의 한계를 극복하기 위하여 HVDC가 새로운 대안으로 떠오르고 있으며, LCC(Line commutated Converter)와 VSC(Voltage Source Converter)의 기술발전이 비약적으로 이뤄지고 있다. 특히, DC Grid화를 위해서 유럽에서는 해상풍력을 연계한 Windfarm을 DC Grid화 하는 프로젝트가 활발히 진행되고 있다. 이러한 신재생 에너지의 계통 연계를 위해서 DC Grid가 본격적으로 논의가 되고 있고 관련분야에서는 기술개발을 앞다퉈 진행하고 있는 상황이다. DC Grid 구현을 위해 VSC HVDC가 최근 주목받고 있으며, VSC로 연계된 DC Grid의 AC 계통과의 연계를 위해 가장 필요한 것이 바로 DC 차단기라고 할 수 있겠다. 본 논문에서는 DC Grid의 고장분석을 위한 기초연구로써 MMC(Modular Multilevel Converter) VSC를 기반으로 한 Point-to-Point HVDC Grid에서의 DC 고장에 대한 분석을 실시하였으며 그 특징을 분석하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.158-159
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• 2011

최근 발표된 제5차 전력수급계획에 의하면 제주도에 3번째 HVDC 연계선 설치가 계획되고 있다. 이전까지 설치된 2개의 HVDC는 LCC(전류형) HVDC로써 안정적이고 우수한 성능으로 제주지역의 전력 수급에 기여를 했지만 전압 불안정 문제를 초래할 가능성을 가지고 있다. 따라서 3번째 HVDC는 VSC(전압형)으로 설치하는 것을 고려해야 한다. VSC HVDC는 유무효 전력이 동시에 제어가 가능하다는 장점이 있으나 비싼 가격과 높은 변환 손실, 그리고 작은 용량으로 제한적인 용도로만 사용되어 왔다. 그러나 최근 Multi-Level Converter 기술이 적용되면서 이전의 많은 문제들이 해결되었다. 이 논문에서는 VSC HVDC의 최신 동향에 대해서 간략히 소개하고 제주 전력망에 VSC HVDC가 설치되었을 때의 효과에 대해서 논의하고자 한다.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.4_1
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• pp.377-385
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• 2021

High voltage direct current(HVDC) systems has been an alternative method of a power transmission to replace high voltage alternate current(HVAC), which is a traditional AC transmission method. Due to technical limitations, Line commutate converter HVDC(LCC-HVDC) was mainly used. However, result from many structural problems of LCC-HVDC, the voltage source converter HVDC(VSC-HVDC) are studied and applied recently. In this paper, after analyzing the reactive power and output voltage ripple, which are the main problems of LCC-HVDC, the characteristics of each HVDC are summarized. Based on this result, a new LCC-HVDC structure is proposed by combining LCC-HVDC with the MMC structure, which is a representative VSC-HVDC topology. The proposed structure generates lower reactive power than the conventional method, and greatly reduces the 12th harmonic, a major component of output voltage ripple. In addition, it can be easily applied to the already installed LCC-HVDC. When the proposed method is applied, the control of the reactive power compensator becomes unnecessary, and there is an advantage that the cut-off frequency of the output DC filter can be designed smaller. The validity of the proposed LCC-HVDC is verified through simulation and experiments.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.162-164
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• 2007

This paper presents a HVDC site selection algorithm to increase transfer capability using VSC HVDC system which can control active power as well as reactive power. Using normal powerflow results and simple index $k_r$ the HVDC site selection algorithm is enhanced and more tightly-coupled transmission lines are identified in a domain of generators.