• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1221-1225
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• 2012

This paper describes CSC(Current Sourced Converters)-based HVDC operational strategy for voltage stability enhancement in the power system. In case of CSC-based HVDC system, rectifier and inverter consume reactive power up to about 60% of converter rating. Therefore, CSC-based HVDC is basically not useful system for voltage stability even if AC filters and shunt capacitors are attached. But, If the particular power system condition is fulfilled, CSC-based HVDC also can be the rapid reactive power source for voltage stability enhancement using a cooperative control with converter and AC filters/Shunt Capacitors. In this paper, the cooperative control algorithm is presented and simulated to ${\pm}80kV$ 60MW HVDC system in Jeju island.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.491-493
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• 2008

This paper presents results of comparing CSC HVDC with VSC HVDC on the stability in case of connecting Haenam to Jeju electrical power system, the steady-state stability in the case of Jeju electrical power system with CSC HYDC or VSC HVDC, is validated through PV curve, QV curve of Jeju electrical power system. And in the case of CSC HVDC, it is considered that synchronous condenser is connected or not. The results are compared each other. PSS/E simulation tool is used for the steady-state stability analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1897-1904
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• 2008

In this paper, the method for effective stability analysis of Jeju power system in 2011 is proposed. The stability analysis of Jeju power system was carried out by using proposed method In case of Jeju power system with wind turbine generators or without wind turbine generators, including CSC HVDC or VSC HVDC. The steady-state stability is validated by SCR and ESCR, PV curve, QV curve. And the transient stability is analyzed by CCT(Critical Clearing Time). VSC HVDC has more advantages than CSV HVDC on the stability. Also, Jeju power system without wind turbine generators has more advantages than Jeju power system with Wind Turbine Generators on the stability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.10
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• pp.1715-1720
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• 2007

The CSC-based HVDC system links the Jeju system to the mainland system. Because CSC-based HVDC is installed in Jeju, the reactive power is needed to transfer active power through the HVDC. In order to supply reactive power, switched capacitors and synchronous condensers are installed in Jeju system. The deterioration of established synchronous condensers, however, causes a reactive power supply capability decline and high maintenance cost. It brings about the instability of Jeju system and the incremental of maintenance and repair costs. In the future the installation of wind generators and additional HVDC system would aggravate the stability of Jeju system. Therefore, it needs to consider a countermeasure against above problems. In this paper, Analysis of several contingencies of Jeju system was peformed, and some contingencies caused voltage-reactive power problem was known. CPF method was introduced in order to make countermeasures to replace the synchronous condensers and to solve the voltage-reactive power problem. The location and capacity of reactive power sources were also decided. It could guarantee medium and long term stability of Jeju system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1311-1317
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• 2008

In this paper, a fault location algorithm using wavelet transform is proposed for HVDC cable lines. The arriving instants of the first and second fault-induced backward travelling waves can be detected by using wavelet transform. The fault distance is estimated by using the time difference between the two instants of backward travelling waves and the velocity of the travelling wave. To distinguish between the backward wave from fault point and the backward wave from the remote end, polarities of backward waves are used. The proposed algorithm is verified varying with fault distances and fault resistances in underground cables of VSC(voltage source converter) HVDC system and CSC(Current Source Converter) HVDC respectively. Performance evaluations of the proposed algorithm shows that it has good ability for a fault location of HVDC cable faults.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1176-1177
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• 2008

오늘날 고유가 시대를 맞아 신재생에너지에 대한 관심이 점점 더 증가하는 추세에 있다. 전세계적으로 풍력발전은 신재생에너지를 이용한 여러 발전방식 가운데 가장 각광을 받고 있으며 실용화된 발전방식이다. 풍력발전의 경우 다른 신재생에너지를 이용한 발전원보다 경제성이 있고 용량이 크기 때문에 이미 상당한 용량의 풍력발전단지가 설치되어 운영중에 있으며 향후 더 많은 풍력발전단지가 건설될 예정에 있다. 특히 제주도 지역의 경우 풍력발전단지의 입지조건에 부합되어 많은 풍력발전단지가 건설될 예정에 있으며, 세계적인 추세인 해양풍력발전단지도 건설예정에 있다. 해양풍력단지의 경우 육지에서 약간 떨어진 바다에 풍력발전기를 건설한 후, 육지로 전력을 수송하게 된다. 육지와 해양풍력발전단지의 연계는 여러 방식이 있는데 본 논문에서는 HVDC를 이용한 해양풍력발전단지의 연계에 관한 연구를 진행하였다. HVDC의 경우 전압형과 전류형 HVDC가 있는데 두 가지 방식을 비교분석하여 해양풍력발전단지의 계통 연계에 알맞은 최적의 방식을 도출해본다.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.594-600
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• 2017

HVDC transmission systems can be configured in many ways to take into account cost, flexibility and operational requirements. [1] For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. For underwater power cables, HVDC avoids the heavy currents required to charge and discharge the cable capacitance of each cycle. For shorter distances, the higher cost of DC conversion equipment compared to an AC system may still be warranted, due to other benefits of direct current links. HVDC allows power transmission between unsynchronized AC transmission systems. Since the power flow through an HVDC link can be controlled independently of the phase angle between the source and the load, it can stabilize a network against disturbances due to rapid changes in power. HVDC also allows the transfer of power between grid systems running at different frequencies, such as 50 Hz and 60 Hz. This improves the stability and economy of each grid, by allowing the exchange of power between incompatible networks. This paper proposed to establish Korean HVDC technology through a cooperative agreement between KEPCO and LSIS in 2010. During the first stage (2012), a design of the ${\pm}80kV$ 60MW HVDC bipole system was created by both KEPCO and LSIS. The HVDC system was constructed and an operation test was completed in December 2012. During the second stage, the pole#2 system was fully replaced with components that LSIS had recently developed. LSIS also successfully completed the operation test. (2014.3)

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.548-549
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• 2014

In Jeju power sytstem, the generation of reactive power depends on the operation of CSC-HVDC filter. Thus, the grid voltage will be affected. Statcom and SVC have demonstrated that it has excellent charateristics to solve this problem. First, this paper analyzes the operation of the Statcom based on the real power system in Jeju. Then, the characteristics of Statcom will be compared to the SVC. The modelling of the Jeju power system including Statcom and SVC will be performed by using PSCAD/EMTDC program and the real data from the real Jeju power system.