• Journal of Power Electronics
• /
• v.18 no.2
• /
• pp.467-481
• /
• 2018

Modular multilevel converter (MMC)-based high-voltage direct current (HVDC) presents attractive technical advantages and contributes to enhanced system operation and reduced oscillation damping in dynamic MMC-HVDC systems. We propose an advanced small-signal multi-terminal MMC-HVDC based on dynamic phasors and state space for power system stability analysis to enhance computational accuracy and reduce simulation time. In accordance with active and passive network control strategies for multi-terminal MMC-HVDC, the matchable small-signal stability models containing high harmonics and dynamics of internal variables are conducted, and a related theoretical derivation is carried out. The proposed advanced small-signal model is then compared with electromagnetic-transient and traditional small-signal state-space models by adopting a typical multi-terminal MMC-HVDC network with offshore wind generation. Simulation indicates that the advanced small-signal model can successfully follow the electromechanical transient response with small errors and can predict the damped oscillations. The validity and applicability of the proposed model are effectively confirmed.

• Proceedings of the KIEE Conference
• /
• 1999.11b
• /
• pp.219-221
• /
• 1999

HVDC(High Voltage Direct Current) transmission system was constructed between Cheju island and mainland Haenam and has been operating commercially since 1998. But research activities in this area are not so much. That is caused by the facts that HVDC is large scale system and it is not so easy to implement and to test. Though such simulation tools as RTDS(Real Time Digital Simulator) and EMTDC can be useful, these have limitations for actual control and protective system design. Therefore scaled-down HVDC model was developed for the purpose of researches at operating technique, control and protection methods. The design of this model was based on real Cheju-Haenam HVDC system. And additionally faults simulator such as ground fault, short-circuit and change of impedance in transmission line is equipped for analysis of these faults. Control system of the model was implemented fully digitally. So it is very easy for the researchers to develope control and protection algorithm and to test the performance.

• Journal of Power Electronics
• /
• v.5 no.4
• /
• pp.319-328
• /
• 2005

This paper deals with the development of a new type of simulator for the study of the dynamic performance of an HVDC scheme. The new simulator uses a digital model of the power equipment and an analogue model of the existing HVDC controller. This simulator is used to study the dynamic performance of the Cheju - Haenam HVDC system and to verify the control characteristics of the HVDC system. The paper discusses the simulator development requirements and criteria. The paper provides guidelines for the development of the simulator and presents the results of the simulation studies.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.1
• /
• pp.105-113
• /
• 2018

This paper proposes pre-analysis on planning of high-voltage direct current (HVDC) transmission system applied to Korea electric power grid. HVDC transmission system for interface lines has been considered as alternative solution for high-voltage AC transmission line in South Korea since constructing new high-voltage AC transmission lines is challenging due to political, environmental and social acceptance problems. However, the installation of HVDC transmission system as interface line in AC grid must be examined carefully. Thus, this paper suggests three scenarios to examine the influences of the installation of HVDC transmission system in AC grid. The power flow and contingency analyses are carried out for the proposed scenarios. Power reserves in metro area are also evaluated. And then the transient stability analysis focusing on special protection scheme (SPS) operations is analyzed when critical lines, which are HVDC lines or high voltage AC lines, are tripped. The latest generic model of HVDC system is considered for evaluating the impacts of the SPS operations for introducing HVDC system in the AC grid. The analyses of proposed scenarios are evaluated by electromechanical simulation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.67 no.1
• /
• pp.8-15
• /
• 2018

New methodology for probabilistic reliability based grid expansion planning of HVDC in power system including Wind Turbine Generators(WTG) is developed in this paper. This problem is focused on scenario based optimal selection technique to decide best connection bus of new transmission lines of HVDC in view point of adequacy reliability in power system including WTG. This requires two kinds of modeling and simulation for reliability evaluation. One is how is reliability evaluation model and simulation of WTG. Another is to develop a failure model of HVDC. First, reliability evaluation of power system including WTG needs multi-state simulation methodology because of intermittent characteristics of wind speed and nonlinear generation curve of WTG. Reliability methodology of power system including WTG has already been developed with considering multi-state simulation over the years in the world. The multi-state model already developed by authors is used for WTG reliability simulation in this study. Second, the power system including HVDC includes AC/DC converter and DC/AC inverter substation. The substation is composed of a lot of thyristor devices, in which devices have possibility of failure occurrence in potential. Failure model of AC/DC converter and DC/AC inverter substation in order to simulate HVDC reliability is newly proposed in this paper. Furthermore, this problem should be formulated in hierarchical level II(HLII) reliability evaluation because of best bus choice problem for connecting new HVDC and transmission lines consideration. HLII reliability simulation technique is not simple but difficult and complex. CmRel program, which is adequacy reliability evaluation program developed by authors, is extended and developed for this study. Using proposed method, new HVDC connected bus point is able to be decided at best reliability level successfully. Methodology proposed in this paper is applied to small sized model power system.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.49 no.9
• /
• pp.607-617
• /
• 2000

This paper deals with the dynamic performance of Cheju-Haenam HVDC system. The purpose of the simulation study is to verify the control characteristics of the HDVC and to analyse the dynamic performances. Especially because the HVDC system consists of analogue controller and digital controller the simulation is achieved with specification model considered nonlinear function. The dynamic performance simulations is performed by PSCAD/EMTDC

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.2
• /
• pp.145-151
• /
• 2005

Cheju-Haenam HVDC link transmits electrical power up to 300[MW] Because of its size, HVDC system has a great potential for damping power system oscillations. This paper with the frequency control of the KEPCO HVDC system linking Haenam to Cheju island. Frequency control at Cheju island ensures that the island AC system frequency is maintained Performance are evaluated using a reduced Cheju network and a detailed model of the fm system modelled in the PST software. Transient oscillations for the 3 phase fault carried out with HVDC frequency control are well damped as the control parameters have been adjusted.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.3
• /
• pp.140-151
• /
• 2004

This paper presents the HVDC system modelling for analysis of subsynchronous oscillation and the design of the subsynchronous oscillation damping controller in HVDC system with the aid of novel eigenvalue analysis program. The HVDC system models include both the steady-state model for power flow calculation and the dynamic model for constructing the state matrix. The design procedures of the subsynchronous oscillation damping controller (SODC), which is integrated with PI controller at rectifier, consist of three steps:1) to identify the dominant torsional oscillation mode in the AC/DC system;2) to determine the parameters of the SODC for compensating the phase lagging due to the rectifier controller;3) to validate the control parameters and to determine the appropriate gain using a time-domain simulation program. The proposed design method has been tested against two AC/DC systems for validation.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.456-460
• /
• 2004

본 논문은 HVDC시스템의 안정도와 제어 게인과의 상관관계를 다루고 있다. HVDC와 같은 시스템은 비선형적인 요소를 많이 가지고 있기 때문에 수학적인 알고리즘으로 안정도를 판별하고, 제어게인을 구하는 것이 매우 어렵기 때문에 축약된 모델링을 이용하여 제어 게인을 구하였고, 안정도를 분석하였다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.11B no.2
• /
• pp.40-50
• /
• 2001

This paper deals with the development of the simulation models Cheju - Haenam HVDC system and its dynamic performance study and verify the control characteristics of the HVDC system. It discusses the model development requirement and criteria. It provides guedelines for developing large-scale simulation models for detailed electromagnetic studies and presents the results of the modeling project.