전압형 HVDC 송전 시스템의 동적모델링 및 전압제어

Abstract

This thesis is devoted to a study on dynamic modeling and voltage control based on HVDC transmission system and wind farm. The main subjects are the modeling of HVDC and wind farm, control of voltage at the PCC, and simulation. The main contribution of the modeling work is the development of component models for a flexible simulation tool that enables analysis of various wind-HVDC hybrid system configurations. The component models are developed at an equal level of complexity, which are appropriate for voltage control. The models should be accurate enough to predict power quality in terms of voltage deviations at the PCC(point of common coupling). The proposed model framework is flexible, and can easily be extended to represent a general electrical network topology, and to include other renewable energy sources such as photovoltaic, etc. The design of voltage control is a development of a new type of the hybrid control that is made up of HVDC, wind farm, grid, and local load. This contributes an optimization approach for finding the optimal operations that are usually chosen by trial and error. In the simulation studies, three different cases of operations of the wind-HVDC hybrid power system are performed: local load variation, wind farm trip from the grid, and fault in the TL between the wind farm and local load. In the simulation study, it shows that the HVDC is able to support actively the grid due to its capability to control independently active and reactive power production, a reactive power control is presented in order to regulate/contribute the voltage at a remote location with taking into account its operating state and limits.