The Harmonic Analysis Of TIAN-GUANG AC/DC Parallel Transmission System

This paper analyzes the harmonics of TIAN-GUANG AC/DCparallel transmission system. It mainly includes:1. It sets the modal of the TIAN-GUANG AC/DC paralleltransmission system in the PSCAD/EMTDC, and four typicaloperating modes: heavy load in summer, light load in summer heavyload in winter and light load in winter, are selected for analysis2. It analyzes the harmonics of TIAN-GUANG AC/DC paralleltransmission system under the four typical operating modes, and getsthe results of some particular buses in the DC system and the GuangXinet. The conclusion is: The TIAN-GUANG DC system will cause someharmonics in the GuangXi net, but the GuangXi net's THD is withinthe normal limit.3. It analyzes the harmonics of TIAN-GUANG AC/CD paralleltransmission system when the converter bus voltages are unbalance.The conclusion is: the GuangXi net's harmonics will go beyond withthe standard only when one phase voltage on the converter buses fallsdown to zero owing to severe faults.4. It uses a new formula to analyze why there are uncharacteristicharmonics when the convert bus voltages are unbalance. The answer is:it relate to the line voltage's magnitude and phase.The previous analyses are simulated by EMTDC and theimportant results are shown in figures.The study presented in the thesis is essential for the normaloperation of TIAN-GUANG AC/DC parallel transmission system.