Operational experience of 800 kV series capacitors
In Brazil, series compensation has been used since 1989 in the Furnas 765 kV AC power transmission to safeguard stable transmission of large amounts of hydro power. Today, a total of nine series capacitors are in operation, eight of which were supplied by ABB, six at Ivaipora and two at Itabera, the substations located about one third from each end of the tie. Ratings vary between 1017 MVAr (Ivaipora) and 1242 MVAr (Itabera). When introduced, the series capacitors were the first in the world to be installed at 765 kV. The paper gives a description of the series capacitor banks and comment on the operational performance of the banks
Transmission-line theory based study on voltage distribution along the line and the disposition scheme of series capacitors of UHV transmission lines with series capacitors
In this paper, the transmission-line theory based fast algorithm for voltage distribution along the UHV transmission line with series capacitors is proposed. Firstly, the two-port transmission parameter matrix of UHV transmission lines is transformed to the two-port node admittance matrix, therefore, the lumped parameters of strict equivalent π model for UHV transmission line is obtained. Secondly, the parameters are filled into the commercial power flow software to calculate the power flow of the target grid which includes the UHV transmission lines with series capacitors. Thirdly, the power flow calculation results are regarded as the terminal conditions of the UHV lines with series capacitor, and the transmission parameter matrix is used to calculate the voltage distribution along the line rapidly. In the algorithm, the voltage distribution along the line is obtained accurately; moreover, the reactive power supply capacities of both sides of the UHV lines with series capacitors can be taken into account, which implies that the engineering applicability of the proposed algorithm is very strong. At last, the relative disposition scheme of UHV series capacitors and UHV line shunt reactors as well as the centralized/distribution layout scheme of UHV series capacitors are investigated, and some useful conclusions are drawn. According to the proposed algorithm and the conclusions, the guidance suggestion is given for the UHV series capacitors schemes of ‘Wandian Dongsong’ UHV transmission project and ‘Ximeng Waisong’ UHV transmission project.
Microwave source with enhanced radiation power based on orbitron MASERs
We have proposed the design of high power microwave source in a vacuum tube based on the theory of negative mass instability. The proposed source does not operate based on a slow-wave structure but instead makes use of accelerated charged particles. In our structure, an electron emitter injects the charged particles into to the cavity. Emitted particles move around the anode, which leads to electron acceleration and emission of electromagnetic waves with a specific frequency. In this paper, we have enhanced the output power and frequency of microwave source by variation of particles initial energy and the number of anodes incorporating their specific arrangement and applied voltages. Working at room temperature, compactness, wide bandwidth, and tunability of output frequency are among the advantages of the proposed source.