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
Study on system operation voltage characteristics of UHV transmission lines with series capacitors
Adopting series capacitors (SC) on 1000kV UHV AC transmission line can further uprate its transmission capacity, and it can also make impact on operation voltage characteristics of UHV system. Especially for heavy-load mode, as the large voltage step-up caused by SC, the issues on system operation voltage control may be more prominent. The layout manner for SC on lines and the relative fixed position between high voltage shunt reactors (SR) and SC can make great difference. Based on the planned Huainan-Wannan-Zhebei-Huxi 1000kV UHV AC double circuits transmission project, this paper researched the steady-state voltage distribution characteristics of Huainan-Wannan lines which are fixed with 40% series capacitors. Two kinds of simulation tools such as PSD-BPA and EMTPE are adopted in this study. The suggestions on the layout manner for SC and the relative layout manner between SR and SC are put forward, which can supply technique basis for the project implementation.
rPET detectors design and data processing
Small animal PET systems based on rotating planar detectors posses some interesting advantages for high sensitivity, high resolution imaging. We have designed the rPET detectors based on MLS crystals assembled on a 30times30 matrix optically coupled to a flat-panel PS-PMT. Weighted position readout circuits pre-process the 64 signals from the 8times8 anodes matrix, which are digitized using a charge-integrating converter. The amplification electronics, including the trigger output for coincidence detection, and the high voltage supply are integrated in a three PCBs stack that forms the base attached to the back of the PMT. The whole assembly is enclosed in a light tight, lead (Pb) shielded aluminum box. The detectors are mounted on a rotating gantry with more than 180 degrees rotation span. The digitized events are screened and histogramed, and a modified center of gravity algorithm removes from the position calculation those signals with poor signal to noise ratio. Apparent mean crystal size on the 511 keV field-flood images is 0.6 mm, mean peak-to-valley ratio is better than 8, and intrinsic resolution is 1.5 mm at the central row, with the energy window wide open. Sensitivity (CPS) for a pair of these detectors set in coincidence at 160 mm distance is 1%