Research Of Static Frequency Converter Starting In Large Capacity Pumped-Storage Units

Our country have made a big progress in pumped-storage units since Gang Nan Hydropower Station imported the first 11MW pumped-storage unit from Japan in 1968.As yet, our country's economy have entered rapid seedtime. The main power grid's electro-composing had an essence change, and the ratio of Hydropower descended year after year in many power grids. The ability of Hydropower modulation had been weaken and reduced the benefit and security of Thermal Power Generators. This has made the conflict of modulation extrude increasingly. The best way to solve the problem is building up some pumped-storage plants near load center.At present, almost all pumped-storage plants adopt reversible hydroelectric units. That is to say, the water turbine drives the generator to supply power to power grid when it works at generation working condition, and then when it works at pumping working condition, the generator becomes an electric motor to drive the water pump to pump water. This makes the pumped-storage units'working conditions very complicated, especially the starting of pumped-storage unit. This paper makes a full exposition of the static frequency conversion starting process of the pumped-storage machine. It makes deep theoretical analysis of the principles of the reversible pumped-storage synchronous machine, the frequency conversion control. How to deal with the inverting lapping angle during the frequency conversion process and how to eliminate the harmonics at the import and export of the frequency conversion machine are explained as well. Then the paper proposes a simplified method to cope with the inverting lapping angle at the inverting side of the frequency conversion machine. A control scheme using the controlling angleβat the inverting side to continuously control the controlling angleαs at the rectifying side is presented. According to the current characteristic of current supply type frequency conversion machine, the paper proposes a new structure for active filtering.The dissertation establishes the mathematical model for the frequency conversion process, and then set up the simulation model by Matlab-Simulink. It simulates both the naturally inverting process and the interrupted inverting process of pumped-storage units. In the end, the paper reaches the conclusion of some measures to suppress harmonics, the disposal for the frequency conversion machine's inverting lapping angle and the controlling strategy for frequency conversion process. These conclusions supply important references for future development of frequency conversion starting machine of pumped-storage units.