Tham khảo tài liệu 'energy storage in the emerging era of smart grids part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 108 Energy storage in the Emerging Era of Smart Grids CBB20 No of capacitor use 1 unit 2 unit 3 unit Time constant Ũ 68 second 121 second 171 second Voltage Decay v t 1150 e 68 1280 1410 Average Voltage V ave 1 205 lị -i- 1150e68dt 205 V 1 385 n 1280e121 dt 385 V -Ị- 1410 e dt 556 V Energy stored Estored F 36275 2 X Iff J F 3855SV 2 X 1Ơ J F 41Q45y 2 Iff J Energy Efficiency Estored x 1 QQO o source x10s3 J X10ơ o 22Q50x1Cf3J J X10ơ o 22050x1 CP3 J cP3 J __. . x 10Ơ O 22Q50x1QP3J Table 6. Energy efficiency and the energy stored of the capacitor Analysis of experimental data for voltage stored and energy efficiency As mentioned before the energy supplied by the lightning impulse voltage generator is maintained at approximately Joule. Acccrding to Table 4 Table 5 and Table 6 the measurement data shows that thecapacitors used in the testing have the energy efficiency in the range of to . The data also pved that the energy efficiency increases together with the incremen t of capacitance value. Instead of the capacitance value there are a few factors that will give a significance effect to the voltage stored as well as the energy efficiency. One of the factors isthe type of capacitor that was used in the experiments. It knows that the energy efficiency is proportional with the stored voltage. From the measurement result only the capacitor KNU1910 is capable of sustaining the voltage compared toother sample capacitors. In other words even though the energy efficiency for this capacitor is lower from other sample capacitor only a small voltage losses occurred. The opposite of that the sample capacitors CBB20 and CBB20 suffer a huge voltage losses during the isolating period. It means that there will be sometime when the voltage stored in both these capacitor reduces to the zero voltage and causes a zero energy efficiency.
