| Abstract | A simulation model is developed to represent the overall Choshui hydro power system. The whole system consists of six reservoirs or ponds, namely, Wu Sheh, Wu Chieh, Sun Moon Lake, ·Ming Hu and Ming Tan lower reservoir, and Chi Chi reservoir, two pumped storage plants ·Ming Hu and Ming Tan and four
conventional hydro plants Wu Sheh, Ta Kuan, Chu Kung, and Shui Li. (Figs.1 .1 , 1.2, and 1.3). The upstream diversion
consisting of at most seven diversion dams, will divert the flow of each creek into a connecting tunnel and converge
into the Sun Moon Lake. The Chi Chi dam is located at the downstream of the power system tailrace and headwork of the existing canal diversions, so its main functions are to regulate the uncontrolled flow and the release during
the peak hour, and provide the additional regulated flow from the reservoir for irrigation purpose. The reservoirs and power plants are connected both in a series and in parallel. The system generates electricity and provides water for irrigation and downstream requirements. The hydrological data used
cover 28 years from 1954 to 1981, while the recording of irrigation demand is 7 years from 1972 to 1978. One of the pumped storage projects, Ming Hu, is now under construction.
Therefore, the case of excluding pumped storage project in operation will not exist in the system. Consequently, the most feasible combination of the
Wu Sheh and Sun Moon Lake rule curves is recommended based upon the maximum
power benefit and minimum downstream water shortage for irrigation. For estimating the power benefit, the peak and offpeak power rates are considered, at 2 . 09 NT$/kWh for peak power and at 1.25 NT$/kWh for offpeak power. The
operating policy which yields the maximum power benefit and minimum downstream water shortage is selected. Two different release policies are considered: irrigation predominated a nd power generation predominated. Based on the objective of the simulation the case which yields highest maximum power benefit and minimum downstream
water shortage should be selected. It is found that the highest maximum power
benefit occur when taking power generation as higher priority. In this case the rule curve of Sun Moon Lake indicates that the Lake should be kept full at all time while for the Wu Sheh reservoir, the rule curve No. 13 for comparison purpose is selected. The case when irrigation is considered predominated is run. The maximum power benefit obtained is found to be lower than t he case when considering power generation as higher priority though less downstream
water shortage can be achieved. In the study, t he MH and MT psp are operated under mixed pumped condition. |