Study On Evaluation Of Renewal And Reconstruction Effect Of Multi-cascade Water-lifting Project

Large-scale cascade irrigation projects play an important role in the development of agricultural economy in arid areas of Northwest China.Since the 1960s,the country has built many large-scale high-lift cascade irrigation areas in Gansu,Ningxia and Shaanxi provinces.Since their establishment,these irrigation areas have brought into play enormous economic,ecological and social benefits.However,under the background of vigorously advocating energy saving and emission reduction,the problems of high-lift cascade pumping stations such as high energy consumption,low efficiency of water lifting and unclear service conditions need to be solved urgently.Irrigation districts are facing large-scale renovation and transformation,while the evaluation of the effect of the upcoming large-scale renovation and transformation projects is still in the initial stage,lacking scientific and systematic methods.In order to solve the problem that the efficiency of water conveyance system and the overall operation state of the system can not be quantitatively analyzed in the reconstruction of cascade pumping stations,In order to solve the problem that the efficiency of water conveyance system and the overall operation state of the system can not be quantitatively analyzed in the reconstruction of cascade pumping stations,this paper takes the major water science and technology project of Ningxia Water Conservancy Department"Research and Application of Key Technologies for Energy Conservation and Efficiency Increase of Ningxia Yanhuanding Engineering"as the subject source and taking the cascade pumping station system of Salt Ring Ding Common Project as the research object,the following research contents are carried out for the quantitative evaluation of pumping station water lifting efficiency and the comprehensive evaluation of service status:（1）Through appropriate theoretical methods,the mathematical models of water conveyance efficiency of cascade pumping stations based on dynamic flow balance and water balance are constructed.In this paper,two models are used to calculate the water lifting efficiency of the water conveyance system before and after the renovation to quantitatively evaluate the effect of the renovation.The results of the two models are verified and compared with the actual monitoring data to verify the reliability of the calculation model.（2）The uncertain cloud model theory is introduced into the comprehensive evaluation of the high-lift cascade pumping station system.By constructing the evaluation index system of the service state of the cascade pumping station system and determining the weight of each index according to the queuing theory,the multi-level fuzzy evaluation model of the pumping station system based on the improved cloud model is obtained,and the service state before and after the transformation of the salt ring determination project is evaluated comprehensively.At the same time,a standard cloud and a factor layer membership cloud model based on Golden Section Ratio method are constructed,and the stability and reliability of numerical results are reflected by the three digital features generated by the model.The main conclusions of this study are as follows:（1）Compared with the average energy efficiency in the past five years before the renovation,the average energy consumption in the spring irrigation cycle after the renovation of Yanhuanding Project has been reduced from 4.10 kW h/KT m to 3.63 kW h/kt m,the operation efficiency has been increased from 66.4%to over 77.9%,the energy consumption has been greatly reduced and the efficiency has been improved by about 8.5%,basically reaching the level of similar pumping stations abroad with advanced equipment and management level,and more.The effect of the new transformation is remarkable.（2）The comprehensive evaluation clouds of service status of cascade pumping station system in Yanhuanding Project before and after renovation are C_b（0.6264,0.0614,0.0168）,C_a（0.8421,0.1005,0.0126）,and the service status before renovation is"good（V₄）"and after renovation is"better（V₅）".It can be seen that the overall operation efficiency of pumping station has been greatly improved by renovation,optimization of dispatching and management,so as to make the system more efficient.The service status has been improved qualitatively.（3）It is found that the calculation results of the two models are highly consistent in the overall evaluation and are consistent with the actual operation of the project,which shows that the two models are reasonable in the efficiency evaluation of the cascade pumping station system.The uncertainty,fuzziness and fluctuation of the system are solved by introducing cloud theory into the multi-stage fuzzy evaluation of the service state of the cascade pumping station,and the cloud is comprehensively evaluated.The generation of evaluation results makes the information more abundant,objective and credible.