| There are lots of large-scale pumping stations along rivers. In JiangsuProvince, there are14large-scale pumping stations along Yangtze River with atotal designed lfow rate of1575.23m/s and the installed capacity of111425kWsuch as Jiangdu, Gaogang and Changshu Pumping Stations. These pumpingstations play an important role in regional flood control, waterlog control andwater diversion. With the comprehensive consideration of peak-valley electricityprice and tides variation of Yangtze River, the optimal operation studies werecarried out for large-scale pumping stations along Yangtze River，which has animportant practical significance and economic value.At present, the complicated theoretical system has not been completelyformed, because of which it has an important theoretical significanceprogressively to improve optimal operation methods of single pump unit andsingle pumping station with multiple pump units.According to the characteristics that the optimal operation of large-scalepumping stations is influenced by tides, the dynamic programming method andexperimental optimization method were applied to carry out the study andanalysis on optimal operation of single pump unit and single pumping stationwith multiple pump units taking No.4Jiangdu pumping station as a study case,and following aspects of studies were developed.(1) Taking No.4Jiangdu Pumping Station as a study case，the mathematicalmodel of optimal daily operation with single pump unit (includingadjustable-blade operation, variable speed operation, and combined operationwith adjustable-blade and variable speed), the mathematical model of optimaldaily operation for single pumping station with multiple pump units and the sametype(including adjustable-blade operation, variable speed operation, andcombined operation with adjustable-blade and variable speed) were constructed. The1-D dynamic programming method was applied to solve the optimaloperation model of single pump unit with adjustable-blade and the model withvariable speed. According to the optimal combined operation model of singlepump unit with adjustable-blade and variable speed, the method of experimentaloptimization for blade angle, dynamic programming for speed of pump unit wasadopted to solve. The optimal results obtained from this method was used tocompared with the ones obtained from dynamic programming with successiveapproximation method and some analysis was put forward. Based on the optimaloperation model of multiple pump units (with the same type) withadjustable-blade and the model with variable speed in single pumping station, themethod of experimental optimization for blade angle (or speed), dynamicprogramming for pump unit numbers was adopted. Also The optimal resultsobtained from this method were used to compared with the ones obtained fromdynamic programming with successive approximation method and some analysewere put forward. Aiming at the optimal combined operation model of singlepumping station with adjustable-blade and variable speed, the blade angle andpump speed ware firstly combined into a combination, after which the originalmodel was transferred into a dynamic programming model with the combinationand operation numbers of pump units as the double decision variables. Furtherthe dynamic programming with successive approximation method was adopted tosolve the model.(2) A series of optimal operation schemes were put forward for single pumpunit and single pumping station in No.4Jiangdu pumping station. No.4Jiangdupumping station is influenced by Yangtze River and has a great head amplitudewith the amplitude of7.8m～3.8m within one year and1.2m within one day.Taking the typical tidal level process which has a daily average lift of7.8～3.8mand100%,80%,60%loads of water pumping quantity as study cases, thestudies on optimal operation of single pump unit (adjustable-blade operation,variable speed operation, combined operation with adjustable-blade and variable speed) and single pumping station with multiple pump units (adjustable-bladeoperation, variable speed operation, combined operation with adjustable-bladeand variable speed) were carried out, by which a series of optimal operationschemes for single pump unit and single pumping station in No.4Jiangdupumping station were obtained.(3) Adaptability research of optimal operation mode for large-scale pumpingstations which is influenced by tides. Taking single pump unit of No.4Jiangdupumping station as a study case, the comparison and analysis of optimal resultsobtained from the optimal operation (adjustable-blade operation, variable speedoperation, combined operation with adjustable-blade and variable speed) oflarge-scale pumping stations along Yangtze River influenced by tides werecarried out. The optimal results showed that with the consideration of peak-valleyelectricity price, optimal operation with adjustable-blade was the suitableoperation mode with the lowest water pumping cost per unit under the averagedaily head of7.8m and6.8m, while the combined operation with adjustable-bladeand variable speed was the suitable operation mode under the average daily headof5.8m,4.8m and3.8m. Without considering peak-valley electricity price, theoptimal operation with adjustable-blade was the suitable operation mode underaverage daily head of7.8，while the combined optimal operation became thesuitable operation mode under average daily head of6.8m，5.8m，4.8m and3.8m.The optimal operation results above have provided the basis for the optimaloperation mode of large-scale pumping stations along Yangtze River.Supposing that No.4Jiangdu pumping station has a daily head amplitude of2.0m, atfer thafthe optimal operation of single pump unit with adjustable-bladeand with variable were respectively carried out and the obtained results were usedto compare with the one with the daily head amplitude of1.2m, by which toconfirm the influence carried out by tides for the optimal results. The optimalresults showed that the optimal operation has a better effect with adjustable-bladeor with variable speed while the tidal process has a bigger daily amplitude. Considering the different connection mode between frequency converter andelectric motor such as tandem type and by-pass mode, the comparison andanalysis of optimal results obtained from optimal operation of single pump unitwith variable speed with different connection mode were carried out. Also theoptimal results were used to compare with the ones obtained from the ratingoperation and optimal operation with adjustable-blade. The optimal operationresults showed that with the consideration of peak-valley electricity price, underaverage daily head of7.8m-3.8m and100%,80%,60%water pumping loads,by-pass mode of frequency converter connection has respectively saved1.2-3.9%,1.0-3.1%,1.5-3.6%of water pumping cost per unit compared with theconnection mode with tandem type. While without considering peak-valleyelectricity price, the water pumping cost has more than4%of cost saving underaverage daily head of7.8m,6.8m and with100%water pumping loads.(4) The energy characteristics of operation mode with adjustable-blade orwith variable speed in large-scale pumping stations were analyzed and thechanging situation of flow rate, head and efficiency while in various operationprocess with adjustable-blade or with variable speed was studied. By studying theinterpolation mode of energy performance curves of existing large-scale pumpingstations, taking No.4Jiangdu pumping station as a study case, the polynomialbased on common least square method and the moving least squares were appliedto fit the performance curve of large-scale pumping stations along Yangtze Riverand analyze the fitting effect. The study results showed that within the stableoperation region of pump, the precision of polynomial based on common leastsquare method could well satisfy the requirement while applied to fit theperformance curves. |
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