Allocation of Power Generating and Shipping of Hanjiang Upstream Cascade *
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PROGRESS IN NATURAL SCIENCE Vol .15 , No .8 , August 2005 Allocation of power generating and shipping of Hanjiang upstream cascade * LIU Junping1 ** and CHANG Mingqi2, 3 (1 .School of Civil Engineering and Architecture , Zhejiang University of Technology , Hangzhou 310014 , C hina;2 .Institu te of Water Resou rces & Hydroelectric Engineering , Xi' an University of Technology , Xi' an 710048 , China;3.Shanxi Institute of Water Re- sources, Taiyuan 030001 , China) Received November 16 , 2004 ;revised February 28 , 2005 Abstract The optimal model and simulating model of the Hanjiang cascade reservoirs operation with one day asits calculating peri- od are established to coordinate the contradictions betw een pow er generating and shipping .The optimal model is solved by progressive op- timality algorithm method adopting the theory of large system decomposing and coordinating .By analyzing the w ater allocation results ob- tained from six schemes, w hich are tw o cascades, four cascades and seven cascades joint operation considering shipping or not, the contra- diction degree betw een pow er generating and shipping is investigated and some joint operation schemes are proposed . Keywords: cascade , power generating , contradiction, shipping, optimal operation. 1 General situation of the cascades Ankang hydropower stations have been constructed , and Shiquan hy dropower station began to generate 1 .1 Cascades hydropower plants electricity in power netw ork in 1975 .In practical op- eration , Shiquan modulates peaks to meet the net- Hanjiang River is one of the longest tributaries of wo rk demand , w hich brings adverse influences to the Yang tse River , originating from Ning qiang county of low er reaches . Shaanxi province and flowing through Shaanxi province and Hubei province .H anjiang River is Since four big and one small generating units of 1567 km long in total, and 709 km of it in ShaanXi Ankang hy dropow er station have been installed to use province runs through Hanzhong and Ankang regions in 1992 , the five units have played an important role from the east to the west . in modulating peaks fo r the electric netwo rk of Shaanxi province .The Shaanxi network depends The upper reaches of Hanjiang from Yangxian mainly on the w ater pow er stations located on the county to Baihe county in Shaanxi province is 443 km Hanjiang upper reaches to modulate peaks so Shiquan long , and its total head falls is about 280 m high . and Ankang are key plants for modulating peaks , es- With abundant water pow er resources , its total head pecially Ankang .Ankang has generated 159 ×108 kW falls is about 280 m high , its exploitable installed ca- ·h energy accumulatively from 1990 to 1999 , co rre- pacity is about 212 .75 ×104 kW , and its annual ener- sponding to 80 % tasks of modulating peaks in aver- 8 gy output is about 69 .73 ×10 kW·h .Seven cascades age . have been planned o n the main stem of Hanjiang up- per reaches , w hich are Huangjinxia (10 ×104 kW), In the near future plan , namely the four cascades Shiquan (13 .5 ×104 kW), Xihe (18 ×104 kW), plan , Xihe and Xunyang hydropow er stations w ill be Ankang (85 .25 ×104 kW), Xuny ang (32 × developed .Xihe hydropower station has begun to 104 kW), Shuhe (27 ×104 kW), and Jiahe (27 × build at June 26 , 2003 .The construction of the four 104 kW), from the upper reaches to the low er reach- cascades w ill make Shiquan , Xihe , Ankang and Xun- es[ 1 , 2] .The schematic diagram of the seven cascades yang reservoirs end to end to improve the shipping ef- is show n in Fig .1 . ficiency .In the long future plan , all cascades w ill be completed and the w aterw ay will be channelized so Among the seven cascades , only Shiquan and the navigation conditions w ill be greatly im proved . * Supported by National Natural Science Foundation of China (Grant No .50079021) ** To w hom correspondence should be addressed .E-mail:Ljp23 @163 .com 734 w ww .tandf.co .uk/journals Prog ress in Natural Science Vol .15 No .8 2005 Fig .1 . Schematic diagram of the seven cascades. 1 .2 Present status of the waterways synchronously w hen co nstructing dams of Shiquan and Ankang , so the channels used to be checkless be- The shipping in Hanjiang has a long history . come the segmented channels .Though the minimum Early in 107 BC there had been histo rical records of flow of shipping w as considered in desig n , in practical shipping , and the low er reaches of Mianxian county operation , the benefits of pow er generation of stations w as navigable .However , the navigable channel w as are excessively considered , and the stations often do short of regulation in a long period , and it is still in a no t discharge the base load flow according to the de- natural state .Low g rade of the channel results in low sig n.Only w hen modulating peaks , the station dis- transport capacity . charge is focused on the peak hours , causing the steep The w aterw ay from Hanjiang river to Mianxian rising and falling of the w ater level .Therefo re , the county is only suitable to transport logs , not to navi- periods suitable fo r shipping are extremely short and g ate ;that from Mianxian county to Yangxian county the shipping conditions are very bad .Additionally , is plain reach with 112 km long and low riversides , the cascades are not constructed continuously , the de- and at present is innavigable ;that from Yangxian velopment of shipping falls across many difficulties. county to Weimen county with 65 km long passes The minimum flow of shipping cannot be guaranteed , throug h Huangjinxia gorge and is able to run 20 t so the shipping nearly canno t operate normally .To ships;that from Weimen county to Shiquan with coordinate the conflicts between hydropower genera- 65 km long belongs to the Shiquan reservoir channel , tion and shipping , and bring the cascades of trunk and is able to run 100 t ships ;that from Shiquan to stream of the Hanjiang upper reaches into full play , Xihe w ith 48km long discharges unsteadily because of optim al allocation schemes are proposed to investigate Shiquan modulating peaks , and it is able to run 50 t the deg ree of the interaction betw een the tw o sides ships w hen Shiquan releases w ater and generates en- under the conditions of co nsidering o r not considering ergy , and is not able to run ships w hen Shiquan stops the shipping demand . generating energy ;that from Xihe to Ankang with The future plan fo r the shipping on the trunk 128 km long and better navigation conditio ns belongs stream of the Hanjiang upper reaches are :canalization to the Ankang reservoir channel , and is able to run is realized in the channels from Yang xian county to 100 t ships normally , w hich is the most important Danjiang kou , of w hich the channel between Yang xi- shipping base of the Hanjiang upper reaches ;that an county and Ankang w ill be built into the Ⅴ g rade from Ankang to Baihe with 164 km long is go rge w a- channel with 300 t traffic capacity and between terw ay , and is appropriate to run 100 t ships after ab- Ankang and Danjiangkou into the Ⅳ g rade channel orative regulation . w ith 400 t traffic capacity . 1 .3 Contradictions between pow er generation and The navig ation structure of each cascade of the shipping first shipping section adopts the 100 t (in the near fu- The ship-passing-through facilities w ere not built ture)—300 t (in the long run)ship lifts project , and Prog ress in Natural Science Vol.15 No .8 2005 w ww .tandf.co .uk/journals 735 that of the second shipping section adopts the 300 t reservoir sto rage is m 3 , flow is m3/s , water head is (in the near future)—500 t (in the long run)ship m , output is kW , and Δt =24 h . locks project . 2 .2 Constrained conditions 2 Optimal models of power generating and 2 .2 .1 Restricts of reservoir w ater balance shipping Vm (j , t +1) In order to coo rdinate the conflict betw een pow er = Vm (j , t)+(Qin , m (j , t)-Qout , m (j , t) generating and shipping and fully utilize the abundant -3600 Qloss , m (j , t))Δt , (2) w ater resources of the master stream of the Hanjiang w here V (j , t +1)is the reservoir storage of the m upper reaches , the principle of system engineering is m used .Under the conditions of ensuring the minimum reservoir at the end of the t time step of j year , discharg ing flow (considering shipping demand)and Vm (j , t)is the reservoir storage of the m reservoir the firm output of each hydropower station , cascade at the beginning of the t time step of j year ; stations on the Hanjiang upper reaches are operated to Q in, m (j , t), Qout , m (j , t)(including the pow er re- meet the requirements of power generating and ship- lease Qp , m (j , t)and surplus water Qs , m (j , t)), ping , and the operation schemes are optimized to pro- and Q loss , m (j , t )are the input flow , the output vide scientific bases fo r the development and operation flow , and the evaporating and seepage loss of the m of the Hanjiang cascades[ 3 , 4] . reservoir at the t time step of j year . 2 .1 Object function 2 .2 .2 Restricts of w ater balance of the node At present , among the seven cascades , only Shi- Flow dispatching should satisfy the conditions of quan station and Ankang station have been complet- w ater balance of the node .