吳恒卿,黃 強(qiáng),徐 煒,習(xí)樹(shù)峰(.西安理工大學(xué)西北旱區(qū)生態(tài)水利工程國(guó)家重點(diǎn)實(shí)驗(yàn)室培育基地,西安70048;2.深圳市西麗水庫(kù)管理處,深圳58055;.重慶交通大學(xué)河海學(xué)院,重慶400074;4.中山大學(xué)水資源與環(huán)境系,廣州50275;5.深圳市水務(wù)規(guī)劃設(shè)計(jì)院,深圳58000)
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基于聚合模型的水庫(kù)群引水與供水多目標(biāo)優(yōu)化調(diào)度
吳恒卿1,2,黃強(qiáng)1,徐煒3,習(xí)樹(shù)峰4,5
(1.西安理工大學(xué)西北旱區(qū)生態(tài)水利工程國(guó)家重點(diǎn)實(shí)驗(yàn)室培育基地,西安710048;2.深圳市西麗水庫(kù)管理處,深圳518055;3.重慶交通大學(xué)河海學(xué)院,重慶400074;4.中山大學(xué)水資源與環(huán)境系,廣州510275;5.深圳市水務(wù)規(guī)劃設(shè)計(jì)院,深圳518000)
摘要:該文以深圳市城市供水系統(tǒng)中的公明供水調(diào)蓄工程為例,對(duì)區(qū)域水資源的合理配置和高效利用展開(kāi)研究。工程中公明水庫(kù)被用作城市供水的儲(chǔ)備水源,以防止連續(xù)枯水年份或發(fā)生水污染等嚴(yán)重事件對(duì)城市供水構(gòu)成的巨大威脅。為此,充分考慮調(diào)蓄工程的供水運(yùn)行特點(diǎn),將調(diào)蓄工程中的水庫(kù)群聚合為“虛擬水庫(kù)”,并建立調(diào)蓄工程的引水與供水調(diào)度模型;調(diào)度模型以引水量最小和公明水庫(kù)換水量最大為目標(biāo)函數(shù),采用多目標(biāo)遺傳算法NSGA-II對(duì)引水與供水調(diào)度模型進(jìn)行優(yōu)化求解。在此基礎(chǔ)上,采用模糊優(yōu)選方法在Pareto優(yōu)化解集空間中尋找滿意解,并選擇3個(gè)代表解對(duì)調(diào)蓄工程的供水進(jìn)行模擬。對(duì)比與分析模擬計(jì)算結(jié)果,表明優(yōu)化調(diào)度模型能夠高效利用外流域引水資源和提高公明水庫(kù)的水量交換。
關(guān)鍵詞:水庫(kù);優(yōu)化;模型;水庫(kù)調(diào)度;聚合水庫(kù);供水;引水;NSGA-II算法
吳恒卿,黃強(qiáng),徐煒,習(xí)樹(shù)峰.基于聚合模型的水庫(kù)群引水與供水多目標(biāo)優(yōu)化調(diào)度[J].農(nóng)業(yè)工程學(xué)報(bào),2016,32 (01):140-146.doi:10.11975/j.issn.1002-6819.2016.01.019 http://www.tcsae.org
Wu Hengqing, Huang qiang, Xu Wei, Xi Shufeng.Multi-objective optimal operation for multi-reservoirs for water diversion and supply by using aggregation model[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE), 2016, 32(01): 140-146.(in Chinese with English abstract)doi:10.11975/j.issn.1002-6819.2016.01.019 http://www.tcsae.org
隨著社會(huì)經(jīng)濟(jì)和人口的高速增長(zhǎng),城市供水需求不斷增大,而當(dāng)?shù)厮匆巡荒軡M足用水需求,大部分大型城市面臨發(fā)展性缺水、季節(jié)性缺水和水質(zhì)性缺水的問(wèn)題,外流域引水成為支撐城市發(fā)展的重要方式??缌饔蛞こ虅t是改善城市用水現(xiàn)狀,平衡地區(qū)水量分布不均的重要手段。無(wú)論是本地水資源還是跨流域引水,科學(xué)的管理和優(yōu)化配置是水資源高效利用的基礎(chǔ)[1-2]。
目前,國(guó)內(nèi)外針對(duì)地區(qū)性供水系統(tǒng)的管理已有較多的研究成果。20世紀(jì)60年代科羅拉多大學(xué)針對(duì)需水量的估算及滿足情況進(jìn)行研討,是水資源配置思想的最早體現(xiàn),也是國(guó)外水資源優(yōu)化配置研究的起點(diǎn)。1997年Dudley 和Zheng[1]將農(nóng)作物生長(zhǎng)模型和二維狀態(tài)變量的隨機(jī)規(guī)劃模型相結(jié)合,該研究成果以模擬優(yōu)化的方式對(duì)季節(jié)性灌溉用水進(jìn)行合理分配。隨后,Willis和Simonovic[2]以供水費(fèi)用最小和最小缺水損失為目標(biāo),采用線性規(guī)劃模型建立地表水庫(kù)和地下水庫(kù)的聯(lián)合優(yōu)化模型,研究成果對(duì)提高該地區(qū)的水資源利用程度起到明顯的效果。近年來(lái),Helen 等[3]結(jié)合新興的GIS技術(shù)建立了基于風(fēng)險(xiǎn)優(yōu)先級(jí)的水資源模擬系統(tǒng)(risk-based prioritisation system,RBPS),在此基礎(chǔ)上進(jìn)行了流域水資源配置研究的嘗試。在國(guó)內(nèi),水資源分配研究主要圍繞水庫(kù)的優(yōu)化調(diào)度,其中賀北方等[4]對(duì)水庫(kù)群的多目標(biāo)最優(yōu)控制模型和方法進(jìn)行研究,在此基礎(chǔ)上對(duì)灌區(qū)渠系優(yōu)化配水進(jìn)行研究。近年來(lái)隨著中國(guó)經(jīng)濟(jì)的不斷發(fā)展,城市及農(nóng)業(yè)供水問(wèn)題越來(lái)越突出,已有大量研究針對(duì)城市供水、農(nóng)業(yè)灌溉排水和水質(zhì)水量等相關(guān)問(wèn)題進(jìn)行深入研究[5-8]。
在上述研究中,大部分研究主要著眼于本地水資源的優(yōu)化配置,然而跨流域調(diào)水系統(tǒng)通常涉及多個(gè)水庫(kù),水庫(kù)群之間科學(xué)合理的引水、供水對(duì)整個(gè)系統(tǒng)的優(yōu)化運(yùn)行起著至關(guān)重要的作用。在跨流域調(diào)水工程的研究中,主要以受水水庫(kù)目標(biāo)效益最大化或以從引水水庫(kù)和受水水庫(kù)整體效益最大來(lái)確定引水量及引水方式[9-10]。胡堯文等[11]采用并行調(diào)節(jié)和聚合分解法分析分析了簡(jiǎn)單跨流域調(diào)水工程的引水原則。閆春程等[12]以受水水庫(kù)引水量最小為目標(biāo),并進(jìn)行優(yōu)化計(jì)算,建立了大伙房跨流域調(diào)水工程的引水優(yōu)化調(diào)度模型。梁國(guó)華等[13]建立遼寧省東水西調(diào)工程的用水與來(lái)水間的相關(guān)關(guān)系。王國(guó)利等[14]在實(shí)時(shí)調(diào)度中對(duì)預(yù)報(bào)信息的可行性進(jìn)行分析,進(jìn)行了大伙房跨流域調(diào)水工程的調(diào)度。
水庫(kù)群的優(yōu)化調(diào)度對(duì)區(qū)域水資源的合理配置和高效利用起著關(guān)鍵作用,開(kāi)展水庫(kù)群的優(yōu)化調(diào)度研究具有十分重要的理論意義和應(yīng)用價(jià)值。目前,在深圳城市供水系統(tǒng)中東江引水成為主要水源,為防止連續(xù)枯水年份或發(fā)生水污染等嚴(yán)重事件對(duì)城市供水構(gòu)成的巨大威脅,公明水庫(kù)被用作城市供水的儲(chǔ)備水源,因此本文以公明供水調(diào)蓄工程的引水和供水調(diào)度為研究對(duì)象。首先充分考慮調(diào)蓄工程供水運(yùn)行的特點(diǎn),以聚合的方式將調(diào)蓄工程中的水庫(kù)群聚合為“虛擬水庫(kù)”,并在此“虛擬水庫(kù)”基礎(chǔ)上,建立調(diào)蓄工程的引水與供水調(diào)度模型。然后,調(diào)度模型以引水量最小和公明水庫(kù)換水量最大為目標(biāo)函數(shù),采用多目標(biāo)遺傳算法NSGA-II對(duì)引水與供水調(diào)度模型求解得到Pareto解集。最后選擇多個(gè)典型Pareto優(yōu)化解,并依此解對(duì)調(diào)蓄工程的引水與供水過(guò)程進(jìn)行模擬計(jì)算與結(jié)果分析
1.1深圳市西北部水庫(kù)群概況
公明供水調(diào)蓄工程位于深圳市西北部。公明供水調(diào)蓄工程供水系統(tǒng)包括4座水庫(kù):公明、茜坑、鵝頸和石巖水庫(kù)。水庫(kù)之間通過(guò)自流和提水的方式聯(lián)系在一起,各水庫(kù)的基本參數(shù)如下表1。供水調(diào)蓄工程的本地年徑流量相對(duì)較小,無(wú)法滿足城市供水需求,主要水源來(lái)自境外引水。境外引水主要分配至茜坑、鵝頸和石巖3個(gè)水庫(kù),而公明水庫(kù)的主要任務(wù)是儲(chǔ)備水源,用于特枯年份或者連續(xù)枯水年份以及突發(fā)性水污染等特殊情況下供水。公明水庫(kù)作為目前深圳市規(guī)劃建設(shè)的庫(kù)容最大的“水缸”之一,擔(dān)負(fù)著向西部寶安區(qū)、光明新區(qū)各水廠供水及供水調(diào)蓄任務(wù),可提高深圳市西部?jī)?chǔ)備水量、供水調(diào)蓄能力以及對(duì)枯水年的抗旱災(zāi)能力,提高供水安全保證率。
表1 公明供水調(diào)蓄工程各水庫(kù)基本參數(shù)Table 1 Characteristics of reservoirs in Gongming water supply project
1.2公明供水調(diào)蓄工程的運(yùn)行規(guī)則
當(dāng)區(qū)域內(nèi)發(fā)生干旱或連續(xù)枯水年情況下,供水區(qū)域內(nèi)城市可供水量小于計(jì)劃供水量的70%時(shí),則啟動(dòng)儲(chǔ)備水源;當(dāng)發(fā)生突發(fā)性水污染事件情況時(shí),根據(jù)事件評(píng)估結(jié)果決定啟用的供水量。儲(chǔ)備水源啟動(dòng)后,在后續(xù)年份中通過(guò)水系統(tǒng)的統(tǒng)一調(diào)配,按來(lái)水量的70%供水,剩余水量補(bǔ)給公明水庫(kù)。為了保證公明水庫(kù)的供水水質(zhì),適當(dāng)給姜下水廠供水,以保證公明水庫(kù)的交換水量,見(jiàn)圖1。
圖1 深圳市公明供水調(diào)蓄工程水力聯(lián)系及供水結(jié)構(gòu)Fig.1 Hydraulic connection and water supply structuresof Gongming water supply project
根據(jù)以上所述,深圳西北部公明供水調(diào)蓄工程,供水調(diào)度的目標(biāo)是:深圳市供水在90%保證率的前提下,提高公明水庫(kù)的蓄水量及水質(zhì),以備突發(fā)性事件所帶來(lái)的水資源短缺問(wèn)題。公明供水調(diào)蓄工程的本地水資源量有限,供水水源主要來(lái)自境外引水。公明水庫(kù)的主要任務(wù)是蓄水,而茜坑、鵝頸和石巖水庫(kù)主要是蓄存引水和城市供水。在正常來(lái)水情況下,工程系統(tǒng)依靠本地徑流和引水即可滿足供水;在枯水年本地徑流量和跨流域引水均減小的情況下,各水庫(kù)按70%為城市供水,供水缺口由儲(chǔ)備水量補(bǔ)充。2.1基于聚合水庫(kù)的聯(lián)合引水與供水調(diào)度模型
依據(jù)公明供水調(diào)蓄工程供水系統(tǒng)的特點(diǎn),本文采用聚合的方式將供水系統(tǒng)中的水庫(kù)群聚合為一個(gè)“虛擬水庫(kù)”,并在此基礎(chǔ)上建立聯(lián)合供水調(diào)度規(guī)則和引水調(diào)度規(guī)則。
1)公明供水調(diào)蓄工程系統(tǒng)中包含公明、茜坑、鵝頸和石巖水庫(kù),將各水庫(kù)的死庫(kù)容和興利庫(kù)容進(jìn)行疊加,構(gòu)成“虛擬水庫(kù)”的死庫(kù)容和興利庫(kù)容,如圖2(a)所示。在虛擬水庫(kù)中,按調(diào)度方式將庫(kù)容分為3個(gè)功能區(qū),即正常供水區(qū),減小供水區(qū)和儲(chǔ)備水量。正常供水區(qū)中,各水庫(kù)按城市需水量正常供水;減小供水區(qū)中,各水庫(kù)按城市需水量的70%供水,其余水量由公明水庫(kù)補(bǔ)給;儲(chǔ)備水量即為公明水庫(kù)為枯水年或突發(fā)事件留有的備用水源。
2)公明供水調(diào)蓄工程的聯(lián)合引水調(diào)度圖,如圖2(b)所示。聚合水庫(kù)的“引水”控制線將水庫(kù)引水調(diào)度圖劃分為2個(gè)區(qū),即正常引水區(qū)和減少引水區(qū)。正常引水區(qū)即按引水管道能力滿引,而減少引水區(qū)即按滿引能力的60%引水。
圖2 公明供水調(diào)蓄工程的聯(lián)合引水與供水調(diào)度圖結(jié)構(gòu)Fig.2 Hedging rule curves structure of joint water diversion and supply operation for Gongming water supply project
2.2跨流域引水分配模型
在公明供水調(diào)蓄工程的供水水源主要來(lái)自境外引水,科學(xué)合理地分配引水量可提高供水效率和減少棄水。目前,成員水庫(kù)引水量分配方法主要采用固定分水模式,即不同時(shí)段采用統(tǒng)一的分水比例。但供水系統(tǒng)運(yùn)行中,各水庫(kù)庫(kù)容、徑流量及供水量均存在差異,往往由于引水量的分配不合理造成水庫(kù)棄水或缺水。
在引水量分配過(guò)程中,必須明確水庫(kù)群中每個(gè)成員水庫(kù)在相應(yīng)時(shí)段的蓄水、來(lái)水和用水情況,這樣才能使引水的分配具有可操作性。為了避免水庫(kù)供水過(guò)程中,水庫(kù)蓄水的不平衡,本文提出一種動(dòng)態(tài)分水方法。供水分配系數(shù)根據(jù)水庫(kù)當(dāng)前時(shí)段剩余興利庫(kù)容和各水庫(kù)的庫(kù)容系數(shù)確定,各成員水庫(kù)的引水量分配系數(shù)與當(dāng)前時(shí)段剩余興利庫(kù)容成正比,與庫(kù)容系數(shù)的平方成反比。引水量分配系數(shù)計(jì)算如公式(1)。
式中VSn,t為第n個(gè)水庫(kù)在時(shí)段t的剩余興利庫(kù)容;N為水庫(kù)個(gè)數(shù);βn為第n個(gè)水庫(kù)的庫(kù)容系數(shù)。
如實(shí)例概況中所述,公明供水調(diào)蓄工程的引水與供水調(diào)度問(wèn)題,是一個(gè)多水源、多用戶、多目標(biāo)的水資源聯(lián)合調(diào)度問(wèn)題。首要是滿足城市供水的保證率要求,在此基礎(chǔ)上盡量減少外流域的引水量,提高長(zhǎng)距離高成本引水量的利用效率,即在減少水庫(kù)的“棄水量”。
3.1模型優(yōu)化目標(biāo)函數(shù)
結(jié)合研究實(shí)例的具體情況,在聯(lián)合引水和供水調(diào)度模型優(yōu)化中,建立兩個(gè)目標(biāo)函數(shù),即引水量最小公明水庫(kù)交換水量最大,分別如公式(2)和(3)。
式中J為年周期的月時(shí)段數(shù),j=1,2,3,…,12;I為計(jì)算年數(shù),i=1,2,3,…,45;W(·)為境外引水量,m3;R(·)為水庫(kù)徑流量,m3;Rg(·)為公明水庫(kù)的天然徑流量,m3;Wg(·)為分配到公明水庫(kù)的境外引水量,m3。
3.2約束條件
在優(yōu)化過(guò)程中,考慮的約束條件主要有:1)各水庫(kù)多年平均供水保證率不小于90%。2)調(diào)蓄工程中各輸水管道的輸水能力約束(北線引水管道、茜坑—鵝頸、鵝頸—公明、鵝頸—石巖、公明—石巖)。3)各時(shí)段各水庫(kù)的蓄水庫(kù)容限約束,4)水量平衡方程。約束條件計(jì)算公式如下:
3.3模型優(yōu)化求解算法
目前多目標(biāo)優(yōu)化求解方法主要分2種:一是將多目標(biāo)優(yōu)化問(wèn)題轉(zhuǎn)化為單目標(biāo)問(wèn)題進(jìn)行求解,以整體效益最優(yōu)或是以特定目標(biāo)最優(yōu)為目標(biāo)函數(shù),而其它目標(biāo)作為約束條件。二是利用啟發(fā)式算法求得Pareto解集來(lái)反映不同目標(biāo)下最優(yōu)方案的非劣解集。本文采用非支配排序遺傳算法NSGA-II(non-dominated sorting genetic algorithmII)作為聯(lián)合供水優(yōu)化調(diào)度的多目標(biāo)求解算法。
在公明供水調(diào)蓄工程的引水與供水調(diào)度模型優(yōu)化中,首先采用聚合的方式將水庫(kù)群聚合為“虛擬水庫(kù)”,然后在此“虛擬水庫(kù)”基礎(chǔ)上建立公明供水調(diào)蓄工程的引水與供水調(diào)度模型。最后,在調(diào)度模型的優(yōu)化過(guò)程中,以NSGA-II算法與模擬-優(yōu)化方法相結(jié)合的方式對(duì)水庫(kù)引水與供水調(diào)度模型進(jìn)行優(yōu)化。
4.1多目標(biāo)優(yōu)化模型優(yōu)化求解
運(yùn)用多目標(biāo)遺傳算法NSGA-II對(duì)公明供水調(diào)蓄工程的引水與供水調(diào)度模型進(jìn)行求解,并獲得400個(gè)多目標(biāo)Pareto可行解(滿足供水保證率要求)。為了給決策者提供更多的信息,本文將所有Pareto解在平面上全部展示出來(lái),如圖3所示。
圖3 公明供水調(diào)蓄工程聯(lián)合供水調(diào)度模型的Pareto優(yōu)化解集空間Fig.3 The multi-objective Pareto solution set of joint operation for Gongming water supply project
圖3清晰地展示了Pareto解集空間的分布情況,縱坐標(biāo)表示公明水庫(kù)交換水量,橫坐標(biāo)表示引水量。公明水庫(kù)的交換水量隨著引水量的增加而變化。圖3中,A、B和C點(diǎn)為3個(gè)可行解點(diǎn),將3個(gè)點(diǎn)連接為AB和BC兩條線段。通過(guò)對(duì)比兩條線段,線段AB的斜率要大于線段BC的斜率,說(shuō)明公明水庫(kù)的交換水量隨著引水量的增加而不斷提高,但交換水量的邊際效益在不斷減小。沿可行解集最外圍連接起來(lái)構(gòu)成曲線A-B-C,分布在曲線上的可行解為不同目標(biāo)函數(shù)權(quán)重條件下的最優(yōu)解。在供水調(diào)度決策中,決策者會(huì)根據(jù)自己的調(diào)度經(jīng)驗(yàn)和偏好,選擇相對(duì)于的解作為水庫(kù)引水、供水調(diào)度的依據(jù)。
在圖3中,公明水庫(kù)的交換水量隨著引水量的增加而不斷提高,但交換水量的邊際效益卻是在不斷降低的,即交換水量達(dá)到一定程度后,如果要繼續(xù)提高交換水量則需要更多的引水量。由表2可知,引水量不斷增加,公明水庫(kù)的交換水量和供水保證率增加,當(dāng)超過(guò)城市需水量和水庫(kù)群控制能力后,公明供水調(diào)蓄工程開(kāi)始發(fā)生棄水。
4.2供水模擬調(diào)度及方案選擇
針對(duì)各目標(biāo)極端情況下對(duì)Pareto解集空間進(jìn)行分析,決策者需要在考慮不同偏好的情況下,制定不同偏好下的滿意方案集。分別對(duì)解集空間中的183個(gè)解進(jìn)行模擬調(diào)度,采用等權(quán)重的方式模糊優(yōu)選滿意方案。統(tǒng)計(jì)Pareto解的模擬供水調(diào)度指標(biāo),計(jì)算各方案的相對(duì)隸屬度,選擇相對(duì)隸屬度最高的解作為滿意方案。
在此,分別選擇3個(gè)典型可行解(如,圖3中A、B和C)進(jìn)行對(duì)比說(shuō)明,即依據(jù)A、B和C可行解分別對(duì)公明供水調(diào)蓄工程進(jìn)行模擬調(diào)度計(jì)算,可行解A、B和C的供水過(guò)程和供水結(jié)果分別如圖4、圖5和圖6所示。各可行解的模擬調(diào)度效益結(jié)果統(tǒng)計(jì)如表2所示。
表2 三個(gè)典型解條件下水庫(kù)群的調(diào)度效益結(jié)果Table 2 Simulation results of three typical multi-objective Paretosolutions for Gongming water supply project
本文采用模糊優(yōu)選方法[15],對(duì)183個(gè)Pareto解進(jìn)行相對(duì)隸屬度計(jì)算,選擇相對(duì)隸屬度最高的B點(diǎn)作為滿意方案,并以此解作為公明供水調(diào)蓄工程聯(lián)合引水與供水模擬調(diào)度的依據(jù)。
圖6 方案C的水庫(kù)群供水調(diào)度結(jié)果Fig.6 Simulation result of typical Pareto solution C for the project
4.3“虛擬水庫(kù)”水量調(diào)度分析
公明供水調(diào)蓄系統(tǒng)中,公明水庫(kù)具有優(yōu)先蓄水的權(quán)利,當(dāng)公明水庫(kù)蓄滿之后,則北線引水按比例分給茜坑、鵝頸、石巖3座水庫(kù)。當(dāng)特枯年份和連續(xù)枯水年時(shí)期,北線引水全部按比例蓄入茜坑、鵝頸、石巖3座水庫(kù),如果仍不能滿足供水需求,則由公明水庫(kù)進(jìn)行補(bǔ)償;如果滿足供水需求,則多余水量?jī)?yōu)先存入公明水庫(kù)。因此,在“虛擬水庫(kù)”的水量分配過(guò)程中,北線引水量主要在茜坑、鵝頸和石巖水庫(kù)間進(jìn)行分配。以方案B作為公明供水調(diào)蓄工程聯(lián)合引水與供水模擬調(diào)度的依據(jù),對(duì)1960-2005年的水庫(kù)群引水與供水調(diào)度進(jìn)行模擬,茜坑、鵝頸和石巖水庫(kù)月分水系數(shù)如圖7所示,茜坑水庫(kù)、鵝頸水庫(kù)和石巖水庫(kù)的的引水分配比例多年平均值分別為0.28、0.14和0.58。
由此分配比例系數(shù)可知,來(lái)自東江的北線引水量在扣除茜坑、鵝頸和公明水庫(kù)用水之后,大約58%的水量被引至石巖水庫(kù)。各水庫(kù)各月的平均入庫(kù)水量有一定的變化幅度,其中茜坑、鵝頸水庫(kù)的變化幅度不大,而石巖水庫(kù)和公明水庫(kù)的入庫(kù)水量變化幅度較大。其中6、7、8月份的蓄水量變化最大,通過(guò)分析得知該時(shí)期主要為公明水庫(kù)的蓄水期。由于公明水庫(kù)沒(méi)有足夠的天然來(lái)水,為了達(dá)到儲(chǔ)備庫(kù)容,汛期公明水庫(kù)在其他水庫(kù)來(lái)水豐沛期間將多余的引水量存蓄入庫(kù)。
圖7 水庫(kù)群月平均入庫(kù)水量比例Fig.7 Proportion of average monthly inflow for reservoirs
本文針對(duì)水庫(kù)群復(fù)雜的水力聯(lián)系和公明水庫(kù)特殊的功能,對(duì)公明供水調(diào)蓄工程的引水與供水聯(lián)合優(yōu)化調(diào)度研究,結(jié)果表明:
1)公明供水調(diào)蓄工程在引水、供水與交換水的聯(lián)合調(diào)度規(guī)則的指導(dǎo)下進(jìn)行調(diào)度,滿足了各目標(biāo)的保證率,供水及引水過(guò)程合理,說(shuō)明調(diào)度規(guī)則適應(yīng)水庫(kù)群的調(diào)度需求。
2)采用多目標(biāo)遺傳算法NSGA-II可得到公明供水調(diào)蓄工程的聯(lián)合優(yōu)化調(diào)度非劣解集。通過(guò)對(duì)調(diào)度目標(biāo)間協(xié)同競(jìng)爭(zhēng)關(guān)系的分析發(fā)現(xiàn)引水量與供水量存在競(jìng)爭(zhēng)關(guān)系。當(dāng)引水量減少時(shí),其他供水目標(biāo)值會(huì)出現(xiàn)不同程度的衰減。解集提供了多種不同的調(diào)度方案,決策者可根據(jù)調(diào)度經(jīng)驗(yàn)選擇不同偏好下的滿意方案。
3)隨著引水量的不斷增加,水庫(kù)群的供水能力不斷增強(qiáng)。但供水的邊際效益不斷降低,即隨著引水量增加,供水的增加量逐漸趨緩,并開(kāi)始出現(xiàn)棄水現(xiàn)象。因此,滿意解應(yīng)該是不發(fā)生棄水,引水量適度,供水量較大的解。研究中選擇的方案B即可作為一個(gè)比較滿意的解。
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Multi-objective optimal operation for multi-reservoirs for water diversion and supply by using aggregation model
Wu Hengqing1,2, Huang qiang1, Xu Wei3, Xi Shufeng4,5
(1.State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area, Xi’an University of Technology, Xi’an, 710048, China; 2.ShenzhenXili Reservoir Management Department, Shenzhen 518055, China; 3.College of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing 400074, China; 4.Department of Water Resources and Environment, SunYat-sen University, Guangzhou 510275, China; 5.Shenzhen Water Planning and Design Institute, Shenzhen 518000, China)
Abstract:Reservoirs optimal operation can improve the efficiency of water allocation and supply.Gongming water supply project is taken as an example, which is subsystem of Shenzhen urban water supply.The project constituted by hybrid reservoirs,including Gongming reservoir, Qiankeng reservoir, Ejing reservoir and Shiyan reservoir.In this project, Gongming reservoir is used to prevent continuous dry years or serious water pollution incidents, which might take great threat to urban water supply.Thus, the storage water of Gongming reservoir is taken as reserved water source for Shenzhen city water supply.For this special task, the Gongming reservoir need keeping at a relatively high water storage level for a long time, and the reservoir requires a certain amount of exchange water to maintain water quality health.The water supply benefit of the hybrid reservoirs and the amount of exchange water of Gongming reservoir are the key objectives.To study the optimal operation of Gongming water supply project for inter-basin water diversion and water supply operating, firstly, aggregation method is applied to aggregate the reservoirs into a“virtual reservoir”, which is used for simplifying topological structure of hybrid reservoirs.The dead storage and usable storage of“virtual reservoir”is formed by superposing the dead storage and usable storage of hybrid reservoirs respectively.Then based on“virtual reservoir”, the hybrid reservoirs operation rules for water diversion and water supply are established.Further, the multi-objectives genetic algorithm NSGAII is applied to optimize the operation rules, and the multi-objectives of the operation are the minimum amount of diversion water and the maximum amount of supply water.The water supply operation rule curves divide the storage of“virtual reservoir”into 3 functional areas, which are normal water supply area, reduced water supply area and reserved water supply area.When total water storage of“virtual reservoir”keeps during normal water supply area, the urban demand water can be supplied adequately.When total water storage of“virtual reservoir”keeps during reduced water supply area, it indicates that the reservoirs are lacking of water, urban demand water can not be satisfied and water supply needs to reduce appropriately.The third situation is when continuous dry years or serious water pollution incidents occur, reserved water of Gongming reservoir is used to satisfy the urban demand water.The water diversion operation rule curves divide the storage into 2 functional areas, which are reduced water diversion area and normal water supply area.When total water storage of “virtual reservoir”keeps during reduced water diversion area, it indicates that the reservoirs have enough water to satisfy urban demand.The reserves reduce diversion water to prevent abandoned water.However, when total water storage of “virtual reservoir”keeps during normal water supply area, the reserves are lacking of water storage that should do water diversion.Pareto optimization technique is embedded in NSGA-II, which makes NSGA-II deal with multi-objectives at the same time.Firstly, Pareto optimization technique is applied to obtain 400 multi objective feasible solution sets that can meet water supply guarantee rate.In these sets, 183 optimal feasible solutions with different weights are selected.Then according to the 183 Pareto solutions, operation processes of water diversion and water supply are simulated.Based on the simulated results, the amounts of water diversion, exchange water, abandoned water and guarantee rate are counted as indicators, and the fuzzy method is used to analyze the relative membership degree of 183 Pareto solutions.In the scheme selecting process, water diversion and exchange water are assumed to be equal.Thus the highest relative membership degree of solution B is selected as satisfying scheme for real-time operation.Comparing and analysis the results, it demonstratesthat optimization operation can improve efficiency of water supply and water exchange.
Keywords:reservoirs; optimization; models; parallel reservoirs; joint optimal operation; aggregation reservoir; common water user; inter-basin water diversion
作者簡(jiǎn)介:吳恒卿(1976-),男,廣東雷州人,高級(jí)工程師,在讀博士,主要從事水資源系統(tǒng)工程研究。西安西安理工大學(xué),西北旱區(qū)生態(tài)水利工程國(guó)家重點(diǎn)實(shí)驗(yàn)室培育基地,710048。Email:waterwu2004@126.com
基金項(xiàng)目:國(guó)家重大基礎(chǔ)研究973(2011CB403302-2);國(guó)家自然科學(xué)基金(51179148);重慶市前沿與應(yīng)用基礎(chǔ)研究計(jì)劃(cstc2015jcyjA0601)
收稿日期:2015-09-18
修訂日期:20152015-11-16
中圖分類(lèi)號(hào):TV697
文獻(xiàn)標(biāo)志碼:A
文章編號(hào):1002-6819(2016)-01-0140-07
doi:10.11975/j.issn.1002-6819.2016.01.019