安 剛(新疆水利水電勘測設(shè)計(jì)研究院,新疆 烏魯木齊 830000)
調(diào)壓閥技術(shù)在大河沿渠首水電站的應(yīng)用
安剛
(新疆水利水電勘測設(shè)計(jì)研究院,新疆 烏魯木齊 830000)
摘要:以新疆大河沿渠首水電站為例,通過對(duì)引水發(fā)電系統(tǒng)水力過渡過程計(jì)算分析,采用調(diào)壓閥技術(shù)解決長距離引水管道水錘壓力上升與機(jī)組轉(zhuǎn)速上升相互制約的問題,希望對(duì)國內(nèi)中、小型水電站設(shè)計(jì)提供一定的借鑒參考。
關(guān)鍵詞:水電站;調(diào)壓閥;長距離引水管道;水力過渡過程計(jì)算
大河沿渠首水電站位于新疆維吾爾自治區(qū)吐魯番地區(qū)大河沿鎮(zhèn)境內(nèi),設(shè)計(jì)引用流量為4.17m3/s,額定水頭183.0m,配置2臺(tái)3.125MW混流臥式水輪發(fā)電機(jī)組,電站引水管道總長約6.8km。電站主要建筑物由引水渠首、“圓中環(huán)”沉砂池、引水渠道、壓力前池、壓力管道(一管兩機(jī)布置)、廠房及尾水渠等組成。
(1)水流慣性時(shí)間常數(shù)與機(jī)組加速時(shí)間常數(shù)計(jì)算
根據(jù)渠首電站引水系統(tǒng)布置及其特征參數(shù),計(jì)算得出:2臺(tái)機(jī)組中較長一臺(tái)機(jī)組的壓力管總長Σ=6722.56m,水流慣性時(shí)間常數(shù)w=6.624s,機(jī)組加速時(shí)間常數(shù)a=4.164s。
(2)數(shù)值計(jì)算分析
數(shù)值計(jì)算結(jié)果表明,當(dāng)機(jī)組關(guān)閉時(shí)間為5s時(shí),機(jī)組最大轉(zhuǎn)速上升率為47.7%,在轉(zhuǎn)速控制標(biāo)準(zhǔn)55%以內(nèi);此時(shí)的壓力已遠(yuǎn)遠(yuǎn)大于壓力控制值252.94m;相關(guān)計(jì)算表明,若壓力控制在允許值內(nèi),導(dǎo)葉關(guān)閉時(shí)間則要大于25s。
(3)結(jié)論
根據(jù)《水電站調(diào)壓室設(shè)計(jì)規(guī)范》(DL/T5058-1996)可知,當(dāng)水流慣性時(shí)間常數(shù)時(shí),可不設(shè)調(diào)壓室,而渠首水電站的,理論上應(yīng)設(shè)置調(diào)保措施。在此基礎(chǔ)上,無調(diào)保措施下的過渡過程數(shù)值計(jì)算結(jié)果進(jìn)一步論證了設(shè)置調(diào)保措施的必要性。設(shè)置相應(yīng)的調(diào)保措施可以解決引水系統(tǒng)壓力與轉(zhuǎn)速上升的矛盾,以保證引水系統(tǒng)的安全和電站穩(wěn)定安全運(yùn)行。
(1)調(diào)壓井(塔、室)
常規(guī)的電站多采用設(shè)置調(diào)壓井來解決電站調(diào)保的問題,調(diào)壓井具有安全可靠等優(yōu)點(diǎn)。大河沿渠首電站受地形條件限制,引水系統(tǒng)沒有深覆蓋的山體,管道采用淺埋布置。如設(shè)置調(diào)壓井,技術(shù)難度大、工程造價(jià)高、工期長。
(2)調(diào)壓閥
調(diào)壓閥多應(yīng)用在中、小型中、高水頭電站,具有技術(shù)成熟、應(yīng)用廣泛、工程造價(jià)低、節(jié)省工期等多項(xiàng)優(yōu)點(diǎn)。
(3)水阻抗器
當(dāng)機(jī)組甩負(fù)荷時(shí),有功功率消失的同時(shí),由啟動(dòng)元件投入水阻抗作為機(jī)組的假負(fù)荷,將多余的電能經(jīng)水阻抗消耗。當(dāng)機(jī)組帶上水阻抗負(fù)荷穩(wěn)定后,逐步切除水阻抗的功率而正常停機(jī),從而保證壓力上升和轉(zhuǎn)速上升均在允許范圍內(nèi)。
該技術(shù)穩(wěn)定可靠性差、安全保證要求高。
(4)安全閥-爆破膜裝置
當(dāng)機(jī)組急速關(guān)閉,壓力鋼管產(chǎn)生水錘,壓力上升超過爆破膜的整定值時(shí),安全閥開啟,泄放管道中的水流,消減水錘壓力,并允許機(jī)組在較短時(shí)間內(nèi)關(guān)機(jī),進(jìn)而限制機(jī)組轉(zhuǎn)速上升。
該技術(shù)對(duì)爆破膜的性能要求高,爆破膜需常更換,水工布置要設(shè)置消能和泄水措施。
通過對(duì)調(diào)壓井(塔、室)、調(diào)壓閥、水阻抗器、安全閥-爆破膜裝置調(diào)保措施的對(duì)比(從技術(shù)、安全可靠、經(jīng)濟(jì)等方面),大河沿渠首電站選擇了調(diào)壓閥做為調(diào)保措施。
(1)設(shè)置調(diào)壓閥情況下水力過渡過程數(shù)值理論計(jì)算結(jié)論
調(diào)壓閥推薦采用的閥徑0.3m,建議機(jī)組-調(diào)壓閥9s一段直線聯(lián)動(dòng)啟閉,調(diào)壓閥保持最大開度10s后再以180s一段直線關(guān)閉。
(2)調(diào)壓閥結(jié)構(gòu)
旋流消能調(diào)壓閥由閥蓋、閥桿、閥體、導(dǎo)流筒、閥瓣、進(jìn)水偏心導(dǎo)流體以及出水旋流消能體、出水錐管和液壓缸組成(見圖1)。采用進(jìn)水分流、出水旋流消能的結(jié)構(gòu)形式。該閥結(jié)構(gòu)緊湊、外形尺寸大大減小,節(jié)省了安裝空間,消能性能得到有效提高。
(3)工作原理
旋流消能調(diào)壓閥主油缸用于操作閥瓣的開關(guān),其筒體為鑄鋼件,內(nèi)有活塞,從機(jī)組調(diào)速器來的油源分別接入主油缸活塞的前、后兩腔。當(dāng)機(jī)組正常工作時(shí),壓力油通在關(guān)閉腔,使調(diào)壓閥處于關(guān)閉狀態(tài);當(dāng)機(jī)組緊急停機(jī)或瞬間甩負(fù)荷超過3%時(shí),壓力油則自動(dòng)通到開啟腔,拉動(dòng)閥桿連接的導(dǎo)流筒和閥瓣作軸向運(yùn)動(dòng),使調(diào)壓閥打開,泄出設(shè)定大小的水流以確保機(jī)組及壓力管道的安全。
在調(diào)壓閥入口處設(shè)置偏心導(dǎo)流體,出口處設(shè)置旋流消能體。偏心導(dǎo)流體主要功能為引導(dǎo)大多數(shù)介質(zhì)往閥體上方流動(dòng),借助流體對(duì)閥體內(nèi)腔沖擊進(jìn)行消能。旋流消能體是由多片導(dǎo)流葉片組成的螺旋結(jié)構(gòu),作用是將閥門進(jìn)口噴入的高速不規(guī)則水流鎮(zhèn)流、改變成旋轉(zhuǎn)流態(tài),并在過程中消能,然后通過出水錐管進(jìn)一部消能,使進(jìn)人尾水池的介質(zhì)沖擊力大大降低,保證電站安全。
(4)系統(tǒng)控制原理
本閥為全油壓控制水輪機(jī)調(diào)壓閥:當(dāng)機(jī)組轉(zhuǎn)速變化低于3%時(shí),主配閥活塞的行程位移小于2mm,此時(shí)導(dǎo)葉接力器的開度作微動(dòng)調(diào)節(jié),調(diào)壓閥處于關(guān)閉狀態(tài),僅導(dǎo)葉動(dòng)作;當(dāng)機(jī)組轉(zhuǎn)速變化高于3%時(shí),特殊主配壓閥的活塞動(dòng)作超過2mm,讓調(diào)壓閥接力器的開啟腔進(jìn)壓力油快速開啟,同時(shí),調(diào)壓閥接力器關(guān)閉腔排出的油進(jìn)入到導(dǎo)葉接力器的關(guān)閉腔,使導(dǎo)葉接力器快速關(guān)閉,調(diào)壓閥與導(dǎo)葉聯(lián)動(dòng),當(dāng)機(jī)組轉(zhuǎn)速上升時(shí),達(dá)到控制水壓上升值的目的。
現(xiàn)場按照理論計(jì)算值機(jī)組-調(diào)壓閥9s一段直線聯(lián)動(dòng)啟閉,調(diào)壓閥保持最大開度10s后再以180s一段直線關(guān)閉進(jìn)行調(diào)試。發(fā)現(xiàn)調(diào)速器控制存在缺陷,不能保持調(diào)壓閥在最大開度持續(xù)10s。經(jīng)多方討論研究后,將調(diào)壓閥180s一段直線關(guān)閉時(shí)間調(diào)整為220s。
大河沿渠首電站經(jīng)過一年多的運(yùn)行,機(jī)組和發(fā)電引水系統(tǒng)運(yùn)行穩(wěn)定,達(dá)到了設(shè)計(jì)預(yù)期效果。
“以閥代井”技術(shù)在大河沿渠首水電站成功應(yīng)用,為中、小型水電站長距離引水管道建設(shè)提供了一種可靠、經(jīng)濟(jì)的解決方案,為今后國內(nèi)外中、小型電站的設(shè)計(jì)提供一定的借鑒參考。
參考文獻(xiàn):
[1]周泰經(jīng),吳應(yīng)文,等.水輪機(jī)調(diào)速器實(shí)用技術(shù)[M].北京:中國水利水電出版社,2010.
Abstract: The experiment, CFD analysis, optimization design and simulation are conducted to overcome the defects of noise and cavitation when the ZJY46H high pressure reducing valve works at Sinkiang hydropower station. The investigation results show that the noise and cavitation characteristics of the high pressure reducing valve at hydropower station water system are reduced; the performance of the hydropower station water system is improved.
Key words: high pressure reducing valve; noise; cavitation; experiment; simulation
中圖分類號(hào):TV734
文獻(xiàn)標(biāo)識(shí)碼:B
文章編號(hào):1672-5387(2015)03-0069-02
DOI:10.13599/j.cnki.11-5130.2015.03.020
收稿日期:2014-12-22
作者簡介:安剛(1975-),男,高級(jí)工程師,從事水電站水力機(jī)械設(shè)計(jì)工作。
Instability phenomenon of turbine regulating system for power primary frequency control
KONG Zhao-nian1, TIAN Zhong-lu1, YANG Yuan-sheng2, WANG Si-wen2
(1. China Institute of Water Resources and Hydropower Research, Beijing 100048, China; 2. Tianjin Research Institute of Electric Science, Tianjin 300301, China)
Abstract:In China, the Twof middle-small scale hydropower station under construction has reached to 15 s to 25 s, so it is necessary to study the characteristics of the hydraulic turbine regulating system for primary frequency control. In the present paper, the results reveal that the unstable states and frequency control forms of the primary frequency control aiming at power are all closely related to the Tw. The improved primary frequency control aiming at servomotor opening is proposed.
Key words:regulating system for hydroturbine; primary frequency control (PFC); power control; instability phenomenon; opening control; guide vane servomotor
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(Central China Division of the State Grid Corporation, Wuhan 430077, China)
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Key words: hydropower unit; shaft turning; swing; calculation method; 4-points shaft turning method
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ZHOU Kun1, WANG Ji-kang2, ZHANG Rong3
(1. Taian Pumped Storage Hydropower Station of State Grid Xinyuan Co., LTD., Taian 27100, China; 2. State Grid Xinyuan Co., LTD., Beijing 100761, China; 3. Baoding Sinosimu Technology Co., LTD., Baoding 071051, China)
Abstract: The running principle of static frequency converter for pumped storage hydropower station unit is introduced in the present paper. On the basis of star90 graphical simulation platform, the mathematical model of static frequency converter is established, and the real-time dynamic model of power generator under control of static variable frequency and speed regulation systems is verified.
Key words: pumped storage hydropower station; static frequency converter; simulation
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LEI Liang
(Tianjin Institute of Hydroelectric and Power Research, Tianjin 301900, China)
Abstract: The establishment of communication protocol development for the hydroturbine intergraded control unit on Linux platform is clarified, and the program is executed.
Key words: serial port; Linux; Java; control unit
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LI Xiang-bo
(Xinjiang Ili River Basin Development and Construction Administration, Urumchi 830000, China)