白鶴灘水電站：在金沙江上鑄就“國(guó)家名片”

文：《科技日?qǐng)?bào)》 付麗麗

白鶴灘水電站 Baihetan Hydropower Station

白鶴灘水電站投入使用后，每年平均發(fā)電量約為624.43 億千瓦時(shí)，一天的發(fā)電量可滿(mǎn)足50 萬(wàn)人一年的生活用電。每年可節(jié)約標(biāo)準(zhǔn)煤約2500 萬(wàn)噸，減排約6500 萬(wàn)噸二氧化碳、60 萬(wàn)噸二氧化硫，相當(dāng)于少建近6 座年產(chǎn)400萬(wàn)噸的大型煤礦。

截至2 月17 日，白鶴灘水電站累計(jì)安全生產(chǎn)綠色電能200 億千瓦時(shí)，相當(dāng)于減少標(biāo)準(zhǔn)煤消耗624 萬(wàn)噸，減少二氧化碳排放1602 萬(wàn)噸。前不久，白鶴灘水電站交出亮麗的成績(jī)單。

國(guó)產(chǎn)機(jī)組單機(jī)容量100 萬(wàn)千瓦，世界第一；總裝機(jī)容量1600 萬(wàn)千瓦，僅次于三峽水電站，位居世界第二。2021 年6 月28 日，白鶴灘水電站首批機(jī)組正式投產(chǎn)發(fā)電。

在川滇兩省交界的金沙江上，白鶴灘與其上游的烏東德，下游的溪洛渡、向家壩、三峽、葛洲壩水電站共同構(gòu)成一條世界上最大的清潔能源走廊。

世界首臺(tái)最大的百萬(wàn)千瓦水輪機(jī)組、世界最大的地下廠房、世界“最聰明”的智能大壩……大國(guó)重器白鶴灘水電站實(shí)現(xiàn)了多個(gè)世界之最。這背后，是中國(guó)幾代水電人幾十年如一日的不懈探索，他們一步一個(gè)腳印，用行動(dòng)書(shū)寫(xiě)出中國(guó)水電裝備由并跑向領(lǐng)跑沖刺的神話。

特種水泥解決“無(wú)壩不裂”難題

壩高289 米，相當(dāng)于100 層樓高，整體澆筑低熱混凝土803 萬(wàn)立方米，體積超過(guò)3 個(gè)胡夫金字塔——從外形看，白鶴灘水電站絕對(duì)是個(gè)大塊頭。

2021 年5 月29 日，白鶴灘水電站大壩最后一倉(cāng)溢流面混凝土澆筑完成，這標(biāo)志著大壩表孔已具備過(guò)流條件。

白鶴灘水電站處于V 型河谷，兩岸懸崖峭壁，復(fù)雜的地質(zhì)條件決定其只能采用混凝土雙曲拱壩，以使受力更科學(xué)，同時(shí)節(jié)省壩體材料，提高安全性。

在業(yè)界，“無(wú)壩不裂”是橫亙?cè)谒娬窘ㄔO(shè)過(guò)程中的世界級(jí)難題。白鶴灘水電站尤其如此。規(guī)模巨大，壩體結(jié)構(gòu)不對(duì)稱(chēng)，加上持續(xù)的干熱、大風(fēng)天氣，導(dǎo)致溫控難度極大。

為此，科研人員研制出特種水泥——低熱硅酸鹽水泥，也叫低熱水泥。它具有水化熱低、放熱速率慢、堿含量低、后期強(qiáng)度增進(jìn)率高等優(yōu)良性能，為解決大體積混凝土開(kāi)裂問(wèn)題提供了更好的技術(shù)途徑。同時(shí)，在每一處澆筑的混凝土中，都埋設(shè)有數(shù)支溫度傳感器和循環(huán)冷卻水管，可以實(shí)時(shí)監(jiān)測(cè)混凝土內(nèi)部的溫升，并進(jìn)行有針對(duì)性的降溫。

自開(kāi)澆以來(lái)，白鶴灘水電站大壩沒(méi)有出現(xiàn)一條溫度裂縫。2019 年，在鉆孔取芯質(zhì)量檢查過(guò)程中，技術(shù)人員從大壩取出25.7 米混凝土長(zhǎng)芯，混凝土芯樣光滑密實(shí)、骨料分布均勻、氣泡少。這樣一份高質(zhì)量混凝土澆筑施工成績(jī)單的背后，是建設(shè)者對(duì)大國(guó)重器質(zhì)量細(xì)節(jié)的精準(zhǔn)把控。

鳥(niǎo)瞰白鶴灘水電站Aerial view of Baihetan Hydropower Station

“最強(qiáng)大腦”提升工程效率

從長(zhǎng)江到金沙江，三峽集團(tuán)組織創(chuàng)新“300 米級(jí)溪洛渡拱壩智能化建設(shè)關(guān)鍵技術(shù)”，開(kāi)創(chuàng)了中國(guó)智能高拱壩建設(shè)的先河。

白鶴灘水電站進(jìn)一步借助物聯(lián)網(wǎng)、云計(jì)算以及大數(shù)據(jù)等技術(shù)，向建設(shè)管理智能化又邁出了一大步。

在白鶴灘工程建設(shè)部技術(shù)管理部副主任周孟夏看來(lái)，手機(jī)中安裝的智能通水系統(tǒng)和施工過(guò)程智能監(jiān)控系統(tǒng)，是他最親密的“工作伙伴”。

“大壩施工中，混凝土溫度控制的主要手段是冷卻通水。按照規(guī)范，至少每4 個(gè)小時(shí)就要對(duì)所有倉(cāng)號(hào)進(jìn)行一次測(cè)溫，需要投入大量的人員手工操作，對(duì)大壩溫度情況掌握也比較滯后?！?/p>

如今，智能通水系統(tǒng)不僅能實(shí)時(shí)感知溫度，還可以自主分析溫度變化趨勢(shì)，按照預(yù)設(shè)的控制算法進(jìn)行自動(dòng)調(diào)控。在降低人工作業(yè)強(qiáng)度的同時(shí)，極大提升了工程效率與溫控精度。

“這個(gè)‘最強(qiáng)大腦’還可以積累工程實(shí)踐數(shù)據(jù)，通過(guò)大數(shù)據(jù)分析完善預(yù)設(shè)的經(jīng)驗(yàn)算法，進(jìn)行部分自主決策，進(jìn)而實(shí)現(xiàn)現(xiàn)場(chǎng)快速響應(yīng)。如此一來(lái)，工程師便能從大量日常管理工作中解放出來(lái)，僅在數(shù)據(jù)異常時(shí)糾編處理即可，管理效率隨之提高?！敝苊舷慕榻B。

“最強(qiáng)大腦”高效整合物質(zhì)流與數(shù)據(jù)流，為精細(xì)化施工創(chuàng)造了更大的空間。

“以混凝土振搗為例，振搗幾遍，振搗棒型號(hào)如何選擇，初振多久，復(fù)振多久，這些專(zhuān)業(yè)試驗(yàn)的參數(shù)，都會(huì)印成標(biāo)準(zhǔn)化工藝手冊(cè)，用以培訓(xùn)員工。”白鶴灘工程建設(shè)部大壩項(xiàng)目部工程師劉春風(fēng)介紹。

如今，這些標(biāo)準(zhǔn)被“翻譯”成代碼進(jìn)入智能系統(tǒng)，智能系統(tǒng)實(shí)時(shí)分析振搗棒的覆蓋范圍、插入深度、振搗時(shí)長(zhǎng)等數(shù)據(jù)是否“合格”，讓施工質(zhì)量不再僅靠人工肉眼觀察和經(jīng)驗(yàn)判斷，而是“數(shù)”說(shuō)了算。

工人在焊接施工A worker is carrying out welding

勇登水電行業(yè)“珠穆朗瑪峰”

100 萬(wàn)千瓦巨型水輪發(fā)電機(jī)組，是世界水電行業(yè)的“珠穆朗瑪峰”。白鶴灘水電站機(jī)組是全球單機(jī)容量最大的水電機(jī)組，也是中國(guó)自主設(shè)計(jì)制造的完全國(guó)產(chǎn)化百萬(wàn)千瓦機(jī)組，研制與安裝難度遠(yuǎn)大于世界在建和已投運(yùn)的任何機(jī)組。

在白鶴灘建水電站的設(shè)想始于20 世紀(jì)五十年代。當(dāng)時(shí)，在研討白鶴灘水電站機(jī)組單機(jī)容量的時(shí)候，為穩(wěn)妥起見(jiàn)，有專(zhuān)家提出采用兩臺(tái)100 萬(wàn)千瓦機(jī)組，其余機(jī)組采用80 萬(wàn)千瓦的方案。最終決定16 臺(tái)機(jī)組全部用國(guó)產(chǎn)百萬(wàn)千瓦水輪發(fā)電機(jī)組，是在2006 年。

對(duì)于選擇100 萬(wàn)千瓦機(jī)組，白鶴灘工程建設(shè)部主任汪志林是這樣解釋的，其一是具備建設(shè)能力，其二是客觀要求。白鶴灘兩岸均為雄厚山體，復(fù)雜地質(zhì)條件已帶來(lái)一系列世界級(jí)難題。在樞紐建筑工程布置上，單機(jī)容量越大，機(jī)組臺(tái)數(shù)就越少，地下洞室群、地下廠房的規(guī)模將更趨合理，穩(wěn)定性安全性也會(huì)更好。其三是資源稟賦，金沙江干流落差大，水流湍急，白鶴灘水電站是高壩大庫(kù)，水頭高達(dá)200 多米，從水能利用率來(lái)看，可以滿(mǎn)足1600 萬(wàn)千瓦的總裝機(jī)容量。而最重要的一條是，中國(guó)現(xiàn)代化經(jīng)濟(jì)社會(huì)發(fā)展需要與之相適應(yīng)的大規(guī)模清潔電能的支撐，白鶴灘水電站是國(guó)家重大工程，是西電東送骨干電源點(diǎn)，遠(yuǎn)景發(fā)展電力的需要為其提出更高要求。

“水電是清潔能源的主力軍。而白鶴灘水電站即將加入中國(guó)清潔能源的主力陣容，備受關(guān)注。”中國(guó)科學(xué)院院士錢(qián)七虎說(shuō)，電站建設(shè)本身亦是對(duì)藍(lán)天的守護(hù)，對(duì)人類(lèi)可持續(xù)發(fā)展有重要意義。

在保護(hù)中發(fā)展、在發(fā)展中保護(hù)。助力實(shí)現(xiàn)“碳達(dá)峰、碳中和”目標(biāo)，中國(guó)水電人正在持續(xù)書(shū)寫(xiě)生態(tài)文明的新時(shí)代答卷。

After being put into operation, the Baihetan Hydropower Station will generate an average of 62.443 billion kWh of electricity per year, and the electricity it generates per day can meet the annual consumption demands of 500,000 people. It can save about 25 million tons of standard coal, reduce carbon dioxide emissions by about 65 million tons and sulfur dioxide emissions by 600,000 tons every year, which is equivalent to reducing nearly six large coal mines with an annual output of 4 million tons.

A total of 20 billion kWh of green electricity has been safely produced till Feb.17 by Baihetan Hydropower Station, equivalent to reducing standard coal consumption by 6.24 million tons and carbon dioxide emissions by 16.02 million tons. Not long ago, the Baihetan Hydropower Station set multiple world records.

Using domestically produced generating units with a unit capacity of 1 million kW, it ranks first in the world.With a total installed capacity of 16 million kW, it ranks second only to the Three Gorges Hydropower Station in the world. On June 28, 2021, the first units of Baihetan Hydropower Station were put into operation.

On the Jinsha River at the junction of Sichuan and Yunnan provinces, Baihetan has established the world’s largest clean energy corridor, together with upstream Wudongde and downstream Xiluodu,Xiangjiaba, Three Gorges and Gezhouba hydropower stations.

As a pillar of a great nation, the Baihetan Hydropower Station has set multiple world records, including the world’s first and largest million-kWclass hydro-generator unit, the world’s largest underground plant, and the world’s “smartest” intelligent dam.These outcomes should be credited to the decades of unremitting exploration of Chinese builders. Step by step, they have developed cutting-edge hydropower equipment, propelling China into a leading position.

白鶴灘水電站單機(jī)容量位居世界第一The Baihetan Hydropower Station has the world’s largest unit capacity

Special cement solves the problem of “no dam without cracks”

The dam is 289 meters high,equivalent to a 100-story building.With a total volume of 8.03 million cubic meters of low-heat concrete, the Baihetan Hydropower Station is more than three times the size of the Great Pyramid of Khufu.

On May 29, 2021, concreting of the overflow surface was completed, which indicated that the surface outlets of the dam were ready for flood discharge.

The Baihetan Hydropower Station is located in a V-shaped river valley with cliffs on both sides. Due to the complex geological conditions, it can only use a double-curvature arch dam made of concrete to scientifically disperse the stress, save building materials and improve safety.

As the saying goes, “there is no dam without cracks.” Dam cracking is a universal problem in the construction of hydropower stations. This is especially true of the Baihetan Hydropower Station. The large scale and asymmetric structure of the dam, coupled with the continuous dry heat and strong winds,made temperature control extremely difficult.

To address this problem, researchers developed a special cement — low-heat Portland cement, also known as lowheat cement. It has the advantages of low hydration heat, low heat release rate, low alkali content and high growth rate of later strength, which provides a better technical approach to solving the cracking problem of mass concrete. Moreover, in the concrete poured in each place,several temperature sensors and circulating cooling water pipes are embedded to monitor the temperature rise inside the concrete in real time and conduct targeted cooling.

Not a single temperature crack has appeared in the dam since concreting. In 2019, a 25.7-meter-long concrete core sample was taken out of the dam during the quality inspection of core drilling. The core sample was smooth and dense,with uniform aggregate distribution and few air bubbles.Such a high-quality concreting construction is a result of the builders’ solid efforts in quality control.

“Superbrain” improves project efficiency

From the Yangtze River to the Jinsha River, the China Three Gorges Corporation has made innovations in “key technologies for the intelligent construction of the 300-meterhigh Xiluodu arch dam” to build the first intelligent high arch dam in China.

The Baihetan Hydropower Station has further taken a big step towards intelligent construction management with the help of such technologies as the Internet of Things, cloud computing and big data.

According to Zhou Mengxia, Deputy Director of the Technical Management Office of Baihetan Project Construction Department, the intelligent water supply system and the intelligent monitoring system for the construction process installed in his phone are his best “working partners”.

“During the construction of the dam, cooling water is the main approach to controlling the concrete temperature.According to the regulations, temperature measurements should be carried out at least every four hours at all warehouses,which requires a large number of manual operations and has the problem of slow information transfer of dam temperatures.”

Nowadays, the intelligent water supply system can not only sense the temperature in real time, but also analyze the temperature change trend and adjust the temperature automatically according to the preset control algorithm. In addition to reducing manual operations, the project efficiency and temperature control accuracy are greatly improved.

“This ‘Superbrain’ can also accumulate project practice data,improve preset empirical algorithms through big data analysis,conduct autonomous decision-making to some extent, and achieve rapid on-site response. This frees engineers from a load of daily management work. They only need to make corrections when there is a data anomaly. In this way, the management efficiency is improved.” Zhou Mengxia introduced.

This “Superbrain” efficiently integrates material flow and data flow, creating more space for lean construction.

“Taking concrete vibrating as an example, the parameters about how many times to vibrate, how to choose the type of vibrating rod, how long it takes for initial vibration, and how long for re-vibration will be included in a standardized process manual used for training employees.” Liu Chunfeng, Engineer of the Dam Project Office of the Baihetan Project Construction Department, introduced.

Now, these standards are “translated” into codes and entered into the intelligent system. The intelligent system can analyze in real time whether the coverage of the vibrator, the insertion depth,vibrating duration and other data “meet the standards”, so that the construction quality is no longer judged by manual observation and experience, but the real data.

Conquering the “Mount Everest” in the hydropower industry

The 1-million-kW capacity hydro-generator unit is dubbed as the “Mount Everest” in the hydropower industry. The Baihetan Hydropower Station has the world’s first and largest million-kW-class hydro-generator unit, which is designed and manufactured by China. The development and installation of such a generator unit is much more difficult than any other generator units under construction or in operation in the world.

The idea of building a hydropower station in Baihetan was put forward in the 1950s. When discussing the unit capacity of Baihetan Hydropower Station, for the sake of safety, some experts proposed to use two 1 million-kW generator units and some 800,000-kW generator units. The final decision was made in 2006 to use 16 homemade million-kW-class hydro-generator units.

Wang Zhilin, Director of the Baihetan Project Construction Department, explained that the decision on the 1 million-kW hydro-generator unit is based on the construction ability and objective demands. The complex and mountainous geological conditions on both riversides of Baihetan have brought a series of bugbears to the project. In the layout of major buildings, the large unit capacity will contribute to a smaller number of units, a more appropriate size of underground caverns and plants,and stronger stability and safety. In terms of resource endowment, the main stream of the Jinsha River has a large drop and rapid water flow. The Baihetan Hydropower Station has a high dam and a huge reservoir, with a water head of more than 200 meters. From the perspective of hydro-energy utilization efficiency, it has a total installed capacity of 16 million kW.

Most importantly, China’s modern economic and social development requires the support of large-scale clean electricity generation projects that are compatible with it. The nationalclass project of Baihetan Hydropower Station serves as a key power source of the West-to-East Power Transmission Project, and meets the high demands of long-term electricity development.

“Hydropower is an integral part of clean energy. The Baihetan Hydropower Station will soon join the main force of developing clean energy in China, and it has garnered much attention.” Qian Qihu,an academician of the Chinese Academy of Sciences, said that the construction of the power station represents an effort to protect our environment and to realize the sustainable development.