白鹤滩水电站：在金沙江上铸就“国家名片”

文：《科技日报》 付丽丽

白鹤滩水电站 Baihetan Hydropower Station

白鹤滩水电站投入使用后，每年平均发电量约为624.43 亿千瓦时，一天的发电量可满足50 万人一年的生活用电。每年可节约标准煤约2500 万吨，减排约6500 万吨二氧化碳、60 万吨二氧化硫，相当于少建近6 座年产400万吨的大型煤矿。

截至2 月17 日，白鹤滩水电站累计安全生产绿色电能200 亿千瓦时，相当于减少标准煤消耗624 万吨，减少二氧化碳排放1602 万吨。前不久，白鹤滩水电站交出亮丽的成绩单。

国产机组单机容量100 万千瓦，世界第一；总装机容量1600 万千瓦，仅次于三峡水电站，位居世界第二。2021 年6 月28 日，白鹤滩水电站首批机组正式投产发电。

在川滇两省交界的金沙江上，白鹤滩与其上游的乌东德，下游的溪洛渡、向家坝、三峡、葛洲坝水电站共同构成一条世界上最大的清洁能源走廊。

世界首台最大的百万千瓦水轮机组、世界最大的地下厂房、世界“最聪明”的智能大坝……大国重器白鹤滩水电站实现了多个世界之最。这背后，是中国几代水电人几十年如一日的不懈探索，他们一步一个脚印，用行动书写出中国水电装备由并跑向领跑冲刺的神话。

特种水泥解决“无坝不裂”难题

坝高289 米，相当于100 层楼高，整体浇筑低热混凝土803 万立方米，体积超过3 个胡夫金字塔——从外形看，白鹤滩水电站绝对是个大块头。

2021 年5 月29 日，白鹤滩水电站大坝最后一仓溢流面混凝土浇筑完成，这标志着大坝表孔已具备过流条件。

白鹤滩水电站处于V 型河谷，两岸悬崖峭壁，复杂的地质条件决定其只能采用混凝土双曲拱坝，以使受力更科学，同时节省坝体材料，提高安全性。

在业界，“无坝不裂”是横亘在水电站建设过程中的世界级难题。白鹤滩水电站尤其如此。规模巨大，坝体结构不对称，加上持续的干热、大风天气，导致温控难度极大。

为此，科研人员研制出特种水泥——低热硅酸盐水泥，也叫低热水泥。它具有水化热低、放热速率慢、碱含量低、后期强度增进率高等优良性能，为解决大体积混凝土开裂问题提供了更好的技术途径。同时，在每一处浇筑的混凝土中，都埋设有数支温度传感器和循环冷却水管，可以实时监测混凝土内部的温升，并进行有针对性的降温。

自开浇以来，白鹤滩水电站大坝没有出现一条温度裂缝。2019 年，在钻孔取芯质量检查过程中，技术人员从大坝取出25.7 米混凝土长芯，混凝土芯样光滑密实、骨料分布均匀、气泡少。这样一份高质量混凝土浇筑施工成绩单的背后，是建设者对大国重器质量细节的精准把控。

鸟瞰白鹤滩水电站Aerial view of Baihetan Hydropower Station

“最强大脑”提升工程效率

从长江到金沙江，三峡集团组织创新“300 米级溪洛渡拱坝智能化建设关键技术”，开创了中国智能高拱坝建设的先河。

白鹤滩水电站进一步借助物联网、云计算以及大数据等技术，向建设管理智能化又迈出了一大步。

在白鹤滩工程建设部技术管理部副主任周孟夏看来，手机中安装的智能通水系统和施工过程智能监控系统，是他最亲密的“工作伙伴”。

“大坝施工中，混凝土温度控制的主要手段是冷却通水。按照规范，至少每4 个小时就要对所有仓号进行一次测温，需要投入大量的人员手工操作，对大坝温度情况掌握也比较滞后。”

如今，智能通水系统不仅能实时感知温度，还可以自主分析温度变化趋势，按照预设的控制算法进行自动调控。在降低人工作业强度的同时，极大提升了工程效率与温控精度。

“这个‘最强大脑’还可以积累工程实践数据，通过大数据分析完善预设的经验算法，进行部分自主决策，进而实现现场快速响应。如此一来，工程师便能从大量日常管理工作中解放出来，仅在数据异常时纠编处理即可，管理效率随之提高。”周孟夏介绍。

“最强大脑”高效整合物质流与数据流，为精细化施工创造了更大的空间。

“以混凝土振捣为例，振捣几遍，振捣棒型号如何选择，初振多久，复振多久，这些专业试验的参数，都会印成标准化工艺手册，用以培训员工。”白鹤滩工程建设部大坝项目部工程师刘春风介绍。

如今，这些标准被“翻译”成代码进入智能系统，智能系统实时分析振捣棒的覆盖范围、插入深度、振捣时长等数据是否“合格”，让施工质量不再仅靠人工肉眼观察和经验判断，而是“数”说了算。

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

勇登水电行业“珠穆朗玛峰”

100 万千瓦巨型水轮发电机组，是世界水电行业的“珠穆朗玛峰”。白鹤滩水电站机组是全球单机容量最大的水电机组，也是中国自主设计制造的完全国产化百万千瓦机组，研制与安装难度远大于世界在建和已投运的任何机组。

在白鹤滩建水电站的设想始于20 世纪五十年代。当时，在研讨白鹤滩水电站机组单机容量的时候，为稳妥起见，有专家提出采用两台100 万千瓦机组，其余机组采用80 万千瓦的方案。最终决定16 台机组全部用国产百万千瓦水轮发电机组，是在2006 年。

对于选择100 万千瓦机组，白鹤滩工程建设部主任汪志林是这样解释的，其一是具备建设能力，其二是客观要求。白鹤滩两岸均为雄厚山体，复杂地质条件已带来一系列世界级难题。在枢纽建筑工程布置上，单机容量越大，机组台数就越少，地下洞室群、地下厂房的规模将更趋合理，稳定性安全性也会更好。其三是资源禀赋，金沙江干流落差大，水流湍急，白鹤滩水电站是高坝大库，水头高达200 多米，从水能利用率来看，可以满足1600 万千瓦的总装机容量。而最重要的一条是，中国现代化经济社会发展需要与之相适应的大规模清洁电能的支撑，白鹤滩水电站是国家重大工程，是西电东送骨干电源点，远景发展电力的需要为其提出更高要求。

“水电是清洁能源的主力军。而白鹤滩水电站即将加入中国清洁能源的主力阵容，备受关注。”中国科学院院士钱七虎说，电站建设本身亦是对蓝天的守护，对人类可持续发展有重要意义。

在保护中发展、在发展中保护。助力实现“碳达峰、碳中和”目标，中国水电人正在持续书写生态文明的新时代答卷。

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.

白鹤滩水电站单机容量位居世界第一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.