水电工程基础
一、水电基础概念 | Hydropower Fundamentals
二、水电站类型 | Types of Hydropower Plants
三、水轮机 | Hydraulic Turbines
四、发电机与电气 | Generator & Electrical
五、水工建筑物 | Hydraulic Structures
Hydropower Plant Design — Turbine Selection and Layout
Chang, the feasibility study for the Rio Grande project has identified a gross head of 192 meters and a design flow of 120 m³/s. The hydrology study gives a firm flow of 45 m³/s in the dry season and up to 350 m³/s during the monsoon. What's your preliminary plant configuration?
常工，Rio Grande项目的可行性研究确定了总水头192米、设计流量120 m³/s。水文研究给出旱季保证流量45 m³/s、雨季高达350 m³/s。初步电站 配置是什么？
常工: Based on these parameters, I'm recommending a diversion-type layout with a Francis turbine configuration. The net head after head losses in the tunnel and penstock will be about 180 meters — that's right in the sweet spot for Francis turbines which cover heads from 30 to 600 meters.
基于这些参数，我建议引水式布置配混流式水轮机。扣除隧洞和压力钢管 水头损失后净水头约180米——正好是混流式的最佳区间，它覆盖30到600米的 水头。
What specific turbine configuration are you thinking?
你在考虑什么具体的水轮机配置？
常工: With 180 meters net head and 120 m³/s design flow, the theoretical power is P = 9.81 × 180 × 120 × 0.92 ≈ 195 MW. I'd propose three units of 65 MW each — that's 195 MW total installed. The Francis turbines would have a specific speed of about 80, runner diameter approximately 2.4 meters, and a synchronous speed of 600 rpm for a 60 Hz system.
180米净水头、120 m³/s设计流量下，理论功率 P = 9.81 × 180 × 120 × 0.92 ≈ 195 MW。建议3台65 MW——总装机195 MW。混流式水轮机比转速约 80、转轮直径约2.4米、60 Hz系统同步转速600 rpm。
During the dry season with only 45 m³/s firm flow, we'd run one unit at partial load — the Francis turbine can operate efficiently from about 50% to 100% load. Below 50% we'd shut down a second unit. During monsoon, all three units run at full load plus we spill the excess through the spillway.
旱季只有45 m³/s保证流量时，一台机带部分负荷运行——混流式从约50%到 100%负荷都有不错的效率。低于50%就再停一台。雨季三台全满，多余的通过 溢洪道泄掉。
Walk me through the water conveyance system from the dam to the powerhouse.
从坝到厂房的输水系统给我讲讲。
常工: The dam is a 120-meter high concrete gravity dam creating a reservoir with 850 million m³ of active storage. The intake structure is on the left abutment with a trash rack and emergency gate. From the intake, a 3.5 km headrace tunnel — 8-meter diameter, pressure tunnel with reinforced concrete lining — carries the water to a surge tank.
坝是120米高混凝土重力坝，形成8.5亿m³兴利库容。进水口在左坝肩， 带拦污栅和快速闸门。从进水口起，3.5公里引水隧洞——直径8米、有压隧洞、 钢筋混凝土衬砌——把水引到调压井。
The surge tank is a 20-meter diameter shaft, 85 meters deep, that absorbs water hammer pressure spikes when the turbines change load. From the surge tank, a steel penstock — 5.5 meters diameter, branching into three 3.2-meter diameter branch pipes — feeds the three units. The powerhouse is a surface-type structure 2 km downstream of the dam.
调压井是直径20米、深85米的竖井，吸收水轮机变负荷时的水锤压力波。 从调压井起，钢压力钢管——直径5.5米、分岔成三根直径3.2米的支管——给三 台机组送水。厂房是地面式结构，在大坝下游2公里处。
Turbine Model Test and Performance Guarantees
Gentlemen, we're here to review the turbine model test results from the independent hydraulic laboratory. Dr. Weber, your company is proposing the Francis turbine for this project. Please walk us through the key findings.
各位，我们在这里审查独立水力实验室的水轮机模型试验结果。Weber博士， 你们公司为这个项目投标混流式水轮机。请给我们讲讲关键发现。
Thank you, Rebecca. We conducted the model test at a 1:12 scale at the EPFL hydraulic laboratory in Lausanne. The model runner diameter is 350 mm, tested at a head of 20 meters with a test Reynolds number above 4×10⁶ — well above the IEC 60193 minimum requirement of 2×10⁶.
谢谢Rebecca。我们在洛桑EPFL水力实验室做了1:12模型试验。模型转轮 直径350 mm、试验水头20米、试验雷诺数高于4×10⁶——远在IEC 60193最低 要求2×10⁶之上。
常工: What's the peak efficiency, and at what operating point?
最高效率是多少，在什么运行点？
The model peak efficiency is 93.8% at the optimum operating point of Q11 = 0.72 and n11 = 68. Scaling up to the prototype using the IEC 60193 step-up formula — accounting for the Reynolds number effect — we guarantee a prototype peak efficiency of 95.2%. The weighted average efficiency over the operating range is 94.1%.
模型最高效率93.8%，在最优运行点Q11=0.72、n11=68处。用IEC 60193 效率换算公式放大到原型——考虑雷诺数效应——我们保证原型最高效率95.2%。 全运行范围加权平均效率94.1%。
What about cavitation performance? The sigma of the plant — the Thoma cavitation number — is 0.12 at full load. Does the model show any cavitation at that sigma?
空蚀性能呢？电站的装置空化系数——Thoma空化数——满负荷时是0.12。模 型在这个sigma值下有显示空蚀吗？
Excellent question. Our model test included cavitation observation using high-speed video and acoustic detection. At the plant sigma of 0.12, the model shows incipient cavitation on the suction side of the blades — very minor, within the acceptable band per IEC 60193. We've further optimized the blade profile to push the cavitation inception sigma down to 0.08, giving a healthy margin.
非常好的问题。模型试验包含用高速摄像和声学探测做空蚀观测。在电站 sigma值0.12下，模型显示叶片背面有初生空蚀——很轻微，在IEC 60193容许 范围内。我们又优化了叶片型线，把空蚀初生sigma降到0.08，留有足够的裕 量。
常工: What's the runaway speed, and how does it affect the generator design?
飞逸转速是多少，对发电机设计有什么影响？
The maximum runaway speed measured on the model is 178% of rated speed — about 1,068 rpm for a 600 rpm rated machine. The generator rotor must be designed to withstand this overspeed for 5 minutes without damage per IEC 60034. We've informed the generator manufacturer of this requirement.
模型实测最大飞逸转速是额定的178%——对600 rpm额定机组约1,068 rpm。 发电机转子须按IEC 60034设计承受此超速5分钟无损伤。已将这个要求通知 发电机制造商。
Based on these results, I'm satisfied with the hydraulic performance. Chang, your recommendation?
基于这些结果，我对水力性能满意。常工，你的建议？
常工: The model test demonstrates that the proposed Francis turbine meets all technical specifications — efficiency, cavitation margin, and runaway speed. I recommend we accept the technical proposal and proceed to the commercial negotiation for the turbine-generator supply contract.
模型试验证明了所提混流式水轮机满足所有技术指标——效率、空蚀裕量、 飞逸转速。我建议接受技术方案、进入水轮发电机组供货合同的商务谈判。