水电站电气系统
一、水电站电气基础 | Hydropower Electrical Fundamentals
二、发电机系统 | Generator System
三、励磁系统 | Excitation System
四、厂用电系统 | Station Service Power System
五、保护与监控系统 | Protection & Monitoring
Characters: Electrical Supervisor (电气主管 ES) / Generator Specialist (发电机专家 GS) · Characters: Commissioning Engineer (调试工程师 CE) / Excitation System Engineer (励磁工程师 EE)
The stator is set and grouted, the rotor is lowered and coupled to the turbine shaft. Air gap measurements confirmed — uniform 22 mm around the circumference, well within the ±5% tolerance. Now we need to install the isolated phase bus from the generator terminals to the step-up transformer. What's the IPB specification?
定子就位灌浆、转子吊入与转轮轴连接。气隙测量确认——全周均匀22mm，在±5%允差 内。现在需要安装从发电机端子到升压变的离相封闭母线。IPB规格是什么？
The IPB is rated 18 kV, 11,000 A continuous, with a short-circuit withstand of 160 kA for 2 seconds. Each phase is a separate aluminum tube — 800 mm diameter for the main run, enclosed in a 1,200 mm aluminum housing. Cooling is natural air convection. The joints between sections use flexible copper braids with bolted connections — torque to 85 N·m using a calibrated torque wrench. All joints must be accessible for infrared inspection. After installation, we do a DC resistance test on the complete bus run — the resistance per phase must be within 2% of the calculated value.
IPB额定18kV、持续11000A、短时耐受160kA/2秒。每相独立铝管——主段直径800mm、 外壳铝筒1200mm。自然空冷。段间连接用软铜编织带螺栓连接——扭力扳手85牛·米。 所有接点须红外检测可达。安装后做整段母线直流电阻测试——每相电阻须在计算值的 2%以内。
Understood. We'll also need to install the neutral grounding cubicle with the distribution transformer and secondary resistor. The neutral grounding impedance limits the ground fault current to 15 A — that's the design target to minimize stator core damage. I want to verify the grounding transformer ratio and the resistor value before connecting to the generator neutral. One wrong connection and we risk a catastrophic stator ground fault on the first energization.
明白。还要装中性点接地柜带接地变和二次电阻。中性点接地阻抗限制接地故障 电流至15A——这是设计目标以最小化定子铁芯损伤。接入发电机中性点前要验证接地 变比和电阻值。接错一根线第一次送电就可能造成定子接地灾难。
The static excitation system is installed — the excitation transformer connected to the generator terminals, the thyristor bridge, and the field breaker. Before we run the generator for the first time, we need to test the AVR in open-loop mode. Let's inject a simulated generator voltage and verify the AVR response.
静态励磁系统已安装——励磁变接至发电机端、晶闸管桥和磁场断路器。发电机首次 运行前需要在开环模式测试AVR。注入模拟发电机电压验证AVR响应。
I've set up the test set to simulate the generator voltage at 0%, 50%, 100%, and 110% of rated. For each step, I'll check the firing angle of the thyristors and the field current output. At 100% voltage, the AVR should maintain a firing angle that produces rated field current — 1,250 A DC at 380 V. The important test is the ceiling excitation: when I simulate a sudden voltage drop to 80%, the AVR must respond within 20 ms to drive the field current to the ceiling value of 2,500 A — that's 2.0 per unit field forcing. This is critical for system stability during grid disturbances.
设好测试仪模拟发电机电压0%、50%、100%、110%额定。每步检查晶闸管触发角和 励磁电流输出。100%电压时AVR应维持产生额定励磁电流的触发角——1250A直流/380V。 重要测试是强励：模拟电压骤降到80%时，AVR须在20ms内响应将励磁电流推到顶值 2500A——2.0倍强励。这对电网扰动时的系统稳定至关重要。
Understood. After open-loop tests pass, we'll proceed to the closed-loop test with the generator running at rated speed but not connected to the grid. We'll manually ramp up the field current to build terminal voltage to 100%, then switch the AVR to auto. The AVR should hold voltage within ±0.5% under steady state. Then we test the reactive power control — droop mode for grid-connected operation, and constant voltage mode for islanded operation. The FCR (Field Current Regulator) mode should also be tested as a backup. All AVR limiters — over-excitation, under- excitation, volts-per-hertz — must be verified to trip at the correct settings.
明白。开环测试通过后，做闭环测试：发电机额定转速但未并网。手动升励磁电流 建压到100%、然后切AVR自动。稳态下AVR应保持电压在±0.5%以内。然后测无功控制 ——并网运行用下降特性模式、孤岛运行用恒压模式。FCR（励磁电流调节）模式作为 备用也要测。所有AVR限制器——过励、欠励、伏/赫——须验证在正确定值下动作。