设调压室水电站负荷扰动下机组频率波动研究

Generator unit frequency fluctuations of hydropower station with surge tank under load disturbance

通过研究设调压室水电站负荷扰动下机组频率波动过程,推导出机组频率尾波波动方程及其调节时间的计算式,并通过数值计算算例进行了验证。最后分析了调速器参数、调压室面积和负载自调节系数对机组频率尾波波动过程的影响。研究结果表明：机组频率尾波波动周期与调压室水位波动理论周期基本一致,且主要与调压室面积有关;对于机组频率尾波相角的变化范围,突增负荷工况时在π/2-3π/2之间,突减负荷工况时在-π/2-π/2之间;增大调速器参数,机组频率尾波波动的振幅和阻尼比同时增大;负载自调节系数有利于波动的衰减,增大负载自调节系数和调压室面积均能减小系统的调节时间。

Based on the analysis on the process of generator unit frequency fluctuation in hydropower station with surge tank, the stem wave equation of the frequency and formula for calculating the regulating time are derived. The validity of the equation and formula is verified by the numerical calculation result of an example. The influences of governor parameters, cross section of surge tank and load self- regulation coefficient on frequency fluctuations are studied. The results show that the wave cycle of unit＇ s frequency stern wave accord with swell level fluctuation cycle in surge tank, and the main related factor is the cross- section of surge tank. The wave phase are in the range between π/2 to 3π/2 under the condition of sudden load-up operation, and the range is - π/2 to π/2 under the condition of sudden load-down operation. With the increase of governor parameters, the wave amplitude and damping ratio of stern wave of generator frequency increase at the same time. Load self-regulation is in favor of the attenuation of wave, regulating time of stern wave will diminish if increasing the load self-regulation and cross-section of surge tank.