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水轮机调速器性能提高的关键是测频系统,测频精度和实时性是描述测频系统好坏的重要标志.大幅提高水轮机调速器频率测量的可靠性对机组的安全稳定运行起着极大的作用.传统的可编程逻辑控制器(PLC)调速器测频方式由于接口的原因,往往会在精度和实时性上互相矛盾,故PLC测频成为制约调速器发展的瓶颈.针对这种情况,分析了现今比较流行的PLC测频方法,提出了能够保证精度和实时性的PLC测频方法.对基于PLC调速器的直接测周期法以及精度和实时性指标进行了具体分析. 相似文献
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基于PCC的抽水蓄能机组调速器 总被引:2,自引:0,他引:2
提出了一种基于PCC的抽水蓄能机组调速器。它用高可靠性的PCC模块构成双机冗余切换系统;利用PCC模块中的TPU进行频率测量,很好的解决了测频的精度问题;利用PCC的分时多任务操作系统,采用AB高级语言进行编程,更利于描述蓄能机组复杂的工况转换关系,控制具有较好的实时性;采用液晶触摸显示屏作为人机显示界面,人机接口简单、界面友好直观。因而本调速器具有测频精度高、调节速度快、可靠性高、人机接口简单等优点。 相似文献
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介绍了瀑布沟水电站调速器残压测频与齿盘测频两种机组频率测量方法的特点。分析了原齿盘测频回路存在的测值不准、波动大等问题的原因,论述了齿盘测频硬件回路的改造方法和改造后的测量效果。 相似文献
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频率测量是水轮机调速器的关键环节之一,其测量精度、可靠性及速动性对水轮机调节系统的动、静态品质至关重要。本文提出的三路冗余测频方法,可大大提高频率测量环节的精度、可靠性和抗干扰能力。同时,使得测频采样周期缩小到10ms左右。 相似文献
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分析了水轮机调速器测频环节的各个方面,包括测频原理、测频方法、测频信号来源、测频冗余等;最后介绍了桐柏抽水蓄能电站调速器有关测频方面的硬件、软件配置与设计,希望能对调速器测频的研发、设计等提供一定的参考意见。 相似文献
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This paper presents the performance of a multi-stage biodrum system applied to domestic wastewater treatment. The organic stabilization and nitrogen removal efficiency in the system was investigated at different hydraulic retention times (HRT) of 12, 6 and 3 hours. The rotational speed of the biodrum was examined at 2,4 and 8 rpm. Average organic removal efficiencies in the system at different HRTs of 12, 6 and 3 hours were 96.3, 94.4 and 90.9%. Simultaneously, average nitrogen removal efficiencies were 91.5, 90.6 and 81.0%. The effect of rotational speed on nitrogen removal efficiencies in the system was clearly observed at a low HRT of 3 hours. The experimental results suggested that optimum HRT in the system was 6 hours. Moreover, they revealed that nitrogen removal efficiencies in the reactors operated at different rotational speed were in the same degree when considering the effluent nitrogen concentration. However, the reactors operated at lower rotational speed needed to employ higher numbers of biodrums (4 stages) than the others with higher rotational speed (3 and 2 stages at 4 and 8 rpm.) in order to achieve similar effluent qualities. At a rotational speed of 2 rpm, maximum nitrogen removal rate was found to be 0.2 kg/m3/d. 相似文献
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微机液压型调速器的数字测频与鉴相 总被引:4,自引:1,他引:3
在水电站的实际安装运行中发现,已安装运行的中小型微机调速器中,相当一部分还是采用模拟方式测频,然后再将模拟信号转换成数字信号,存在两次信号转换误差。某水电站微机调速器采用既简单方便、测量精度又高的数字测频鉴相电路,具有自动跟踪功能,在实际应用中效果较好。 相似文献
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王涛 《水动力学研究与进展(A辑)》2009,24(5)
该文利用非定常双时间NS方程的预处理方法对摆翼地效推进器进行了推力和推进性能的分析,结果显示沉浮振动的推力和效率与速度的变化关系表现出一致性;固定频率,改变速度,发现推力和效率存在极大值点;随着频率增大,极大值点右移.最大推力和效率的动力攻角为 6o-9o,利用速度矢量图和压力云图显示了分离涡的输运和扩散,再一次展示了地效的存在. 相似文献
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GUO Xiao-hui LIN Jian-zhong TU Cheng-xu WANG Hao-li China Jiliang University Hangzhou China 《水动力学研究与进展(B辑)》2009,21(2):143-151
Measurements were performed using Particle Image Velocimetry(PIV) to analyze the modification of flow by the combined effects of the rotation and the Reynolds number on the flow past two rotating circular cylinders in a side-by-side-arrangement at a range of 425 ≤ Re≤ 1130,0 ≤α≤ 4(α is the rotational speed) at one gap spacing of T / d =1.11(T and d are the distance between the centers of two cylinders and the cylinder diameter,respectively).A new Immersed-Lattice Boltzmann Method(ILBM) scheme was used to st... 相似文献
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混流式水轮机弯肘型尾水管在部分负荷工况下产生带气泡的尾水涡流, 涡流在离心力的作用下形成与水流共同旋的涡带,由此产生的低频压力脉动是混流式水轮机面临的一个普遍性问题。水轮机中存在的水力压力脉动现象将诱发转轮叶片疲劳破坏。更有甚者对整个机组、厂房构成威胁, 严重影响了机组的安全稳定运行。本文采用全流道三维非定常流动数值模拟方法, 研究三峡混流式水轮机在部分负荷工况运行时,由尾水管涡带以低频的周期在尾水管内旋进引起的压力脉动现象。采用全流道非定常流动粘性湍流计算,计算结果表明在各记录点都捕捉到了涡带低频压力脉动:频率为0.333Hz, 是转频1.25Hz的3.75分之一,相近工况模型试验实测涡带频率为5.31Hz, 是转频18.62Hz的3.51分之一,从涡带频率看计算结果与试验测量结果一致。 相似文献
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Yun-Lu T Dong-Fang L Xian-Rong M Jie Y Jin W Yu-Xing L Ke-Xun L Lander J 《Water science and technology》2012,66(9):2014-2019
A new method based on rotating biological contactor (RBC) was employed for solving the problems of long hydraulic retention times (HRT) low specific surface area and organic loading rates (OLR) in conventional RBCs. The system showed its particular adsorption ability of microorganisms in the biofilm-attaching period. Microbes on the first cage were observed in comparison with the second one. Packing biodisc also had a good shock load tolerance. It was observed that the system performance improved at higher HRTs, while at the increased level of input OLR, the removal performance worsened slightly. The positive role of rotational speed in the treatment of municipal wastewater was more pronounced in the range of 10-12 rpm. Chemical oxygen demand (COD) removal rate achieved 94% under the optimal operating conditions, which were HRT of 1.5 h, rotational speed of 9.9 rpm. The modified RBC system is highly beneficial to engineering application for better system performance and lower energy consumption. 相似文献
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水泵起动过程中泵站前池水位降落值的分析 总被引:1,自引:2,他引:1
本文论证了水泵起动过程中扬程与流量、转速的关系,分析了泵装置系统的特征值与前池内的水流流态,在此基础上,推导出了水泵起动过程中前池水位降落值的计算方法. 相似文献