贯流式机组孤网运行过渡过程调节品质研究

发布时间：2018-10-26 10:42

【摘要】：随着我国开始对低水头河流及潮汐水力资源的开发,贯流式水电机组的应用也不断增加,但贯流式机组由于自身具有水头低、水流惯性大、机组惯量小,且在过渡过程中水体附加转动惯量占整体转动惯量比重较大等特点,其在孤网模式下运行调节品质较差,在带超过40%负荷时机组不易稳定,严重时导致孤网崩溃。所以对贯流式机组孤网运行的研究对其在孤网中的稳定运行有非常重要的意义。本文针对贯流式水轮发电机组自身特点,在PSCAD仿真软件中建立了水-机-电结合的仿真模型,通过仿真结果分析了在大、小两种开度下,贯流式机组孤网运行,机组受到负荷扰动时,PID参数、导叶及桨叶开启和关闭时间、导叶及桨叶接力器反应时间常数,负荷扰动量,机网容量占比等因素对机组运行状态的影响。仿真结果表明,机组的调节品质及稳定性在小开度下优于大开度。而主要影响机组调节品质的主要因素有比例增益、积分增益、导叶桨和叶关闭时间、负载扰动量和机网容量占比。比例增益在小开度下对转速最大偏差值的影响相比于大开度更为明显;积分增益同样的在小开度下对转速偏差最大值影响较大,而在大开度下对调节时间影响较大;导叶及桨叶关闭时间在大开度下对机组出力影响较大;负载扰动量在小开度下的调节品质略微优于大开度下;在大开度下,不同机网占比对调节时间影响较大,在小开度下,对转速最大偏差值影响较大,且在小开度下机组的运行的稳定性优于大开度下。
[Abstract]:With the development of low-head rivers and tidal hydraulic resources in China, the application of tubular hydropower units is increasing, but due to their low water head, the inertia of water flow is large, and the inertia of units is small. In the process of transition, the additional moment of inertia of water body occupies a large proportion of the whole moment of inertia, which is poor in operation and regulation quality in the isolated network mode, and it is not easy to stabilize when the load is more than 40%, leading to the collapse of the isolated network when the load is more than 40%. Therefore, the research on the operation of the tubular unit has a very important significance for its stable operation in the isolated network. In this paper, according to the characteristics of the tubular turbine generator set, a simulation model of the combination of water, machine and electricity is established in the PSCAD simulation software. Through the simulation results, the isolated network operation of the tubular turbine unit is analyzed under the conditions of large opening and small opening. When the unit is disturbed by load, the factors such as PID parameters, the opening and closing time of guide vane and blade, the reaction time constant of guide vane and blade relay, the load disturbance quantity, the ratio of power grid capacity and so on affect the operating state of the unit. The simulation results show that the regulation quality and stability of the unit are superior to those of the large opening under the small opening. The main factors affecting the regulating quality of the unit are proportional gain, integral gain, guide vane and blade closing time, load disturbance and the proportion of power network capacity. The effect of the proportional gain on the maximum deviation of rotational speed is more obvious than that of the large opening, while the integral gain has the same effect on the maximum deviation of the rotational speed at the small opening, but on the adjusting time at the large opening. The closing time of the guide vane and the blade has a great influence on the generating force under the condition of large opening, and the adjustment quality of the load disturbance is slightly better than that under the large opening. Under the condition of large opening, the ratio of different machine net has a great influence on the adjusting time, and at small opening, it has a great influence on the maximum deviation value of rotational speed, and the running stability of the unit under small opening is better than that of large opening.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM312

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