蒸汽参数变化对汽轮机系统稳定性影响的机理分析

Mechanism of Steam Parameters' Influence on the Stability of Steam Turbine Power System

与广域的互联大电网相比,小型及微型电力系统具有能源综合利用效率高的优点。但小型汽轮机变工况运行频繁,蒸汽参数变化范围大。为了分析蒸汽参数对汽轮机系统稳定性的影响,通过对汽轮机工作机理的研究,建立了汽轮发电机组电磁功率随蒸汽压力变化的数学模型,避免了水蒸气的熵和焓等复杂物理量的测量。研究了蒸汽受限时,汽轮机入口蒸汽压力的变化过程;分析了给定系统在蒸汽受限时的安全稳定域,给出了极限时间与蒸汽受限严重程度、带载量的关系式。该成果对于实际运行中蒸汽受限时的紧急切负荷控制具有重要的指导意义。

Compared with a wide area power grid, the small and micro power system possesses the advantages of high efficiency of energy utilization.But a small steam turbine varies its operation condition frequently, and steam parameters change along a large range.In order to analyze stability under the disturbance of steam parameters, this experiment studied the working mechanism of steam turbine and established the relationship between electrical pow-er and steam pressure.Complex physical quantities, such as the entropy and enthalpy of steam, were avoided for the difficulty of measurement.In the case of limited steam, the changing process of the turbine inlet steam pressure was studied and the security domain was given.Furthermore, the critical time can be written as a function of limit-ed steam pressure and load.The results can be used to guide emergency load control in order to avoid instability, when steam was restricted.