基于分段曲线拟合的稳态检测方法

Steady-state detecting method based on piecewise curve fitting

稳态检测对热工过程的建模、优化和控制具有重要的意义。通过对变量信号采样数据的分段拟合得到其一阶导数和二阶导数序列,利用重叠数据加权来保证边界的连续性和光滑性。并根据变量信号的一阶和二阶导数序列信息,与相应的阈值比较后得到其变化趋势,进而得到该变量的稳态指数。稳态指数值的范围是0到1,代表稳定程度从非稳态到稳态。对系统的各个关键变量的稳态指数加权并考虑系统的响应延迟得到整个系统的稳态指数,进而判断系统工况是否稳定。最后以某电厂600MW机组的给水流量系统等数据进行稳态检测,结果表明该方法具有一定的工程实用价值。

Steady-state detection has vital significance for thermal process modeling, optimization and control. The first order and second order derivative sequences are obtained based on piecewise fitting of the sampling data of variable signals. The smoothness and continuity of the boundary is guaranteed through weighting the over-lapping data. The process trends are extracted after comparing the information of the derivative sequences with relevant threshold. Furthermore, a steady-state index, which ranges from 0 to 1 representing the status from unsteady to steady, is also obtained. The steady-state index of the whole system is calculated through weighting the index of each key variable after system response delay is considered. Lastly an application is explored using the data of feedwater flow and etc. from a 600 MW set system. Experimental result indicates that the method proposed in this paper has certain engineering practicability.