数据噪声对天然气管网在线仿真的影响研究

Influence of data noise on online simulation of natural gas pipeline network

SCADA系统实时测量的压力、流量、温度及组分等数据,是天然气管网在线仿真的关键边界条件,由于实时数据存在噪声和异常值,因此影响在线仿真精度和运行稳定性。为此,以应用广泛的隐式差分仿真模型为分析对象,结合实际管网系统中压力表、流量计的测量精度,采用Gaussian白噪声模拟不同的测量噪声水平,分析压力噪声、流量噪声对模型收敛性和仿真精度的影响,从而明确隐式差分模型对压力和流量的不同敏感性,优选管网在线仿真模型滤波参数。结果表明:第一,在0.5%的单压力噪声条件下,流量最大相对误差为63.41%,压力最大相对误差为0.15%;第二,在1%的单流量噪声条件下,流量最大相对误差为0.11%,压力最大相对误差为0.07%;第三,压力噪声导致的仿真误差远大于流量噪声,且仿真的流量误差远大于压力误差;第四,随计量精度降低,噪声导致的仿真压力误差和流量误差均逐渐增加。隐式差分仿真模型对于压力参数的敏感性高于流量参数,测量压力的较小噪声将导致严重的仿真流量误差。因此,在线仿真中应重点对压力边界进行滤波处理,从而有效提升模型的仿真精度。

Data such as pressure,flow rate,temperature,and components measured in real time by supervisory control and data acquisition(SCADA)system are the key boundary conditions for online simulation of natural gas pipeline network,and noise and outliers are bound to exist in real-time data,thus affecting the accuracy of online simulation and operation stability.Therefore,the widely used implicit difference simulation model was taken as the analysis object.By considering the measuring accuracy of pressure gauges and flowmeters in the actual pipeline network system,Gaussian white noise was adopted to simulate different measured noise levels,and the influence of pressure noise and flow noise on the model convergence and simulation accuracy was analyzed.As a result,the different sensitivities of the implicit difference model to pressure and flow were clarified,and the filtering parameters of the online simulation model of the pipeline network were optimized.The results show that:①For the maximum relative error of simulation results caused by the single pressure noise of 0.5%,the flow rate is 63.41%,and the pressure is 0.15%;②for the maximum relative error of simulation results caused by the single flow noise of 1%,the flow rate is 0.11%,and the pressure is 0.07%;③the simulation error caused by pressure noise is much larger than that caused by flow noise,and the simulation flow error is much larger than pressure;④with the decrease in measuring accuracy,the simulation pressure and flow errors caused by noise increase gradually.The sensitivity of the implicit difference simulation model to the pressure parameter is higher than the flow parameter,and the small noise of the measured pressure will lead to serious simulation flow errors.Therefore,the filter processing of pressure boundary should be emphasized in online simulation,so as to effectively improve the simulation accuracy of the model.