基于瞬变流和故障检测的管线泄漏监测试验分析

根据动态系统分布参数模型的故障检测与诊断技术思想,结合管道流动的水力瞬变模型与适用于时变非线性系统的故障检测滤波器——扩展卡尔曼滤波算法,探讨了海底管道泄漏监测与定位技术.增广的状态向量包含管段各点的压力、流量和泄漏尺寸,进出口压力和流量4个参数组合成系统输入和输出向量,以卡尔曼增益阵修正由特征线结合差分法求解瞬变流离散方程得到的状态预测值,从而利用"新息"得出更准确的状态估计.在泄漏发生伊始即探测出异常,并给出泄漏发生时刻.基于压力梯度线性的假设计算泄漏位置,对一段试验水管的进出口压力流量测量序列进行上述分析,得出了与实际相当吻合的结果,初步验证了方法的有效性.

Experimental analyses of pipeline leak detection and location based on fluid transient theory and fault detection principle

Based on the fault detection and isolation for the distributed parameters system (DPS), the pipe flow transient model in seabed was combined with the expanded Kalman filter, which functions as fault detection filter of the variable nonlinear DPS. Furthermore the pipe leak location problem is discussed. The state vector of the DPS includes pressure, flow rate of pipe sections with leak sizes as argument components. Based on the solution of the discrete transient equation by characteristic, the Kalman gain matrix as an innovation corrects prediction state value to be more exact. Leak was found as the beginning time was estimated once leak happened. Leak position was estimated at the time when the pressure head of pipeline sections decreased nonlinearly and abnormally rather than decreased linearly and normally. In a water pipe test for observing flow rates and pressures at inlet and outlet, the estimated value of leak size and location agreed well with practice. Basically the effect of the present method is verified.