管道强制电流阴极保护电流和电位计算的数值方法

Numerical Calculation Method on Current and Potential of Impressed Current Cathodic Protection System for Pipeline

针对强制电流阴极保护的埋地钢管道,研究了相邻两个阴极保护站间的管道电位和电流的数值计算方法。通过离散化,将埋地钢质管道强制电流阴极保护系统模拟成一个电阻电路。用网孔电流法计算出管道电流和电位。数值计算结果与天津-北京航煤管道的实测电位和解析方法结果相吻合。数值计算结果表明,局部覆盖层破损使得保护电流有所增加,沿线各点电位的大小有所下降;覆盖层破损对管道最小电位(指绝对值)所处位置的影响不大,而电源输出电压的变化对最小电位点位置有着较大的影响;覆盖层破损点越靠近某个阴极站,两个阴极站的保护电流的差值就越大。

A numerical method is presented to calculate the current and potential of impressed current cathodic protection system for the buried steel pipeline protected by two cathodic protection stations jointly. A resistance circuit with DC supplies is usd to simulate the system through the discretization scheme. Impressed potential and current along the pipeline are found out by mesh--current method. The numerical results have a good agreement with the analytic results and measured ones from Tianjin to Beijing aviation kerosene pipeline. The numerical results show that the coating damage causes increase in protective current and decrease in absolute value of potential along pipeline. The coating damage has less effect on the position where absolute value of potential is minimal, while the output voltage of DC supplies has more on the position. The nearer the location of coating damage is to a cathodic protection station, the bigger the difference of protective currents of the two stations is.