OPGW的热稳定计算及应用

Application of OPGW Thermal Stability Calculation

在选择OPGW时 ,除了要满足光通信条件 ,还要考虑热稳定问题。OPGW的热稳定控制条件是 :流过OPGW和分流线 (或地线 )的最大短路电流必须小于其允许的短路电流。当OPGW和分流线型号不变时 ,短路电流最大值出现在变电所进出线档内 ,该电流值作为OPGW选型的控制条件。当型号变化时 ,OPGW中的短路电流在变线塔NK处发生突变 ,若最大值出现在NK至NK +1档内 ,则INK + 1为控制条件。为了降低OPGW中的电流 ,在不改变分流线型号和长度的情况下 ,可采用将靠近变线塔处的绝缘地线增加几个接地点的方法 ,解决OPGW的热稳定问题。

For selection of OPGW the thermal stability should be considered except complying with communication conditions. The control conditions of OPGW thermal stability are as follows: the maximum short-circuit current through OPGW and its branch (or ground wire) must be less than its allowable value. For models of OPGW and its branch without variation: the maximum SC current value occurs at the inline and outgoing spans of substation and this value should be taken as a control condition for model selection of OPGW. For variation of models,the SC current of OPGW will have sudden change at the NK position of the OPGW mode-change tower. If the maximum value occurs within the span of NK to NK +1, I NK+1 should be the control conditions. For reduction of the current in OPGW in case of no change to model and length of its branch the number of ground points for the insulated ground wire close to the OPGW mode-change tower can be added to solve the OPGW thermal stability.