Method for Raising Load Capacity of Underground Cable Line

Abstract

An optimized method for calculating the maximum current loadings of underground cables are developed based on the International Electrotechnical Commission (IEC) standard. Increasing the load of lateral cable and at the same time reducing the inside cable’s load, with the temperature of every cable lower than maximum permissible temperature as a constraint condition and taking the maximum sum of total current as objective function. The optimal operation value of each loop is calculated by the barrier function method and the improved Newton’s method is used to calculate the maximum value of current. The results reveal that this method can improve the total current of the cable by 5% greater than standard ampacity method and the effect is better in the case of multi loop, exploring the load potential of existing cable lines effectively and improving the economy of the cable.