MAXIMUM TEMPERATURE EVALUATING DEVICE FOR POWER CABLE BURIED UNDERGROUND

摘要

PURPOSE:To obtain a maximum temperature value in a lengthwise direction of power cable by measuring temperatures of each part with a series of optical fibers, thereby obtaining a calorific value of the power cable by calculation, and further obtaining a temperature of cable conductor. CONSTITUTION:Linear temperature distribution on the optical fiber is measured by a temperature distribution measuring device 16 with a series of optical fibers 2 installed nearly along the power cable 10 as sensors. By a maximum temperature evaluation processing device 17, the calorific value of cable 10 is obtained from the measured value of device 16, and also from temperatures on at least two points within a cross-sectional area of installed cable 10, unknown intrinsic thermal resistance and bottom temperature of surrounding soil on that part are obtained and therefrom the temperature of cable 10 within the cross-sectional area of this installation is calculated. In this case, this temperature is relatively obtained in such a manner that the calorific value of cable and thermal condition of soil are obtained by utilizing those and dimensions of buried position and a thermal constant for the main body of cable. This procedure is repeated to obtain the maximum temperature of cable 10 in the lengthwise direction for an overall length of line.