Simple

fast and accurate evaluation of the temperature rise of core of the directly buried cable group is of great practical significance for ensuring its reliable and safe operation as well as managing the realtime load of the cable group.When the thermal conductive coefficient of the heat medium around the direct soil-buried cable group is known

the thermal process can be represented by a linear equation between the cable body and the adjacent cable

so that a transfer matrix can be constructed to estimate the temperature rise of the cable core in real time.The finite element calculation result is used to obtain the temperature rise and heat sample data sets of the cable core and the heat and temperature rise sample data sets between adjacent cables.Then

the data matching is used to obtain the relations among the temperature rise of cable core and the loss of cable core

dielectric and adjacent cables

to obtain selfheating conductivity coefficient and mutual thermal conductivity coefficient and a transfer matrix for rapid calculation of temperature rise of directly buried cable group core is constructed.By comparing the finite element calculation results of 12 pieces of twolayer threecore cable groups with the calculation results of the transfer matrix

it is proved that the method has higher accuracy and faster calculation speed and is convenient for the use by field engineers.