Cross linked polyethylene (XLPE) insulators are used as insulation in ultra-high voltage electric power cables. This study investigated the electrical properties of XLPE at different temperatures. The electrical properties of the changing tree phenomenon was examined as a function of temperature applied to the electrical conductors by measuring the partial discharge at $25^{circ}C$ to $80^{circ}C$ and applied voltages to the electrodes ranging from 1 kV to 40 kV. The activity of the partial discharge was examined at various temperatures using the K-means distribution. The results revealed the specimen at $80^{circ}C$ to have the lowest inception voltage and breakdown voltage. In addition, the core of clusters was moved $0^{circ}$ and $180^{circ}$ at the positive region and $180^{circ}$ and $360^{circ}$ in the negative region in the K-means. The distribution of clusters was concentrated on the inception condition and spread out widely at the breakdown voltage.