With thermally stimulated depolarization currents, we researched the relaxations of crosslinked polyethylene as it is used in medium-voltage cable insulation. Through conventional polarization two heteropolar peaks stand up in the spectra, at 80 and 105 degreesC. As the sample is annealed, a homopolar peak is developed at about 99 degreesC. With window polarization, our results indicated that the 80 degreesC peak is a structured peak related to polar crosslinking subproducts and impurities. The 105 and 99 degreesC peaks are fitted to the general kinetic-order model because the 105 degreesC peak is related to free-charge detrapping at the crystalline phase, in the bulk and maybe at the amorphous-crystal interphases, and the peak that is observed at 99 degreesC is due to injected charge. Annealing at high temperatures promotes the creation of traps in the material. Charge trapping at T < 70 degreesC seems to be related to the increased insulator resistivity with annealing time. (C) 2003 Wiley Periodicals, Inc.