The overview of fiber-optic technologies for real-time monitoring of the technical condition and operational characteristics of modern power cables with cross-linked polyethylene insulation and with the fiber-optic module integrated into their structure is presented. In particular, the new intelligent means for monitoring of the temperature, load current, deformation (mechanical damages), partial discharges in the insulation, moisture penetration inside the cables and control over sheath voltage limitation are described. The topicality of using and developing the technologies of smart diagnostics for power cable lines in order to achieve the effective and safe operation of cables as well as the high reliability of networks is shown. Ref. 47, fig. 7. Key words: power cables, power cable lines, cross-linked polyethylene insulation, integrated fiber-optic modules, power networks, smart monitoring.