Reserve Power Arrangements in Rural Area Underground Cable Networks

The popularity of underground cables to replace overhead lines is increasing. This is partly a consequence of the requirement for better reliability and supply security. In some countries, the authorities have set maximum interruption durations for distribution system operators to steer the operators to avoid the use of overhead lines. However, although faults are typically of a rare occurrence in underground cable networks, they cannot be completely avoided. Since the fault repair process in an underground cable network is time consuming, the distribution network should be meshed, and the rate of disconnecting switches should be high enough. However, this is not always possible or economically feasible and, therefore, other opportunities to restore the electricity supply should also be considered. This is especially the case for branch lines without a backup option. Yet, the power should be restored in a reasonable amount of time, which emphasizes the significance of an appropriate switch placement strategy and reserve power planning. This paper proposes a methodology to analyze the costs of different reserve power strategies and to optimize the reserve power arrangements. The reserve power strategies under consideration are the application of reserve power cables and reserve power generators and looping of the existing branch lines.