A new agent concept for managing technically advanced electrical distribution networks is presented. The essence of the concept consists of three aspects: the secondary substation object, decentralized functionality and an information access model. In this framework, a primary substation area is modeled so that secondary substations are represented as copies of the secondary substation object, local function copies in every substation represent functions and they are executed by a token passing procedure that occurs between neighboring secondary substations. The permission to execute a function is delegated to different power system hierarchy levels according to the information access model. The concept is illustrated by the use of case studies of condition assessment and fault management. In addition, a small-scale implementation is described and results of some test runs are presented.

A new agent concept for state estimation in electrical distribution networks is presented. The responsibility for state estimation is delegated to local agents in secondary substations. These use historical data and probabilistic means to assess the performance of the substation and to detect bad data. Topology and observability analysis as well as bad data identification are performed with a token that traverses the secondary substations of the primary substation feeders. The feasibility of the concept is evaluated in a case study where data from real sensor measurements are used as input. According to the study, the state estimation concept performs well.

The falling trees on covered-conductor (CC) overhead distribution lines produce partial discharges (PDs). The measurements have been taken in the laboratory and PD signal characteristics under various circumstances have been described. In this paper, an on-line single-phase PD monitoring system using Rogowski coil is simulated in EMTP-ATP. The simulation results are compared with those obtained from the laboratory measurements. The proposed model can be used to estimate the length of the practical CC lines at which PDs due to falling trees can be detected and localized; thus, deciding the number and positioning of the sensors over a particular length of the CC lines. The different noise sources have been described that cause interference with low level PD signals, which is a major challenge for on-line/on-site condition monitoring. The design aspects of the wireless sensor for this specific application are also discussed. Automatic detection of falling trees will reduce visual inspection work after storms and it will improve reliability and safety of the CC distribution system.

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