Noninvasive contactless methods for electric power line monitoring based on magnetic field measurement have become an interesting topic for researchers and the electric power industry since introduction of the Smart Grid concept. By measuring and analyzing magnetic field originating from currents in power line conductors, it is possible to detect faults in the network. In medium voltage distribution networks, where a variety of different pole geometries are present, different criteria for fault detection have to be employed for each geometry, which complicates detection and influences accuracy. This paper proposes a novel approach for fault detection in medium voltage distribution networks which is based on processing of signals measured by low cost contactless magnetic field sensors. In order to create a generalized method for fault detection, a sequence of mathematical transformations of the measured magnetic field components is applied. A novel geometric transformation which eliminates influence of pole geometry is introduced, providing signals from which steady-state symmetrical components of the rotating magnetic field are computed. Those components are used as general fault detection criteria. The proposed approach is confirmed to be applicable for different fault types by a set of experiments on three-phase overhead power line model scaled to laboratory conditions.

In this paper a methodology for determining proper number and positions of fault passage indicators (FPIs) in medium voltage distribution networks with installed fault locators (FLs) is proposed and discussed. The main goal is to achieve the techno-economic balance, by obtaining maximum improvement of the reliability indices while using the minimum number of FPIs. The method is verified by Monte Carlo simulation on a real combined urban/rural distribution network in Bosnia and Herzegovina. The purpose of the simulation tests is to assess performance of the proposed methodology, as well as to discuss the results and propose potential actions required to improve their reliability for several possible scenarios: the use of FLs only, the use of FPIs only and the combined use of FLs and FPIs.

Distributed energy resources (DER), located close to end use loads, have the potential to meet consumer requirements more efficiently than the existing centralized grid. In this paper, a specific scenario is considered, where the consumer center uses distributed resources to meet a part of its energy requirements, while the rest of the needed electricity is purchased from the utility distribution company. In order to minimize total consumer costs, a robust optimization algorithm based on a search method has been developed. The main outputs of this algorithm are optimal dispatch between distributed resources generation and the electricity purchased from the utility as well as the particular contribution of every on-site generating unit in the dispatch schedule. The algorithm was tested using several characteristic simulations and two basic areas of its application have been discovered-optimal dispatching of existing distributed energy resources and economic evaluation concerning installation of new generating facilities.