Fault location in electrical energy distribution networks is an important task, as faults in distribution grids are among the main causes of electricity supply disruption. Fault location in the distribution systems, however, is a challenging task because of the topology of the distribution networks, as well as the main and side branches. Therefore, it is necessary to address these challenges through an intelligent approach to fault location. In this paper, fault location in electric energy distribution networks is addressed considering the changes in fault distance and fault resistance in the presence of different fault types. A new method for fault location is developed for conditions where the minimum information is available and only information at the beginning of the feeder is used. This facilitates wide adoption of the technique as it does not require significant investments in instrumentation and measurement. The proposed intelligent method is based on the impedance and transient state estimation. This technique employs a specific impedance analysis for determining possible fault locations considering the unbalanced performance of distribution systems, distances, and different fault resistances. To determine the real faulty section, real fault frequency component analysis and the simulated faults at possible fault locations are used. At this stage of the process, it is possible to eliminate multiple estimations with the help of comparison and identification of the similarities. Therefore, a real faulty section is determined. It is observed that some conditions of electric energy distribution networks affect the accuracy and performance of the proposed method significantly; thus, a detailed investigation is conducted to neutralize these conditions. Simulation results and calculations based on MATLAB along with a practical test of the proposed method in power network simulator confirm a satisfactory performance.

Determining the optimal reserve in power systems is closely related to uncertainties in power generation and risks of outage of supply to consumers. Distributed generation sources such as wind farms are usual reasons for uncertainties in MW production. This uncertainty can be alleviated by providing enough reserve in which demand response (DR) programs can play role of resources for reserve. In an electricity market structure, the mentioned points are usually handled by Independent System Operator (ISO) in energy and reserve markets. This paper deals with the problem of reliability-based reserve management. In the mentioned problem, the DR program in the form of interruptible loads is also considered. A new method is proposed in which ISO settle energy and reserve markets simultaneously while employing the DR in the first stage. In addition, consumers’ requirements of reliability are included by assuming that they have possibility to offer their desired levels of reliability to the ISO. The amount of reserve obtained from market settlement is adjusted based on the different reliability requirements of the consumers and different scenarios of the wind farm operation, in the second stage of the proposed method. Also the cost of the reserve adjustment is fairly allocated to producers and consumers. The proposed method applies stochastic programming formulation and its validity is assessed by the GAMS software. Simulation results show that how amount and cost of reserve could be adjusted to cover power balance, cost of power production and load interruption and required reliability of consumers.