This paper presents the development, simulation results, and field tests of an automated fault location system for primary distribution networks. This fault location system is able to identify the most probable fault locations in a fast and accurate way. It is based on measurements provided by intelligent electronic devices (IEDs) with built-in oscillography function, installed only at the substation level, and on a database that stores information about the network topology and its electrical parameters. Simulations evaluate the accuracy of the proposed system and the experimental results come from a prototype installation.

This research presents the development and implementation in a computational routine of algorithms for fault location in multiterminal transmission lines. These algorithms are part of a fault-location system, which is capable of correctly identifying the fault point based on voltage and current phasor quantities, calculated by using measurements of voltage and current signals from intelligent electronic devices, located on the transmission-line terminals. The algorithms have access to the electrical parameters of the transmission lines and to information about the transformers loading and their connection type. This paper also presents the development of phase component models for the power system elements used by the fault-location algorithms.

This paper presents a proposal for functional testing of protection and automation systems based on the IEC61850 standard. The proposed methodology is based on the development of tests scenarios which properly represent the actual systems and their operative conditions. It includes the selection of hardware and software that are used to simulate the operational events and acquire data for further analysis. This methodology was developed to evaluate the protection and automation systems of large-sized substations mainly regarding the interoperability between intelligent electronic devices of different manufacturers. This paper explains in detail the proposed methodology and an actual case study.

This work presents a time-domain protection solution based on integrated quantities. In order to provide a deterministic differential protection method, two algorithms that use voltage and current samples to estimate energy flow and reactive power entering a protection zone are used. The algorithms work by integrating time-domain measurements and generated signals in order to achieve stable quantities that are afterwards used for protection. After the description of the differential fault identification method, a phase selection scheme is presented in order to provide a complete protection solution. The proposed system was extensively tested on simulations based on data from five actual transmission lines, the power systems were simulated using ATP/EMTP and the protection was implemented using GNU Octave software. Thousands of cases were generated using automation scripts in order to validate the protection algorithms. The work also describes the conducted sensitivity test, which includes current transformer saturation, and unsynchronized measurements. The proposed solution proved itself secure and dependable under the tested conditions.

Electric forklifts are extremely important for the world’s logistics and industry. Lead acid batteries are the most common energy storage system for electric forklifts; however, to ensure more energy efficiency and less environmental pollution, they are starting to use lithium batteries. All lithium batteries need a battery management system (BMS) for safety, long life cycle and better efficiency. This system is capable to estimate the battery state of charge, state of health and state of function, but those cannot be measured directly and must be estimated indirectly using battery models. Consequently, accurate battery models are essential for implementation of advance BMS and enhance its accuracy. This work presents a comparison between four different models, four different types of optimizers algorithms and seven different experiment designs. The purpose is defining the best model, with the best optimizer, and the best experiment design for battery parameter estimation. This best model is intended for a state of charge estimation on a battery applied on an electric forklift. The nonlinear grey box model with the nonlinear least square method presented a better result for this purpose. This model was estimated with the best experiment design which was defined considering the fit to validation data, the parameter standard deviation and the output variance. With this approach, it was possible to reach more than 80% of fit in different validation data, a non-biased and little prediction error and a good one-step ahead result.

A solid demand to integrate energy consumption and co-generation emerged worldwide, motivated, on one hand, by the need to diversify and enhance energy supply, and, one the other hand, by the pressure to attend to the requirements of a heterogeneous class of users. The coupling between energy service provision and final users also includes balancing user needs, eliminating excesses, and optimizing energy supply while avoiding blackouts. Another motivation is the challenge of having sustainable sources and many adapted to the user ecosystem. Altogether, these motivations lead to more abstract design approaches to co-generation-distributed systems, such as those based on goal-oriented requirements used to model smart grids. This work considers the available design practices and its difficulties in proposing a new method capable of producing a flexible requirement model that could serve for design and maintenance purposes. We suggest coupling the approach based on goal-oriented requirements with model-based engineering to support such a model. The expected result is a sound and flexible requirements model, including a model for the interaction with the final user (now being considered a producer and consumer simultaneously). A case study is presented, wherein a small energy service system in an isolated community in the Amazon rain forest was designed.