The advances in wireless communication, microelectronics, digital electronics, and highly integrated electronics and the increasing need for more efficient controlled electric systems make the development of monitoring and supervisory control tools the object of study of many researchers. This paper proposes a digital system for energy usage evaluation, condition monitoring, diagnosis, and supervisory control for electric systems applying wireless sensor networks (WSNs) with dynamic power management (DPM). The system is based on two hardware topologies responsible for signal acquisition, processing, and transmission: intelligent sensor modules (ISMs) and remote data acquisition units (RDAUs). The gateway function of the wired network is carried out by remote servers (RSs) based on the Soekris architecture, which is responsible for receiving the data collected and transmitting it to the supervisory controller (SC). To extend the WSN lifetime, sensor nodes implement a DPM protocol. The basic characteristics of the presented system are the following: 1) easy implementation; 2) low-cost implementation; 3) easy implementation of redundant routines (security); 4) portability/versatility; and 5) extended network lifetime.

Smart grid can be defined as a modern electric power grid infrastructure for improved efficiency, reliability and safety, with smooth integration of renewable and alternative energy sources through automated control and modern communications technologies. The increase need for more effective power electrical systems control turned the development of smart grids, the main object of study for many researchers. This paper proposes a digital system for condition monitoring, diagnosis and supervisory control applied to smart grids. The system is based on hybrid network architecture (HNA), consisting of a wired infrastructure, a wireless sensor network (WSN), a power line communications (PLC) and a controller area network (CAN). The system is based on three hardware topologies: remote data acquisition units (RDAUs), intelligent sensors modules (ISMs) and a PLC modem. The basic characteristics are: a) easy/low cost implementation, b) easy to set up by user, c) easy implementation of redundant routines (security), d) portability/versatility, and e) open system. To validate the developed system, it was implanted in one underground electric substation power distribution, characterized as an extremely hostile environment for supervisory control applications. In this application, the main challenge is to establish a communication system installed inside the substation with the outside (operations center-OC) considering that there are not commercial solutions appropriate to solve completely this problem.

Condition monitoring and diagnosis of industrial systems avoids unexpected failures and greatly improves system reliability and maintainability. Advances in wireless communication, microelectronics, digital electronics and highly integrated electronics in addition to the increasingly need for more efficient controlled electric systems, makes the development of monitoring and supervisory control tools object of study of many researchers. This paper proposes a digital system for energy usage evaluation, condition monitoring, diagnosis and supervisory control for electric systems applying wireless sensor networks (WSNs) connected to a wired infrastructure. The system is based on two hardware topologies responsible for the signal acquisition, processing and transmission: Intelligent Sensors Modules (ISMs) and Remote Data Acquisition Units (RDAUs). The gateway function of the wired network is carried out by Remote Servers (RSs) based on the AMD-Soekris NET4521 architecture, responsible for receiving the data collected and transmitting it to the Supervisory Controller (SCs) based on a PC Pentium IV architecture. The basic characteristics of the presented system are: (a) easy implementation, (b) low cost implementation, (c) easy implementation of redundant routines (security), and (d) portability/versatility.

According to the International Energy Agency/USA (lEA): “a smart grid (SG) is an electricity grid that uses digital technology to monitor and manage the transportation of electricity from all sources of generation, finding a variety of demands and users. These networks will be able to coordinate the needs and capabilities of all generators, operators, end-users and stake holders of the electricity market in order, to optimize the use and operation of the assets in the process, minimizing environmental costs and impacts while maintaining reliability, resilience and stability of the system”. The increasing need for more effective power electrical systems (generation, transmission and distribution) control has made the development of SG the main object of study for many researchers. In this context and looking for the integration and convergence of different systems to incorporate an infrastructure of a SG, this work designs and implements an flexible intelligent electronic device (lED). The proposed lED differs from the existing lEDs presenting a flexible capacity, as it can perform the acquisition of different variables (voltage, current, temperature, pressure, etc.) with different conditioning values, furthermore, the conditioning is carried out by software. The IED can operate as a smart meter, as a dynamic controller (local) and/or as a supervisory controller, thus improving the efficiency, reliabihty and security of the system. Other advantages of the proposed lED are: low cost, versatility (changes can be made by software), high processing capacity (ARM processor), communication features (hybrid network architecture (HNA)), easy integration (interoperability), easy maintenance (modularity) and scalability.

In this paper a hybrid topology of Modular Multilevel Cascade Converter (MMCC) - Double-Star Chopper-Cells (DSCC) is proposed. This configuration is applied as a unidirectional controlled single-phase rectifier, wherein one of the converter legs is composed by diodes instead of the submodules (SMs) connections. In order to ensure the energy balance among the local SM capacitors, a voltage balancing control strategy is also presented. Besides, a grid current control strategy associated to a method that eliminates zero-crossing distortion caused by the diode leg is proposed, resulting in a power-factor correction (PFC) and a sinusoidal grid current. Experimental results are presented and allow validating the control strategies.

Nowadays, to improve power quality and meet the energy demand, several studies point to the widespread use of Distributed Generation (DG) units equipped with power line conditionning capability. This work proposes a simplified structure and its related control system for Photovoltaic (PV) generation that embodies an Active Power Line Conditioner (APLC), allows harmonic minimization and active power injection to grid. Besides, it allows control of the grid voltage by using a Battery Energy Storage (BES) integrated to the system, which allows controlled bi-directional power flow. Simulation and pseudo-experimental results are presented to demonstrate the correctness of the methodology as well as the feasibility of the proposed distributed generation photovoltaic system and its related feedback control laws.