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This paper addresses a study of Dynamic Voltage Restorers (DVRs) and Series Voltage Compensators (SVCs) applied to voltage surge protection and able to regulate the voltage on sensible loads. The DVR is applied on industrial environments when reliability of drives and electronics systems is desired, avoiding stops by voltage surges and problems from electrical grid, such as voltage sags and swells. It is estimated that power quality problems generate production losses and downtime in manufacturing process at industries, in consequence of sensible loads to voltage variation. Three simplified topologies will be discussed, with the proposal of a square-wave series voltage compensator (SW-SVC) able to compensate voltage sags and swells with improved cost-efficiency. This paper argues that for rectifying electronic loads, the quality of the voltage waveform does not have to be the best possible, and this impacts on the DVR simplifications and cost reduction. The design includes a description of the inherent system parts, such as the coupling transformer, harmonic filters, the switches arrangement and converters topology, the input rectifier and grid synchronization systems. Then will be discussed the SW-SVC performance analysis, mitigating voltage sags and swells, increasing industrial power quality.

This paper assesses a method of locating the source of voltage sags based on the power flow behavior at the point of common coupling (PCC) between systems. With the information of voltages and currents flowing in the interconnection transformers, the method is a suitable solution to locate the source of faults using a set of Boolean logic. The method is tested with the integration of a wind farm that remains connected through the appropriate control of its power converters during contingencies on the IEEE 34 node test feeder with distributed and spot loads, single-phase lines and distributed generation in parallel using a Real Time Digital Simulator (RTDS). Comparative tests are performed between the system with and without the power electronics interfaced generation, observing its dynamic response to the required Low voltage ride-through (LVRT) requirements and verifying the robustness and efficiency of the localization method.

Among many challenges regarding the management of the conventional power systems, the distribution system has been facing the penetration of Distributed Energy Resources (DERs) in relation to the amount of photovoltaic (PV), which can be hosted by existing radial distribution feeders without compromising the system constraints. PV technologies carry out a major role due to advances in their knowledge, thus decreasing capital costs and subsidies. When the distribution grids are transited from a passive network to an active, it is important to consider the PV deployment, as well as quantifying the system losses. Thus, these phenomena are addressed as the greatest concern to guide utilities actions to avoid technical violations. This paper aims a sensitive study in order to conduct an analysis regarding the harmonic hosting capacity of PV integration evaluating. Moreover, the harmonic distortions will be acting in accordance with international standards, as well as the assessment of the system electrical losses. Furthermore, their location-dependence and background influence will be considering. Simulations were performed using MATLab scripts to course several cases of power flow through the Open Source Distribution System Simulator (OpenDSS) based on the IEEE 13-bus distribution feeder.