The growing use of sensitive loads in the electric power system, especially in industrial applications, increases voltage sags related production losses considerably, stimulating a demand for power electronics' based solutions to mitigate the effects of such problems. This paper shows the implementation and some industrial certification tests of a power equipment prototype designed to correct sags and swells, a dynamic voltage restorer, which is one of the many possible solutions for voltage sags and swells problems.. Experimental results of a 75kVA prototype are shown both in laboratory and full load conditions, in a certification institution (IEE-USP).

This work presents a case study on technology assessment for power quality devices. A system compatibility test protocol for power quality mitigation devices was developed in order to evaluate the functionality of three-phase voltage restoration devices. In order to case test this test protocol, a development platform with reduced power for DVR (Dynamic Voltage Restorer), the micro-DVR, was tested, and results were discussed based on voltage disturbances standards.

This paper deals with the design and analysis of a Dynamic Voltage Restorer output voltage control. Such control is based on a multiloop strategy, with an inner current PID regulator and an outer P+Resonant voltage controller. The inner regulator is applied on the output inductor current. It will be also demonstrated how the load current behavior may influence in the DVR output voltage, which justifies the need for the resonant controller. Additionally, it will be discussed the application of a modified algorithm for the identification of the DVR voltage references, which is based on a previously presented positive sequence detector. Since the studied three-phase DVR is assumed to be based on three identical H-bridge converters, all the analysis and design procedures were realized by means of single-phase equivalent circuits. The discussions and conclusions are supported by theoretical calculations, nonlinear simulations and some experimental results.

This work presents a development platform with reduced power for DVR and FACDS applications and development. The proposed equipment allows testing control algorithms, hardware behavior as well as the strategy applied in the development of the power circuitry. The DVR (Dynamic Voltage Restorer) is one way to mitigate Voltage Sags and Voltage Swells, which are a common cause of damage for the industry, because of the growing number of equipment sensitive to the quality of the delivered electrical energy. The same equipment can be operated as a FACDS (Flexible Alternating Current Distribution Systems) allowing series compensation of distribution lines, as well as power flow control between parallel feeders, as well as an UPFC (Unified Power Flow Controller). This paper emphasizes the implementation of a DVR topology and its results.

The power electronics-based FACTS technology, applied to transmission systems, can also be useful in distribution systems. To this end, it is necessary to follow a consolidation procedure of the utilization and performance of this technology so that they can be applied with no risks. The application of this technology will bring along several benefits for the expansion of the distribution systems, namely: flexibility in the networks' utilization, interconnection of feeders allowing the manipulation of energy blocks without the need of disconnecting them, continuous adjustment of reactive power during the operation, and a dynamic control of the power flow. In this work, two aspects for the application of this technology in distribution systems, will be studied. The first aspect is referred to the application of a FACTS device that acts as a series compensator and which offers the possibility of making feasible the continuous control of the series reactance. The second aspect is referred to its utilization in the interconnection of two feeders, where active power between them is dynamically controlled. The simulation program used was the ATP (alternative transients program).