Smart microgrids offer a new challenging domain for power theories and compensation techniques, because they include a variety of intermittent power sources, which can have dynamic impact on power flow, voltage regulation, and distribution losses. When operating in the islanded mode, low-voltage smart microgrids can also exhibit considerable variation of amplitude and frequency of the voltage supplied to the loads, thus affecting power quality and network stability. Due to limited power capability in smart microgrids, the voltage distortion can also get worse, affecting measurement accuracy, and possibly causing tripping of protections. In such context, a reconsideration of power theories is required, since they form the basis for supply and load characterization, and accountability. A revision of control techniques for harmonic and reactive compensators is also required, because they operate in a strongly interconnected environment and must perform cooperatively to face system dynamics, ensure power quality, and limit distribution losses. This paper shows that the conservative power theory provides a suitable background to cope with smart microgrids characterization needs, and a platform for the development of cooperative control techniques for distributed switching power processors and static reactive compensators

Smart grids offer a new challenging domain for power theories and compensation techniques, because they include a variety of intermittent power sources which can have dynamic impact on power flow, voltage regulation, and distribution losses. When operating in the islanded mode, smart micro-grids can also exhibit considerable variation of amplitude and frequency of the voltage supplied to the loads, thus affecting power quality and network stability. Due to the limited power capability of smart micro-grids, voltage distortion can also get worse, affecting measurement accuracy and possibly causing tripping of protections. In such a context, a reconsideration of power theories is required, since they form the basis for supply and load characterization and accountability. A revision of control techniques for harmonic and reactive compensators is also required, because they operate in a strongly interconnected environment and must perform cooperatively to face system dynamics, ensure power quality and limit distribution losses. This paper shows that the Conservative Power Theory (CPT) provides a suitable background to cope with smart grids characterization needs, and a platform for the development of cooperative control techniques for distributed switching power processors and static reactive compensators.

Abstract-In

This paper presents a flexible control technique for power electronics converters, which can function as an active power filter, as a local power supply interface, or perform both functions simultaneously. Thus, it can compensate for current disturbances while simultaneously injecting active power into the electrical grid, transforming the power converter into a multifunctional device. The main objective is to use all the capacity available in the electronic power converter to maximize the benefits when it is installed in the electricity grid. This objective is achieved by using the orthogonal current decomposition of the Conservative Power Theory. Each current component is weighted by compensation coefficients ( ), which are adjusted instantaneously and independently, in any percentage, by means of load conformity factors ( ), thus providing online flexibility with respect to the objectives of compensation and injection of active power. Lastly, simulated and experimental results are presented to validate the effectiveness and performance of the proposed approach.

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