Power Quality Improvement of Smart Microgrids

智能微电网是将可再生能源（RES）集成到公用电网并允许客户参与能源企业的有前途的解决方案。在不久的将来，智能微电网将为客户提供负担得起的电力，并为依赖无排放能源铺平道路。智能微电网通常被分类为交流、直流和混合交流/直流，并且提供优于传统电力系统的若干优点，例如，它们提供了更高的可靠性、安全性、效率，允许通过分布式发电（DG）单元开发可再生能源，减少损失，并且有利于健康、气候和世界经济。尽管它们具有优势，但存在与智能微电网的有效设计和使用相关的若干技术挑战。一些主要的挑战是电力质量（PQ）退化的公用电网，和稳定性问题，由于间歇性的RES和负载变化。此外，配电网中非线性和不平衡负载的扩散导致智能微电网的许多PQ和稳定性问题。PQ不佳会给公用电网和消费者带来许多问题，例如，电力损失、敏感设备故障、电力中断、负载性能差、安全问题，并导致巨大的成本。例如，EPRI-CEIDS进行的一项调查显示，

Smart microgrids are promising solutions to integrate renewable energy sources (RESs) into the utility grid and allow the customers to participate in the energy enterprise. In the near future, smart microgrids will contribute to affordable electricity for customers, and will pave the path to rely on an emission-free form of energy. Smart microgrids are usually categorized into ac, dc and hybrid ac/dc, and provide several advantages over conventional power systems, e.g., they provide increased reliability, security, efficiency, allow the exploitation of the RESs through distributed generation (DG) units, reduce losses, and are beneficial for health, the climate, and the world economy. Despite their advantages, there exist several technical challenges associated with the efficient design and use of smart microgrids. Some of the main challenges are power quality (PQ) degradation of the utility grid, and stability issues due to the intermittent nature of the RESs and load variations. Moreover, the proliferation of nonlinear and unbalanced loads in distribution networks results in a number of PQ and stability problems for smart microgrids. Poor PQ results in a multitude of problems for both utility grid and consumers, e.g., power losses, malfunction of sensitive equipment, power interruptions, poor performance of the loads, safety issues, and incur huge costs. For example, a survey conducted by EPRI-CEIDS shows that the North American economy loses