ABSTRACT
This paper discusses the power quality issues for distributed generation systems based on renewable energy sources, such as solar and wind energy. A thorough discussion about the power quality issues is conducted here. This paper starts with the power quality issues, followed by discussions of basic standards. A comprehensive study of power quality in power systems, including the systems with dc and renewable sources is done in this paper. Power quality monitoring techniques and possible solutions of the power quality issues for the power systems are elaborately studied. Then, we analyze the methods of mitigation of these problems using custom power devices, such as D-STATCOM, UPQC, UPS, TVSS, DVR, etc., for micro grid systems. For renewable energy systems, STATCOM can be a potential choice due to its several advantages, whereas spinning reserve can enhance the power quality in traditional systems. At Last, we study the power quality in dc systems. Simpler arrangement and higher reliability are two main advantages of the dc systems though it faces other power quality issues, such as instability and poor detection of faults.
I. INTRODUCTION
The conventional large-scale generation of electricity at centralized facilities include fossil-fuel-fired power plants, nuclear power plants, hydroelectric dams, wind farms etc. These are now being troubled with the shortage of fossil fuel, the exceeding amount of emission and the electrical power loss due to long transmission line [1]. ‘‘Power Quality’’ refers to the electrical system’s ability to create a perfect power supply that has a pure noise-free sinusoidal wave shape, and is always stable if voltage and frequency is considered. However, practically many loads regularly impose disturbances on the systems that make deviations from this ideal power supply [2]. EPRI carried out a study between 1992 and 1997 in the US and characterized the average duration of disturbances. The result for a typical site, during this period is presented in fig. 1.
X. CONCLUSION
This paper discusses the power quality issues for distributed generation systems based on renewable energy sources such as solar and wind energy. A thorough discussion about power quality issues, their sources, and parameters have been presented here. Discussion on power quality standards have been carried out afterwards. After that, power quality issues in renewable energy systems, techniques to monitor power quality, the devices used for that purpose, and application of CPDs for mitigating power quality problems have been described. Ways of improving power quality in renewable systems, and analysis of power quality in DC systems have followed all these; and the outcomes have been presented finally to summarize the findings of this work.
From the outcomes of this research, transient has been found out to be the most severe power quality issue, followed by voltage spike and fluctuation. The power quality monitoring techniques have been found to be employed for monitoring harmonics mainly, while UPQC, STATCOM, and spinning reserve have been found out to be the most effective CPDs. It has been resolved that STATCOM can be a potential choice due to the advantages it offers.
