Sag compensation in smart grid with distributed generation

Power quality (PQ) is the most discussed topics in the power industry. It is nothing but the interaction between the electrical power and electrical equipment. If the electrical equipment can operate correctly as well as reliably without damaged or stressed, that means the electrical power is of good quality. There are different types of issues in power quality like Transients, Interruptions, Sag or under-voltage, Swell or Overvoltage, Waveform distortion, Voltage fluctuations, Frequency variations and Harmonics which are more sensitive due to large use of power electronic equipment as well as nonlinear loads. These all issues are almost present in industry, commercial and domestic applications. Smart grid has been emerged as promising technology for enabling bi-directional communication between the power company and its users to facilitate intelligent and robust emerging power grid systems [1][2]. One important challenge for smart grid designers is demand side management, which can lead to avoid peak hours as well as to reduce the cost for the consumers and power quality issues. In this paper we will use Fuel cell (FC) as well as wind generator as DG sources. Boost converters are used for boosting the output of the FC and then by using inverter it converts DC to AC. In the wind generation, Doubly Fed Induction Generator (DFIG) is used as generator which gives large power output, mostly it is used for wind generation [2][3]. The scope of this paper covers the issues in Power Quality for Distributed Generation of Smart grid with storage devices. MATLAB software is used for simulation. Here power quality issues are discussed and focus on sag, which is become common issue. FC and wind generators are used as Microgrid which of 0.5 MW and 1.5 MW rating respectively. If sag occurs in present system, it will be cover by using injection transformer. To recover sag, battery may be used as an inverter input. Control signal will give to inverter and by using control signal the sag will cover by injecting voltage.