Archivo para febrero 24th, 2016


A example of DC microgrid

Many examples there is in this blog about DC microgrids (see last post or search in blog). This blog is for share information of actual tendence in electricity. It is part of my research as doctoral student in physics in National University of Engineering in Lima, Perú; and actually I am writing in english. For last post, the blog have a traductor box option. Near to 1000 post about diferents topic in renewable energy focused in microgrid, smartgrid and its modelling ans simulation witn Matlab/Simulink. I know this software and its very good, practical for science and engineering. In May or June is possible I will expose mi thesys doctoral, previus days or weeks I posted the exact time for all people see in live or via internet. This figure is other DC microgrid scheme with different technologies interconnected at a some bus DC for transfered electric power. Jorge Mírez (please visit and link my fanpage http://www.facebook.com/jorgemirezperu  )

Source of Figure:
N. R. Rahmanov, N. M. Tabatabaei, K. Dursun, O. Z. Kerimov. “Combined AC-DC Microgrids: Case Study – Network Development and Simulation” International Journal on Technical and Physical Problems of Engineering. September 2012, Issue 12, Volume 4, Number 3, Pages 157 – 161.

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Example of power supply for office building using DC bus

In the office there are many electronic equipment, it for the general, to use DC voltage. There is certain paradigme about the data center made more for market that for technical reasons… ups, many companies it not like. Ok, the figure shown the special configuration (a example) of electrical supply to equipment office. Very good, it is a representative used of potential DC microgrids.

Source of Figure:
N. R. Rahmanov, N. M. Tabatabaei, K. Dursun, O. Z. Kerimov. “Combined AC-DC Microgrids: Case Study – Network Development and Simulation” International Journal on Technical and Physical Problems of Engineering. September 2012, Issue 12, Volume 4, Number 3, Pages 157 – 161.


 

Example of a hybrid microgrid

This a typical scheme of a microgrid AC/DC. It maybe contain many technologies as micro-source, storage, loads and monitoring and control. Un Microgrid Bus linked the different components.

Source:
N. R. Rahmanov, N. M. Tabatabaei, K. Dursun, O. Z. Kerimov. “Combined AC-DC Microgrids: Case Study – Network Development and Simulation” International Journal on Technical and Physical Problems of Engineering. September 2012, Issue 12, Volume 4, Number 3, Pages 157 – 161.


DC grid unipolar and bipolar

DC grid of a Microgrid DC may be unipolar with ground as return path or bipolar with positive and negative terminal. The figure (a) and (b) depicts unipolar and bipolar grid respectively.  If load connected to DC bus is DC such as TV, computers, fluorescent lamps; DC bus requires less power conversion stages. Since power conversion stages are less, losses in conversion also gets reduced.

Source:
Ganesh Patil, M. F. A. R. Satarkar, Gorakshanath Abande “New Scheme for Protection of DC Micro grid” International Journal of Innovative Reseach in Science, Engineering and Technology. Volume 3, Special Issue 3, March 2014.


Microgrid operation of islanded operation

The figure illustrates the concept of the power management method in the islanded mode. When a DC micro-grid must be separated from the ac grid and switch to the islanded mode, the grid-tied converter released control of the DC grid voltage and one of the converters in the micro-grid must take over that control. Since each converter of DGs is used for optimal control of each source, only the converters of the energy storage elements are free to regulate the DC grid voltage. During the islanded mode, the battery plays a main role in regulating the DC grid voltage and the super-capacitor plays a secondary role in responding to the sudden power requirement as an auxiliary converter.

Source:
Ji-Heon Lee, Hyun-Jun Kim, Byung-Moon Han, Yu-Seok Jeong, Hyo-Sik Yang and Han-Ju Cha “DC Micro-Grid Operational Analysis with a Detailed Simulation Model for Distributed Generation” Journal of Power Electronics, Vol. 11, No. 3, May 2011


Microgrid operation of grid-tied mode

The figure illustrates the concept of the power management method in the grid-tied mode and the bolded curve represents a load demand curve during a day. If the output sum of the DGs is sufficient to charge the storage elements, any excessive power is supplied to ac grid. If the sum of the power of the DGs and the storage elements is deficient with respect to the load demand, the required power is supplied from the ac grid. In the grid-tied mode, power management is performed in a complementary manner between storage elements and as a result the DC micro-grid can operate safely and efficiently

Source:
Ji-Heon Lee, Hyun-Jun Kim, Byung-Moon Han, Yu-Seok Jeong, Hyo-Sik Yang and Han-Ju Cha “DC Micro-Grid Operational Analysis with a Detailed Simulation Model for Distributed Generation” Journal of Power Electronics, Vol. 11, No. 3, May 2011