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Friday, 27 November 2015

Modeling and Simulation of Micro-grid Based on Small-hydro



ABSTRACT:

As a renewable resource, small hydro is gaining more and more attention due to its variable advantages. The paper focuses on the operation of the micro-grid based on small-hydro. A simulation model of the micro-grid is established by Simulink, which takes the following two cases into account, the grid-connected operation and isolated operation. Under these two cases, the differences of the excitation voltage and rotator speed are analyzed respectively. Power quality of the voltage is also analyzed. Faults are pre-set in the grid and micro-grid. Then the operations of the micro-grid when faults happen are simulated. By comparison of the results, the effects of the fault-cutting-off time are discussed.

KEYWORDS:

1.      Small-hydro
2.       Micro-grid
3.       Model
4.       Simulation
5.      Faults

SOFTWARE: MATLAB/SIMULINK

 SIMULING BLOCK DIAGRAM:



 Fig. 1. Simulation model of the entire system


EXPECTED SIMULATION RESULTS:
             

  Fig. 2. Field voltage of generator
             
                                            
    Fig. 3. Rotator speed of generator
 
                                
    Fig. 4. Output voltage (RMS) of generator 1(THD=0.80%)

                              
                               
      Fig. 5. Active power assumption of load 1
                                    
                                
         Fig. 6. Field voltage of generator

    
                               
 Fig. 7. Rotator speed of generator
                              

 
  Fig. 8. Output voltage (RMS) of generator 1(THD=1.91%) 

 
  
   Fig. 9. Active power assumption of load 1
        
       Fig. 10. Field voltage of generator
         
 Fig. 11. Rotator speed of generator
              
    Fig. 12. Output voltage (RMS) of generator 1
 
         
Fig. 13. Active power assumption of load 1
 
                                    

  Fig. 14. Field voltage of generator     

         Fig. 15. Rotator speed of generator
 
    
       Fig. 16. Output voltage (RMS) of generator 1


 

       
Fig. 17. Active power assumption of load 1
          
   Fig. 18. Field voltage of generator
                                    
                                  
Fig. 19. Rotator speed of generator

 
                                 
  Fig. 20. Output voltage (RMS) of generator 1
                                  
 
Fig. 21. Active power assumption of load 1

CONCLUSION:
The micro-grid based on small-hydro can work normally without disturbance by simulating the grid-connected operation and islanded operation. The power quality would have been improved when the micro-grid connected to the grid by comparing the waveforms of output voltage and active power assumption. And the THD would have decreased when the micro grid is in grid-connected operation. Analyze the recovering time and influence of fault-cutting time by setting fault to the micro-grid and grid. The simulation results stress the importance of fault-cutting time. Cutting off the fault in time would suppress the system oscillation, and the generators are easier to get synchronous again. The system would oscillate fiercely with high frequency if the fault could not be cut off in time. However, the actual situation is more complex. Considering the change of load, actual situation of small-hydro power plants (changes of water level and so on), development of different distributing power and so on, the structure of the conventional micro-grid will become more complex, so the model in the paper needs some improvement.
 REFERENCES:
[1] Tao YU,Haihua LIANG. “Smart power generation control for microgrids islanded operation based on reinforcement leaning”,. Master's degree thesis of south china university of technoiogy,2012
[2] Fred H. Schwartz, Mohammad Shahidehpour. “Small Hydro As Green Power.” Power Engineering Society General Meeting, USA, 2005, pp. 2050 - 2057.
[3] ZHANG YuanSheng, et al. “The effects on the load model of the distributed network with small hydro power.” 2011 The International Conference on Advanced Power System Automation and Protection, China, 2011, pp.911-916.
[4] Anuradha Wijesinghe, Loi Lei. “Small Hydro Power Plant Analysis and Development,” Electric Utility Deregulation and Restructuring and Power Technologies (DRPT), China, 2011, pp.25 –30.

[5] Guillermo C. Zu˜niga-Neria, Fernando Ornelas-Tellez,J. Jesus Rico. “Optimal Operation of Energy Resources in a Micro-grid.” Power Systems Conference, USA, 2014, pp. 1-6.