An Enhanced Voltage Sag Compensation Scheme for Dynamic Voltage Restorer

ABSTRACT:  

This paper manages enhancing the voltage nature of touchy burdens from voltage droops utilizing dynamic voltage restorer (DVR). The higher dynamic power necessity related with voltage stage hop remuneration has caused a generous ascent in size and cost of dc connect vitality stockpiling arrangement of DVR. The current control procedures either moderate the stage bounce or enhance the usage of dc interface vitality by (I) diminishing the abundancy of infused voltage, or (ii) advancing the dc transport vitality bolster. In this paper, an upgraded list pay procedure is suggested that mitigates the stage bounce in the heap voltage while enhancing the general droop remuneration time. A scientific examination demonstrates that the proposed strategy essentially builds the DVR list bolster time (over half) contrasted and the current stage bounce pay strategies. This upgrade can likewise be viewed as a significant decrease in dc interface capacitor measure for new establishment. The execution of proposed technique is assessed utilizing recreation contemplate lastly, confirmed tentatively on a scaled lab model.

 

CIRCUIT DIAGRAM:

 

 Fig. 1 Basic DVR based system configuration.

 EXPECTED SIMULATION RESULTS:

 

Fig. 2. Simulation results for the proposed sag compensation method for 50% sag depth. (a) PCC voltage, (b) load voltage, (c) DVR voltage, (d) DVR active and reactive power, and (e) dc link voltage.

Fig. 3. Simulation results for the proposed sag compensation method for 23% sag depth. (a) PCC voltage, (b) load voltage, (c) DVR voltage, (d) DVR active and reactive power, and (e) dc link voltage.

 CONCLUSION:

In this paper an upgraded hang remuneration conspire is proposed for capacitor bolstered DVR. The proposed procedure enhances the voltage nature of touchy loads by ensuring them against the lattice voltage droops including the stage bounce. It likewise builds remuneration time by working in least dynamic power mode through a controlled change once the stage bounce is redressed. To show the viability of the proposed technique a scientific correlation is completed with the current stage bounce pay plans. It is demonstrated that pay time can be reached out from 10 to 25 cycles (considering presag infusion as the reference strategy) for the planned furthest reaches of half droop profundity with 450 stage bounce. Further expansion in remuneration time can be accomplished for middle of the road droop profundities. This all-inclusive pay time can be viewed as extensive decrease in dc connect capacitor estimate (for the examined case over half) for the new establishment. The viability of the proposed strategy is assessed through broad recreations in MATLAB/Simulink and approved on a scaled lab model tentatively. The trial results exhibit the plausibility of the proposed stage hop remuneration strategy for viable applications.

 

An Enhanced Voltage Sag Compensation Scheme for Dynamic Voltage Restorer

IEEE Transactions on Industrial Electronics, 2013

ABSTRACT

This paper deals with improving the voltage quality of sensitive loads from voltage sags using dynamic voltage restorer (DVR). The higher active power requirement associated with voltage phase jump compensation has caused a substantial rise in size and cost of dc link energy storage system of DVR. The existing control strategies either mitigate the phase jump or improve the utilization of dc link energy by (i) reducing the amplitude of injected voltage, or (ii) optimizing the dc bus energy support. In this paper, an enhanced sag compensation strategy is proposed that mitigates the phase jump in the load voltage while improving the overall sag compensation time. An analytical study shows that the proposed method significantly increases the DVR sag support time (more than 50%) compared with the existing phase jump compensation methods. This enhancement can also be seen as a considerable reduction in dc link capacitor size for new installation. The performance of proposed method is evaluated using simulation study.

 

KEYWORDS:

  1. Dynamic voltage restorer (DVR)
  2. Voltage source inverter (VSI)
  3. Voltage sag compensation
  4. Voltage phase jump compensation.

 

SOFTWARE: MATLAB/SIMULINK

  

BLOCK DIAGRAM:

Fig. 1. Basic DVR based system configuration

 

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation results for the proposed sag compensation method for 50% sag depth. (a) PCC voltage, (b) load voltage, (c) DVR voltage, (d) DVR active and reactive power, and (e) dc link voltage.

Fig. 3. Simulation results for the proposed sag compensation method for 23% sag depth. (a) PCC voltage, (b) load voltage, (c) DVR voltage, (d) DVR active and reactive power, and (e) dc link voltage.

 

CONCLUSION

In this paper an enhanced sag compensation scheme is proposed for capacitor supported DVR. The proposed strategy improves the voltage quality of sensitive loads by protecting them against the grid voltage sags involving the phase jump. It also increases compensation time by operating in minimum active power mode through a controlled transition once the phase jump is compensated. To illustrate the effectiveness of the proposed method an analytical comparison is carried out with the existing phase jump compensation schemes. It is shown that compensation time can be extended from 10 to 25 cycles (considering pre sag injection as the reference method) for the designed limit of 50% sag depth with 450 phase jump. Further extension in compensation time can be achieved for intermediate sag depths. This extended compensation time can be seen as considerable reduction in dc link capacitor size (for the studied case more than 50%) for the new installation. The effectiveness of the proposed method is evaluated through extensive simulations in MATLAB/Simulink and validated on a scaled lab prototype experimentally. The experimental results demonstrate the feasibility of the proposed phase jump compensation method for practical applications.

 

REFERENCES

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