M. Tech M. Tech Thesis Thesis On On POWER SYSTEM STABILITY ENHANCEMENT BY SIMULTANEOUS AC-DC POWER TRANSMISSION Submitted By: ABHISHEK CHATURVEDI ID No. : 11MTEEEPS019 Advisor: Er. Vinay Kumar Tripathi (Asst. Professor) Department of Electrical and Electronics Engineering Shepherd School of Engineering and Technology Sam Higginbottom Institute of Agriculture, Technology and Sciences (Deemed-To-Be-University) Allahabad-211007, Uttar Pradesh
Transcript
M. Tech M. Tech ThesisThesis
OnOn
POWER SYSTEM STABILITY ENHANCEMENT BY SIMULTANEOUS AC-DC POWER TRANSMISSION
Submitted By:ABHISHEK
CHATURVEDI ID No. : 11MTEEEPS019
Advisor:Er. Vinay Kumar Tripathi
(Asst. Professor) Department of Electrical and Electronics Engineering
Shepherd School of Engineering and TechnologySam Higginbottom Institute of Agriculture, Technology and
Sciences(Deemed-To-Be-University)
Allahabad-211007, Uttar Pradesh
INTRODUCTION
The concept of simultaneous ac-dc power transmission.Long extra high voltage (EHV) ac lines cannot be loaded to their thermal limits due to this instability occurs in the power system
It is possible to load these lines very close to their thermal limits.
The conductors are allowed to carry usual ac along dc superimposed on it.
The advantage of parallel ac-dc transmission for improvement of transient stability and dynamic stability and damp out oscillations have been established.
Simulation study is carried out in MATLAB software package. The results shows the stability of power system when compared with only ac transmission.
OBJECTIVE OF THE THESIS
To emphasize the possibility of simultaneous ac-dc transmission with its inherent advantage of power flow control improves stability and damps out oscillations in power system.
To achieve the advantages of parallel ac-dc transmission in some specific applications LV (low voltage) and MV (Medium voltage) system.
METHODSAND
METHODOLOGY
Using flexible ac transmission system (FACTS) components .
Very fast control of SCRs in FACTS devices like state VAR system (SVS), controlled series capacitor (CSC), static phase shiftier (SPS) and controlled braking resistors oscillations as well as to control the voltage profile of the line by controlling the total reactive power flow.
The flexible ac transmission system (FACTS) concepts, based on applying state-of-the-art power electronic technology to existing ac transmission system, improve stability to achieve power transmission close to its thermal limit.
BASIC BLOCK DIAGRAM
Simulation Model
Result’s and Discussion
Sending end Voltage, receiving end voltageSending end Voltage, receiving end voltage
Sending end current, receiving end current
Sub system 4, Active & reactive power
Combined AC DC Current
Ac current to Zig- Zag Transformer
Rectifier dc side Voltage
Inverter sending, receiving end Voltage
FFT analysis of combined ac-dc power transmission
TABLE ICOMPUTED RESULTS
Power Angle 30 45 60 75 AC Current(kA) 0.416 0.612 0.80 0.98 DC Current(kA) 5.25 5.07 4.80 4.50 AC Power(MW) 290 410 502 560 DC Power(MW) 1685 1625 1545 1150 Total Power(MW) 1970 2035 2047 1710
The benefits of utilizing FACTS devices in electrical transmission systems
can be summarized as follows Better utilization of existing transmission system assets Increased transmission system reliability and availability Increased dynamic and transient grid stability and reduction of loop flows Increased quality of supply for sensitive industries Environmental benefits Better utilization of existing transmission system assets
CONCLUSION A simple scheme of simultaneous EHV ac-dc power transmission
through the same transmission line has been presented.
Active and reactive powers associated with ac and dc, conductor voltage level and total power have been obtained for steady state normal operating condition.
Simulation studies are being made for the co-ordinated control and also individually the control of ac and dc power transmitted through the lines.
There is substantial gain in the loading capability of the line
The possibility of converting a dual circuit ac line into simultaneous ac-dc power transmission block to improve power transfer as well as to achieve reliability in the power transfer.
The added dc power flow is flawless and is not the cause of any transient instability.
REFERENCES
[1] N. G. Hingorani, “FACTS—flexible A.C. transmission system,” in Proc. Inst. Elect. Eng. 5th. Int. Conf. A.C. D.C. Power Transmission,
[2] Padiyar.’HVDC Power Transmission System.’ Wiley Eastern, New Delhi, 1993)
[3] H. Rahman and B H Khan “Stability Improvement of Power Systemby Simultaneous AC-DC Power Transmission” Electric Power System Research Journal, Elsevier, Paper Editorial ID No. EPSRD- 06-00732, Press Article No. EPSR-2560— Digital Object.
