HVDC TRANSMISSION SYSTEM Presented by Vinay Vishwakarma Yogesh
“HVDC TRANSMISSION SYSTEM” Presented by: Ø Ø Vinay Vishwakarma Yogesh Mishra Ø Ø Devesh Pandey Ashish Tiwari Ravi Mishra Amit Shukla Guided by: Er. Gaurav Kumar Mishra Head of Electrical Engg. Department Of Electrical Engineering 6 th Semester
HVDC TRANSMISSION LINE
CONTENT 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. INTRODUCTION HISTORY OF HVDC PROCESS DIAGRAM THE LINK BETWEEN RIHAND TO DADRI SUBSTATION COMPONENT USED WHY HVDC IS NECESSARY OVER AC LIMITATION OF HVDC APPLICATION OF HVDC THE FUTURE PROSPECTS CONCLUSION
INTRODUCTION • • • A high-voltage, direct current (HVDC) electric power transmission system uses direct current for the bulk transmission of electrical power. For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. High voltage is used for electric power transmission to reduce the energy lost in the resistance of the wires. Recent developments in conversion equipment have reduced their size and cost and improved their reliability. The major components of a HVDC transmission system are converter stations where conversion from AC to DC and from DC to AC are performed.
HISTORY OF HVDC
THE LINK BETWEEN RIHAND TO DADRI SUBSTATION
PROCESS DIAGRAMS 6 V/12 V---12 V AC to 12 V DC—transmission– 12 V DC to 12 V AC--12 V/6 V– sub transmission– 6 V/3 V--- distribution and lightning.
COMPONENT USED • • • Converter Transformer Step up Transformer ( at Generation Station). Step up Transformer (at Substation). Step down Transformer (at Distribution). Rectifier is a static device which converts AC into Pulsating DC voltage. Filter is used to make the ripple free supply (pure DC). Invertor is a static device which converts DC into AC voltage with desired frequency. Power LEDs is used for lightning a plant.
WHY HVDC IS NECESSARY OVER AC The reasons for selecting HVDC instead of HVAC are : 1. Lower cost at operating condition. 2. Lower transmission losses. • As only two conductor are required in HVDC hence I 2 R losses are low for same power transfer. 3. Cheaper in cost. • Require two wire for transmission but AC needs Three wire. • Size of Pole, Insulators, Cross Arm are to be reduced. • The phase to phase clearance, phase to ground clearance and tower size are smaller in case of DC transmission. 4. Asynchronous interconnections. • A DC link can be used to inter-connect two AC systems of different frequency.
CONTINUED…… 6. § 7. • 7. 8. 9. No Skin effect: There is no skin effect in DC, because skin effect is directly proportion to frequency and hence there is uniform distribution of current over the cross-section of the conductor. Better voltage regulation. Because there is no inductance and capacitance therefore voltage regulation is 0%. Absence of charging current. Low short circuit currents. Direct Current saves forest and lands.
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ADVANTAGES OF HVDC
LIMITATION OF HVDC 1. • • • 2. 3. 4. Costly terminal equipments. The convertors required at both the ends are more expensive. The convertors produce a lot of harmonics both on DC and AC sides and may cause Radio Interference. To remove ripples from the DC output, filtering & smoothening equipments are to be provided. More maintenance of insulators is required in HVDC system. Complexity of control. Voltage transformation is not easier in case of DC system.
APPLICATIONS OF HVDC For long distance high power transmission. 2. For interconnection (tie lines) between two or more AC systems having their own load frequency control. 3. For back to back asynchronous tie substation where two AC systems are interconnected by a convertor substation without any AC transmission line in between. 4. For underground or submarine cable transmission over long distances at high voltage. 1.
THE FUTURE PROSPECTS There are the following future aspects of the project as: 1. The complete system from generation to distribution is in the from of DC i. e. possible by using power electronics circuits. 2. By using DC Choppers in place of transformers, we have resolved complete system into DC system.
CONCLUSION Availability of non- renewable resources is limited. • HVDC is used for increasing the efficiency of transmission lines. • Dependency of source from foreign countries are to be reduced. • HVDC transmission line gives the Reliable, Economical and Stable supply as compares to AC. •
ANY QUERY……
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