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Presented by:-Manas Ranjan MahantaElectrical Engg. Regd.1101221009

Guided by:-Asst. Prof. Santwana Pradhan

SUPERCONDUCTIVITY IN ELECTRIC POWER SECTOR

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Contents:-

• Introduction• Types of SC• LTS Vs HTS• Properties of SC• Energy Applications• Conclusion

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Introduction:-• Superconductors(SC) are materials which exhibit

zero resistivity below a certain temperature.

• The phenomenon of superconductivity was first observed in mercury by the Dutch physicist Heike Kamerlingh Onnes in 1911 .

• Discovery of High Temperature superconductors in 1986 reignited interest in superconducting Power application because of lower cooling costs.

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What is Superconductivity?• Superconductivity is a phenomenon observed in

several metals and ceramic materials cooled to temp. ranging from near abs. zero (0 K, -2730 C) to liquid nitrogen temp. ( 77 K, -1960 C), their electrical resistance drops with a jump down to zero.

• The temperature at which electrical resistance is zero is called the critical temperature (Tc).

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Types of Superconductor:-

• Low Temperature Superconductors (LTS) Ex- Nb3Sn,Nb3Ge

• High Temperature Superconductors (HTS) Ex- YBCO

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Disadvantages of LTS:-• Critical Temperatures are Very low

• Cost of cooling is very high using Liquid Helium

• For LTS TC < 20K Advantages of HTS:-• Comparatively higher critical temperatures

• HTS show superconductivity at or above 77K

i.e. temp. of Liquid Nitrogen.

• Liquid nitrogen is 15 times cheaper than liquid

helium.

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   Properties of Superconductors:-• Zero resistivity.• Critical temperature (Tc).• Critical magnetic field (Bc).• Critical current (Jc).

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Applications:-

• Superconducting transmission line cables• Superconductor magnetic energy storage (SMES)• Superconducting generator• Other power applications.

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Transmission line cables:-

LTS Cables..

• Superconducting cable has to be cooled (nearly absolute temp -273.16 ).℃

• Cooled by liquid Helium (too expensive).

• Difficult to utilized in industrial field, such as power transmission system.

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 HTS Cables..

• Superconducting property about temp 70[K] .• Cooled by liquid Nitrogen [Liquid N2].

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Cross-sectional view of HTS cable..

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Advantages of superconducting cable over underground cable:-• Zero resistance • Small physical size • Reduced clearance for terminal facilities• Higher reliability • Overload capability

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Superconductor magnetic energy storage(SMES):-

• SMES is a device for storing and instantaneously discharging large quantities of power.

• It stores electric energy in the magnetic field generated by DC current flowing through a coiled wire.

• The SMES recharges within minutes and can repeat the charge/discharge sequence thousands of times without any degradation of the magnet.

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Components Of SMES System• Superconducting Coil • Power Conditioning System (PCS)• Refrigeration unit

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Operation Of SMES System:-

• SMES stores energy in form of magnetic field.• The magnetic field is created with the flow of DC

current.• Conversion of AC to DC in PCS .• DC Voltage charges the Superconducting Coil.• The coil discharges and acts as a source of energy

when AC network requires power.

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• Superconductors have zero resistance to DC electrical current at low temperatures.

• Very low Ohmic heat dissipation. • Energy stored within the coil is given by

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Advantages Of SMES :-

• Time Delay during charge and discharge is quite short.

• Very High Power is available almost instantaneously.

• Loss of power is less than other storage method.• High Reliability.• Environmental friendly and highly efficient.

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Uses of SMES:-

• Power quality control at manufacturing plants.• Grid stability.• Power system transmission control and

stabilization.• High penetration of renewable energy sources,

such as wind and solar.

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Superconducting generator:-

Characteristics :-

• Rotor with the HTS field windings spinning.• The HTS field windings is cooled at 25 - 40 K

temp. range. • The field coils are cooled by a cryocooler

system using either cold gas or liquid as the heat transfer medium.

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Schematic Diagram Of Superconducting Generator:-

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Advantages:-• 50% reduced the size and weight .• Approximately 70% lower transportation costs. • Easier transportation.• Cheaper foundations and buildings.• 1% higher electrical efficiency.• Higher stability due to lower machine reactance.

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Disadvantages…..

• High cost.• Difficult for maintaining cryoogenic temp.

required for cooling.• Generator fails to work ,if the SC leave their

superconductivity state.

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Other power applications:-

1. Transformers2. Fault Current Limiters3. MRI (Magnetic Resonance Imaging)4. Transportation (Maglev Trains)5. Military

• SQUID (Superconducting Quantum Interference Device)• E-Bombs

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Conclusion• In this era SC Generators and Energy Storage

seems to be the only solution to our ever-increasing energy demand.

• They help by ensuring good quality power and system-stability.

• SCPA is the technology of tomorrow.

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Reference…

• http://en.wikipedia.org/wiki/Superconducting_magnetic_energy_storage

• http://www.ornl.gov/• http://www.superconductorweek.com/• http://www.ieeexplore.org/

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