seminar ppt sfcl ppt
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COLLEGE OF TECHNOLOGY AND ENGINEERING A Seminar on
ObjectivesIntroduction Requirement of FCL Properties of SFCL Operating principle of FCLDesired Characteristic of an ideal FCLTypes of FCLApplications of FCLConclusions
To study the various types of fault current limiters for Power system Protection and its applications.
SFCL is a new power device to automatically limit a fault current to a safe level with the superconducting property. These fault-current limiters, unlike reactors or high-impedance transformers, will limit fault currents without adding impedance to the circuit during normal operation.
Increasing of fault levels beyond existing circuit breaker capacities
Fault current limiters(FCL) are urgently needed
The equipment installed at power grids and at generating station is very expensive and its cost, if estimated, would be in million of dollars. In order to save this expensive equipment from fault currents during faults and short circuits, fault current limiters are required.
High impedance in fault operation
Low impedance in normal operation
Limits fault current before first peak
Normal operation Load current flows through superconducting unit. SFCL introduces nearly zero impedance and zero voltage drops.Fault Condition Superconductor inherently senses fault current, quenches, inserts high resistance in ~ 1 ms. Current transfers to shunt and limits fault current.Recovery Superconducting unit recovers superconducting state quickly (seconds)
An Ideal Fault Current Limiter would- Increase the impedance on the line well before the first peak.
No power loss in normal operation.
Diminish the fault current by at least a factor of 2 for its duration.
Return the impedance to its original value.
Resistive FCLInductive shielded core FCL
Superconductors connected in series with the line to be protected and is immersed in a coolant to keep superconducting property. In case of the fault the inrush of current take the superconductor into the transition region, thereby the increasing the resistance limits the fault current.
Resistive FCL with protective shunt
Inductive shielded core current limiter is a transformer device with: Copper primary winding Superconducting shorted secondary windingPrimary winding is in series with the line to be protected.
Inductive shielded FCL in a network system
Three main application areas are:
Fault current limiter in the main position on bus : Protects the entire bus. A larger transformer can be used. I^2 Rt damage to the transformer is limited.
Fault- current limiter in the feeder position:It protects an individual circuit on the bus.
A FCL can also be used to protect individual loads on the bus.
Fault current limiter in bus tie position:
The buses are tied, yet a faulted bus receives the full fault current of only one transformer.
This limiter requires only a small load current rating.
Unlike traditional grid technology, superconducting fault current limiters are smart.
They increase their resistance abruptly in response to overcurrents from faults in the system, thus limiting the overcurrents and protecting the grid from damage.Fault Current Limiters - Inherently Smart
Fault Current Limiters are new devices, using the unique electrical properties of HTSto almost instantaneously protect power grids against short circuits and thereby prevent costly outages. They are a key member of a family of ultra-fast HTS devices and machines used for conditioning electrical power.