Explain current limiting reactor.

Explain current limiting reactor.
by

1 Answer

Answer :

Current Limiting Reactor: A Reactor is a coil of number of turns designed to have large inductance with negligible ohmic resistance connected in series with equipment to limit the short circuit current. Generally reactance of the system under fault condition is low and fault currents may rise to dangerously high values. In order to limit the fault current to reasonable magnitudes which the CB can handle, additional reactances (reactors) are connected in series with system at suitable points. These reactors are called “Current Limiting Reactors”.


Classification of reactors : 1) Generator reactors 2) Feeder reactors 3) Busbar reactors i) Ring Systems ii) Tie bar system

by

Related questions

What is a current limiting reactor ? How many types and what are they ?

Description : What is a current limiting reactor ? How many types and what are they ?

Last Answer : Answer : A current limiting reactor is basically an inductive coil which limits the short circuit current by providing inductive reactance when required. Types: 1. Based on the structure- a) Dry type ... reactor. Basbar reactors are again of 2 types- a) Ring system reactor b) Tiber system reactor

Draw neat circuit diagram of i) Feeder reactor and ii) Generator reactor

Description : Draw neat circuit diagram of i) Feeder reactor and ii) Generator reactor

Last Answer : 1) Circuit Diagram of Feeder Reactor : 2) Circuit Diagram of Generator Reactor :

Explain over-current protection of transformer.

Description : Explain over-current protection of transformer.

Last Answer : Over-Current Protection of Transformer: Simple over-current & earth fault protection of transformer against external shortcircuit and excessive overloads is shown in the above figure. The ... trip command to the circuit breaker and the transformer is disconnected from load or fault.

Explain construction and operation of induction type directional over current relay.

Description : Explain construction and operation of induction type directional over current relay.

Last Answer : Directional overcurrent relay: Construction: It consists of two units: i) Non-directional Over-current unit ii) Directional power unit The directional unit consists of upper electromagnet ... closes the trip circuit. This operates circuit breaker which isolates the faulty section. 

If a circuit breaker that utilizes built-in, current limiting fuses (CLF's) cannot be closed, the problem may be traced to __________. A. a blown CLF plunger holding the trip bar in the open position B. a missing CLF C. a misaligned limiter housing assembly D. all of the above

Description : If a circuit breaker that utilizes built-in, current limiting fuses (CLF's) cannot be closed, the problem may be traced to __________. A. a blown CLF plunger holding the trip bar in the open position B. a missing CLF C. a misaligned limiter housing assembly D. all of the above

Last Answer : Answer: D

Which one is not the basic electrical protection measures in the Philippine Electronics Code? A. Voltage/ current limiting and interrupting B. Undergrounding C. Grounding and bonding D. Shielding

Description : Which one is not the basic electrical protection measures in the Philippine Electronics Code? A. Voltage/ current limiting and interrupting B. Undergrounding C. Grounding and bonding D. Shielding

Last Answer : B. Undergrounding

What is meant by current limiting?

Description : What is meant by current limiting?

Last Answer : Current limiting refers to the ability of a regulator to prevent the load current from increasing above a preset value.

How special current limiting resistance is connected with the seal in contact?

Description : How special current limiting resistance is connected with the seal in contact?

Last Answer : Special current limiting resistance is connected in series with the seal in contact.  

Foldback current limiting has the advantage of A) Better pass transistor protection for long term overloads B) A defined turn on point C) Circuit simplicity D) All of the above.

Description : Foldback current limiting has the advantage of A) Better pass transistor protection for long term overloads B) A defined turn on point C) Circuit simplicity D) All of the above.

Last Answer : A) Better pass transistor protection for long term overloads

A crow bar is a power supply circuit that provides A) Conventional current limiting B) Foldback current. limiting C) Temperature control D) Voltage limiting.

Description : A crow bar is a power supply circuit that provides A) Conventional current limiting B) Foldback current. limiting C) Temperature control D) Voltage limiting.

Last Answer : D) Voltage limiting.

What is the limiting factor as to the amount of current an electrodynamometer meter movement can handle?

Description : What is the limiting factor as to the amount of current an electrodynamometer meter movement can handle?

Last Answer : Size of spiral conducting.

What is the limiting factor as to the amount of current an electrodynamometer meter movement can handle?

Description : What is the limiting factor as to the amount of current an electrodynamometer meter movement can handle?

Last Answer : Size of spiral conducting.

Describe the operation of current differential relay with neat sketch.

Description : Describe the operation of current differential relay with neat sketch.

Last Answer : Operation of Current Differential Relay: Figure shows an arrangement of an overcurrent relay connected to operate as a differential relay for alternator protection under fault conditon. ... current flows through relay coil, causing relay to operate for protection of alternator winding.

Define the following terms with respect to protective relays i) Relay time ii) Reset current iii) Plug setting multiplier and iv) Time setting multiplier

Description : Define the following terms with respect to protective relays i) Relay time ii) Reset current iii) Plug setting multiplier and iv) Time setting multiplier

Last Answer : 1) Relay Time: The time interval between occurrence of fault and closure of relay contacts.  2) Reset Current: The value of current below which the relay resets and comes back to ... The adjustment arrangement provided for setting the operation time of relay is known as Time setting multiplier. 

Define the following terms related to circuit breaker. 1) Breaking Capacity 2) Making Capacity 3) Short time rating and 4) Normal current rating

Description : Define the following terms related to circuit breaker. 1) Breaking Capacity 2) Making Capacity 3) Short time rating and 4) Normal current rating

Last Answer : 1) Breaking Capacity: It is current (r.m.s) that a circuit breaker is capable of breaking at given recovery voltage under specified conditions (e.g. power factor, rate of rise of ... under specified conditions. The only limitation in this case is the temperature rise of current-carrying parts.

Draw a typical time-current characteristic for IDMT relay.

Description : Draw a typical time-current characteristic for IDMT relay. 

Last Answer : Time-Current Characteristic for IDMT Relay:

Describe over current relay with time-current characteristic.

Description : Describe over current relay with time-current characteristic.

Last Answer : Over current relay with time-current characteristics:- 1. Definite time over current relay: Operating time is constant, the relays operates after a predetermined time when the current exceeds the pickup ... of fault current and definite time characteristics at higher values of fault current.

The burden of protective Current Transformer (CT) is specified in

Description : The burden of protective Current Transformer (CT) is specified in

Last Answer : The burden of protective Current Transformer (CT) is specified in Volt - Ampere

Zero-sequence current is used for relaying purpose only in the case of

Description : Zero-sequence current is used for relaying purpose only in the case of   (a) Phase over current relay (b) Phase impedance relay (c) Ground over current relay (d) Ground impedance relay

Last Answer : Zero-sequence current is used for relaying purpose only in the case of Ground impedance relay

In order to reduce the voltage surges due to current chopping and capacitive current breaking,

Description : In order to reduce the voltage surges due to current chopping and capacitive current breaking, we connect (A) A resistor across the CB contacts. (B) A capacitor across the CB contacts. (C) An inductor across the CB contacts. (D) A switch across the CB contacts

Last Answer : In order to reduce the voltage surges due to current chopping and capacitive current breaking, we connect A resistor across the CB contacts.

The operating point of a protective current transformer is near the

Description : The operating point of a protective current transformer is near the

Last Answer : The operating point of a protective current transformer is near the Ankle point

If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug

Description : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be

Last Answer : If the fault current is 6000 A, the relay plug setting is 150% and the CT ratio is 400/5, the plug setting multiplier will be 10

If the % reactance upto the fault point is 20%, then the short circuit current will be

Description : If the % reactance upto the fault point is 20%, then the short circuit current will be

Last Answer : If the % reactance upto the fault point is 20%, then the short circuit current will be 5 times the full load current

The inrush current of a transformer at no load is maximum if the supply voltage is switched on

Description : The inrush current of a transformer at no load is maximum if the supply voltage is switched on  (1) at peak voltage value (2) at zero voltage value (3) at half voltage value (4) at 0.866 time voltage value

Last Answer : At 0.866 time voltage value

The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density.

Description : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is :  (A) 256 W (B) 320 W (C) 500 W (D) 625 W

Last Answer : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : 625 W

In the induction type directional over current relay, when a short-circuit occurs in the circuit

Description : In the induction type directional over current relay, when a short-circuit occurs in the circuit (A) power flows in reverse direction (B) power flows in normal direction (C) directional power element does not operate (D) over current element is not energized

Last Answer : In the induction type directional over current relay, when a short-circuit occurs in the circuit power flows in reverse direction

ln HRC fuse the time between cut-off and final current zero is called

Description : ln HRC fuse the time between cut-off and final current zero is called

Last Answer : ln HRC fuse the time between cut-off and final current zero is called the arcing time

The inverse definite mean time relays are used for over current and earth fault protection of transformer against?

Last Answer : The inverse definite mean time relays are used for over current and earth fault protection of transformer against internal short-circuits.

The current zero interruption, in oil and air blast circuit breakers, is achieved by?

Description : The current zero interruption, in oil and air blast circuit breakers, is achieved by?

Last Answer : The current zero interruption, in oil and air blast circuit breakers, is achieved by lengthening of the gap, cooling and blast effect.

In order that current should flow without causing excessive heating or voltage drop, the relay contacts should?

Last Answer : In order that current should flow without causing excessive heating or voltage drop, the relay contacts should have low contact resistance, be clean and smooth, be of sufficient size and proper shape.

Thermal overload relays are used to protect the motor against over current due to?

Last Answer : Thermal overload relays are used to protect the motor against overcurrent due to heavy loads.

In which fault the maximum short circuit current occurs?

Description : In which fault the maximum short circuit current occurs?

Last Answer : In three phase bolted fault the maximum short circuit occurs.

Explain the term limiting factor? -Biology

Description : Explain the term limiting factor? -Biology

Last Answer : A limiting factor is simply anything in short supply that prevents photosynthesis occurring at its maximum rate. If photosynthesis occurs more slowly in plant cells then a lower quantity of sugar will be produced and the quantity of chemical energy available for cell growth will be reduced.

Explain the term limiting factor? -Biology

Description : Explain the term limiting factor? -Biology

Last Answer : A limiting factor is simply anything in short supply that prevents photosynthesis occurring at its maximum rate. If photosynthesis occurs more slowly in plant cells then a lower quantity of sugar will be produced and the quantity of chemical energy available for cell growth will be reduced.

Which of the device is employed in substation to limit the short circuit current in the power system: a) Shunt condenser b) Reactor c) Series capacitor d) Shunt capacitor

Description : Which of the device is employed in substation to limit the short circuit current in the power system: a) Shunt condenser b) Reactor c) Series capacitor d) Shunt capacitor

Last Answer : Ans: B

Basically, a magnetic amplifier is a saturable reactor with the addition of _____________. A. AC to the bias winding B. variable capacitance to all windings C. eddy current protectors D. a rectifier in the load circuit

Description : Basically, a magnetic amplifier is a saturable reactor with the addition of _____________. A. AC to the bias winding B. variable capacitance to all windings C. eddy current protectors D. a rectifier in the load circuit

Last Answer : Answer: D

The point of operation for a saturable reactor in a power circuit is that at which _______________. A. a large change in control current results in small change in load current B. a small change in load current results in a large change in control current C. a small change in control current results in a large change in load current D. a large change in load current causes a small change in control current

Description : The point of operation for a saturable reactor in a power circuit is that at which _______________. A. a large change in control current results in small change in load current B. a small change in ... change in load current D. a large change in load current causes a small change in control current

Last Answer : Answer: C

A nuclear reactor is a device used to carry out controlled nuclear reaction whereas GM counter is a device used to detect? A. Current B. Voltage C. Nuclear Radiation (Answer) D. power E. None of these

Description : A nuclear reactor is a device used to carry out controlled nuclear reaction whereas GM counter is a device used to detect? A. Current B. Voltage C. Nuclear Radiation (Answer) D. power E. None of these

Last Answer : C. Nuclear Radiation (Answer)

Justify the use of saturable reactor to control the magnitude of welding current.

Description :  Justify the use of saturable reactor to control the magnitude of welding current.

Last Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Explain the “Differential Protection Scheme” used for alternators with neat labeled diagram.

Description : Explain the “Differential Protection Scheme” used for alternators with neat labeled diagram.

Last Answer : Differential Protection Scheme for Alternator: Figure shows the differential protection provided to 3 phase alternator. Here identical CTs are placed on both sides of 3 phase alternator and ... causing its operation. Relay sends trip signal to the CB, thereby alternator circuit is tripped.

With the help of neat diagram, explain operation of static relay.

Description : With the help of neat diagram, explain operation of static relay.

Last Answer : Operation of Static Relay: Operation: 1) The solid-state component used are transistors, diodes, resistors, IC s, capacitor etc. The function of comparison and measurement are accomplished by ... ) An auxiliary dc supply is provided for operation of static relay elements as shown in figure.

Explain the working of single phasing preventer with neat diagram.

Description : Explain the working of single phasing preventer with neat diagram.

Last Answer : Working of single phasing preventer:  Single phasing preventers are generally used for small / medium capacity motors. Single phasing preventers are connected in secondary of line CTs. These ... contact gets opened which stops the motor to avoid further damage when single phasing occurs. 

Explain with neat sketch, the Pilot wire protection scheme applied to transmission line.

Description : Explain with neat sketch, the Pilot wire protection scheme applied to transmission line.

Last Answer : Pilot Wire Protection scheme of Transmission Line : Figure shows the single line diagram of Merz price voltage balance system for pilot wire protection of three phase transmission line. ... through the relay, which gives trip signal to the circuit breaker for protection of transmission line.

Explain differential protection scheme for busbars with neat sketch.

Description : Explain differential protection scheme for busbars with neat sketch.

Last Answer : Differential Protection Scheme for Bus bar:  Under normal conditions, the sum of the currents entering the bus bar zone is equal to those leaving it and no current flows through the relay ... of these currents will flow through the relay coil causing opening of circuit breaker of bus-bar.

With a neat sketch, explain the working of Thermal relay.

Description : With a neat sketch, explain the working of Thermal relay.

Last Answer : Working of Thermal Relay: 1) When the system is in normal operating condition, the heating element carries normal current from CT, this current produces heat = I2Rt. This heat ... of the spring releases which operates relay contacts resulting into providing trip signal to trip circuit.

With neat diagram explain the operation of Horizontal break isolator.

Description : With neat diagram explain the operation of Horizontal break isolator.

Last Answer : Operation of Horizontal Break Isolator: 1) Fixed female contacts of metal are supported on stack of insulator. 2) Male contact rod is connected to central insulating support which can be ... on galvanized steel channel or steel frame. The moving male contact can be move through 90o.

Explain differential protection of busbar.

Description : Explain differential protection of busbar.

Last Answer : Differential protection Scheme for bus bar: Under normal conditions the sum of the currents entering the bus bar zone is equal to those leaving it and no current flows through the relay ... . The difference of these currents will flow through the relay coil causing opening of circuit breaker.

Explain negative phase sequence protection of alternator.

Description : Explain negative phase sequence protection of alternator.

Last Answer : Negative phase sequence protection of alternator: Unbalanced loading on alternator mainly causes the negative sequence currents which generate the negative sequence components of magnetic fields. These fields ... components due to unbalance and operates the relay which further operates CB.

Explain operation of balanced beam type relay.

Description : Explain operation of balanced beam type relay.

Last Answer : Balanced Beam Type Relay: Under normal operating condition the current through relay coil is such that the beam is held in the horizontal position by the spring. When the fault occurs on the system the ... becomes greater than pick-up value and beam is attracted to close the trip circuit.