Explain distance protection of transmission line with neat sketch diagram.

Explain distance protection of transmission line with neat sketch diagram.
by

1 Answer

Answer :

Distance protection of Transmission line: Distance protection scheme uses impedance relay. The relay operation is based on the impedance (or distance) between the relay and point of fault. Figure shows arrangement for distance protection for typical transmission line. The voltage element of impedance relay receives supply from PT secondary and current element receives supply from CT secondary. It measures Impedance at relay location( Z = V / I ) The protection zone of line is between A and B under normal working conditions, the impedance of line is ZL. The impedance relay is so designed that, it operates only when line impedance becomes less than ZL. When fault occurs between points A & B, the impedance of line becomes less than ZL and impedance relay operates which operates the CB and line is protected.

image

by

Related questions

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.

Explain working of ELCB with neat sketch diagram.

Description : Explain working of ELCB with neat sketch diagram.

Last Answer : Earth Leakage Circuit Breaker(ELCB): Earth leakage circuit breaker is a safety device used in electrical installations with high earth impedance to prevent shocks and disconnect power under earth fault ... tripping in domestic installations with tripping time being as low as 25 msec.

Explain single phasing preventer with neat sketch diagram.

Description : Explain single phasing preventer with neat sketch diagram.

Last Answer : Single phasing preventer: Single phasing preventers are generally used for small / medium capacity motors. Single phasing preventers are connected in secondaries of line CTs. These mainly contains ... command is given to circuit breaker or starter. Thus it protects motor from damage.

Explain Horn-gap lightning arrester with neat sketch diagram.

Description : Explain Horn-gap lightning arrester with neat sketch diagram.

Last Answer : Horn Gap Type Lightning Arrester: It consists of two horn shaped metal rods A and B separated by a small air gap. The horns are so connected that distance between them gradually increases towards the ... being hot, moves up naturally along the horns. So it is elongated and naturally quenched.

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 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.

State two requirements of transmission line protection.

Description : State two requirements of transmission line protection. 

Last Answer : Requirements of Transmission Line Protection: 1) Faults on lines should be quickly detected to initiate actions to maintain system stability. 2) For very long lines the protection system must be capable ... backup protection in the event of failure of circuit breaker (nearest to fault) to operate.

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.

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. 

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 Buchholz relay with neat labelled diagram.

Description : Explain Buchholz relay with neat labelled diagram.

Last Answer : Buchholz relay: The relay is located in the path of the oil from transformer tank to conservator. As seen from diagram, the upper mercury switch operates the alarm circuit due to tilting of the ... manner that it senses the sudden violent movement of oil from transformer tank to conservator.

Explain working of surge absorber with neat diagram.

Description : Explain working of surge absorber with neat diagram.

Last Answer : Surge Absorber: Voltage transients or surges on the power system may originate from switching or lightning. These surges set up traveling waves in the transmission lines. These traveling waves may reach ... heat due to transformer action. Generally, it is used for the protection of transformers.

Explain with neat sketch overload protection for power circuit of locomotive.

Description : Explain with neat sketch overload protection for power circuit of locomotive.

Last Answer : Overload Protection for Power Circuit of Locomotive:  1. To protect the main power circuit from overload, the thermal overload relays are used. 2. The overload is sensed by the ... overload relay OLR3 operates for overload fault on traction motor due to the flashover of traction motors. 

Describe the construction of SF6 circuit breaker with neat diagram.

Description : Describe the construction of SF6 circuit breaker with neat diagram.

Last Answer : Construction of SF6 Circuit Breaker : A sulphur hexafluoride (SF6) circuit breaker consists of fixed and moving contacts enclosed in a chamber. The chamber is called arc interruption ... contact, moving contact and arcing horn are coated with a copper-tungsten arc-resistant material. 

Describe the construction and Operation of Buchholz relay with neat labeled diagram.

Description : Describe the construction and Operation of Buchholz relay with neat labeled diagram.

Last Answer : Construction of Buchholz Relay: It takes the form of a domed vessel placed in the connecting pipe between the main tank and the conservator. The device has two elements. The upper element ... manner that it senses the sudden violent movement of oil/gas from transformer tank to conservator. 

Describe the working of HRC fuse with neat diagram.

Description : Describe the working of HRC fuse with neat diagram.

Last Answer : Working of HRC Fuse: Under normal conditions, the fuse element is at a temperature below its melting point. Therefore, it carries the normal current without overheating. When a fault ... powder and results in the formation of high resistance substance that helps in quenching the arc. 

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 :

With the help of constructional diagram, explain the working of LDR with neat sketch.

Description : With the help of constructional diagram, explain the working of LDR with neat sketch.

Last Answer : Working Principle The resistance depends on the intensity of light, as resistance decreases with increase in light intensity. Characteristics Applications of LDR 1. They are often ... circuits, light intensity meters, for counting the packages moving on a conveyor belt, etc.

Explain string diagram with a neat sketch.

Description : Explain string diagram with a neat sketch. 

Last Answer : String Diagram: 1. A string diagram is defined as a scale plan or model on which a thread is used to trace and measure the path of workers, materials or equipments during a specified sequence of events ... movement. 6. A String diagram for a particular process is shown in following fig.

Explain with neat sketch block diagram of optical fiber communication system and list out sources and detectors suitable for it.

Description : Explain with neat sketch block diagram of optical fiber communication system and list out sources and detectors suitable for it.

Last Answer : OR 1. The light source is normally an infrared LED or LASER device which is driven by the current value from the V to I convertor. It emits light which is proportional ... optical energy electrical signal. The light detectors which are used as PIN photodiode and avalanche photo diode.

Explain with neat sketch method of drawing displacement diagram for SHM of follower.

Description : Explain with neat sketch method of drawing displacement diagram for SHM of follower. 

Last Answer : The displacement diagram is drawn as follows for SHM of follower : 1. Draw a semi-circle on the follower stroke as diameter. 2. Divide the semi-circle into any number of even equal ... number of equal parts. 4. The displacement diagram is obtained by projecting the points as shown in Figure

Draw a neat sketch of earth fault protection of auxiliary circuit of electric loco. State the function of relay and isolating resistance.

Description : Draw a neat sketch of earth fault protection of auxiliary circuit of electric loco. State the function of relay and isolating resistance.

Last Answer : Ans: Earth fault protection for auxiliaries in Loco: Function of relay: The earth fault occurring anywhere in the auxiliary circuit gets monitored by the relay which acts to trip the main CB. Function of ... star point to earth through a high resistance so that the relay operation is avoided.

Discuss in brief the principle of distance protection and state four advantages of distance protection scheme.

Description : Discuss in brief the principle of distance protection and state four advantages of distance protection scheme.

Last Answer : Advantages: 1. System is economical 2. High speed of interruption 3. Suitable for very long and high voltage transmission lines. 4. No problem of pilot wires.

Draw neat sketch of valve timing diagram for 4-stroke petrol engine & label it.

Description : Draw neat sketch of valve timing diagram for 4-stroke petrol engine & label it.

Last Answer : Figure: Valve timing diagram of 4 stroke SI engine  

With the help of neat sketch, describe block diagram of Electronic Diesel Control Unit (EDC).

Description : With the help of neat sketch, describe block diagram of Electronic Diesel Control Unit (EDC).

Last Answer : EDC: The ECU determines the correct quantity of the fuel to be injected based on the inputs and the data in the look up table. The fuel input depends on the rack position and thus ECU ... ECU can also protect the engine against overheating by regulating the maximum quantity of fuel delivered.

A transmission line is protected by (a) inrush protection (b) distance protection (c) time graded and current graded over current protection (d) both (b) and (c) (e) none of the above

Description : A transmission line is protected by (a) inrush protection (b) distance protection (c) time graded and current graded over current protection (d) both (b) and (c) (e) none of the above

Last Answer : (d) both (b) and (c)

Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at the line terminals (c) Possibility of better protection for the line due to possible use of higher terminal reactants (d) Improvement of power factor at times of moderate and heavy loads (e) Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Description : Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at ... of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Last Answer : (a) Increase of short-circuit current of the system

Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at the line terminals (c) Possibility of better protection for the line due to possible use of higher terminal reactants (d) Improvement of power factor at times of moderate and heavy loads (e) Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Description : Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at ... of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Last Answer : (a) Increase of short-circuit current of the system

The transmission line distance protection relay having the property of being inherently directional is

Description : The transmission line distance protection relay having the property of being inherently directional is (A) impedance relay (B) MHO relay (C) OHM relay (D) reactance relay

Last Answer : The transmission line distance protection relay having the property of being inherently directional is MHO relay

With neat diagram explain use of “reactive power controller” to reduce technical losses in transmission and distribution system.

Description : With neat diagram explain use of “reactive power controller” to reduce technical losses in transmission and distribution system.

Last Answer : Reactive power compensation in Transmission and Distribution systems: The reactive power is present in lines due to the reactive loads and device/ component reactance. This leads to heavy currents for active ... switched to the line as per the requirement of lagging or leading reactive VA. 

Describe sacrificial anodic protection with neat diagram.

Description : Describe sacrificial anodic protection with neat diagram.

Last Answer : Method: The metallic structure to be protected from corrosion is connected to anodic metal (upper placed in galvanic series) by an insulated wire. Thus externally added metal like Zn, Al, Mg, etc ... hot water tanks to prevent corrosion. The protection of underground pipelines is shown in Fig.

Explain skip zone and skip distance with neat diagram.

Description : Explain skip zone and skip distance with neat diagram.

Last Answer : Skip distance:-Skip distance is defined as the shortest distance from a transmitter, measured along the surface of earth at which a sky wav of fixed frequency returns back to the earth. Skip zone: skip zone where signal is not detectable

Explain with neat sketch Phreatic line in earthen dam with pressure head at different point and show construction points of this line.

Description : Explain with neat sketch Phreatic line in earthen dam with pressure head at different point and show construction points of this line. 

Last Answer : Procedure for locating the Phreatic line i) Draw an earthen dam having upstream face AB with water surface. ii) On water surface measure distance BC = 0.3 L C is starting pt of base parabola. Let F' ... parabola i.e. Phreatic line. viii) Here G,Q1,Q2,Q3,Q4 and B represent Phreatic line 

For complete protection of a three-phase line:

Description : For complete protection of a three-phase line: A) three Phase relays and three Earth fault relays are required B) three Phase relays and two Earth fault relays are required C) two Phase relays and two Earth fault relays are required D) two Phase relays and one Earth fault relay are required

Last Answer : For complete protection of a three-phase line: two Phase relays and one Earth fault relay are required

For complete protection ofa 3-phase line:

Description : For complete protection ofa 3— phase line: (1) Three phase and three—earth fault relays are required (2) Three phase and two—earth fault relays are required (3) Two phase and two—earth fault relays are required (4) Two phase and one-earth fault relays are required

Last Answer : For complete protection ofa 3— phase line: Two phase and one-earth fault relays are required

Transmission efficiency of a transmission line increases with the

Description : Transmission efficiency of a transmission line increases with the

Last Answer : Transmission efficiency of a transmission line increases with the increase in power factor and voltage

Which relay is preferred for phase fault on short transmission line?

Last Answer : Reactance relay is preferred for phase fault on short transmission line.

When a wave propagates on a transmission line, it suffers reflection several times at?

Last Answer : When a wave propagates on a transmission line, it suffers reflection several times at sending and other end.

The interaction between a transmission line and communication line is minimized by?

Last Answer : The interaction between a transmission line and communication line is minimized by transposing transmission as well as communication lines, increasing the height of the transmission line tower, increasing the distance between the two lines.

When a transmission line is energized, the wave that propagates on it is?

Last Answer : When a transmission line is energized, the wave that propagates on it is current wave and voltage wave.

A transmission line is protected by?

Last Answer : A transmission line is protected by distance protection, time graded and current graded overcurrent protection.

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 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 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 fault bus protection scheme.

Description : Explain fault bus protection scheme.

Last Answer : Fault bus protection of busbar: In this scheme, the substation is so designed that every fault on the bus bar is converted to earth fault. Under normal operating conditions, there is no current flowing ... This results in operation of relay to actuate trip coil of CB to trip the circuit.

Define base line and check line with neat sketch.

Description : Define base line and check line with neat sketch. 

Last Answer : 1)Base Line : The longest line running roughly through the middle of the area to be surveyed is known as base line 2) Check line: The line joining the apex of a triangle to some fixed point on the ... A line joining some fixed point on any two sides of a triangle is known as check line. 

Define ‘ Fore bearing ’ & ‘ back bearing ’ of line with a neat sketch

Description : Define ‘ Fore bearing ’ & ‘ back bearing ’ of line with a neat sketch

Last Answer : Fore bearing : The bearing of line observed in the direction of progress of survey is called fore bearing of the line. Bearing of line AB is observed at A' towards B' is called as fore bearing of the line ... The bearing observed at B' towards A' is called as back bearing of the line AB'  

Describe in brief with neat sketch: i) Base line ii) Check line

Description : Describe in brief with neat sketch: i) Base line ii) Check line

Last Answer : i) Base line:  Base line is generally the longest line running roughly through the middle of the area. It is laid on a level ground as far as possible. The whole frame work is built upon this line. ... on the opposite side or a line joining some fixed point on any two sides of the triangle.