What are the protections provided for 220 kV lines and bus bars?

What are the protections provided for 220 kV lines and bus bars? 
by

1 Answer

Answer :

a. Bus bar differential protection.

b. Distance protection.

c. Over current protection.

d. Earth fault protection. 
by

Related questions

Why earth switches are provided in 220 kV bays?

Description : Why earth switches are provided in 220 kV bays?  

Last Answer : When bay CB trips, both end (station and grid) CB will trip. The earth switches are provided because the grid will always be alive so to prevent any shocks to the operator or maintenance personnel who is working on the line or bay due to accidental energizing of the bus.  

What is the design basis of 6.6 kV aluminium bus bars?

Description : What is the design basis of 6.6 kV aluminium bus bars?  

Last Answer : a) Temperature rises not exceed 90 ºC. b) Withstand short ckt stresses. c) Take care of thermal expansion. 

Cables for 220 kV lines are invariably (a) mica insulated (b) paper insulated (c) compressed oil or compressed gas insulated (d) rubber insulated (e) none of the above

Description : Cables for 220 kV lines are invariably (a) mica insulated (b) paper insulated (c) compressed oil or compressed gas insulated (d) rubber insulated (e) none of the above

Last Answer : (c) compressed oil or compressed gas insulated

What are the levels of SF6 gas in 220 kV breaker and their significance?

Description : What are the levels of SF6 gas in 220 kV breaker and their significance?

Last Answer : 7 kg/cm2 - normal pressure 5.2 bar - alarm 5.0 bar - closing/tripping operation blocked. 

What is the type of 220 kV circuit breaker?

Description : What is the type of 220 kV circuit breaker? 

Last Answer : 220 kV, SF6 breaker, single pole, puffer type. 

What are the main parts of 220 kV Circuit Breaker?

Description : What are the main parts of 220 kV Circuit Breaker? 

Last Answer : Pole column filled with SF6 Pneumatic drive system with compressed air circuit Control cubicle unit 

Give the details of switchyard 220 kV CB, Isolator, CT, CVT and lightning arrestor.

Description : Give the details of switchyard 220 kV CB, Isolator, CT, CVT and lightning arrestor.  

Last Answer : 220 kV SF6 Circuit Breaker 1. Make - ABB 2. Air pressure blocking a. Close Block - 17.3 bar. b. Open block - 16.7 bar. c. Auto reclose block - 19 bar. 3. SF6 pressure block a. Alarm - 5. ... , storage and erection. Rated voltage : 216 kV rms. Operating voltage : 184 kV rms. 

In 220 kV switchyard why lightning arrestor should be properly grounded?

Description : In 220 kV switchyard why lightning arrestor should be properly grounded?

Last Answer : a. During lightning, surges should be discharged to ground, otherwise it will puncture the equipment insulation and it is possible only when lightning arrestor is grounded properly.  b. In order to make it effective ... kV. Soil resistivity a should be minimum and may be it is 3.5 ohm per meter.  

What is the difference in action of lock out pressure signal on 6.6 kV and 220 kV breakers?

Description : What is the difference in action of lock out pressure signal on 6.6 kV and 220 kV breakers?

Last Answer : When lock out signal comes to 6.6 kV breakers the breaker will trip. Where as in case of 220 kV breakers the breaker will not trip. If the breaker is open it will be open only and can not be closed. If it is in closed condition it will be closed.

What are the protections provided for DG?

Description : What are the protections provided for DG?

Last Answer : 1. Differential protection (87). 2. Over speed of engine. 3. Reverse power protection (in LOCA condition time delay). 4. Low lubricating oil pressure. 5. Cooling water temperature high. 6. 6 ... 8. Emergency stops push button. In LOCA condition 4 - 8 protections are not permitted to operate. 

What are the protections provided in charger?

Description : What are the protections provided in charger?  

Last Answer : 1. Over load (49). 2. Over voltage (59). 3. Short-circuit (3250 Amps). 4. Phase sequence and phase fail. 5. di/dt and dv/dt protection. 

What are the in-built protections provided in MCC cell?

Description : What are the in-built protections provided in MCC cell? 

Last Answer : Fuses for short circuit protection. OLR for over load and single phasing protection. Electrical and Mechanical interlock in valve cell against short circuit. 

What are the protections provided in PMCC circuit breakers?

Description : What are the protections provided in PMCC circuit breakers?

Last Answer : 1. IDMT O/C (CDG 34). 2. IDMT E/F (CDG 11).  3. Under voltage (40% of 110V). 

What are the protections provided for motor feeder?

Description : What are the protections provided for motor feeder?  

Last Answer : Ith - Thermal over load I2S - Unbalance load I0S - Earth fault protection I1t - Stalling protection I1Inst. - Short circuit protection 

Why all 415V transformers are chosen Dyn 11? What are the protections provided for the 415V transformers?

Description : Why all 415V transformers are chosen Dyn 11? What are the protections provided for the 415V transformers?

Last Answer : a) To facilitate interchange. b) To have momentary parallel during changeover. Protections a) Door interlock to trip HT and LT breakers. b) LT breaker can on only after HT breaker is in on position. c) ... and restricted E/F (51N + 64). f) Winding temp high trip (140°C trip and 130°C alarm) 

What are the built in protections provided in 415 V breaker?

Description : What are the built in protections provided in 415 V breaker?  

Last Answer : a. DINF (making current magnetic release) This consists of a laminated magnetic circuit. This is placed under the lower current terminal pole. This is provided for all the three poles. It has a core that rotates ... by a lever. It is placed in front of the breaker. Setting range is 60% to 100%.  

What are the protections are there for lines?

Description : What are the protections are there for lines?  

Last Answer : Directional earthfault protection Directional over current protection Local breaker back up protection Pole discrepancy Main protection (distance protection)

How 6.6 kV-bus supply was chosen?

Description : How 6.6 kV-bus supply was chosen?

Last Answer : 11 kV was rejected in view of the high insulation cost with 11 kV motors. 3.3 kV was rejected, since max motor size with 3.3 kV bus is limited to 2 MW. But we are having the motors having rating more than 2 MW, which cannot suit to 3.3 kV bus. 6.6 kV bus we can start upto 5 mw size motor. 

The minimum clearance between the ground and a 220 kV line is about (a) 4.3 m (b) 5.5 m (c) 7.0 m (d) 10.5 m

Description : The minimum clearance between the ground and a 220 kV line is about (a) 4.3 m (b) 5.5 m (c) 7.0 m (d) 10.5 m

Last Answer : (c) 7.0 m

For transmission of power over a distance of 500 km, the transmission voltage should be in the range (a) 150 to 220 kV (b) 100 to 120 kV (c) 60 to 100 kV (d) 20 to 50 kV

Description : For transmission of power over a distance of 500 km, the transmission voltage should be in the range (a) 150 to 220 kV (b) 100 to 120 kV (c) 60 to 100 kV (d) 20 to 50 kV

Last Answer : (a) 150 to 220 kV

The spacing between phase conductors of a 220 kV line is approximately equal to (a) 2 m (b) 3.5 m (c) 6 m (d) 8.5 m

Description : The spacing between phase conductors of a 220 kV line is approximately equal to (a) 2 m (b) 3.5 m (c) 6 m (d) 8.5 m

Last Answer : (c) 6 m

The minimum clearance between the ground and a 220 kV line is about (a) 4.3 m (b) 5.5 m (c) 7.0 m (d) 10.5 m

Description : The minimum clearance between the ground and a 220 kV line is about (a) 4.3 m (b) 5.5 m (c) 7.0 m (d) 10.5 m

Last Answer : (c) 7.0 m

A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum

Description : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm

Last Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm

The X:R ratio of 220 kV line as compared to 400 kV line is?

Description : The X:R ratio of 220 kV line as compared to 400 kV line is?

Last Answer : The X:R ratio of 220 kV line as compared to 400 kV line is smaller.

What type breakers are provided in 6.6 kV buses?

Description : What type breakers are provided in 6.6 kV buses?

Last Answer : ABB. Make, SF6 gas, 1250A and 2000A capacity circuit breakers are provided in 6.6 kV buses. 

State the types of protections provided by MCB.

Description : State the types of protections provided by MCB. 

Last Answer : The types of protections provided by MCB: 1. MCB provides short circuit protection. 2. MCB provides overload protection

Multiple grounds have developed and were initialy indicated by the grounddetecting system as one ground. The FIRST step in locating the grounds is to _____________. A. examine the main bus bars for signs of overheating B. eliminate the individual circuits one by one until the ground detecting system no longer indicates any grounds C. change over generators D. check each circuit with a megohmmeter

Description : Multiple grounds have developed and were initialy indicated by the grounddetecting system as one ground. The FIRST step in locating the grounds is to _____________. A. examine the main bus bars ... no longer indicates any grounds C. change over generators D. check each circuit with a megohmmeter

Last Answer : Answer: B

How does increase in steam input of the Alternator connected to infinite bus-bars affect this operation?

Description : How does increase in steam input of the Alternator connected to infinite bus-bars affect this operation?

Last Answer : KW output power of alternator increase with increase in steam input keeping excitation constant.

How does increase in excitation of the Alternator connected to infinite bus-bars affect this operation?

Description : How does increase in excitation of the Alternator connected to infinite bus-bars affect this operation?

Last Answer : Increase in excitation level of the synchronous generator will effectively increase the reactive power supplied by the generator keeping steam input constant.

What is meant by infinite bus-bars?

Description : What is meant by infinite bus-bars?

Last Answer : The source or supply lines with non-variable voltage and frequency are called infinite bus-bars. The source lines are said to have zero source impedance and infinite rotational inertia.

Why aluminium bus bars are silver-plated in IPBD?

Description : Why aluminium bus bars are silver-plated in IPBD?

Last Answer : Aluminium bus bars are silver-plated at flexible connection to prevent the galvanic corrosion ant also for low contact resistance. 

What are the different Generator Protections employed in Thermal Power Plants?

Description : What are the different Generator Protections employed in Thermal Power Plants?

Last Answer : Answer: Faults in the windings, Over load protection, Over heating of windings or bearings, Over speed protection, Loss of Excitation protection, Motoring operation protection, Inadvertent ... , out of step operation protection, sub-synchronous oscillations protection and earth fault protection

What are the different Generator Protections employed in Thermal Power Plants?

Description : What are the different Generator Protections employed in Thermal Power Plants?

Last Answer : Faults in the windings, Over load protection, Over heating of windings or bearings, Over speed protection, Loss of Excitation protection, Motoring operation protection, Inadvertent energisation ... , out of step operation protection, sub-synchronous oscillations protection and earth fault protection

What are the protections used in 415 V Class II side?

Description : What are the protections used in 415 V Class II side?

Last Answer : LV to UPS 1. CTZM 2. 50 (instantaneous over current) 3. short circuit UPS to PMCC S & T 1. 51 RYB (inverse over current) 2. 27 (under voltage) 3. 51N (earth fault) From Class III to Class II tie CTZM at Class III and 51, 51N at Class II. 

What are the protections used in Class III & Class IV 415 V LV side?

Description : What are the protections used in Class III & Class IV 415 V LV side?  

Last Answer : Class III 415 V LV side 1. 51 (inverse over current) 2. 50 (instantaneous over current) 3. 27 (under voltage) 4. 51N (earth fault) 5. 64 (REF)  Class IV 415 V LV side 1. 51 RYB (inverse over current) 2. 51N (earth fault) 

What are the protections adopted in UPS or PMCC supply?

Description : What are the protections adopted in UPS or PMCC supply?

Last Answer : LV (incomer) or UPS input CTZM, Over current, Short circuit protections PMCC S or T input or UPS output Under voltage (27), 51RYB, 51N protections. 

What are the protections are there for BUSBAR?

Description : What are the protections are there for BUSBAR?

Last Answer : Instantaneous over current protection Bus bar differential protection Local breaker back up protection 

What are the protections for UT?

Description : What are the protections for UT?  

Last Answer : a) Differential protection b) LV restricted earthfault protection c) LV back up earthfault and over current protection d) Buchholz and high oil, winding temperature protection. 

What are the protections for SUT?

Description : What are the protections for SUT? 

Last Answer : a) Over current protection for phase and earth fault b) Differential protection c) HV and LV restricted earthfault protection  d) HV side directional back up over current protection for phase ... protection f) Over fluxing protection g) Buchholz and high oil, winding temperature protection. 

What are the protections for GENERATOR TRANSFORMER?

Description : What are the protections for GENERATOR TRANSFORMER?  

Last Answer : a) Differential protection b) Restricted earthfault protection c) Backup earthfault protection d) GT phase back up protection e) Overfluxing protection f) Oil surge (gas) protection g) High winding temperature and oil temperature protection. 

What are the built in protections for transformers?

Description : What are the built in protections for transformers?

Last Answer : a) Buchholz relay b) Explosion vent or relief valve c) Gas operated relay for on load tap changers. 

What are the working principles of generator main protections?

Description : What are the working principles of generator main protections?

Last Answer : GENERATOR START UP PROTECTIONS SUPPLEMENTARY PROTECTION OF GENERATOR The generator is normally expected to run rated speed before excitation power is applied by closing the field breaker. ... position to ensure that the protection is inoperable when the machine is connected to grid.  

Which of the following is/are true concerning electric power operated watertight door systems? A. Each motor driven door must use the main bus as its source of power. B. Each distribution panel for the system must be on the lowest level where berthing quarters are located. C. Distribution panels must not be provided with a means of locking in order to permit quick activation of the system. D. Each system must have a separate branch circuit.

Description : Which of the following is/are true concerning electric power operated watertight door systems? A. Each motor driven door must use the main bus as its source of power. B. Each distribution panel for ... to permit quick activation of the system. D. Each system must have a separate branch circuit.

Last Answer : Answer: D

In the illustrated 450 VAC system, what should be provided between the bus and the device labeled 'F'? EL-0003 A. a potential transformer B. a current transformer C. an emergency disconnect device D. an audible alarm and indicating light

Description : In the illustrated 450 VAC system, what should be provided between the bus and the device labeled 'F'? EL-0003 A. a potential transformer B. a current transformer C. an emergency disconnect device D. an audible alarm and indicating light

Last Answer : Answer: A

cables are used for 132 kV lines. (a) High tension (b) Super tension (c) Extra high tension (d) Extra super voltage

Description : cables are used for 132 kV lines. (a) High tension (b) Super tension (c) Extra high tension (d) Extra super voltage

Last Answer : (d) Extra super voltage

A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now...

Description : A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed (a) The same power but at a leading power factor (b) The same power ... a lagging power factor (c) More power at unity power factor (d) Less power at unity power factor

Last Answer : A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed The same power but at a lagging power factor 

Generating capacity connected to the bus bars and ready to take load when switched on is known as ?

Last Answer : Generating capacity connected to the bus bars and ready to take load when switched on is known as spinning reserve.

In a three-phase electrical system, three ground detecting lamps are provided. One lamp goes dark and the others increase in brightness. When the test button is pushed, all lamps have equal illumination. You should conclude that ____________. A. there is a ground on the line with the dark lamp B. the dark lamp must be replaced C. there are grounds on the lines with the bright lamps D. this is a normal condition

Description : In a three-phase electrical system, three ground detecting lamps are provided. One lamp goes dark and the others increase in brightness. When the test button is pushed, all lamps have equal illumination. You ... C. there are grounds on the lines with the bright lamps D. this is a normal condition

Last Answer : Answer: A

Why Earth Wire is provided in the overhead transmission lines?

Description : Why Earth Wire is provided in the overhead transmission lines?

Last Answer : Earth wire is provided above the overhead transmission lines for protection against lightning strokes. The ground wire or earth wire protects the phase conductors or line conductors by attracting itself the ... traveling waves set in the lines by acting a short circuit secondary of the line current

Why non-return valves are provided in the steam extraction lines?

Description : Why non-return valves are provided in the steam extraction lines?

Last Answer : Non-return valves are provided because when the turbine trips there will be an instant drop in pressure inside the turbine. But there will be steam in feed water heaters, which is at high pressure ... . So non-return valves are provided in steam extraction lines to prevent over speeding of turbine.