What is Corona? How is corona organized? What are the factors influencing corona? What is the effect of corona?

 What is Corona? How is corona organized? What are the factors influencing corona? What is the effect of corona?

What is Corona? Ans: When the spacing of two conductors is kept greater than the diameter, they are gradually increased by applying AC voltage across them. Then at a certain stage the air on the four sides of the conductor is ionized and the insulation trace of the air is broken. In this condition, light dull violet rays appear in and around the conductor, hissing sound and the formation of weight gas is called corona.

How is corona organized? is done Answer: When ac supply is applied across two conductors i.e. ac supply is gradually increased, there comes a stage when the air around the conductor gets ionized and the insulation strength of the air breaks. The result is a hissing sound around the conductor and a purple glow discharge is seen. This results in the formation of weight gases.

Ways to reduce the corona effect. Answer: Corona effect can be reduced in the following ways a) By increasing the size of the conductor. Increases Conductor Spacing.

What are the factors affecting Corona? What is corona power loss? Ans: Factors affecting Corona are: Ans: Causes of Corona 1. Weather m is called corona power loss. This is P2. Conductor size 3. Distance between Conductor +25 P= -242.2 (B Line Voltage.

What is the effect of corona? f = Supply frequency (HE) V = J to neutron voltag V = Critical Disruptive (r.m.s) per phase Answer: Coronar Effects: 1. Violet rays appear on all four sides of the conductor. 2. Corona produces a hissing sound. 3. Creates ozone gas. 4. Corona causes power loss. 5. Corona harmonics create current

What are the advantages and disadvantages of corona? Answer: Advantages of corona are 1. Limits the virtual or resultant diameter of the conductor. 2. Limits the transient effect. Power is wasted. Causes interference in nearby communication circuits. Weight (Os) creates gas.

What is Disruptive Critical Voltage?

Answer: The minimum phase to neutral voltage at which corona occurs is called disruptive critical voltage. It is published by V. g=rloged/rV/cm What is Visual Critical Voltage? Answer: The minimum phase to neutral voltage at which corona light is visible around the conductor is called visual critical voltage. It is denoted by V.Vv = my go or loge (1+ d 0.3 √or my = New/Another Irregularity factor. = 1 for Polished Conductor. = 0.72 to 0.82 for rough Conductor. What is corona power loss? Answer: The energy loss caused due to corona formation It is called corona power loss and is denoted by P

What is the skin effect? Uttara Skin Effect AC current flows through any conductor. For religion that tries to flow over the surface without entering the conductor when it occurs is called the three effects.

What are the effects of skin effect on transmission lines? OPTIMIE Answer: Effects of skin effect are: Power loss on the line. As the diameter of the line increases, the skin effect also increases. The skin effect depends on the size of the conductor in the transmission line. Depends on the conductor material. 4. What is puncture voltage? Answer: The voltage that can completely break the insulation of the insulator is called Puncture voltage. 8. What is flash-over voltage? Ans: If the voltage is increased, the dielectric strength of the air is destroyed and causes severe lightning.

This voltage is called Flash-over voltage. Why is there no skin effect in DC? Answer: When DC current flows in a conductor, the same amount of current flows uniformly across the entire cross section. But if ac current is made to flow in the said conductor, then the current will not flow evenly but it tends to concentrate on the conductor surface and due to this reason skin effect does not occur in DC. Skin effect depends on what factors. Answer: Generally skin effect depends on the following factors: 1. On the quality of Conductor material: Skin effect is more in the case of materials that have high Conductivity.2. On the diameter of the conductor: Skin effect increases with the increase in diameter. On Frequency : Skin effect increases with increase in frequency.

On temperature: Solid conductor strandard conductor skin effect is less. If the supply frequency is less than 50Hz and the diameter of the conductor is small (<1cm), the skin effect is not considered.

What are the ways to reduce the skin effect? Answer: 1. Reducing the radius of the conductor. . Uses non magnetic materials. 3. Using Stranded Conductor. Using Aluminum Conductor. 5. Using hollow cylinder shaped Conductor.

What is the proximity effect? Answer: When a current conducting conductor is next to another current conducting conductor. Then its flux is related to the previous current conducting conductor. The result of this flux is greater in the near half than in the far half of both conductors. As a result, uneven current distribution occurs across the entire cross section of the conductor and resistance increases like the skin effect. This phenomenon is called proximity effect.

What happens due to the proximity effect? Answer: 1. Uneven current distribution is created in the conductor. 2. Resistance increases.

Proximity effect depends on the subject. Answer: Proximity effect depends on the following factors: 1. Conductor material. 2. On the diameter of the conductor. 2. On Frequency. 4. On permeability. 5. On type of structure or size of conductor.

In what ways can the proximity effect be reduced? Answer: 1. By increasing the spacing of the conductor. 2. Using Stranded Conductor. 3. Keeping the frequency range low. 4. Mechanical design of over head line's.

What are the main parts of the overhead line? Answer : The main parts in over head line are: 1. Conductor 2. Support 3. Cross arm 4. Insulator. 5. Guy and stay 6. Lighting Arrestor 7. Fuse and isolating switching 8. Guard wire 9. Bird Guard 10. Danger plate 11. Anti-climbing wire etc.

What are the properties of conductor material?Answer: The qualities are: 1) High electrical conductivity. 2) High tensile strength. 3) Price is low. 4) Low relative gravity. 5) Shall not be brittle. 6) Wire must be moisture and rust proof.

What are the conductors used in over head lines? Answer: Conductors are: 1. Copper conductor. 2. Aluminum Conductor. 3. Steel cored aluminum. 4. Galvanized steel. 5. Cadmium copper. 15. What are the characteristics of copper conductor? Answer: The characteristics of copper conductor are: 1. High electrical conductivity. 2. High tensile strength. 3. Relative importance is high. 4. The price is high. 5. Its lifespan is very long.

What are the characteristics of aluminum conductors?Answer: The characteristics of aluminum conductors are: 1. Electrical conductivity is lower than that of copper. 2. Low tensile strength. 3. Low specific gravity. 4. The price is low. 5. Aluminum is 33 percent heavier than copper wire of the same volume.

Compare between copper and aluminum conductors?

Answer: The differences between copper and aluminum conductors are given below: IDE OPTIMUM COACHING Copper Conductor 1. High power transmission capacity. 2. High tensile strength. 3. Relative importance of aluminum conductors 1. The electrical conductivity is less than that of copper. 2. Low tensile strength. Relative to 8.9gm/cc. 2.71gm/cc. 4. Equal Resistance 4. The diameter of aluminum wire is 1.27 times smaller than that of copper wire for equal resistance. More than wire. Price 5. The cost of aluminum is much lower than that of copper. much more

Go Next Page