Answer / md. faruque

A combination of disconnect switches and breakers used to isolate equipment in substations. It refers to electrical equipment that regulates the flow of electricity within an electrical system. It is used by utility providers and private facilities alike for two reasons: to prevent overloads and short circuits, and to de-energize circuits for testing and maintenance. The most familiar types of switchgear are circuit breakers , fuses & lighting arrestors, which interrupt the flow of electricity to a circuit when its current becomes too high and directly pass the surge voltage to earth.
Main considerations in apparatus protection – transformer, generator and motor protection – protection of busbars. Transmission line protection – zones of protection.CTs and PTs and their applications in protection schemes.
Types of circuit breakers – air blast, air break, oil, SF6 and vacuum circuit breakers. Types of lighting arrestors are- horn gap, expulsion type, gapless metal oxide type etc. It is also classified on the basis of class.

Answer / k.prakashchandra

Switch gears include c.b.and isolators

Answer / younas

what is the important think in switchgear room

Comparative difference between 33Kv & 66KV for transmitting the load of 7 MW at a distance of 34 Km.

6 Answers   NHPC,

---

what is the radio of kva & kvar or why calculated kva & kvar

3 Answers  

---

what is conductor copnstant of ab cable

0 Answers  

---

seromechanism

4 Answers   Bhel,

---

How to calculat the ratio of HT\LT in energy meter

0 Answers  

---

Who are the manufactures those manufacturing 3Cx2.5sqmm FRLS cables. I heard about FRLS technology adopted only in wires useful for wirings

0 Answers  

---

Define norton equivalent circuit?

0 Answers  

---

I am designing new project sub station with 220 kV / 11 kV, 40 MVA capacity. This project have many recifier sets, which can generate 3rd harmonics. Now I have to select vector group of This transformer. To minimise 3rd harmonics, what care should I take in selection of Transformer Vecrtor group? If it is Y-Y with open Delta tertiary then what should be the rating & voltage of Tertiary Winding?

0 Answers  

---

What is WLD System????

3 Answers   Emerson, HCL, Honeywell, Tata Communications,

---

how to test vector groups in transformer differential relay.

1 Answers  

---

why current transformer secondary is short circuited an what will happen if connect very high resistance acrossthe secondary side of current transformer?

1 Answers   NPCIL,

---

Why is back emf used for a DC motor? Highlight its significance.

0 Answers   ABB,

---