Question: In aluminium conductors, steel core is provided to____________?

• 1. compensate for skin effect
• 2. neutralise proximity effect
• 3. reduce line inductance
• 4. increase the tensile strength

Question: By which of the following methods string efficiency can be improved?

• 1. Using a guard ring
• 2. Grading the insulator
• 3. Using long cross arm
• 4. Any of the above

Question: Owing to skin effect:

• 1. current flows through the half cross-section of the conductor
• 2. portion of the conductor near the surface carries more current and core of the conductor carries less current
• 3. portion of the conductor near the surface carries less current and core of the conductor carries more cur¬rent
• 4. any of the above

Question: Which of the following bus-bar schemes has the lowest cost?

• 1. Ring bus-bar scheme
• 2. Single bus-bar scheme
• 3. Breaker and a half scheme
• 4. Main and transfer scheme

Question: In AC.S.R. conductors, the insulation between aluminium and steel conductors is_________?

• 1. insulin
• 2. bitumen
• 3. varnish
• 4. no insulation is required

Question: A conductor, due to sag between two supports, takes the form of____________?

• 1. semi-circle
• 2. triangle
• 3. ellipse
• 4. catenary

Question: Which of the following characteristics should the line supports for transmission lines possess?

• 1. Low cost
• 2. High mechanical strength
• 3. Longer life
• 4. All of the above

Question: Which of the following distribution systems is more reliable?

• 1. Radial system
• 2. Tree system
• 3. Ring main system
• 4. All are equally reliable

Question: The steel used in steel cored conductors is usually__________?

• 1. alloy steel
• 2. stainless steel
• 3. mild steel
• 4. high speed steel

Question: Which of the following relays is used on long transmission lines?

• 1. Impedance relay
• 2. Mho’s relay
• 3. Reactance relay
• 4. None of the above