Explain the three types of wire systems employed in a built environment. 1. Conduits wiring II. Surface wiring III. Coupling of the two electrical systems

Two wire systems have the voltage at the supply end maintained at 500 V. The line is 4 km long. If the full-load current is 15 A, what must be the booster voltage and output in order that the far end voltage may also be 500 V. The resistance of the cable is 0.5 ohm/km.

(i) List any three factors to be considered for mechanical design of overhead lines

The loads on a 300-meter ring distributor are depicted in figure 2.1 (a), where the distances are given in metres. Each conductor has a resistance of 0.20 per 1,000 metres, and the loads that are tapped off at points B, C, and D are as shown in the diagram. Determine the voltages at B, C, and D given that the distributor is fed at point A. 50 A 70 1 240 V A (a) 60 B 70 A 100 A 80 50 A 91A D T 41 A 220 V A (b) 129 A B 100 A 729 A 70 A

3. A 250 m, 2-wire d.c. distributor fed from one end is loaded uniformly at the rate of 0-8 A per metre. The resistance of each conductor is 0.0002 2 per metre. Find the necessary voltage at the feeding point to maintain 250 V at the far end of the distributor. [260 V]

A cable is tested by loss of charge Method using a Ballistic galvanometer with following results : Discharged immediately after electrification deflection 200 divisions. Discharged after 30 second and after electrification (i) Deflection 126 divisions (ii) When in parallel with a resistance of 10 V deflection 100 divisions. Calculate the insulation resistance of the cable.

Subject: Electrical & Electronics Engineering Course: Power Systems

Discuss the concept of electrical load shedding and its significance in power management.