Power System Analysis

1. POWER SYSTEM
ANALYSIS

2. CHAPTER NO # 3
DISTRIBUTORS

3. DISTRIBUTORS
• A distributor is characterized by various tapping taken it along its length ro provide a supply to
the various consumers
• The distributor will supply from substation at which transformation take place from a high
transmission voltage to a very much low distribution voltage
• It is possible to incorporate in transformer some means by which the distributor voltage can be
controlled and it is not possible to do this at consumer terminal
• Although the voltage at the supply end may be fixed at a required value and the voltage along
the length of the distributor will vary accordingly to the cross-sectional area (and therefore the
resistance)and the actual value of the load current at various section of distributor at various
time
• Since the voltage at the consumer’s terminals must remain within the specific limits as laid
down by the appropriate authorities
• The main basis of distribution design is the drop in voltage at any point under any anticipated
loading conditions

4. D.C. Distributor fed at one end

5. Three-wire D.C. Distributor fed at one end
• System consist of outer two conductors supplied at +/-V and an earthed middle wire or neutral
connected to the center point of supply.
• It has the advantage over the two conductor system in that two voltages are available for the
consumer, the loads being connected either
• between one of the wires and neutral and supplied at V volts
• between the two outers in which case the potential applied to the load is 2V volts
• The total current in the middle wire is the algebraic sum of the currents from the outers, those from
the positive being considered positive and the others negative
• If the resultant drop in the neutral is positive it is added to the drop and deducted from the drop in
the negative outer, if negative then converse applies
• EXAMPLE

6. Distributor fed at both ends
• Used when long distributors carry heavy loads the total voltage drop at the far end of the run may
become unacceptably large, and one method by which the effect may be mitigated is to feed the
distributor at both ends
• The total voltage drop can be considerably reduced without increasing the cross-section of the conductor
• EXAMPLE: Here in the book the example is about the two end fed with unequal voltage so

7. EXAMPLE

10. Uniformly Loaded Distributor
• FED FROM ONE END

12. Uniformly Loaded Distributor
• FED FROM BOTH ENDS