EE6501
       Power System Analysis
        Power Flow Analysis
     Dr.P.UshaRani, Professor/EEE
          EE 6501 POWER SYSTEM 
                  ANALYSIS
    UNIT II POWER FLOW ANALYSIS 
    Importance of power flow analysis in planning and operation of power
    systems - statement of power flow problem - classification of buses -
    development of power flow model in complex variables form - iterative
    solution using Gauss-Seidel method - Q-limit check for voltage controlled
    buses – power flow model in polar form - iterative solution using
    Newton-Raphsonmethod.
 • A power flow study (load-flow study) is a steady-state
 analysis whose target is to determine the voltages, currents,
 and real and reactive power flows in a system under a given
 load conditions.
 • The purpose of power flow studies is to plan ahead and
 account for various hypothetical situations. For example, if a
 transmission line is be taken off line for maintenance, can
 the remaining lines in the system handle the required loads
 without exceeding their rated values.
     Load flow studies are one of the most important aspects of power
 system planning and operation. The load flow gives us the sinusoidal
 steady state of the entire system  voltages, real and reactive power
 generatedandabsorbedandlinelosses
     This is rather important as the magnitudes of the bus voltages
 are required to be held within a specified limit. Once the bus voltage
 magnitudes and their angles are computed using the load flow, the real
 and reactive power flow through each line can be computed. Also based
 on the difference between power flow in the sending and receiving ends,
 the losses in a particular line can also be computed. Furthermore, from
 the line flow we can also determine the over and under load conditions.
 The steady state power and reactive powers supplied by a bus in a power
 network are expressed in terms of nonlinear algebraic equations. We
 therefore would require iterative methods for solving these equations.