2.1 Approx_LoadFlow (1).ppt

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The document discusses load flow analysis and the power flow problem. It provides an overview of approximate power flow solutions, a two-bus demonstration example, and the power flow equation. It also discusses classification of system variables, approximate load flow methods, and provides data for a four bus lossless system. Solution steps are outlined which involve finding voltage angles, reactive power injections, active and reactive power flows, and checking power balance.

Engineering

LOAD FLOW ANALYSIS
Approximate Power Flow Solution
Book: Electric Energy System Theory- An
Introduction by Olle L. Elgerd

A TWO-BUS DEMONSTRATION
EXAMPLE
S1 = P1 + jQ1 = PG1 – PD1 + j(QG1 – QD1)
S2 = P2 + jQ2 = PG2 – PD2 + j(QG2 – QD2)

SYSTEM MODEL-THE POWER-
FLOW EQUATION(PFE)
1. Injected current at bus

3. Writing the PFE’S in Complex Form
(a) For Two Bus Problem
(b) For many buses

General Power Flow Equation in Real Form

Power Flow Equation in Real Form for Two Bus Problem

Classification of System Variables in
Two Bus Demonstration Problem

APPROXIMATE LOAD FLOW
1. Line resistance, being small, are neglected (shunt conductance
of overhead lines is always negligible), i.e.γij= 90⁰, γii= ₋ 90⁰
2. Sine of small angle (< pi/6) is equal to angle (Radians) itself.
3. All buses other than the slack bus (numbered as 1) are PV
buses, i.e, voltage magnitudes at buses, including the slack bus,
are specified.
Real Power Flow Equation can be reduced to:

Steps to be followed in Approximate Load Flow
1.To find out voltage angles, δ (δ2, δ3, δ4) by
writing PFE of Pi
2. To find out reactive power injections.
3.To find out active power flows in each line, Pij &
Pji
4.To find out reactive flows in each line.
5.To find out active power at slack bus
6.Draw single line diagram with all power flows.
7.Check power balance at each bus.

THANK YOU
For any query you may write to avdheshmbm15@gmail.com

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