POWER FLOW ANALYSIS

UNIT-II
POWER FLOW ANALYSIS
Find out the Y matrix of the sample power system as shown in fig. Data for this system is given in table.



Find out the Y matrix of the sample power system network diagram as shown in fig.





3. Consider the system shown in fig. It shows a transmission network with impedance of transmission lines all in p.u as shown. Compute Ybus matrix.





y12 = 10 - j 20
y13 = 10 - j 30
y32 = 16 - j 32
Ybus = [■(20-j50&-10+j20&-10+j30@-10+j20&26-j52&-16+j32@-10+j30&-16+j32&26-j62)]

Explain Gauss seidel load flow problem.








The following is the system data for a load flow solution. Determine the voltages at the end of first iteration using Gauss-Seidel method. Take α=1.6 .
The line admittances:

Bus code Admittance
1-2 2-j8.0
1-3 1-j4.0
2-3 0.666-j2.664
2-4 1-j4.0
3-4 2-j8.0

The schedule of active and reactive powers:

Bus code P in p.u Q in p.u V in p.u Remarks
1 - - 1.06 Slack
2 0.5 0.2 1+j0.0 PQ
3 0.4 0.3 1+j0.0 PQ
4 0.3 0.1 1+j0.0 PQ

Solution
〖Y 〗_bus [■(3-j12&-2+j8&-1+j4&0@-2+j8&3.666-j14.664&-0.666+j2.664&-1+j4@-1+j4&-0.666+j2.664&3.666-j14.664&-2+j8@0&-1+j4&-2+j8&3-j12)]

V_2^1 = 1/Y_22 [(P_2-jQ_2)/(V_2^* )-Y_21 V_1^0-Y_23 V_3^0-Y_24 V_4^O ]
V_2^1 = 1/(3.666-j14.664) [(-0.5+j0.2)/(1-j0.0)-1.06(-2+j8)-1.0(-0.666+j2.6664)-(-1+j4)1.0]
= 1.01187-j0.02888
V21acc = (1.0+j0.0)+1.6(1.01187-j0.02888-1.0-j0.0) = 1.01899-j0.046208
V31 = 0.994119-j0.029248 ; V31acc = 0.99059-j0.0467968
V41 = 0.9716032-j0.064684 ; V41acc = 0.954565-j0.1034944
Fig shows that the one line diagram of a simple three bus system with generation at bus 1.The magnitude of voltage at a bus 1 is adjusted to 1.05 p.u. The scheduled loads at buses2 and 3 are as marked on the diagram. Line impedances are marked in n p.u on a 100MVA base and the line charging susceptances are neglected.
Using the Gauss-Seidel method, determine the phasor values of the voltages at the load buses 2 and 3(P-Q buses) accurate to decimal places.
Find the slack bus real and reactive power.
Determine the line flows and line losses. Construct a power flow diagram showing the direction of line flow.










Explain Newton raphson seidel load flow problem.






























Explain Fast decoupled load flow problem.