BUS ADMITTANCE MATRIX – 15 - ONE PROBLEM - ADDING OFF-NOMINAL TAP CHANGING TRANSFORMER IN A LINE

Formulate Y-bus matrix for the given figure.

Transformer admittance = j0.05 ohms

Line admittance = 0.437 - j3.275 mho

Half line charging admittance = j0.01

BUS ADMITTANCE MATRIX - PART – 14 - MODIFICATION OF BUS ADMITTANCE MATRIX WHEN A TRANSFORMER IS ADDED IN A LINE

Let us assume that a transformer is connected in a line between p and q in a multibus system. The transformer is represented a series admittance Ypq. Nominal tap ratio 1 : a and 't' is the imaginary bus between the ratio and admittance of the transformer.

BUS ADMITTANCE MATRIX - PART – 13 - NODE ELIMINATION - KRON METHOD

Bus admittance of four bus system is given below.

Eliminate node three and form a new Y-Bus matrix.

BUS ADMITTANCE MATRIX - PART -12 - NODE ELIMINATION TECHNIQUE - KRON METHOD

PROBLEM

Form, an admittance matrix for a four bus system shown in the figure. The line reactance values are in per unit. Neglect shunt capacitances.

Eliminate node 4 from the network and form, the new Y-bus matrix using KRON method.

BUS ADMITTANCE MATRIX - PART – 11 NODE ELIMINATION TECHNIQUE – MATRIX PARTITIONING

For a large network, the bus admittance matrix may be of large order.

The matrix operation can be simplified by node elimination technique using matrix partitioning method.

Nodes at which no current enters or leaves may be eliminated.

BUS ADMITTANCE MATRIX – PART – 10 – FORMATION OF Y–BUS – ONE PROBLEM

PROBLEM

Form, an admittance matrix for a four bus system shown in the figure. The line reactance values are in per unit. Neglect shunt capacitances.

If two line lines are between across the bus 01 & bus 02 and bus 02 and three. The reactance value of each line is j0.4 per unit. Form a new bus admittance matrix. 

BUS ADMITTANCE MATRIX - PART – 09 – FORMATION OF Y-BUS - ONE PROBLEM

An admittance diagram for a two bus network has been in the figure. Neglect line charging admittance.

Case - 01 - Add shunt capacitor in bus 01 and bus 02. Form, bus admittance matrix and calculate bus voltage V1 and V2.

Case - 02 - Add shunt reactor in bus 01 and bus 02. Form, bus admittance matrix and calculate bus voltage V1 and V2 

BUS ADMITTANCE MATRIX - PART – 08 - FORMATION OF Y-BUS - ONE PROBLEM

PROBLEM - 01

An admittance diagram for a two bus network has been in the figure. Find Y-bus matrix and find the bus voltage V1 & V2.

Add line charging admittance j0.05 p.u in the line find the new Y-bus matrix and also calculate the bus voltage V1 & V2.

BUS ADMITTANCE MATRIX - PART – 07 – FORMATION OF Y-BUS - ONE PROBLEM

PROBLEM

(a) A 3-phase transmission line bus 230 kV, 250 MVA, 400 km line of a symmetrical type. Find the bus admittance matrix for the two bus system. Assume R = 0.075 ohms, L = 1.5 mH, C = 12 nf.

(b) A shunt capacitance of 1.5 mf is connected to bus 1 and 2 mf is connected to bus 2. form the new Y-bus matrix.

BUS ADMITTANCE MATRIX - PART - 06 - FORMATION OF Y-BUS - ONE PROBLEM

PROBLEM - 01

For the system shown in the figure write the elements of Y-bus directly by inspection method. Neglect line charging admittance of lines connected between buses (4-1); (4-3) and (4-2), while the half line charging admittance of lines between buses 1-2 and 3-2 is j0.25 p.u.

CASE – 01 – Remove the line between bus 2-4 and find the new admittance matrix.

CASE – 02 – Remove the line between bus 3-4 and find the new admittance matrix.

BUS ADMITTANCE MATRIX - PART - 05 - FORMATION OF Y-BUS - TWO PROBLEMS

PROBLEM - 01

For the system shown in the figure write the elements of Y-bus directly by inspection method.

PROBLEM - 02

Determine Y-bus matrix of the system network shown in the figure. Assume half line charging admittance of each line as j0.01 p.u. Find the modified Y-bus matrix. 

BUS ADMITTANCE MATRIX - PART - 04 - FORMATION OF Y-BUS - TWO PROBLEMS

PROBLEM - 01

For the system shown in the figure write the elements of Y-bus directly by inspection method.

PROBLEM - 02

Determine Y-bus matrix of the system network shown in the figure.

BUS ADMITTANCE MATRIX - PART - 03 - FORMATION OF Y-BUS - TWO PROBLEMS

PROBLEM - 01

For the system shown in the figure write the elements of Y-bus directly by inspection method.

PROBLEM - 02

Determine Y-bus matrix of the system network shown in the figure.