ELECTRICAL DIAGRAMS - PART – 03 - DIFFERENCE BETWEEN BLOCK AND LAYOUT DIAGRAM

BLOCK DIAGRAM - It is a functional drawing which shows and describes the main operating principles of the equipment or devices. It consists of principle functions or parts represented by blocks and is connected through lines that show the relationship between the blocks.

LAYOUT DIAGRAM - A drawing meant to show the physical arrangement of the wires and the components they connect is called layout design. 

ELECTRICAL DIAGRAMS PART – 02 - DIFFERENCE BETWEEN PICTORIAL AND SCHEMATIC DIAGRAM

ELECTRIC CIRCUIT – An electrical circuit is a path through which an electrical current flows. A closed circuit makes electrical current flow possible. An open circuit does not allow electrical current to flow.

An electric circuit made up of the basic elements resistance, inductance, and capacitance in a simple arrangement such that its performance would duplicate that of a more complicated circuit or network.

PICTORIAL CIRCUIT DIAGRAM - A pictorial circuit diagram uses simple images of components.

SCHEMATIC CIRCUIT DIAGRAM - A schematic circuit diagram is used to give a visual representation of an electrical circuit to an electrician.

ELECTRICAL DIAGRAMS PART – 01 - DIFFERENCE BETWEEN VECTOR AND PHASOR DIAGRAM

VECTOR - A quantity having direction as well as magnitude, especially as determining the position of one point in space relative to another.

VECTOR DIAGRAM - Vector diagram shows the direction and relative magnitude of a vector quantity by a vector arrow. Vector diagrams can be used to describe the velocity of a moving object during its motion. Vector diagrams can be used to represent any vector quantity. For example, acceleration, force, and momentum.

PHASOR - A phasor is a line whose direction represents the phase angle in electrical degrees and whose length represents, the magnitude and of the electrical quantity.

PHASOR DIAGRAM - The graphic representation of the phasors of sinusoidal quantities taken all at the same frequency and with proper phase relationships with respect to each other is called a phasor diagrams. The relative position of the phasors or phase difference which is important in a.c. calculations. 

UNSYMMETRICAL FAULT CALCULATIONS – PART – 32 – DOUBLE LINE TO GROUND AND LINE TO LINE FAULT - PROBLEM

A 33 kV bus bar has a three phase fault level of 1000 MVA. The negative and zero sequence source reactances are 2/3 and 1/3 of positive sequence reactance. The zero sequence resistance of the source is 50 ohms. A 30 MVA, 33 / 132 kV solidly grounded delta/star transformer having a reactance of 0.2 per unit. Is fed from 33 kV bus. Find fault current and fault MVA at 132 kV bus for the following faults. (a) Double line-to-ground fault and (b) Line to Line fault.

UNSYMMETRICAL FAULT CALCULATIONS – PART – 31 – THREE PHASE FAULT AND SINGLE LINE TO GROUND FAULT - PROBLEM

A 33 kV bus bar has a three-phase fault level of 1000 MVA. The negative and zero sequence source reactances are 2/3 and 1/3 of positive sequence reactance. The zero sequence resistance of the source is 50 ohms. A 30 MVA, 33 / 132 kV solidly grounded delta/star transformer having a reactance of 0.2 per unit. Is fed from 33 kV bus. Find fault current and fault MVA at 132 kV bus for the following faults. (a) Three phase fault and (b) Single line to ground fault.

UNSYMMETRICAL FAULT CALCULATIONS – PART – 30 – LINE-TO-LINE FAULT - PROBLEM

A 25 MVA, 11 kV, three-phase, 50Hz generator has Z1 = j0.25 p,u., Z2 = j0.35 p,u., Z0 = j0.1 p.u. and Zn = 0.3 ohms. If a line to line fault occurs on Y and B phases. Calculate the fault current and per phase voltages.

UNSYMMETRICAL FAULT CALCULATIONS – PART – 29 – LINE-TO-LINE FAULT (Zn & Zf)

UNSYMMETRICAL FAULT CALCULATIONS – PART – 29 – LINE-TO-LINE FAULT (Zn & Zf)

Consider a three-phase circuit diagram of an unloaded generator, the neutral is connected through impedance Zn and fault impedance is Zf. If a line-to-line fault between Y and B phases derive the fault current and per phase voltages.

UNSYMMETRICAL FAULT CALCULATIONS – PART – 28 – LINE-TO-LINE FAULT

Consider a three-phase circuit diagram of an unloaded generator, if a line-to-line fault between Y and B phases derive the fault current and per phase voltages.

UNSYMMETRICAL FAULT CALCULATIONS – PART – 27 – DOUBLE LINE-TO-GROUND FAULT - PROBLEM

Two generators A and B are of rating 50 MVA, 11kV, three-phase and 50 Hz are connected in parallel and supply a substation feeder.

Generator A and B positive, negative and zero sequence impedances are Z1= j0.6 ohms, Z2 = j0.4 ohms, Z0 = 0.2 ohms and neutral impedance Zn = j0.1 ohms.

Feeder positive, negative and zero sequence impedances are

Z1 = Z2 = (0.4 + j0.7) ohms, Z0 = (0.7 + j3.0) ohms.
If fault involves in Y and B phases, calculate the fault current.

UNSYMMETRICAL FAULT CALCULATIONS – PART – 26 – DOUBLE LINE-TO-GROUND FAULT - PROBLEM

A 25 MVA, 11 kV, 50 Hz and three-phase generator has Z1 = j0.25 p,u., Z2 = j0.35 p,u., Z0 = j0.1 p.u. and Zn = 0.3 ohms. If a double line to ground fault occurs on Y and B phases. Calculate the line current, fault current, line to neutral voltages and line to line voltages during the occurrence of fault conditions.