Subject and UNIT: Transmission and Distribution: Unit II: (b) Corona
In the free space surrounding the conductors, some ionization is always present due to radioactivity, cosmic rays and ultraviolet rays.
Modelling and Performance of Transmission Lines
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines : Two Marks Questions with Answers
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
It can be seen that for a long transmission line under no load conditions, the voltage at receiving end is more than that at sending end because of the effect of the line capacitance.
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
With increase in load demand, it becomes necessary to make use of high voltage transmission lines for transmitting the power over long distances.
Modelling and Performance of Transmission Lines
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
When the current flows through the transmission line conductors, due to its resistance there is loss which generates heat increasing the temperature.
Power Angle Diagram
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
The term stability with respect to the transmission line refers to the stable operation of the power system with sending end and receiving end terminals in synchronism with each other.
Modelling and Performance of Transmission Lines
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
The flow of active power (P) and the reactive power (Q) through transmission system has influence on voltage magnitudes and phase difference of voltages at terminals and voltage along the line.
Steps for drawing -
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
With the help of circle diagram at sending end we can get PS,QS and power factor on complex plane.
Modelling and Performance of Transmission Lines
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
We already know that synchronous machine can take lagging or leading current depending upon whether it is under excited or overexcited.
Procedure to Draw Receiving
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
We had already seen in the previous sections how to calculate the real and reactive power at sending end and at the receiving end mathematically. Now we will see how to represent characteristics of transmission line graphically.
Short Transmission Line
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
The flow of power at any point along a transmission line can be determined with the knowledge of voltage, current and power factor.
Modelling and Performance of Transmission Lines
Subject and UNIT: Transmission and Distribution: Unit II: (a) Modelling and Performance of Transmission Lines
These methods are said to be nominal methods as they do not take into account the actual conditions i.e. instead of taking the parameters of the lines as uniformly distributed they are considered to be concentrated or lumped at one point in the transmission line network.