Mell What are the methods to improve the string efficiency?
Methods of Improving String Efficiency
- 1.By using longer cross-arms. The value of String Efficiency of Insulator depends upon the value of K i.e., ratio of shunt capacitance to mutual capacitance.
- 2.By grading the insulators.
- 3.By using a guard ring.
What is significance of string efficiency?
String efficiency is an important consideration since it decides the potential distribution along the string. The greater the string efficiency, the more uniform is the voltage distribution. Thus 100% string efficiency is an ideal case for which the voltage across each disc will be exactly the same.
What is string efficiency in a string of suspension type insulators?
String Efficiency shows the utilization of suspension insulator. More the utilization of discs of insulator more will be the string efficiency. String Efficiency is defined as the ration of conductor voltage and the voltage across the disc nearest to conductor multiplied by number of discs.
What is the string efficiency?
The string efficiency is defined as the ratio of voltage across the string to the product of the number of strings and the voltage across the unit adjacent string. The voltage across the string is equal to the phase voltage, i.e., the voltage between the line and earth.
What is transposed line?
Transposition is the periodic swapping of positions of the conductors of a transmission line, in order to reduce crosstalk and otherwise improve transmission. In telecommunications this applies to balanced pairs whilst in power transmission lines three conductors are periodically transposed.
How are methods used to improve string efficiency?
String Efficiency: Now let us discuss about string efficiency and the methods used to improve string efficiency.What is string efficiency ? String efficiency is the ratio of voltage across the whole string to the product of number of discs and the voltage across the disc nearest to the conductor.
How is string efficiency related to voltage distribution?
Therefore, this unequal voltage distribution is undesirable and usually expressed in terms of string efficiency. String efficiency = Voltage across the string / (number of discs X voltage across the disc nearest to the conductor). Greater the string efficiency, more uniform is the voltage distribution.
How to calculate the efficiency of a transmission line?
Actually, transmission line has its own line resistance. So, there will be an ohmic loss in the resistance of line. If Ps is the input power at sending end, then only (Ps – Loss) will be available at the receiving end. Therefore (100 -η)% is the loss in transmission line resistance. This gives us a new method to calculate transmission efficiency.
How are insulators used to improve string efficiency?
In this method, different dimensions of insulators are chosen which have different capacitance. The insulators are capacitance graded i.e. they are assembled in the string in such a way that the top unit has the minimum capacitance, increasing progressively as the bottom unit (i.e., nearest to conductor) is reached.