Question 1.
The three bus-bar conductors in an outdoor substation are supported by units of post type insulators. Each unit consists of a stack of 3 pin type insulators fixed one on the top of the other. The voltage across the lowest insulator is 13.1 kV and that across the next unit is 11 kV Find the bus-bar voltage of the station.
Question 2.
An insulator string consists of three units, each having a safe working voltage of 15 kV The ratio of self-capacitance to shunt capacitance of each unit is 8 : 1. Find the maximum safe working voltage of the string. Also find the string efficiency.
Question 3.
Each conductor of a 3-phase high-voltage transmission line is suspended by a string of 4 suspension type disc insulators. If the potential difference across the second unitfrom top is 13.2 kV and across the third from top is 18 kg determine the voltage between conductors.
Question 4.
The three bus-bar conductors in an outdoor substation are supported by units of post type insulators. Each unit consists of a stack of 3 pin type insulators fixed one on the top of the other. The voltage across the lowest insulator is 13.1 kV and that across the next unit is 11 kV Find the bus-bar voltage of the station.
Question 5.
An insulator string consists of three units, each having a safe working voltage of 15 kV The ratio of self-capacitance to shunt capacitance of each unit is 8 : 1. Find the maximum safe working voltage of the string. Also find the string efficiency.