Underground Cables
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Questions : 1. Derive an expression for insulation resistance of a cable 2. A single core cable has a conductor diameter of 1 cm and insulation thickness cf 0.5 cm. If the specific resistance of an insulation is 5 × 1014 Ω cm. Calculate the insulation resistance for 3 km length of the cable.
Properties - Poly Vinyl Chloride (PVC) - Paper - Cross Linked Polythelene - Vulcanised India Rubber (VIR)
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Questions : 1. List out the properties of insulating materials used for the cables. 2. List the various insulating materials used for the cables and discuss their features.
Belted - Screened - Super Tension (S.T.) - Oil Filled - Gas Pressure
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Question : 1. With neat diagrams explain constructional features of various types of cables.
Underground Cables
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Question : 1. Draw the cross sectional view of a single core cable and explain its construction.
Underground Cables
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Question : 1. Mention the requirements of underground cable.
Advantages of Underground Cables
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Question : 1. What are the advantages of underground cables over overhead lines?
Transmission and Distribution
Subject and UNIT: Transmission and Distribution: Unit IV: Underground Cables
Transmission and Distribution: Unit IV: Underground Cables : Syllabus, Contents
Transmission and Distribution: Unit III: (b) Insulators : Two Marks Questions with Answers
Subject and UNIT: Transmission and Distribution: Unit III: (b) Insulators
Transmission and Distribution: Unit III: (b) Insulators : Two Marks Questions with Answers
Insulators
Subject and UNIT: Transmission and Distribution: Unit III: (b) Insulators
When the number of units in a string of suspension type of insulator increases, calculation of voltage across each unit and the string efficiency becomes tedious, laborious and time consuming by the method discussed earlier.
Mechanical - Electrical Insulation - Environment and Temporary Cycle - Corona and Radio Interference T- Other Important
Subject and UNIT: Transmission and Distribution: Unit III: (b) Insulators
The insulators are tested according to the standards. The following tests are performed while testing an insulator : 1. Mechanical tests 2. Electrical insulation tests 3. Environmental tests 4. Temporary cycle tests 5. Corona and radio interference tests.
Reducing Ratio of Shunt Capacitance to Self Capacitance - Grading the Insulators - Use of Guard Ring (Static Shielding)
Subject and UNIT: Transmission and Distribution: Unit III: (b) Insulators
We have seen that higher the value of the string, efficiency, more uniform is the potential distribution over a string of suspension insulators.
Method of Calculating
Subject and UNIT: Transmission and Distribution: Unit III: (b) Insulators
The nonuniformity in the voltage distribution over a string of suspension insulators is expressed in terms of a parameter called "string efficiency".