JNTU
JNTU B.Tech IV ELECTRICAL DISTRIBUTION SYSTEMS Previous Question Paper (July - 2023 - R16)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
Part A
What are the types of basic distribution system?
Answer
The basic distribution systems are primarily classified based on the nature of the current and the configuration of the supply lines:
- Classification by Current: Direct Current (DC) distribution systems and Alternating Current (AC) distribution systems.
- Classification by Configuration: Radial distribution systems and Ring main distribution systems.
What are the purposes of load forecasting?
Answer
Load forecasting is essential for the efficient planning, operation, and management of electrical distribution systems. Its primary purposes include:
- System Planning and Expansion: It helps in determining the required capacity for new distribution substations, feeders, and transformers to meet future load growth, ensuring long-term reliability and cost-effectiveness.
- Operational Efficiency and Control: It enables utilities to schedule maintenance, manage power flows, and optimize voltage regulation by predicting peak load periods, thereby reducing losses and preventing equipment overloading.
- Economic Dispatch and Financial Planning: Accurate forecasts allow for better procurement of power, effective budget allocation for infrastructure upgrades, and the determination of appropriate tariff structures based on projected demand patterns.
What is a substation?
Answer
Sign in to view the complete answer paper.
What is the importance of voltage drop calculation for distribution systems?
Answer
Sign in to view the complete answer paper.
What are the types of protection coordination?
Answer
Sign in to view the complete answer paper.
What are the objectives of distribution system protection?
Answer
Sign in to view the complete answer paper.
What is the need of power-factor control?
Answer
Sign in to view the complete answer paper.
What are the difference between shunt and series capacitors?
Answer
Sign in to view the complete answer paper.
What are the equipment for voltage control?
Answer
Sign in to view the complete answer paper.
What are the importance of voltage control?
Answer
Sign in to view the complete answer paper.
Part B
Discuss the factors effecting distribution system planning.
Answer
Sign in to view the complete answer paper.
A substation supplied the following loads: 175MW, 120MW, 80MW, 60MW and 10 MW. The station has a maximum demand of 220MW. Calculate the following, if annual load factor of the station is 55%, number of units supplied annually, diversity factor and the demand factor.
Answer
Sign in to view the complete answer paper.
Discuss the HVDS and LVDS? List out merits and demerits of these distribution systems.
Answer
Sign in to view the complete answer paper.
Explain the objectives of secondary mains.
Answer
Sign in to view the complete answer paper.
What are the rules to be considered for selection of an ideal location of substations?
Answer
Sign in to view the complete answer paper.
Discuss how do you analyze a substation service area with ‘n’ primary feeders.
Answer
Sign in to view the complete answer paper.
In terms of resistance and reactance of the circuit, derive the equation for load power factor for which voltage drop is maximum.
Answer
Sign in to view the complete answer paper.
Prove that the power loss due to load currents in the conductors of the single-phase two-wire unigrounded lateral with full capacity neutral is 6 times larger than the one in the equivalent three phase 4-wire lateral.
Answer
Sign in to view the complete answer paper.
What are the types of common faults? Discuss the procedure for fault calculations.
Answer
Sign in to view the complete answer paper.
What are the different protective devices used in the distribution system? Give comparison between them.
Answer
Sign in to view the complete answer paper.
Describe the general coordination procedure between protective devices.
Answer
Sign in to view the complete answer paper.
Explain the coordination between a fuse and a circuit breaker.
Answer
Sign in to view the complete answer paper.
Explain how reduction in line current and hence power losses are obtained with p.f improvement.
Answer
Sign in to view the complete answer paper.
Give the best values of capacitor banks to improve the load p.f. from 0.75 to 0.9 from the following data: Load 700 kVA, operating voltage 3.6 kV (i) Star connection (ii) Delta connection.
Answer
Sign in to view the complete answer paper.
Explain the procedure to determine the best capacitor location.
Answer
Sign in to view the complete answer paper.
A single phase system supplies the following loads: i) Light load of 40 kW at unity power factor ii) Induction motor load of 125 kW at p.f. 0.8 lagging iii) Synchronous motor load of 60 kW at p.f 0.85 leading iv) Other miscellaneous loads of 40 kW at p.f. 0.75 lagging. Find the total kW and kVA delivered by the system and p.f at which it works.
Answer
Sign in to view the complete answer paper.
Explain the effect of series capacitor over voltage control with necessary diagrams and expressions.
Answer
Sign in to view the complete answer paper.
Explain about line drop compensation with neat diagram.
Answer
Sign in to view the complete answer paper.
Explain briefly different types of voltage control methods.
Answer
Sign in to view the complete answer paper.