PG Diploma Solar Semester Two Paper 2 Exam Section A

Long Answer / Applied Questions (01–30)

1. Explain how BOS selection affects the safety, efficiency, and reliability of a solar PV plant.
Model Answer: BOS selection determines how safely and efficiently the solar plant operates because these components carry, protect, convert, and monitor power. Correct selection of mounting structures ensures mechanical stability, while proper junction boxes, combiner boxes, MCBs, MCCBs, SPDs, and grounding improve electrical safety. Efficient BOS design reduces losses, simplifies maintenance, and improves long-term reliability. A poorly selected BOS can lead to overheating, faults, low performance, and reduced system life.
Marks: 05

2. Discuss the importance of module mounting structure material selection in different site conditions.
Model Answer: Material selection for mounting structures is important because it affects corrosion resistance, strength, weight, and lifespan. Hot dip galvanized iron offers corrosion protection and strength. Aluminium is lighter and corrosion-resistant. Mild steel can be used where suitable protection and structural strength are needed. The selected material must withstand environmental exposure, mechanical loading, and installation requirements while supporting the modules securely for the long term.
Marks: 05

3. Explain the role of protection devices in DC and AC sections of a solar PV system.
Model Answer: Protection devices such as fuses, MCBs, MCCBs, SPDs, and disconnect switches are essential in both DC and AC sections. In the DC section, they protect strings and equipment from overcurrent, surges, and fault conditions. In the AC section, they protect inverters, distribution panels, and connected loads or grid interfaces. These devices also allow safe isolation for maintenance and emergency conditions.
Marks: 05

4. Explain the significance of cable conductor material and insulation in solar applications.
Model Answer: Solar cable performance depends strongly on conductor material and insulation. Copper and aluminium are common conductors, with copper usually preferred for lower resistance and flexibility. Insulation such as XLPE provides high thermal, UV, and moisture resistance. Proper conductor and insulation selection ensures safe current carrying capacity, resistance to outdoor conditions, lower losses, and longer service life.
Marks: 05

5. Discuss the practical consequences of undersized solar cables in a PV system.
Model Answer: Undersized cables overheat under normal operating current, increase voltage drop, waste power, and can damage insulation. They may lead to connector failure, loose joints, reduced system efficiency, and serious fire risk. In a PV system, where cables are exposed to heat and sunlight, undersizing becomes even more dangerous. Hence cable sizing must consider current, derating, and voltage drop carefully.
Marks: 05

6. Explain how duct material, cable grouping, and solar exposure affect cable current carrying capacity.
Model Answer: Duct material affects heat dissipation, and PVC ducts reduce current rating more than metal ducts due to higher thermal resistivity. Grouped cables heat each other and reduce mutual cooling, so their effective current carrying capacity falls. Direct solar exposure raises cable temperature and further reduces current rating. These effects require derating and may demand a larger cable cross-section.
Marks: 05

7. Discuss common cable faults in solar plants and the methods used to detect them.
Model Answer: Common cable faults include loose connections, insulation damage, corrosion, and overheating. Loose connections may show discoloration, melting, or hot spots. Corrosion may be identified by rust or damaged connectors. Damaged insulation may be observed visually or through insulation testing. Overheating can be detected using infrared thermal cameras. Routine inspection and testing help identify these faults early and prevent system failure.
Marks: 05

8. Explain why site readiness is critical before installing a rooftop solar system.
Model Answer: Site readiness ensures that the roof and surrounding conditions can safely support the solar installation. It includes structural integrity checks, shading analysis, roof condition, and electrical infrastructure evaluation. Without these checks, the installation may suffer from poor performance, leakage issues, safety hazards, or structural problems. Good site readiness reduces rework and improves installation quality.
Marks: 05

9. Discuss the complete sequence of rooftop solar installation in proper order.
Model Answer: Rooftop installation begins with site preparation, locating rafters, and planning the layout. Roof attachments are installed, followed by mounting rails. Panels are lifted carefully onto the roof and fixed to the rails. Electrical wiring is then connected, followed by junction box/inverter interconnection, grounding, inspection, and testing. The sequence must be systematic to ensure mechanical and electrical safety.
Marks: 05

10. Explain the importance of organized wiring and correct routing in solar plant installation.
Model Answer: Organized wiring reduces tangling, accidental damage, electrical interference, and maintenance difficulty. Correct routing through conduits, raceways, and cable trays protects wires from sharp edges, heat, moisture, and movement. Good wire management also improves appearance, safety, troubleshooting efficiency, and long-term reliability of the solar system.
Marks: 05

11. Explain the importance of inverter location and installation checks.
Model Answer: The inverter location affects cooling, accessibility, cable routing, and maintenance convenience. It should be mounted securely and in a location suitable for the system type. Installation checks include isolation of power sources, correct DC and AC connection, grounding, polarity verification, physical stability, and testing. Proper location and checks reduce faults and improve inverter life.
Marks: 05

12. Discuss quality assurance and documentation during solar plant installation.
Model Answer: Quality assurance includes component verification, design review, documented procedures, trained personnel, site inspections, testing, and commissioning. Documentation is essential to track component quality, installation compliance, inspections, and performance records. Proper documentation supports maintenance, troubleshooting, legal compliance, and long-term project management.
Marks: 05

13. Explain how project planning improves cost efficiency and operational efficiency in solar projects.
Model Answer: Good project planning defines scope, schedule, resources, and responsibilities clearly. It reduces confusion, avoids unnecessary delays, optimizes resource use, and ensures proper technology integration. These benefits improve operational efficiency and prevent cost overruns. Planning also supports long-term sustainability, adaptability, and stakeholder coordination.
Marks: 05

14. Discuss the major permits and approvals required before a solar project can proceed.
Model Answer: Important approvals include land acquisition and use permission, environmental clearances, grid connectivity and interconnection, Power Purchase Agreement, financial approvals, customs/import approvals, SERC permissions, building and construction permits, power generation license, local authority clearance, net metering approval, occupancy certificate, and tax/incentive approvals. These are essential for lawful execution and operation.
Marks: 05

15. Explain the role of environmental impact assessment in responsible solar development.
Model Answer: Environmental Impact Assessment evaluates the possible environmental effects of the project throughout its life cycle. It examines land disturbance, water usage, noise and visual impact, chemical usage, electromagnetic fields, and waste management. EIA helps reduce negative environmental effects, improve regulatory compliance, and support responsible project planning and design.
Marks: 05

16. Discuss the engineering specifications that must be decided during solar system design.
Model Answer: Engineering specifications include system capacity and sizing, module selection, inverter selection, mounting structure, electrical design, DC and AC disconnects, overcurrent protection, wiring and cable management, energy storage if applicable, grid connection requirements, and monitoring and control systems. These decisions determine performance, safety, cost, and reliability.
Marks: 05

17. Explain the cost structure of a 1 MW solar power plant based on the notes.
Model Answer: The notes state that a 1 MW solar power plant in India may cost approximately Rs 4–5 crore. Major cost components include solar panels, inverter, combiners and junction boxes, protective gear arrangement, SCADA and data logger system, land, and project erection. Understanding this cost structure helps in budgeting, financing, and ROI analysis.
Marks: 05

18. Discuss major financing sources and subsidy mechanisms for solar projects in India as given in the notes.
Model Answer: Major financing sources mentioned include IREDA, IFC, ADB, REC, KfW, World Bank-linked Clean Technology Fund, and EIB-linked funding through SBI. The notes also mention MNRE solar schemes such as off-grid agriculture pump subsidy and grid-connected rooftop subsidy for households and RWAs/GHS. These funding routes reduce capital burden and improve financial viability.
Marks: 05

19. Explain ROI and NPV concepts in solar project analysis.
Model Answer: ROI refers to the effective return generated by the investment over the life of the solar system. It depends on initial investment, energy production, electricity savings, incentives, maintenance cost, and financing. Net Present Worth or NPV considers the present value of future returns and costs. Both help assess financial viability and compare investment options.
Marks: 05

20. Discuss the importance of milestones and dependency relationships in project scheduling.
Model Answer: Milestones indicate important stages such as engineering, material delivery, installation, and system go-live. Dependency relationships define how one activity affects another, such as finish-to-start, start-to-start, finish-to-finish, and start-to-finish. Understanding these relationships helps prepare realistic schedules, avoid delay, and manage the critical path more effectively.
Marks: 05

21. Explain the critical path concept with reference to solar project execution.
Model Answer: The critical path is the sequence of activities that directly determines the total project duration. In the notes, critical activities include permitting, site investigation, detailed civil engineering, procurement of posts, transformer production and transport, electrical installation, commissioning, and plant start-up. Delay in any critical path activity delays the whole project.
Marks: 05

22. Discuss procurement strategy for ensuring quality and timely project completion.
Model Answer: Procurement strategy involves choosing optimally rated, certified equipment, working with reputed vendors and OEMs, auditing manufacturer facilities, developing long-term supplier relationships, buying in bulk where useful, and selecting freight forwarders wisely. These steps reduce quality risk, delay, and cost inefficiency while supporting project completion on time.
Marks: 05

23. Explain supplier and contractor partnership requirements in solar EPC execution.
Model Answer: Strong supplier-contractor partnerships require clear communication, quality products and services, technical support, timely delivery, collaborative problem-solving, cost-effective solutions, regulatory compliance, performance monitoring, documentation, and clear contracts. These factors improve coordination and reduce project risk.
Marks: 05

24. Discuss construction phase activities and quality checks in a solar project.
Model Answer: Construction activities include site survey, marking locations, panel mounting, wiring panels together, inverter connection, and substation-related work. Quality control includes design review, material inspection, documented procedures, training, on-site audits, testing, commissioning, quality documentation, and continuous improvement. These checks ensure safe and reliable execution.
Marks: 05

25. Explain testing and commissioning activities in a solar PV plant.
Model Answer: Testing and commissioning ensure system performance, safety, compliance, and reliability. Activities include voltage polarity checks, I-V curve testing, ground resistance testing, and thermal imaging. Thorough testing also supports grid integration, fault diagnosis, and quality assurance of components before the plant enters normal operation.
Marks: 05

26. Discuss performance evaluation parameters used after solar plant commissioning.
Model Answer: Key performance evaluation parameters include array yield, system yield, capacity factor, performance ratio, inverter efficiency, and PV module efficiency. These indicators help compare actual plant performance to expected output and identify operational problems or losses. They are essential for post-commissioning review and ongoing maintenance planning.
Marks: 05

27. Explain the importance of monitoring and maintenance in sustaining solar plant output.
Model Answer: Monitoring and maintenance help detect faults, maintain energy production, reduce downtime, and extend equipment life. The notes mention thermal imaging, visual inspection, voltage/current checks, and ground fault monitoring. Routine panel cleaning, inverter maintenance, and component inspection improve performance ratio, safety, and long-term plant reliability.
Marks: 05

28. Discuss emerging and future trends in solar energy mentioned in the notes.
Model Answer: The notes mention tandem solar cells, perovskite solar cells, bifacial panels, floating solar farms, transparent solar cells, solar tracking systems, and energy storage integration. Future advancements also include AI and machine learning, blockchain technology, space-based solar power, hybrid renewable systems, community solar models, and circular economy concepts in solar manufacturing.
Marks: 05

29. Explain the process of forming a research question for a solar project thesis.
Model Answer: A research question begins with curiosity and the desire to learn. The student should review literature thoroughly, identify a problem connected to the topic, understand who is involved, define what they want to learn, and set the assignment goal. The question should be clear, focused, feasible, original, and within the area of study.
Marks: 05

30. Discuss how case study sizing guidance can be used in academic solar project work.
Model Answer: The case study guidance provides scale-based project categories for residential, commercial, and industrial applications. Students can use electricity bills to estimate load and size suitable solar systems. Residential cases start from 25 kW and above, commercial from 250 kW and above, and industrial from 5 MW and above. This framework helps connect classroom learning with practical project design.
Marks: 05