project proposal on discrete resistance type elc

project proposal on ELC

1. A Project Proposal On Control of isolated micro-hydro under unbalanced load using modified discrete resistance type ELC Presented By: Bharat Thapa (77002) NarayanTamang (77005) Sushant Basnet (77011) Kathmandu Engineering College Department of Electrical Engineering Presented To: Department Of Electrical Engineering

2. contents 1. INTRODUCTION 2 . LITERATURE REVIEW 3. PROBLEM STATEMENT 4. OBJECTIVES 5. METHODOLOGIES 6. EXPECTED RESULT 7.PROJECT TIMELINE 8. REFRENCES

3. INTRODUCTION Micro hydro plant had been installed for rural electrification where population is very few and the site is very far from the natural grid. Extension of natural grid to supply power such rural is not economical due to high cost of transmission and extensive power loss in the transmission loss. ELC is used for speed(frequency) control of micro hydro plant as ELC is cheaper than the conventional mechanical governor. Electric Load Control (ELC) systems in micro hydro plants are indeed designed with the consideration of maintaining balanced loads. An unbalanced load occurs when the electrical loads connected to a 3 phase system are not evenly distributed across the phases. This imbalance can lead to Overheating of generator winding, Voltage fluctuations Reduced overall efficiency. In micro hydro plant, the generator is driven by unregulated water turbine with constant mechanical power input to the generator. However the load is variable in nature, in order to make power balance ELC is used as shown in figure below. Fig: block diagram of micro hydro with ELC

4. A review of existing literature reveals that traditional methods for managing unbalanced loads in micro hydro, such as static compensators and advanced inverter controls, are often costly and complex. Recent advancements in Electronic Load Controllers (ELCs) have shown promise in addressing these challenges more effectively[1]. There are two types of ELCs. They are as follows - AC voltage controller based ELC - Discrete resistance type ELC AC Voltage controller based ELC Among various types of ELCs, AC Voltage Controller-based ELCs have gained attention due to their effectiveness in managing the voltage and frequency stability under varying load conditions.An AC Voltage Controller-based ELC typically uses semiconductor devices such as thyristors or triacs to control the RMS value of the AC voltage supplied to a load. By adjusting the phase angle of the voltage waveform, the controller can modulate the power delivered to the load, effectively balancing the generated power and the consumed power in the micro hydro. Fig 1 shows the detailed circuit diagram of ac voltage controller based ELCS. LITERATURE REVIEW

5. z DISCRETE RESISTANCE TYPE ELC Discrete Resistance Type ELCs offer a reliable, cost-effective solution for managing power balance in isolated micro hydro. Their simplicity, robustness, and low harmonic distortion make them ideal for a variety of applications, from rural electrification to hybrid renewable systems. Ongoing research and development are essential to address scalability and adaptability challenges, ensuring that these ELCs can meet the evolving demands of modern micro hydro systems.Figure 2 shows the detail circuit diagram of an ac voltage controller based ELC implemented with the synchronous generator. Fig 1: Detail circuit diagram of ac voltage controller based ELC

6. Figure 2: Detail circuit diagram of discrete resistance type ELC .

7. PROBLEM STATEMENT Traditional method uses firing angle control method to control the RMS value of AC voltage supplied to a load. By adjusting the firing angle, the controller can modulate the power delivered to the load. Though its simplicity, it introduces discontinuity and plentiful harmonics in load current and a lagging power factor occurs at load side when firing angle is increased The imbalance current generates zero sequence components, where identical currents flow in each phase and return through the neutral.The AC voltage controller-based ELC may struggle to effectively mitigate the impact of zero sequence components due to its primary design focus on voltage and frequency regulation. In this project, it is proposed to develop a new control logic for ELC so that ELC draws unbalanced current when load is unbalanced results in balanced generator circuit.

8. OBJECTIVES To demonstrate the effectiveness of the proposed system in mitigating effect of zero sequence components. To ensure stable voltage and frequency in the presence of unbalanced loads. To enhance the reliability and efficiency of the micro hydro operation.  To eliminate discontinuity and harmonics in load current.

9. + - No Yes Start Get input from current sensor of R phases I R     Is I f - I R = 0?   Input full load current I f Continue operation without problem Stop   Calculate no of Ballast load switches N R Open N R no of switches Fig 1 shows flow chart of working process of proposed system in R phase only. so, this proposed system operates identically in all three phases until current is balanced. FIG 1 : Flow chart showing working of proposed system in R phase METHODOLOGY

10. EXPECTED RESULT With the implementations of new proposed ELC in the isolated micro-hydro system, problem of zero sequence current in generator side will gradually reduce even though load is unbalanced. Our main target is to eliminate problem of introduction of zero sequence in generation side. As there is no firing angle control method , problems of harmonics will be eliminated .

11. PROJECT TIMELINE

12. Months Task June July Aug Oct Nov Dec Jan Feb March Studying conventional ELC system                  Semester BREAK                 Analyzing and simulation of the conventional ELC model           Studying the behaviour of ELC at different conditions               Designing simulation model of micro hydro with proposed ELC       Analyzing and implementation of the new approach at various condition           Studying the final design          

13. [1] NW Aung, AZ Ya “Design Of Electronic Load Controller By Using Combination Method For Micro-Hydro Power Plant And Its Control And Monitoring Program Simulation” International Journal of Electrical, Electronics and Data Communication, Volume-3, Issue-6, June-2015 [2] J. Chan; W. Lubitz “Electronic load controller (ELC) design and simulation for remote rural communities: A powerhouse ELC compatible with household distributed-ELCs in Nepal” 2016 IEEE Global Humanitarian Technology Conference (GHTC) [3] I. Tamrakar, R. Adhikari, R. Bhattarai “Improved Electronic Load Controller for Three Phase Isolated Micro-Hydro Generator”Fifth International Conference on Power and Energy Systems , October 2013 REFRENCES