control of isolated micro hydro using elc

final defense on discrete elc

1. Final Presentation On Final Year Project -I Control of isolated micro-hydro under unbalanced load using 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. EXISTING ELC FOR BALANCED LOAD 4. PROBLEM STATEMENT 5. OBJECTIVES 6. METHODOLOGIES 7. EXPECTED RESULT 8.PROJECT TIMELINE 9. REFRENCES

3. Micro hydro plant had been installed for rural electrification where population is very few and the site is very far from the national grid. Extension of national 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. INTRODUCTION Fig 1 : Block Diagram of micro hydro with ELC unbalanced

4. INTRODUCTION Electronic 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 1.

5. There are two types of ELCs in practice , they are as follows. 1. AC voltage controller based ELC 2. Discrete resistance type ELC LITERATURE REVIEW

6. LITERATURE REVIEW 1. 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 2: Detail circuit diagram of ac voltage controller based ELC

7. LITERATURE REVIEW 2. 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 3 shows the detail circuit diagram of an ac voltage controller based ELC implemented with the synchronous generator. Figure 3: Detail circuit diagram of discrete resistance type ELC .

8. Existing model of Discrete Resistance Type ELC Under Balanced Load Condition Fig4 : Simulation Model of Discrete Resistance type ELC

9. Figure 5 : Detail of simulink model of discrete resistance type ELC

10. Figure 6 : Detail of discrete switching block. The input to this block is the number of discrete resistance to be turn on. There are fifteen number of logic gates for fifteen number of discrete resistances. The output of each logic gate is ‘1’ if the first input is less than or equal to the second input, otherwise, the output is ‘0’. The second input of all the fifteen gates are same and equal to the number of discrete resistance to be turn on and the first inputs of the fifteen logic gates are assigned as 0.5 to 14.5 respectively with an unit increment. Hence, the required number of logic gates gives output of ‘1’ and the remaining logic gates give output of ‘0’.

11. Simulation Results Fig i : Waveform of Pu Generated line to line voltage Fig ii : Waveform of rotor speed in Pu

12. Fig iii : Magnitude of load active power Fig iv:Magnitude Of Ballast load active power

13. Fig v : Magnitude of No of ballast load switches

14. 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.

15. After Semester Break Till now we have completed the Simulation of existing discrete resistance ELC under balanced Load. The waveform of generated active power, speed of rotor, output active power, generated voltage and active power drawn by ELC were observed, there was loss of 4kw in system. After the semester break we will be performing simulation of ELC under dynamic load with our proposed method.

16. OBJECTIVE To develop simulation model of new type of discrete ELC to take care of unbalanced load.

17. Start Get input from current sensor of R phases I R Input full load current I f Calculate no of ballast load switches Nr Stop   + Open N R no of switches D ivider Ir (FL) of one ballast load Generate logic signal to open no of switches METHODOLOGY 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 + -

18. IR IY IB Refrence current + - + + - _ Nr Ny Nb Ire Iye Ibe ELC Block Ir Iy Ib Divider Blocks unbalanced load METHODOLOGY Fig: Circuit Diagram of Proposed System

19. 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 .

20. PROJECT TIMELINE

21. 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          

22. [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