Projects:2019s1-180 Nanogrid Development for Households Applications

Members & Supervisors:

Supervisor -Dr.Nesimi Ertugrul

Members: Shuting Dai, Wassim Saad, Dehong Wang

Introduction

Due to the recent blackouts and load shedding in Australia, energy costs become higher.The project is for the purpose of providing higher quality reliable electrical power with lower costs.The aim of this project is to design, develop and implement a small scale standalone renewable nanogrid for households and small business applications. A traditional electrical grid can be referred as a typical centralised macrogrid while the nanogrid is a localised power distribution system that is less than 5kW. The nanogrid is a mobile system that can be deployed without additional electricity approval and with lower installation costs.

System Design

AC coupled (left) and DC coupled (right) Advantage of DC couple compare with AC couple: Easy to synchronise the system Easy to expand Less power transmission loss through the inverter Less cost due to the inverter more suitable for households applications level

The nanogrid system is setting up to 48V DC level for human safety operation and 1.3kW output power to satisfy household daily demand which is 14.2kWh in Australia , and central controller is monitoring and controlling voltage and current output from the converter and inverter to ensure the energy management of the system.

System Layout

Component Specification

Solar panel

Max power: 260W

Max power voltage: 30.6V

Max power current: 8.50A

Open circuit voltage: 38.2V

Short circuit current: 9.00A

Wind turbine

Rated power: 600W

Rated voltage: 24V

Rated current: 25A

PV & battery controller Output current rating: 60A continuously at 25 degree celsius ambient Default battery system voltage: 12, 24, 36, 48 or 60VDC

Wind & battery controller

Battery voltage: 24V

Rated wind power input: 600W

Wind Max current: 35A

Battery 1

Lead acid

Capacity/voltage: 12V 40Ah

Battery 2

Lithium

Capacity/Voltage: 2.4kWh/ 50Ah/48V

Charge voltage: 52.4-54V

Generator (back up)

Cont output: 2700W

Voltage: 240V

Frequency: 50Hz

Component Testing

In order to obtain accurate measurements and calculate the real system efficiency, a four-channel picoscope is used to measure input and output data with more decimal places during the whole testing procedure. Also, five-turn measurements of the probes are applied for higher data accuracy.

Solar testing

1. PV controller testing with power supply Generated solar power is simulated with DC power supply with average efficiency 86.7%.

2. Solar panel testing only The maximum power point is tracked to be 79.3W, roughly 80% of the rated maximum power of the tested solar panel.

3. PV controller testing without load This solar controller is functional as expected and the efficiency range from 87.5% to 92% is achieved.

4. PV controller testing with load With the addition of the variable resistances and the diode to control the direction of the current flow, the efficiency of the solar controller is in the range 86.5% - 91%.

Wind generator testing

1.Wind turbine generator testing only To simulate the wind generator under real life operation condition and easier to test the output performance, using the DC motor to drive the generator. The output voltage from the wind generator is balance smooth sine wave.

2.Wind controller testing without load The output voltage and current from generator have distortion due to load.

3.Wind controller testing with load The result shows the efficiency of the wind turbine generator system under different power of load varied from 42% to 82%.

Conclusion

In general, the efficiency of the solar panel is 80% and an overall 90% average efficiency of the PV controller is achieved in the nanogrid solar system.The high efficiency PV controller is feasible and functional as required. Additionally, the efficiency of the wind generator system is varied from 42% to 82% based on the load, however, this controller is not stable enough to satisfy daily power demand.

Future works With the completion of preliminary testing of all components, the controller testing and validating of the battery. Assembly components into a cabinet, monitoring and energy management need to be further conducted.