Difference between revisions of "Projects:2019s1-180 Nanogrid Development for Households Applications"

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Members & Supervisors:
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=='''Project team'''==
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Supervisor - Nesimi Ertugrul
 
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Wassim Saad
 
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Dehong Wang
 
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Shuting Dai
 
  
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'''Abstract:'''
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=== '''Supervisors''' ===
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Supervisor -Dr.Nesimi Ertugrul
  
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'''Background:'''
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=== '''Project members''' ===
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Members: Shuting Dai, Wassim Saad, Dehong Wang
  
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''What is a grid?''
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== '''Introduction''' ==
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'''Introduction'''
  
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An electrical grid (macrogrid) is electrical power system network which consists of a generating plant, transmission lines, the substation, transformers, the distribution lines, and the person who consumes the electricity. Typically, electrical grids have depended on a central generation plant which usually far away from the main consumption areas, being towns and cities.
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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.
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The electrical grid can be broken down into 3 subsections. It consists of: Generation, Transmission & Distribution, and Consumption.
 
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The generation components of the electrical grid can be classified as either centralized generation, or decentralized generation. Centralized generation consists of a large electrical production plant, which distributes electricity to the consumers via the grid. Centralized generation may include coal, nuclear, natural gas, hydropower, wind farms, and large solar arrays.
 
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Decentralized generation is generated power that occurs close to consumption, such as rooftop solar.
 
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Once the electricity has been produced in the generation stage, it must pass through the transmission & distribution component in order to reach the consumers. This component consists of transformers, substations, and transmission lines which transmit the electricity over long distances.
 
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After the transmission & distribution stage, the electricity reaches the consumption stage, where the electricity is consumed by the consumers at their demand.
 
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The goal of an electrical grid is to safely and stably distribute electrical power, based on consumer’s demand, at prescribed levels of security, whilst ensuring system frequency and voltage levels remain relatively constant.
 
  
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Managing an electrical grid consists of several challenges, which arise from managing the supply of electricity production to match consumer demand, as well as ensuring that the voltage and frequency remain constant at prescribed levels across the entire grid. In recent years, maintaining the constant frequency and voltage levels has become increasingly challenging due to the rapid integration of renewable energy sources.
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== '''System Design''' ==
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Before the introduction of renewable energy to the electrical grids, grids relied on a non-renewable power source to produce the electricity. Maintaining constant frequency and voltage is simplified with these non-renewable sources due to them being synchronous generators - which converts mechanical power from a prime mover into an AC electrical power at a particular voltage and frequency. The constant speed of the generator - called the synchronous speed - results in the constant voltage and frequency output, and hence allows for energy management to be accurately managed, allowing for grid reliability and stability.
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'''System Design'''
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On the other hand, renewable energy sources particularly wind and solar energy, can have fluctuating output. Wind turbine power output may fluctuate due to wind speed rarely being constant, and with the tendency to completely drop off at any given moment.
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[[File:Design123.png|800px|frameless|center]]
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The fluctuating wind speed leads to a variety of rotational speeds of the wind turbine, which impacts its output, as different speed correspond to different frequency voltage levels.
 
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The output of a solar photovoltaic cell may also fluctuate due to clouds impacting solar intensity, which also leads to a unpredictable output.
 
  
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Around the world, the integration of renewable energy into electrical grids - through either centralized systems (wind/solar farms) or distributed generation (rooftop solar) - has led to significant difficulties with managing the power system due to these exact fluctuations in output, leading to unstable frequency, hence a degree of unreliability.
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AC coupled (left) and DC coupled (right)
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This case of management difficulty is relevant to South Australia, due to the SA government making a long term commitment of maximising renewable energy output, with the eventual goal of achieving 100% renewable. This led to South Australia closing down the Northern Power Station - SA’s largest coal power plant - making the main source of electricity production renewable energy. This led to significantly high electricity prices, and reliability issues.
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Advantage of DC couple compare with AC couple:
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These management difficulties have lead to the potential need to research different grid options so that renewable energy can become a reliable and dependable source for the future.
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Easy to synchronise the system
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This is where smaller scale grids, such as microgrids and nanogrids, become significant.
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Easy to expand
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A microgrid is defined as a small network of electricity users with a local source of supply that is usually attached to a centralized national grid, but is able to function independently. A microgrid is essentially the same as the macrogrid, but at a communal level. The same definition of this applies to nanogrids, except that nanogrids typically applies for a single building, whether it be a household or office building.
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Less power transmission loss through the inverter
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In order to completely integrate renewable energy to become a dependable source, the issue of reliability and costs must be solved. Currently, there are a few different methods that grids largely dependent on renewable sources use. One method is the use of large scale battery storage. Battery storage was introduced to South Australia’s grid, when Tesla-Neoen constructed a 100 MW lithium-ion grid support battery. The aim of implementing the large scale batteries was to improve the stability of the SA grid, which experienced a significant amount of instability prior to the battery’s construction. The goal of the battery’s construction was to identify if the grid could become fully dependent on renewable energy with the inclusion of energy storage, as a precursor for the rest of the world. Since its implementation, the battery has demonstrated success in stabilising grid frequency and managing the Rate of Change of Frequency (RoCoF). The similarities this has to the proposed nanogrid system is the dependence the grid has on renewable energy sources, as well as integrating it with battery storage. The key difference to the proposed nanogrid system is the use of battery storage to maintain stability of the grid frequency. The proposed nanogrid project aims to use the battery storage as a backup energy source, rather than frequency management.
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Less cost due to the inverter
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more suitable for households applications level
  
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An example of a microgrid being used is at the Santa Rita Jail, where a microgrid consisting of a 1.2 MW PV system, battery storage, as well as backup diesel generators. This particular system is a larger scale version of the proposed nanogrid, except without the combination of wind and solar.
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[[File:Dehong.png|700px|frameless|center]]
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Despite these methods working, the large scale grid in SA still leads to extremely high electricity prices, and less stability. The aim of the project is to develop a nanogrid system for household/office applications, which can replicate the results identified by the jail microgrid, of being able to provide secure and reliable energy to the household/office, at a low cost of energy. The goal is also to achieve a nanogrid that can be dependent on itself to provide constant and reliable energy to meet demand.
 
  
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'''Introduction:'''
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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. 
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== '''System Layout''' ==
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'''Component Specification'''
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'''Solar panel '''
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Max power: 260W
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Max power voltage: 30.6V
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Max power current: 8.50A
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Open circuit voltage: 38.2V
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Short circuit current: 9.00A
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[[File:Solar.png|500px|frameless|center]]
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'''Wind turbine'''
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Rated power: 600W
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Rated voltage: 24V
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Rated current: 25A
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'''PV & battery controller'''
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Output current rating: 60A continuously at 25 degree celsius ambient
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Default battery system voltage: 12, 24, 36, 48 or 60VDC
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'''Wind & battery controller'''
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Battery voltage: 24V
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Rated wind power input: 600W
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Wind Max current: 35A
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'''Battery'''
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Battery 1
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Lead acid
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Capacity/voltage: 12V 40Ah
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Battery 2
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Lithium
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Capacity/Voltage: 2.4kWh/ 50Ah/48V
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Charge voltage: 52.4-54V
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'''Generator (back up)'''
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Cont output: 2700W
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Voltage: 240V
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Frequency: 50Hz
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=='''Component Testing'''==
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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.
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'''Solar testing'''
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1. PV controller testing with power supply
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Generated solar power is simulated with DC power supply with average efficiency 86.7%.
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2. Solar panel testing only
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The maximum power point is tracked to be 79.3W, roughly 80% of the rated maximum power of the tested solar panel.
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3. PV controller testing without load
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This solar controller is functional as expected and the efficiency range from 87.5% to 92% is achieved.
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4. PV controller testing with load
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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%.
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'''Wind generator testing'''
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1.Wind turbine generator testing only
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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.
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2.Wind controller testing without load
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The output voltage and current from generator have distortion due to load.
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3.Wind  controller testing with load
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The result shows the efficiency of the wind turbine generator system under different power of load varied from 42% to 82%.
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=='''Conclusion'''==
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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.
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Future works
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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.

Latest revision as of 12:15, 30 October 2019

Project team

Supervisors

Supervisor -Dr.Nesimi Ertugrul

Project members

Members: Shuting Dai, Wassim Saad, Dehong Wang

Introduction

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

System Design

Design123.png

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

Dehong.png

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

Solar.png

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

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.

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