micro turbine generator system
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Joined: Jun 2010
01-07-2010, 06:30 AM
Could you send me more info about micro turbine generator system? I need such idea for my final project and implimentation study in electrical engineering. Thanks in advance! My email address is firstname.lastname@example.org
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Joined: Jun 2010
01-07-2010, 12:08 PM
One is emerging from perhaps the most deliberate and least colourful engineering fields of all: gas turbine engineering. Gas turbines are internal combustion engines, like the ones that drive cars, except that they use a rotating shaft or rotor instead of pistons "reciprocating" in cylinders. This makes their operation smooth and steady, which lowers maintenance costs and increases reliability. Though they became practical only sixty years ago, today gas turbines are one of the keystone technologies of the civilization. As jet engines, they deliver most of our air transport, while stationary gas turbines are responsible for an increasing fraction of our electrical power generation.Partly because of this critical role, gas turbine engineers tend to innovate one tiny step at a time. In a field where liability exposures and development costs both can run into nine and ten figures, any kind of sweeping enthusiasm makes people nervous. Still, that doesn't mean engineers can't dream on their own time. In the spring of 1994, when a MIT turbine engineer named Alan Epstein found himself sitting in a jury pool, he started to think about what it would take to build the smallest possible jet engine. He concluded that in theory the device could be shrunk a lot, perhaps to the size of a collar button.
Depending on how much fuel came with the turbine, a laptop might run for months on a single charge; a cellphone, for half a year. Given the insatiable appetite our portable gizmos have for batteries, the microturbine project and implimentation suddenly became very interesting. The U.S. Army, which badly wants to reduce the weight carried by their "soldier systems", agreed to write the checks.
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12-01-2011, 05:19 PM
final report2010.doc (Size: 253.5 KB / Downloads: 117)
Microturbine generator systems are considered as distributed energy resources which are interfaced with the electric power distribution system. They are most suitable for small to medium-sized commercial and industrial loads. The microturbine provides input mechanical energy for the generator system, which is converted by the generator to electrical energy. The generator nominal frequency is usually in the range of 1.4-4 kHz. This frequency is converted to the supply frequency of 50 Hz by a converter .The electrical energy, passing through the transformer, is delivered to the distribution system and the local load. A mathematical model of a microturbine generator system includes electromechanical sub-system, power electronic converter, filters, interface transformer, local load, distribution system, turbine-generator control and converter control.
In recent years, modern precision manufacturing techniques and design methods have substantially improved the performance of micro-turbine generators (MTG). Compared to conventional generators, micro-turbine power sources are much smaller and portable. Microturbine generators are also proving to be more efficient, easier to maintain, and more environmentally friendly with fewer emissions. Although power generators running on microturbines can use various types of energy sources, Micro-turbine Generators brings together a wide range of engineering experience to describe the emergence of micro-turbine technology, its viability and its future potential.
Recuperated Micro-Turbine:- Recuperated microturbines , which recover the heat from the exhaust gas to boost the temperature of combustion and increase the efficiency.
Uncuperated Micro-Turbine:- Unrecuperated (or simple cycle) microturbines, which have lower efficiencies, but also lower capital costs.
MTG ‘s are small, high speed power plants that usually include the turbine, compressor, generator and power electronics to deliver the power to the grid. These small power plants typically operate on natural gas. Future units may have the potential to use lower energy fuels such as gas produced from landfill or digester gas. The generic MTG can be divided into three primary sub-systems :
Mechanical : including turbine, generator ,compressor and recuperator.
Electrical : including main control software, inverter and power firmware.
Fuel : including fuel delivery and combustion chamber.
Mechanically the MTG is a single shaft ,gas turbine with compressor ,power turbine and permanent magnet generator being mounted on the same shaft. The MTG incorporates centrifugal flow compressors and radial inflow turbine.
MTG ‘s have a high speed gas turbine engine driving an integral electrical generator that produces 20-100 KW power while operating at a high speed generally in the range of 50,000-120,000 rpm. Electric power is produced in the range of 10KHz converted to high voltage dc and then inverted back to 60 Hz, 480 V ac by an inverter.
During engine operation, engine air is drawn into the unit and passes through the recuperator where temperature is increased by hot exhaust gases. The air flows into the combustor where it is mixed with fuel , ignited and burnt. The ignitor is used only during start up and then the flame is self-sustaining.
The combusted gas passes through the turbine nozzle and turbine wheel converting the thermal energy of the hot expanding gases to rotating mechanical energy of the turbine. The turbine drives the generator. The gas exhausting from the turbine is directed back through the recuperator and then out of the stack.
A. ENGINE CONTROLLER : The features of an engine controller includes
automated start sequence
Battery or utility start
Gas or liquid fuel algorithm
Recuperated or simple cycle engines
Fault detection and protection
Advanced user interface
The design is fully digital to give it the flexibility of adaptation to different engine types and makes it more precise .
B. Power Conditioning System
The power conditioning system converts the unregulated, variable-frequency output of the generator into a high quality ,regulated waveform and manages the interaction with any applied load both in stand-alone and utility connect modes. The waveform quality surpasses general utility standards and is suitable for supplying sensitive equipment. Output voltage and frequency are software adjustable between 380-480 V and 50-60 Hz ,allowing the system to be easily configured for operation anywhere. The system can be selected to operate as a stand-alone power source [island mode] and in parallel with a site utility supply [utility mode]. Emergency power and back start are also possible.
C. Power Controller
The overall power conversion process is managed by an advanced microprocessor-based control system. Unique control algorithms and active filtering techniques are used which allows the system to maintain voltage distortion levels under 3% even with severe non-linear loads [crest factor of 3]. The control system optimizes the capability of the power conditioning electronics and achieves a robust and tolerant supply which surpasses any UPS performance. An intelligent fault-clearing feature permits the supply of sufficient, short duration overload current to operate as appropriately sized circuit breaker. This feature prevents interruption to the remaining site load in the event of localized load faults. Other real time intelligent algorithms are used to cope with a variety of overload conditions commonly experienced in island mode. These include dc-offset control and current limiting which optimizes transformer energization and motor start capability. Utility mode protection includes over and under voltage and frequency, incorrect phasing and loss of supply.