Generator Blog

The  first wind turbine generators rolled off the assembly line owned by GE Energy on May 10 at its factory in Nomura-Hai Phong Industrial Park in the northern city of Hai Phong.After a year of construction the factory is now ready for producing turbines generators for export.

The US$61 million plant, which is expected to create 500 jobs for local people, will export GE Energy’s turbines and services around the world.

The Hai Phong facility will provide an installation, maintenance and repair service for the components it produces.

GE Energy is a subsidiary of the global infrastructure, finance and media company General Electric, which employs more than 300,000 people worldwide.

Since 1960, GE Energy has provided technical support for a number of power generation projects in Vietnam. A recent survey shows that 8.6 per cent of Vietnam’s land mass is suitable for generating power from the wind.

Under a draft national power development strategy, currently being considered by the government, renewable energies will account for 5 per cent of the nation’s energy output by 2020, with wind and solar power accounting for half of all renewable energies.

ABB has introduced a new standard series of slip-ring generators designed to fit doubly fed wind turbines. The new generators cover the power range of 1.5 MW to 2 MW.

The standard base construction for different powers enables large-scale manufacturing, and the modular turbine interface connections can be changed to suit individual customers’ specifications, according to the company. Both air and water cooling are available, as is a 60 Hz version for North American installations.

Features of the new generator series include a patented rotor design with an optimized winding-end support ring.

An improved insulation level offers high-voltage peak integrity and allows the use of various types of converters, ABB says. The new design also incorporates minimized total harmonic distortion levels.

A vaneless ion wind generator is a device that produces electricity directly by using the wind to pump an electrical charge from one electrode to another. It is a type of wind power, although wind energy is usually extracted to make electricity by means of a wind turbine.

Electrostatic wind generators work by spraying water from a nozzle facing a toroidal charged electrode. This induces an opposite charge in the water and when the water flows out of the nozzle, each drop carries a small amount of charge. These water droplets are then blown by the wind, going through the center of the charged toroid without touching it. The droplets then hit a fine mesh, adding to its charge. The other alternative is to use the Earth as the second electrode. The main advantage of this system is that it has no moving parts except the water droplets. The disadvantages are that it needs a constant supply of water, its wind profile can’t be reduced, it requires many small parts, and it has to be well-crafted to reduce corona discharge losses.

A generator is a machine which is designed to generate AC electricity. Generators are used by companies for getting power to job sites where power may not be available and for homeowners to provide backup electricity in case of an extended power outage. Generators come in a variety of different sizes and designs. Picking the right one is an important step towards ensuring that your electrical needs are meet if the power goes out.

Standby Generators

Standby generators are larger generators which are designed specifically for the purpose of powering most or the entire house during an extended power outage. Most standby generators use a small car engine to operate the generator. Standby generators can be found in a variety of different sizes. The size is rated by the number of KW the generator can produce. Most home standby generators range between 20KW and 60KW. Industrial standby generators are significantly larger. These produce anywhere between 100KW and 1MW or mega watt. A megawatt is equal to 1000KW.

Fuel Sources for Standby Generators

Home standby generators are powered by either propane or natural gas. In most states it’s illegal to operate a gas or diesel powered stand by generator in a residential zone. Industrial standby generators are almost always powered by diesel.

Portable Generators

Any generator which is on wheels or designed to be moved is classified as a portable generator. Most portable generators are relatively small in size. These range between 1KW and 5KW. They are primarily used for providing power to tools in areas where power is not available. Larger portable units range between 5KW and 15KW. These can be used in the field as well but they are commonly used by homeowners to power small portions of their home if the power is out for an extended period of time.

Fuel Sources for Portable Generators

Nearly all portable generators run on standard gasoline. Some run on propane supplied by a small propane tank but these are rare.

Maintaining a Generator

Generators are all engine driven. Most portable models utilize engines that are similar in style to a lawnmower engine. Many of the home standby variety use a car engine. This means that generators need similar maintenance to a car.

Change Oil: The oil should be changed on a generator periodically. For models without an oil filter the oil should be changed every 50 hours or once a year. For models which do have an oil filter every 250 hours or once a year is recommended.

Air Filter: The air filter should be visually inspected every time the oil is replaced. If it appears dirty then it should be replaced with a new air filter.

Exercise: Generators should be run for one hour once a month. This keeps the engine running properly. This will also prevent the battery from wearing out if it is a model with a battery.

Inspect: Inspect the generator with every oil change. Look at the hoses and any belts. If you see any cracks or other signs of dry rot they should be replaced.

Foster Wheeler AG (Nasdaq: FWLT) announced today that a subsidiary of its Global Power Group has been awarded a contract to design, supply and erect a heat recovery steam generator (HRSG) by the Spanish company, REPSOL PETROLEO S.A. The HRSG and auxiliary equipment will be integrated in a cogeneration plant being built at the REPSOL Cartagena Refinery in Murcia, Spain. Foster Wheeler will also provide start-up supervision services.

Foster Wheeler has received a full notice to proceed on this contract.

The HRSG will be coupled with a General Electric PG-6581 gas turbine and recover heat from the gas discharge stream, producing high pressure and medium pressure steam for use in refinery processes and electricity generation at the Cartagena facility. The unit will be equipped with a bypass stack and diverter, as well as post-firing and fresh air capability, for continuous operation even after a combustion turbine trip.

“This boiler is the seventh HRSG awarded to Foster Wheeler by REPSOL, a true testimony that Foster Wheeler meets the high degree of design and quality standards demanded by REPSOL,” said Eric Svendsen, chief executive officer of Foster Wheeler Energia, S.L. in Madrid.

Foster Wheeler AG is a global engineering and construction contractor and power equipment supplier delivering technically advanced, reliable facilities and equipment.The company’s Global Engineering and Construction Group designs and constructs leading-edge processing facilities for the upstream oil and gas, LNG and gas-to-liquids, refining, chemicals and petrochemicals, power, environmental, pharmaceuticals, biotechnology and healthcare industries.

Siemens Energy has received an order from the Russian company OOO RN-Tuapsinskiy NPZ, a fully owned subsidiary of OAO Rosneft, for the supply of six industrial gas turbine generators. The SGT-800 gas turbine-generators each rated at 47 megawatts will be operated in the Tuapse refinery located on the Black Sea. The first three gas turbines are scheduled for delivery by late 2010, with the remaining three units to follow by the end of 2012. The order is valued at approximately EUR 90 million.

The order encompasses six gas turbines and six generators that are needed for the generation of electricity and steam to accommodate expansion of the Tuapse refinery’s capacity. Tuapse is an important petroleum port on the Black Sea. The customer OOO RN-Tuapsinskiy NPZ is currently undertaking extensive expansion and upgrading projects at the refinery to increase the plant’s capacity from a current 5 million to about 12 million metric tons (38 million to 88 million barrels). At the same time refining depth will be increased from 56 to 95 percent.

The SGT-800 stands out with its first-class efficiency, high availability and reliability, and low life cycle costs. NOX emissions are minimized thanks to its Dry Low Emissions (DLE) combustion system. A critical project requirement for the gas turbines being supplied to the Tuapse refinery is their capability to operate on various fuels. The SGT-800’s DLE system is unique in that it can achieve low emissions on a wide variety of fuels.

Including this order, 29 SGT-800 gas turbines have already been ordered by customers from Russia or have been delivered to Russia. For instance, between 2007 and 2008 Siemens received orders from Rosneft for a total of seven SGT-800’ machines for the gas turbine power plant at the Priobskoye oil field.

In June 2009, the Kolomenskoe gas turbine power plant in Moscow, supplied by Siemens with three SGT-800 machines, was able to start commercial operation. The cogeneration power plant supplies the Russian capital with 136 megawatts of electricity as well as 171 Gcal/hour of district heat. Overall plant efficiency is 83 percent.

(The SGT-800 gas turbine features high efficiency and low life-cycle costs. It is used for simple cycle power generation, for combined cycle power generation (CCPP) and because of its excellent waste heat recovery potential it is ideal for combined heat and power (CHP). The photo shows the SGT-800 gas turbine with a capacity of 47 megawatts at the Finspong plant in Sweden.)

Trident Energy’s plans to create power from sea waves suffered a setback after an 80-tonne floating generator capsized off the coast of Suffolk.

Trident Energy’s experimental device was being towed out to sea to begin a year-long offshore trial when the accident happened on Monday, 21 September near Southwold, Suffolk, eastern England.

The technology was being tested in the sea to gather detailed information on how the machine performed.

The generator was to have been placed 8km off Southwold for the year-long evaluation that may lead to new wave farms being developed that are capable of powering 60,000 homes.

Coastguards alerted local shipping as the 18-metre-tall machine drifted with the tide until tugs could secure lines and take it to nearby Dunwich Bay.

Trident Energy confirms that the generator has been grounded and made secure, about 5km east of Southwold harbour.

A spokeswoman for Trident Energy said that the company is in the process of making arrangements to move the platform to a suitable location where any damage can be fully assessed before determining next steps.

The spokeswoman added: “Trident Energy can confirm that the incident was in no way related to its patented technology to convert sea wave energy into electricity.”

The technology, developed by Trident, is designed to stand on giant legs that sit on floating pontoons anchored to the seabed. This enables special floats between the legs to move up and down with the waves and drive a turbine, which generates electricity.

It is not known at this stage whether the machine was badly damaged.

An induction generator is a type of electrical generator that is mechanically and electrically similar to a polyphase induction motor. Induction generators produce electrical power when their shaft is rotated faster than the synchronous frequency of the equivalent induction motor. An electric voltage (electromotive force) is induced in a conducting loop (or coil) when there is a change in the number of magnetic field lines (or magnetic flux) passing through the loop. When the loop is closed by connecting the ends through an external load, the induced voltage will cause an electric current to flow through the loop and load. Thus rotational energy is converted into electrical energy.

Induction generators are often used in wind turbines and some micro hydro installations due to their ability to produce useful power at varying rotor speeds. Induction generators are mechanically and electrically simpler than other generator types. They are also more rugged, requiring no brushes or commutators.

Induction generators are not self-exciting, meaning they require an external supply to produce a rotating magnetic flux. The external supply can be supplied from the electrical grid or from the generator itself, once it starts producing power. The rotating magnetic flux from the stator induces currents in the rotor, which also produces a magnetic field. If the rotor turns slower than the rate of the rotating flux, the machine acts like an induction motor. If the rotor is turned faster, it acts like a generator, producing power at the synchronous frequency.

In fact, an induction generator may operate as a motor or a generator. For instance, a standard, 3 phases, AC motor may be powered from the 50 Hz grid, with the motor speed “slipping” at less than for 50 Hz synchronism. If this motor is itself forced to rotate at more than for 50Hz synchronism by a rotating power source, (e.g. a diesel engine or wind turbine), while connected to the grid, it delivers current to the grid as a generator. The current flow is proportional to the slip, i.e. the small difference, 3%, between synchronised rpm and the actual rpm. This slip is too small to notice as a speed change of a wind turbine rotor, so induction generators are classed, somewhat erroneously, as fixed-speed generators. This type of generator is very simple, rugged, and relatively cheap. Usually it is “excited” into operation.

In induction generators the magnetizing flux is established by a capacitor bank connected to the machine in case of stand alone system and in case of grid connection it draws magnetizing current from the grid. It is mostly suitable for wind generating stations as in this case speed is always a variable factor.

 MHD (magneto hydrodynamic) power plants offer the potential for large-scale electrical power generation with reduced impact on the environment. Since 1970, several countries have undertaken MHD research programs with a particular emphasis on the use of coal as a fuel. MHD generators are also attractive for the production of large electrical power pulses.

The MHD generator or dynamo transforms thermal energy or kinetic energy directly into electricity. MHD generators are different from traditional electric generators in that they can operate at high temperatures without moving parts. MHD was developed because the exhaust of a plasma MHD generator is a flame, still able to heat the boilers of a steam power plant. So high-temperature MHD was developed as a topping cycle to increase the efficiency of electric generation, especially when burning coal or natural gas. It has also been applied to pump liquid metals and for quiet submarine engines.

The basic concept underlying the mechanical and fluid dynamos is the same. The fluid dynamo, however, uses the motion of fluid or plasma to generate the currents which generate the electrical energy. The mechanical dynamo, in contrast, uses the motion of mechanical devices to accomplish this. The functional difference between an MHD generator and an MHD dynamo is the path the charged particles follow.

MHD generators are now practical for fossil fuels, but have been overtaken by other, less expensive technologies, such as combined cycles in which a gas turbine’s or molten carbonate fuel cell’s exhaust heats steam for steam turbine. The unique value of MHD is that it permits an older single-cycle fossil-fuel power plant to be upgraded to high efficiency.

Natural MHD dynamos are an active area of research in plasma physics and are of great interest to the geophysics and astrophysics communities. From their perspective the earth is a global MHD dynamo and with the aid of the particles on the solar wind produces the aurora borealis. The differently charged electromagnetic layers produced by the dynamo effect on the earth’s geomagnetic field enable the appearance of the aurora borealis. As power is extracted from the plasma of the solar wind, the particles slow and are drawn down along the field lines in a brilliant display over the poles.

In electricity generation, an electrical generator is a device that converts mechanical energy to electrical energy, generally using electromagnetic induction.

The reverse conversion of electrical energy into mechanical energy is done by a motor; motors and generators have many similarities. A generator forces electric charges to move through an external electrical circuit, but it does not create electricity or charge, which is already present in the wire of its windings. It is somewhat analogous to a water pump, which creates a flow of water but does not create the water inside. The source of mechanical energy may be a reciprocating or turbine steam engine, water falling through a turbine or waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed air or any other source of mechanical energy.

Today, the technology of electrical generator is to come to maturity, but its historic developments are complicated.

Before the connection between magnetism and electricity was discovered, electrostatic generators were invented that used electrostatic principles. These generated very high voltages and low currents. They operated by using moving electrically charged belts, plates and disks to carry charge to a high potential electrode. The charge was generated using either of two mechanisms:

Electrostatic induction

The turboelectric effect, where the contact between two insulators leaves them charged.

Because of their inefficiency and the difficulty of insulating machines producing very high voltages, electrostatic generators had low power ratings and were never used for generation of commercially-significant quantities of electric power. The Wimshurst machine and Van de Graff generator are examples of these machines that have survived.

In 1827, Hungarian Anyos Jedlik started experimenting with electromagnetic rotating devices which he called electromagnetic self-rotors. In the prototype of the single-pole electric starter (finished between 1852 and 1854) both the stationary and the revolving parts were electromagnetic. He formulated the concept of the dynamo at least 6 years before Siemens and Wheatstone but didn’t patent it as he thought he wasn’t the first to realize this. In essence the concept is that instead of permanent magnets, two electromagnets opposite to each other induce the magnetic field around the rotor. Jedlik’s invention was decades ahead of its time.

In 1831-1832 Michael Faraday discovered the operating principle of electromagnetic generators. The principle, later called Faraday’s law, is that a potential difference is generated between the ends of an electrical conductor that moves perpendicular to a magnetic field. He also built the first electromagnetic generator, called the ‘Faraday disc’, a type of homopolar generator, using a copper disc rotating between the poles of a horseshoe magnet. It produced a small DC voltage, and large amounts of current.

The Dynamo was the first electrical generator capable of delivering power for industry. The dynamo uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator. The first dynamo was built by Hippolyte Pixii in 1832.

A dynamo machine consists of a stationary structure, which provides a constant magnetic field, and a set of rotating windings which turn within that field. On small machines the constant magnetic field may be provided by one or more permanent magnets; larger machines have the constant magnetic field provided by one or more electromagnets, which are usually called field coils.