Generator Distribution System


  • Introduction

 WHAT IS A GENERATOR?

Generator is a machine which converts any type of energy into electrical energy in places where power cuts occur. It is used as an alternate energy source. Rotator gasoline or diesel engine is the general name given to the group composed of a panel, chassis and an alternator rotated by the engine. It comprises of two main parts: alternator and engine. The alternator can be used with or without a brush. On the other hand, the systems driven by wind are called wind turbine or wind generator except the generators operating on liquid fuels or natural gas.

Generators are manufactured in varying sizes and capacities from the smallest facilities to the biggest ones. The generators which produce alternating current are called alternator while the ones producing direct current are called direct current generators or dynamo. In conclusion, whether the current obtained is AC (alternating current) or DC (direct current), source of the electrical energy is identical. Only the machine design differs. The mechanical energy required to operate a generator is supplied by devices which provide the first drive such as water turbine, steam turbine, internal combustion engine or gas turbine.

HISTORY OF INVENTION OF GENERATOR

When Thomas Edison and Joseph Swarm invented the electric bulb in 1880, great need has arisen for generators and power supplies. The Edison Company established DC-producing centers in New York, London and Milan in 1882 for the purpose of using electrical energy in lighting. Soon after this, a debate started on the use of DC and AC currents. As a result of the developments in transformers and generator systems until early 1890, American Nikola Teola proved the usage advantages of AC in electrical power transfer. The first big hydroelectric power plant using AC generators was put into operation in Niagara Falls in 1895.

OPERATION PRINCIPAL

Operation principle of most electric generators is based on Faraday’s law. When the number of magnetic flow lines (Maxwell) that surrounds a wire coil is changed, an electromotor power emerges in the coil which is proportionate to the number of turn that varies according to magnetic flow.

 

Voltage spike value is E = -n (df)/dt) 10-8 volt. Here, n represents the number of turns; f represents the magnetic flow as Maxwell while t is time in seconds. The minus sign indicates that the voltage induced counters the force that generates it. When one part of the generator is moved mechanically relative to the other one, voltage is induced in generator windings. In this way, magnetic flow occurs around the coil, which is called armature winding. Magnetic flow can constantly be obtained from DC field winding or AC source of the magnet.

We can think of generators as instruments working in reverse to electric engines. The electrical energy we use in our daily life is produced with the help of generators in power plants (electric plants).

  • The motion energy required in order for generators to generate electrical energy in electric plants is supplied through different ways.
  • In thermal power plants, such fossil fuels as coal and fuel oil are burnt and the water in the boiler is turned into vapor. The high pressure water vapor that is formed enables the turbine to move and electrical energy is generated.
  • In nuclear power plants, the water in the boiler evaporates through nuclear energy.
  • In hydroelectric power plants, the water accumulating in the dam flows rapidly from height and falls on turbine blades. In this way, electrical energy is supplied from the generator connected to the turbine.

(Transformer: After being generated in power plants, the electrical energy is carried to our cities with a high voltage of 250000–500000 V. This is the reason why wires carrying electrical energy are called high voltage line. The voltage of electrical energy that reaches cities is decreased. In this way, the voltage is adapted to operation of devices used at houses. In our country, the voltage used in houses is 220 Volt. The instruments used to increase or decrease the mains voltage are called transformers.)

 

SPECIAL TYPE OF GENERATORS

Homopolar Generator (HPG): This is the only machine that directly generates direct current. All other types of DC generators generate AC in armature windings and afterwards, convert AC into DC through commutator. HPG does not have armature windings or commutator. This difference causes this generator to be a very durable machine. Although HPG is the first electromechanical generator, it was included in the area of application last.

Magneto hydrodynamic Generator: This generator essentially consists of electrically-conductive gas which is blow at a high speed (ionized gas), two electrodes and windings that generate a magnetic field. These generators are not very affective yet as a high temperature and large amount of potassium are required to render the gas adequately conductive.

High Frequency Generators: When minimum weight and size of the electric device matter, frequencies over 60 Hertz are especially useful. For example, power supply of 400 Hertz is widely used in airplanes.

SAFETY MEASURES

In the case that necessary safety measures are taken, it is highly unlikely that generator poses danger. Ersel Engineering assembles and maintains the generator in a completely safe manner.

Our personnel, who will make the technical interventions when required, are trained and experienced in all processes related to generators.

In case failure occurs in the generator;

  • Stop its operation by cutting the energy connection of the generator.
  • The room where the generator is used should be resistant to fire at least 1.5 hours and in case of a possible fire, it should be positioned in such a way that it does not block the fire exit.
  • In generator use, changes in regulation input voltage of a generator should be checked. Voltage stability should be measured (the feature of output voltage remaining stable under changing conditions).
  • It should be ensured that the voltage remains stable despite the changes in loads at exit.