Page 310 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Light intensity

More power is produced from the panel in bright sunlight. For 1000W/M2 of sunlight, the rated output power will
be full. But, if it is 500W/M2 only the rated power output will be half. The output power is directly proportional with
the increasing of solar in isolation.
Temperature
The higher the temperature the output power is reduced from a module, due to power loss. It is tested at standard
temperature at 25°C. During the bright sunlight, cell may reach 70°C also. If crystalline silicon decrease from

0.4 to 0.5% per°C temperature increases above 25°C. Amorphous silicon module temperature coefficient is 0.2
to 0.25 % per°C of temperature increase.
Charge controller

If the charger controller is in continuous operation and draws a small current of about 5mA to 25mA, then the
power loss is around 1%.
Semiconductor energy loss

The charge controller is having the components as MOSFET and blocking diodes, which is cause for heat energy
loss.
Cabling loss
The cables are also cause for power loss, It can be minimized by choosing a large diameter of wire size.

Improper connection
If the electrical connections are not made properly, it results in less power is fed to the battery. It can be reduced
by keeping clean, and tight connections.
Wind power generation

Objectives: At the end of this lesson you shall be able to:
• explain the features of wind power generation
• state the advantages and disadvantages of wind power generation.

The method of generating the electrical energy by using the wind is termed as wind power generation. Since the
wind has velocity and kinetic energy, it can be used to produce electricity. For that, we can use windmills. The
important part of a windmill is a structure with large leaves, fixed at the top of a high tower. The speed of leaves
changes with the speed of the wind. If the rotation of the windmill is given to the rotor of a generator, then the
electricity will be obtained from the generator. If the windmill is connected to a water pump, the leaves of the
windmill rotate the pump and pumping out the water.
Wind power can be usefully exploited for the generation of electricity as there are large, coastal, hill and desert
areas. Wind turbines comprising of machines with blade diameter of 17 m, which can generate about 100
kilowatts. A strike of blowing wind on specially designed blades of a windmill’s rotor causes both to rotate. This
rotation, which is the mechanical energy, when coupled to a turbine, drive the power generator.
Operation

The schematic arrangement of wind power station is given in Fig 1.
When the wind strikes the rotor blades, blades start rotating. Rotor is directly connected to high speed gear box.
Gear box converts the rotor rotation into high speed which rotates the electrical generator. An exciter is needed
to give the required excitation to the coil so that it can generate required voltage. The exciter current is controlled
by a turbine controller which senses the wind speed based on that it calculate the power what we can achieve at
that particular wind speed.
The output voltage of electrical generator is given to a rectifier and rectifier output is given to line converter unit
to stabilise the output ac that is fed to the grid by a high voltage transformer. An extra units is used to give the
power to internal auxiliaries of wind turbine (like motor, battery etc), this is called internal supply unit. ISU can
take the power from grid as well as from wind. Chopper is used to dissipate extra energy from the Rectifier Unit
(RU) for safety purpose.

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CITS : Power - Electrician & Wireman - Lesson 106-116