Windmill Power Station in Poolavadi near Udumalpett, Tamilnadu ~ Suman Blogz

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Windmill Power Station in Poolavadi near Udumalpett, Coimbatore, Tamil Nadu

It is one of top most energy producing windmill power station in india producing more than 10MW. The name of the power station is Cherranjji wind energy limited. It consist of nearly 140 wind mill systems with 20-25 service men. The cost of individual system is about Rs 1.25 crores and it is serviced every month which costs approximately Rs 10,000. They had made an agreement for 20 years with the local electricity board to share the power generated in the windmill power station.

The main parts of the wind-mill:
   1. Anemometer
   2. Rotor
   3. Generator
   4. Tower
   5. Gear box
   6. Brake
   7. Wind wane
   8. Motors
   9. Blade
10. Nacelle
11. Yaw drive
12. Hub
13. Transformer
14. Cable
15. Microprocessor
16. Power panel

Anemometer: The instrument used to measure the wind speed is anemometer.

Wind wane: Its is a small instrument used to measure the wind direction and it communicates with the yaw drive. There are two types of turbines namely (a)Upwind turbine (b) Down wind turbine. Upwind turbine is one which is facing into the wind whereas the downwind turbine is one which is facing away from the wind.

Rotor: Usually rotor consists of two parts namely hub and the rotating blades or wings.

Hub is used to connect the blades/wings to the gear box through high speed shaft. The actual size of the hub is about 1.5m.

Blade: The blades used are made up of fibre materials which weighs about 750Kg and are imported from Germany. Each blades is about 11.5m length. In some system the aerodynamic brakes are used which are about nearly 1m length. It makes 40 to 50 rotation per minute (rpm).

Gear box: The purpose of the gear box is to convert the low rotating speed of the blades nearly 40-50rpm into high speed nearly about 960-1000rpm. The one end of the gear box is connect to the low speed shaft whose extension is connected to the hub and the another is connected to the high speed shaft which is connected to the generator. the gear box used in Poolavadi windmill power station is about 1:24 parts which means that 40rpmX24parts = 960rpm at high speed shaft. There is another gearbox of 1:38.35 parts.

Tower: The tower used in power stations are nearly ranging from 30m to 80m high. Its because to to have the undistrubed wind blow.

Generator:The power generated in poolavadi is about 250KW which is the minimum power usually generated using this system. By changing the gear box or using 4 or 6 poles generator, we can vary the power generated to 1.25MW, 1.65MW also. During peak wind 3500 units can be generated.

Motor: Usually three types of motors are used namely air motor, gear motor, hydraulic motor.

Air motor: It is usually used for yawing or adapting the blades towards the wind direction.
Gear motor: It used for oil pulling. Mostly the synthetic oil is used which is of more thickness namely 1710/320 gear oil.
Hydraulic motor: It is used to operate the hydraulic brake. In hydraulic motor, the less lubricant oil is used namely DTE11M.

Rotating union: Oil is supplied to the dividing piece in hub for opening and closing of the disc brake.

Brake: There are two types of brake in the wnd mill system namely:

(1) hydraulic brake (2) tip brake.

Hydraulic brake: it is controlled by hydraulic motor.

Tip brake/Aerodynamic brake: It is used reduce to the speed of the blade to 300 rpm from 960 rpm by extending the tip or it will damage the whole system if sudden brake is applied.

Yaw drive: It can be operated by yaw motor / air motor. The yaw drive is connected to the communication cable to microprocessor and its operated at its entrance.

Interdistance positionizing windmill system:

for column-wise arrangement: Maximum blade’s diameter X 7

for row-wise arrangement: Maximum blade’s diameter X 5

EB Meter: It is used to kow the export and import of the current. There are two parts of settings: (1) EB line (2) consumer line.

Power panel:

MCCB
Junction contact
Thyristor

MCCB (Main current circuit breaker): The voltage obtained from the EB (Electricity Board) is about 22,000V is step-down to 110KV and step down to 415V. It is opearated at 415V.

Thyristor: During cut-in position, the generator is in operating or generating mode whereas during cut-off position , the generator will be in free wheeling mode.

Varistor : It is a over voltage controller which used to ground the high voltages generated.

By-pass contact: During cut-off mode, the generator recieves power from EB through thyristor whereas during cut-in mode, the generator supplies power to the EB.

Earth fault relay: The leakage current will dripped or grounded in this earth fault relay.

Consumption unit: During April – October, the power consumption is about 4 unit whereas during July –August ie peak wind months the power capacity generation is about 250KW. Nearly 4000 units (app.) during grid-off whereas no units is consumed while grid-on.

Multipilication factor: M.F = current transformerpotential transformer
Multification factor can defined as the ration of current tranformer to the potential transformer.