AGUS HARYANTO

The objective of a hydropower scheme is to convert the potential energy of a mass of water, flowing in a stream with a certain fall to the turbine (termed the "head"), into electric energy at the lower end of the scheme, where the powerhouse is located. The power output from the scheme is proportional to the flow and to the head.

DAM

PENSTOCK INTAKE

TURBINE

POWER HOUSE

GENERATOR

POWER LINE

TRANSFORMER

 The movement of water can be used to make electricity. Energy from water is created by the force of water moving from a higher elevation to a lower elevation through a large pipe penstock). When the water reaches the end of the pipe, it hits and spins a water wheel or turbine. The turbine rotates the connected shaft, which then turns the generator, producing electricity.

 A water intake must be able to divert the required amount of water into a power canal or into a penstock without producing a negative impact on the local environment.

 “Conveying water from the intake to the power house”.

The water in the reservoir is considered stored energy (potential energy). When the gate opens the water flowing through the penstock becomes kinetic energy because it is in motion.

 The water strikes and turns the large blades of a turbine, which is attached to a generator above it by way of a shaft. The most common type of turbine for hydropower plants is the Kaplan Turbine, Francis Turbine, and Pelton Turbine.

    Low head (from 70 meter and down to 5 meter) Large flow rates The runner vanes can be governed Good efficiency over a vide range

   Heads between 15 and 700 m.

Medium Flow Rates Good efficiency  = 0.96 for modern machines

    Large heads (from 100 meter to 1800 meter) Relatively small flow rate Maximum of 6 nozzles Good efficiency over a vide range

*Q = 28,5 m 3 /s *H = 1130 m *P = 288 MW

Jostedal, Norway

 After passing through the turbine the water returns to the river trough a short canal called a tailrace.

  As the turbine blades turn, so do a series of magnets inside the generator. Giant magnets rotate past copper coils, producing alternating current (AC) by moving electrons.

Basic parts of generator : 1. Shaft 2. Excitor 3. Rotor 4. Stator

The heart of the hydroelectric power plant is the generator. The basic process of generating electricity in this manner is to rotate a series of magnets inside coils of wire. This process moves electrons, which produces electrical current.

 As the turbine turns, the excitor sends an electrical current to the rotor. The rotor is a series of large electromagnets that spins inside a tightly-wound coil of copper wire, called the stator. The magnetic field between the coil and the magnets creates an electric current.

is a device that transfers electrical energy one circuit to another through a shared from magnetic field . A changing current primary) creates a changing magnetic field; in turn, this magnetic field IP in the first circuit (the induces a voltage VS in the second circuit (the secondary). The secondary circuit mimics the primary circuit, but it need not carry the same current and voltage as the primary circuit. Instead, an ideal transformer keeps the product of the current and the voltage the same in the primary and secondary circuits.

 Used water is carried through pipelines, called tailraces, and re-enters the river downstream.

 In the scheme of hydropower the role of power house is to protect the electromechanical equipment that convert the potential energy of water into electricity.

 Following are the equipments of power plant: 1.Valve 2.Turbine

3.Generator

4.Control System 5.Condensor 6.Protection System 7.DC emergency Supply 8.Power and current transformer

Flowing water creates energy that can be captured and turned into electricity. This is called hydropower. Hydropower is currently the largest source of renewable power, generating nearly 10% of the electricity used in the United States.

The most common type of hydropower plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which, in turn, activates a generator to produce electricity. But hydropower doesn't necessarily require a large dam. Some hydropower plants just use a small canal to channel the river water through a turbine.

Sumber air pada ketinggian h = 14 ft memberikan debit Q = 9 ft 3 /dt untuk menggerakkan kincir air berdiameter D = 12 ft. Kincir air berputar pada kecepatan N = 5 RPM dan memiliki 36 buah mangkuk yang terisi air tidak lebih dari separohnya.

   Berapakah volume tiap mangkuk?

Bila luas penampang mangkuk 1.2 ft 2 , berapa lebar kincir?

Berapa kecepatan spesifik? (Asumsi  = 60%)

 Volume mangkuk: N = 5 RPM  Tiap putaran = 12 dt Q = 9 ft 3 /dt  Vol air jatuh tiap putaran = (9 ft 3 /dt)*12 dt = 108 ft 3 Vol tiap mangkuk = 108

ft

3 36  0 .

5  6

ft

3  Lebar kincir = 6 ft 3 /1.2 ft 2 = 5 ft

  Daya yang dihasilkan: P =  Q  g h = (60%)(9 ft 3 /dt)(62.4 lb/ft 3 )(14 ft) = 4717.4 ft.lb/dt = 8.58 Hp Kecepatan spesifik Ns = (5)(8.58) 0.5

(14) -1.25

= 0.54

 Kecepatan jet:

V



C

2

gh

 C = koefisien transmisi Kecepatan titik di luar roda Pelton U = a.V  a = konstanta U =  DN  Daya =  Q  g h

Sebuah roda Pelton dipakai untuk menghasilkan daya dari air berketinggian h = 14 ft. Jika U = 0.45 V dengan V adalah kecepatan jet air pada nozel. N = 300 RPM. Pertanyaan:   Berapa diameter roda Pelton? (Asumsi C = 0.95) Bila diameter nozel 2 in, berapa debit air?

  Berapa daya (HP) jika efisiensi 88%?

Berapa kecepatan spesifik roda Pelton?

 Diameter roda Pelton

V



C

D = U/  2 

gh

2 ( 32 .

2 )( 75 V = 0.95 = 66 ft/dt U = 0.45 V = 0.45(66) = 29.7 ft/dt ) N = 29.7/(0.88*300) = 1.89’ = 22.7”

  Debit air Q = A.V

A nozel =  d 2 /4 =  (2/12) 2 /4 = (  /144) ft 2 Q = A.V = (  /144) ft2 (66 ft/dt) Q = 1.44 ft 3 /dt P =  Q  g h = (0.88)(62.24)(1.44)(75)/550 P = 10.78 HP

 Ns = N(Daya) 0.5

(h) -1.25

Ns = 300(10.78) 0.5

(75) -1.25

Ns = 4.46

Note: Ns optimum untuk turbin roda Pelton adalah 5