MICRO HYDEL UNITS USING INDUCTION GENERATOR

By –

Nikhil Kumar Rai (8th sem)

107509, NIT Kurukshetra

Submitted to: Dr. L M Saini

Energy crisis•India , a country

hardly 40%

urbanized.

•Only 52.5 %

rural household

get electricity

access

•Demand to reach

950,000MW by

2030 & current

generation is

171,000MW

IntroductionTypes of hydro power projects hydro potential of India Basic requirementsA layoutWhy only induction generatorsVoltage & frequency regulation of IGPossible solutions for voltage and freq controllerAdvantages & constraintsConclusion Video Queries

Contents

Fossil fuel, oil are the limited source of energy

Govt. looking for exploring renewable sources Hydro energy – a better & significant optionIndia -ranks 5th in terms of exploitable hydro-

potential on global scenario.India is endowed with economically

exploitable hydro-power potential to the tune of 1 48 700 MW of installed capacity

Installing big power projects is not good option always

Hence small hydro projects comes in play

Introduction

Big hydro projectsRequire big sum of

moneyTakes around 20 yrs

for completionNot feasible at every

place of requirementNeeds connection to

gridA big reservoir is

created

Small investment done

Hardly 1 yr is required

Feasible at many places

No connection to grid is necessary

Reservoir may not be created again

Can be made by community on its own

Comparison

Small hydro projects

Upto 100KW – Micro Hydro Power 101Kw to 2000Kw – Mini Hydro Power •2001Kw to 25000Kw – Small Hydro Power

Even pico hydro projects are also there. Currently in operation at Kenya and Namibia

Types of hydro projects

River flow to provide average 1585 gal/min flowPenstock of 20cm diameterTank of 2m*2m*2m dimensionPowerhouse of 3m*3m*3m dimensionPelton wheel turbine with horizontal shaftInduction generatorA gasifier-cum- diesel fed generator of 20 KVA capacity is

used as standby An automatic frequency & voltage regulator

courtsey: THULAPPALLY MICRO HYDEL PROJECT

Basic requirements (for 20KW project)

This project would feed around 200 houses and few shops

Also this would provide 20Kw power for nine months for two months it would be 15KW and approx for 1 month in summer electricity would be zero

Other details

Types of connection

Closer view of the turbine-gen set

Courtesy : Toshiba Electric, Japan

Why only induction

generators???

All though all big hydro power plants and the thermal; power plants are using synchronous generators then why we should use induction generators????

Synchronous gen.Runs at synchronous

speed onlyProvide constant voltage

and frequency Require high maintenanceHigh costFault may disrupt working

of whole electro-mechanical system

High stator and rotor resistance

Runs at sub synchronous & super synchronous speed

Gives a variable voltage and frequency if self excited

Low maintenance and highly robust

No rotor windings requiredShut down of gen. can be

done in milliseconds by de-excitation of generator

Comparison

Induction gen.

Provide both active and reactive power

D.C excitation is required

Higher efficiencyComplex systemLesser market in

comparison

Provide active energy only

Reactive energy excitation iis given either by grid or capacitor bank

Quite simple systemLower costHigher market cover

than other motorsWide speed of

operationNo synchronizing

unit is required for SEIG

Generates only when running above synchronous speed( N=120*f/p)

Requires reactive power to excite its coilGenerates active power onlyRequires grid connection or capacitor bank

for operationVery small rotor & stator resistanceHighly robustRequire automatic voltage and frequency

controller

Few details about induction gen.

Self excited generator

Grid connected generator

Equivalent circuit diag

Since for a SEIG the output voltage is directly proportional to the capacitance voltage connected across it, also the speed varies at varying input of water flow.

So as the generation is required we try keeping the generation i9n process so the frequency is varied to have a lower synchronous speed and continue the generation. Also sometimes we try keeping the input frequency constant so that output voltage remains the same

Having constant and regulated voltage is good for supply to the household

Need for voltage & frequency regulator

the first one implies the use of a speed regulator that controls the amount of water that enters in the turbine; the second solution is to add in the circuit an electronically controlled additional load. The drawbacks of the first alternative are the high mechanical constants, hydraulic and mechanical stress and the additional cost.

Possible solution for controlling the frequency & voltage

The second solution relies on an impedance controller (also known as dump load) that feeds a dissipative resistor, thus consuming the excess active power. In this way, at any moment, the power supplied by the generator will be equal with the sum between the power consumed by the loads and the one dumped on the dissipative resistor.

Voltage regulation relies on reaching equilibrium between thereactive power circulations within the system. Unlike the activepower case, where temporary unbalances are transformed intoother forms of energy (kinetic or thermal), the reactive powercannot suffer such transformation.If the reactive power is unbalanced, then the voltage amplitudewill decrease (for inductive loads) or increase (for capacitive

ones).Thus, controllers must be used in order to keep the voltage

withinacceptable limits. Whereas for SGs the voltage is controlled bydirectly modifying the rotor excitation current, for IGs the

excitationcurrent must be supplied from external circuits acting likea reactive power source (for example capacitors).These sources should be able to supply, besides the inductiongenerator magnetizing current, the extra capacitive current

requiredby other inductive loads from the circuit.

Proposed freq. & Voltage controller

Two PI controllers are used to regulate the system voltage, asshown . The first PI controller is the leading voltage regulator.It compensates the voltage drops across the inverter arms andfilter, IG leakage impedances, and other circuit elements, whichusually led to a decrease of the IG voltage. The IG root-mean-square(RMS) voltage (VAB) is the feedback signal, it is compared with the 400 V reference signal (VREF), and the error feeds the PI controller,giving the reference signal (VDCref) for the second controller. Thesecond PI is used to maintain constant the CDC voltage. The allowed voltage variation (ripple) across CDC capacitor (DVDC) will give the frequency and the width of the pulses that drive the Td transistor from the dump load.

RESULTS

A long shunt SEIG requires high magnetizing current

The stator current, stator voltage and load voltage increases with the increase in the shunt capacitance value

short shunt SEIG provides cost-effective operation because of lower capacitance requirement and improved voltage regulation.

For keeping the frequency constant the load torque should be controlled optimally

conclusions

Power generated P = 9.81 x efficiency x HQ P = 9.81 x 0.80 x 25 x 100 = 19,620 W The energy generation is as follows: For 9 months : 9 x 30 x 24 x 20 x 0.7 =

90,720 KWh For 1 months : 1x 30 x 24 x 15 x 0.7 = 7,560

KWh Total Generation = 98,280 KWh Say 98,000 KWH

ECONOMIC ASPECT OF THE PROJECT

Total Cost for the weir = Rs. 2, 53,380.00 Length of pipe= 600m. Cost per meter @Rs.200. Therefore = 600 x 200 = Rs.

1, 20,000.00 Tank = Rs. 40000.00Penstock Length of Penstock = 100m Diameter of Pipe = 20 cm. Thickness of pipe = 3mm Weight per meter = 14.7 Kg. Total weight = 14.7 x 100 = 1470 Kg. Cost @ Rs.50/- per Kg = 1470 x 50 = Rs. 73,500.00

PROJECT COST

Cost of Generator, Turbine and Control equipment at Rs.0.20 lakh/KW = 0.20 x 20 Rs. 4,00,000.00

Erection and commissioning cost = Rs. 1,00,000.00

Unforeseen items & contingency = Rs. 63,120.00

Total project cost = Rs. 11, 00,000.00

Installed capacity = 20 KW Total project cost = 11 lakhs Cost of installation/KW = 11/20 = Rs.0.55

lakhs Usual cost of installing a Hydel project is to

the tune of Rs.450 lakhs to 500 lakhs per MW. For this project the cost/MW is to the tune of the usual value. Hence it is economically viable.

Economic justification

Interest on capital @ 12% = 11.0 x 0.12 = 1.32 lakhs

Depreciation @ 3% = 11 x 0.03 = 0.33 lakhs Operation expenses @ 2% = 11 x 0.02 = 0.22

lakhs Total recurring charges = Rs.1.87 lakhs Total possible KWh generation = 0.98 lakhs Cost/KWh = 1.87/0.98 = Rs.1.91 / unit and

is lower than the usual values The present energy charges are more than this

value and hence it is economically viable.

Cost per KWh generated.

The living condition of the local people is improved

It also improves the water tableEconomic generation Self-dependence is achievedHydro potential is tappedRenewable resource is used

Advantages

In-sufficient management of the projectLow quality factorNon- standard designOver estimate of constant stream flowPlants operating in remote area only

Constraints

Such plants can be built at the drainage water plants where the stream rate is quiet high & effective head of 5-25m can be obtained

They can be also installed on platform of regulating gates of dams

Future prospects

Courtesy: Toshiba Electric, Japan

Top ten states with high SHP potential

J.k chatterjee, A Novel Non-Fragile Single-Loop Voltage and Frequency Controller for Induction Generator Based Isolated Renewable Energy Conversion System, IEEE 2010

C.P. Ion*, C. Marinescu Autonomous micro hydro power plant with induction generator , Elseivier 2011

G.K Singh, self excited induction generator research, Elseivier 2003

Toshiba electric corporationAdvanced electric generator & control for high speed micro/mini

turbine based system, Jai vaidya , president , electrodynamics associates

Implementation of a portable micro hydro plant using induction generator controller, V aravinthan (http://hydropowerstation.com/?p=2601) submitted 2011

Power electronics handbook by M H rashid

Refrences

Queries….