Hybrid Distributed Generation Systems

Presented by:

Satabdy Jena

Roll No.T14EE003

M.Tech (Power & Energy Systems)

Department of Electrical and Electronics EngineeringNATIONAL INSTITUTE OF TECHNOLOGY, MEGHALAYA

Outline

1.Introduction

2.Hybrid Distributed Generation Systems (HDGS)

3.HDGS Requirements and system configurations

4.HDGS Schemes

5.Application of HDGS

6.Benefits of HDGS

7.Power Quality Issues with HDGS

8.Distributed Power Generation Scenario in India

9.Successful HDGS ventures

10. Future research directions in HDGS

11.Conclusion

12.References

1.Introduction

With the ever increasing demand for energy, oil reserves are being depleted. The

wide-scale exploitation of the limited conventional fuel reserves has also lead to

several environmental threats like climate change, global warming, depletion of

ozone layer, increase in green-house gas (GHG) emission levels, etc.

SLIDE 1Fig.1. World energy demand and consumption

Traditionally, large, remote centralized power plants use nuclear coal, oil or hydro to generate electricity.

Centralized generation

For Against

Financial risk on utility.

Management capacity already

exists.

Technical capacity already exists.

No stake in power supply so lack of

interest in maintaining it.

Repairs take longer because they must

be approved by the government.

Tariff collection expensive.

No load management.

Disputes between utility and

community possible.

 

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Table.1. Pros and Cons of centralized generation

SOLUTION: Alternatives that can provide energy solutions to customers that are more cost effective, more environment friendly and provide higher power reliability than conventional solutions.

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Fig.2.Renewable energy sources

2.Hybrid Distributed Generation

Definition:

IEEE defines the generation of electricity by facilities sufficiently smaller than central plants, so as to allow interconnection at nearly any point in the power system, as Distributed Resources.

Electric Power Research Institute (EPRI) defines distributed generation as generation from a few kilowatts up to 50 MW.

SLIDE 4Fig.3.Distributed Generation

Classification of Distributed Generation

SLIDE 5

Fig4. DG types

SLIDE 6Fig.5.DG sources

MicroturbineBattery

Biomass

Fuel cellResidential PV Wind Turbine

3.HDGS system requirements and configuration

Harnessing energy from various sources can prove challenging as the entire system requires a certain level of co-ordination.

Complex supervisory control schemes are needed to maximize the entire system sustainability.

The key requirements for hardware design of such system are adequate technology selection and generation unit sizing.

A robust control scheme is needed in order to ensure optimal operation of the hardware in order to achieve high reliability and efficiency.

Due to uncontrollable nature of some renewable energy sources, a choice of diversified multisource generation configurations and storage devices are required to ensure reliability and sustainable autonomous HDGS.

SLIDE 7

Common DC Bus Configuration

Allows all the energy sources to be connected to a common DC Bus.

Can be connected directly to the DC Bus.

The supervisory control for such systems needs to have a fast dynamic response .

Drawback: Failure of inverter

4.HDGS System Schemes

SLIDE 8Fig.6.Common DC bus

Common AC Bus Configuration

(i) PFAC

All sources can either be connected to the PFAC bus directly or through their respective power conditioning unit.

This arrangement is more reliable as any malfunctioning energy sources can be isolated from the rest of the system without impacting any of the other energy resources.

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SLIDE 9

Fig.7. PFAC

(ii) HFAC

Generally used in space station applications.

Energy sources can be connected either directly or through their respective power conditioning unit.

Have higher overall efficiency.

Higher order harmonics can be easily filtered at higher frequencies.

Reduction in the physical size and weight of harmonic filters and magnetics.

SLIDE 10

SLIDE 11Fig.8. HFAC

Hybrid coupled system configuration

More flexible and modular design .

Diverse energy sources can be connected to either a DC bus directly or through a power conditioning unit if necessary and also to a PFAC bus directly.

SLIDE 12Fig.9.Hybrid coupled system

5. Application of HDG Systems

Standby

Stand Alone

Peak load shaving

Rural and Remote Applications

Providing combined heat and power

Base load

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6. Benefits of HDGS

• Provide the required local load increase.• Assembled easily anywhere as modules.• Location flexibility.• Reduce the wholesale power price.

(a) From the economical point of view:

• reduce the distribution power network losses, distribution load demands.• system continuity and reliability .• transmission capacity release.• reduce output process emission.

(b) From operational point of view:

SLIDE 14

7. Power Quality Issues with HDGS

Voltage Regulation

DG Grounding issue

Harmonic Distortion

Islanding

SLIDE 15

POWER QUALITYISSUES

Fig.10. Islanding

Inherent intermittent nature of renewable energy sources leading to relatively lower capacity utilization factors.

Relatively high capital costs when compared to conventional power systems which in turn require incentives and financial arrangement for capacity building, promotion and development of energy.

Requirement of servicing companies for local program implementation.

Need for adequate mobilization for payment of user charges involving perhaps Non-Government Organizations and local bodies.

Lack of operation and maintenance services providers is an issue that needs attention.

Need for developing sustainable revenue / business models.

Assistance for project preparation.SLIDE 16

8. Challenges with HDGS

9. Distributed Energy Scenario in India

India was the first country in the world to set up a ministry of non-conventional energy resources in early 1980s.

India’s cumulative grid interactive or grid tied renewable energy capacity has reached 29.9 GW.

The Electricity Act, 2003 specifies distributed generation and supply through stand-alone conventional and renewable energy systems.

The National Electricity Policy notified on 12 February 2005 recommends to provide a reliable rural electrification system, wherever conventional grid is not feasible, decentralized distributed generation facilities (using conventional or non-conventional sources of energy) together with local distribution network be provided.

The Rajiv Gandhi Grameen Vidyutikaran Yojna and the Remote Village Electrification Scheme, will provide up to 90% capital subsidy for rural electrification projects using decentralized distributed generation options based on conventional and non-conventional fuels. SLIDE 17

10. Successful HDGS ventures

• Location: China, Date of installation: 2006, Performance: Provides electricity to 55 households, Implementer: Solar World AG.Photovoltaic/ diesel hybrid system

• Location: Tanzania, Date of installation: 2006, Performance: Provides electricity to several households, community services, small workshops, cabinet making, and logical equipment, Implementer: CONERGY/Schott Solar.

Photovoltaic/ diesel hybrid system

• Location: Algeria, Date of installation: 1998 to 2000, Performance: Provides electricity to 12 households and community services, Implementer: CDER

Photovoltaic/ diesel hybrid system

• Location: China, Date of installation: 2002, Performance: Provides electricity to 3 villages composed of 500 households, community services and a tourist facility. Implementer: Bergey.

Photovoltaic/wind/diesel hybrid system

• Location: Ecuador, Date of installation: 2006, Performance: Provides electricity to 20 households and community services, Implementer: Trama Tecno Ambiental.

Photovoltaic/ diesel hybrid system

• Location: Laos, Date of installation: 2007, Performance: Provides electricity to 98 households and community services, Implementer: Entec.

Hydro/ PV/ Diesel hybrid system

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11. Future research fields in HDGS

Improvement of existing distribution generation technologies and research and development of new technology.

Installation site, capacity and permeation limit of different types of DG in distribution network should be determined in order to ensure the optimization of economy and security.

Research on relay protection of multi terminal power should be carried out.

New SCADA system should be established.

Influence on the existing electricity market of DG, as well as the impact on the investment system would be researched.

The hybrid distributed generation system helps to reduce the cost of the transmission

line and the transmission losses. HDGS plays an important role in the field of the

electricity generation whereas different issues related to power quality when DR is

integrated with the existing power system has been discussed in the report .It can be

concluded from this discussion that when interconnecting DR to the power system,

these issues must be considered which could affect power quality and safety.

Penetration of DR can be successfully integrated with the power system as long as

the interconnection designs meet the basic requirements that consider not only power

quality but also system efficiency and power reliability and safety.

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12. Conclusion

REFERENCES

‘A Review of Hybrid Distributed Generation Systems’, Amish A. Servansing and Praveen K. Jain, IEEE Transactions, 2012.

‘Distributed generation technologies, definition and benefits’, W. El Khattam and M.M.A. Salama, Electric Power Systems Research, vol 71, pg 119-128,2004.

‘An Integrated Hybrid Power Supply for Distributed Generation Application fed by Non Conventional Energy Sources’, Sachin Jain and Vivek Agarwal, IEEE Transactions on Energy Conversion, vol 2, June 2008.

‘Comparison of options for Distributed Generation in India’, Rangan Banerjee, Energy Policy, Elseveir.

Forum for Smart Grid

‘Hybrid power systems based on renewable energy’, by Alliance for Rural Electrification.

‘Energy: Fossil fuels to Renewable Energy Sources’, CSIR.

Microgrids, Hiroshi Asano et al, IEEE power and energy magazine.

Distributed Resources, Frank R Leslie, LS IEEE

Renewable Energy Integration, Prof. Stephen Lawrence, Leeds School of business

Overview of Renewable Energy potential in India, Global Energy Network Institute(GENI)

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