Benefits of Distributed Generation on Power Delivery System

Transcription

1 EE 5250 Distribution Engineering Benefits of Distributed Generation on Power Delivery System Rakesh Date:17 th April 2006

2 Topics Covered Introduction Distributed Generation Why Distributed Generation Advantages of Distributed Generation Reliability Power Quality Transmission Benefits Environmental Benefits Hindrances Conclusion

3 Definitions of Distributed Generation: Distributed Generations are parallel and stand-alone electric generation units located within the electric distribution system at or near the end user.

4 Why Distributed Generation? Recent Energy Policy Act (EPAct) of 1992, which required interstate transmission line owners to allow all electric generators access to their lines. Cost of renewable technologies have fallen [5]

5 Main benefits associated with Distributed Generation 1. Reliability 2. Power Quality 3. Transmission Benefits 4. Environmental Benefits

6 1.Reliability Power reliability is required for Life-safety systems. Systems that prevent damage to plant infrastructure. Processes that would cause sizeable financial losses because of power outages. Equipment and processes for which operation is not time-critical.

7 Ways to increase the reliability of power. Redundancy Redundant power supplies do not always improve reliability Distributed Generation Standby generation, uninterruptible power supplies (UPS), flywheels, or fuel cells.

8 Indices used by utilities (IEEE standard 1366, 2001) to measure the reliability. System Average Interruption Duration Index (SAIDI): = Customer Average Interruption Duration Index (CAIDI): % # )( = )( '( &! $ # "

9 System Average Interruption Frequency Index (SAIFI): Total no of customer interruption SAIFI = Total no of customer served Customer Average Interruption Frequency Index (CAIFI) CAIFI = Total no of customer interruptions Total no of customer interrupted

10 Example! "! " Customers#327 Customers#220 System without DG Customers#327 System without DG Customers#220

11 RESULTS Total no of customer interruption Sum of interruption duration in minutes No of affected customers Without DG With DG Total no of customers served Without DG With DG Feb Aug Dec CAIFI SAIFI SAIDI Without DG With DG Without DG With DG Without DG With DG Feb Aug Dec The improvement would have been better in case of DG supplying larger part Of network

12 2. Power Quality Technical attributes for quality Voltage Profile Line Losses Lots of study have been to stress upon the advantages of Distribution Generation upon conventional Generation using following two indexes VPII: Voltage Profile Improvement Index LLRI: Line Loss reduction Index

13 VPII: Voltage Profile Improvement Index VPw/DG VPII = VPwo/DG VPw/DG is voltage profile of the system with DG VPwo/DG is the voltage profile of the system without DG V i VP= N i= 1 N i= 1 k i = 1 VL k i i i is the voltage magnitude at bus i in per unit L i is the load at bus i in per unit k i is the weighting factor for load bus i

14 Example Simulations of following four cases were done Case (1): D.G located at bus 9. Case (2): D.G located at bus 10. Case (3): 50% DG located at Bus 9 and 50% DG located at Bus 4. Case (4): 50% DG located at Bus 9 and remaining 50% located at Bus 10.

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16 LLRI: Line Loss reduction Index LLRI = LLw/DG LLwo/DG LLw/DG = LLwo/DG = M i= 1 M I i= 1 2 Ai I R D 2 Li i i i R D i I Ai is the per unit line current in distribution line i, with the employment of DG R i is the line resistance (pu/km) for line i D i is the i th distribution line length (km) M I Li is the number of lines in the distribution system is the per unit line current in distribution line I, without the employment of DG.

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18 3. Transmission Benefits/ Substitute of Power Delivery Investments Remote areas to which the distribution system does not yet reach New Large Loads Areas experiencing load growth

19 4. Environmental Benefits: EIRI: Environment Impact Reduction Index EIRI = i PE PE iw/dg iwo/dg for i th pollutant (CO 2, SO2, NOx) PE iw/dg is the amount of emission i th pollutant with DG PE iwo/dg is the amount of emission of i th without DG

20 PE iw/dg = B j= 1 (EG) AJ (AE) ij + H k= 1 (EDG) k (AE) ik PE iwo/dg = B j= 1 (EG) j (AE) ij (EG) AJ & (EDG) k (AE) ij are the amount of electrical energy generated by the j th conventional power plant with and without distribution generation respectively. is the amount of emission of the i th pollutant for the j th conventional plant per MWh (AE) ik is the amount of emission of i th pollutant for the k th DG power plant per MWh of energy generated

21 NP EIRI = (EI) i= 1 0 (EI) i NP i= 1 (EI) i = i (EIRI) 1 1 i Where (EI) i is the weighting factor for the i th pollutant and NP is the total number of pollutants of interest.

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23 Hindrances Contractual and technical requirements Surcharge imposed by utilities on operators of Distributed Generators Pricing Environmental and permitting requirements of Local governments

24 Conclusion: Indices in favor of distributed generation Other issues Safety Reliability Economics

25 References [1] WHITE PAPER ON DISTRIBUTED GENERATION (National Rural Electric Cooperative Association) Jay Morrison NRECA Regulatory Counsel [2] Impact of Distributed Generation on Volt/Var Control in Distribution Networks 2003 IEEE Bologna PowerTech Conference, June 23-26, Bologna, Italy. [3] On Optimization for Security and Reliability of Power Systems with Distributed Generation (2003 IEEE Bologna PowerTech Conference, June 23-26, Bologna, Italy) [4] Benefit of Distributed Generation: A Line Loss Reduction Analysis (2005 IEEE/PES Transmission and Distribution) [5]A C.B.O Paper

26 Comments/Questions?