Steady State Analysis Of A Microgrid Connected To A Power System Presentation by Program FoS School Ramesh Paudel EPSM Energy SERD

Presentation Outline Conventional Power System Future Electric Power System Distributed Generation? Microgrid and Its Architecture Objectives of the Study Flowchart of the Methodology Test Systems and Modes of Operation Results Conclusion

Conventional Power System

Conventional Power System Pollution 67% Total Waste Power Plant 33% delivered electricity Fuel 100% Line Losses 9% T & D Loss = 0.9 kW Generation 1 kW End user 0.91 kW

Effects of Emission Pollutant Climate Change Local Effect More underground fault conditions in older cables Local Effect Global Effect NOx, SOx Particulate Matter CO2, CH4 Acid Rain Smug Green House Effect More overhead damage due to harsh storms Climate Change Demand increases for heating & pumping in winter & air conditioning in summer

Future Electric Power System Small Hydro Off Shore Wind Farm Solar Power Plant Hydro Power Station Biomass Low Emission Plant Local Control Center Wave Energy Microgrid Solar Underground Cable

Distributed Generation? Distributed or dispersed generation may be defined as a generating resource, other than central generating station, that is placed close to load being served, usually at customer site. Advantages Concern about climate change. Improve power quality and system reliability. Reduce transmission and distribution line losses. Constraints on construction of new transmission lines. Relatively low capital cost compared to centralized generation due to avoided T&D capacity upgrades. Disadvantages With faults in system, DG has to be disconnected from grid. Loads will be cut off from power.

Microgrid “Microgrid” is an independent entity which combines loads and distributed generators and can be controlled locally instead of central dispatch of grid. Microgrid follows grid rules and separates itself from distribution system during disturbances without harming integrity of distribution network. Customers will be able to enjoy an uninterrupted power supply with enhanced reliability and better power quality thereby meeting their demand for power as well as heat. From utility prospective MG helps in congestion management, manage local power requirement and voltage support and delay requirement of new power plants.

Microgrid Architecture HL Sensitive Loads Adjustable Loads Shade-able Loads Grid Supply A B C Point of common coupling Static switch Reciprocating engine Circuit breaker Heat load Fuel cell Electronic interface PV panel Micro turbine Electric wires Protection data Communication data HL

Objectives of the Study Siting of MG within a distribution system. To find optimal size DGs in MG. Interaction between MG and distribution system during Normal supply condition Island operation.

Flow Chart of Methodology Start End Read input data Run distribution load flow in base case. Find suitable location of MG based on loss sensitivity factor. Find optimal size of DGs and their location in MG using loss optimization technique. Analyze performance of MG and distribution system under various operating conditions. Print results

Test Systems and Modes of Operation IEEE 33 Bus System IEEE 69 Bus System 2.378 MW 0.8725 MW IEEE 33 Bus System with Microgrid Isolated from Distribution Network IEEE 33 Bus System with Microgrid

Reactive power loss (kVAR) Results Loss Reduction Feeder Loading Capacity Sl no Particular Real power loss (kW) Reactive power loss (kVAR) 1 Conventional system 211.2 143.21 2 MG connected to power system 113.51 96.81 3 Percentage reduction in loss 46.25 32.4 Loss reduction 93.69 kW Network with MG Generation saving 107.35 kW CO2 emission reduction 1109 ton/yr Annual Energy saving 940 MWhr

Results Voltage Profile

Conclusion A methodology has been developed to identify a possible location of MG in a distribution system. Placement of DGs is done for optimal system loss. System loss can be reduced nearly by 46% with the introduction of MG into distribution system. Less electricity to be generated and hence less emission. Voltage profile of the system is greatly enhanced. Better performance of electrical devices. Feeder loading capacity is increased. Postpone construction of new lines. Isolated mode of operation of MG ensures an uninterrupted power supply to loads. Consumers can enjoy good quality of power supply without any interruption.

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