Grid Interconnection of Renewable Energy Sources at the Distribution Level

With Power Quality Improvement Features

Under the Guidance ofMrs. M.Padma(Assistant Professor)

Batch No-EE5

1. M.Krishnaveni(11B71A0206)

2. A.Pradeep(11B71A0244)

3. E.Soumya(11B71A0249)

4. P.Srinivas(11B71A0246)

SINDHURACOLLEGE OF ENGG & TECH

(EEE BRANCH)

ABSTRACT

Renewable energy resources (RES) are being increasingly connected in distribution systems utilizing power electronic converters.

This project presents a novel control strategy for achieving maximum benefits from these grid-interfacing inverters when installed in 3-phase 4-wire distribution systems.

The inverter can thus be utilized as: 1) power converter to inject power generated from RES

to the grid &2) shunt APF to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current.

Renewable Energy Sources:Def: Energy that comes from resources which are

naturally replenished on a human timescale such as sunlight, wind, rain, tides, waves and geothermal heat.

• The main items under RES are as follows:

1. Wind Power2. Solar Power 3. Hydro Power4. Bio-mass Power5. Geothermal 6. Ocean energy 7. Wave energy

Distributed Generation:

RES integrated at distribution level is termed as distributed generation.

Distributed generation is also called as onside generation, dispersed generation, embedded generation etc.

Used to provide “clean power” to critical loads, isolating them from disturbances with origin in the grid.

Power Quality:

Power Quality means quality of the normal voltage supplied to your facility.

The growing use of microprocessors and electronic equipments has made us to focus on power quality .

Equipment and machinery can be damaged or even fail when subjected to power anomalies .

Power Quality Issues:

Power Factor

Voltage sags

Voltage swells

Micro-interruptions

Long interruptions

Voltage spikes

Active Power Filters are simply power electronic converters, specifically designed to inject harmonic currents to the system.

Active Power Filter Capabilities;Eliminating Voltage and Current HarmonicsReactive Power CompensationRegulating Terminal VoltageCompensating the Voltage flickering

Active Power Filters:

BLOCK DIAGRAM

Control of Grid Interfacing Inverter:

DC-Link Voltage and Power Control Operation:

Fig: DC-Link equivalent diagram

Simulation Results:

Simulation results: (a) Grid voltages, (b) Grid Currents (c) Unbalanced load currents, (d) Inverter Currents

Simulation results: (a) PQ-Grid, (b) PQ-Load, (c) PQ-Inverter,(d) dc-link voltage

Simulation Results:

CONCLUSION

The grid-interfacing inverter with the proposed approach can be utilized to:

1) inject real power generated from RES to the grid, and/or,

2) operate as a shunt Active Power Filter (APF).

The grid interfacing inverter thus eliminates the need for additional power conditioning equipment to improve the power quality at PCC.

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