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.

1. Grid Interconnection of Renewable Energy
Sources at the Distribution Level With
Power Quality Improvement Features
Under the Guidance of
Mrs. M.Padma
(Assistant Professor)
Batch No-EE5
1. M.Krishnaveni (11B71A0206)
2. A.Pradeep (11B71A0244)
3. E.Soumya (11B71A0249)
4. P.Srinivas (11B71A0246)

2. 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.

3. 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 Power
2. Solar Power
3. Hydro Power
4. Bio-mass Power
5. Geothermal
6. Ocean energy
7. Wave energy

4. 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.

5. 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 .

6. Power Quality Issues:
 Power Factor
 Voltage sags
 Voltage swells
 Micro-interruptions
 Long interruptions
 Voltage spikes

7.  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 Harmonics
 Reactive Power Compensation
 Regulating Terminal Voltage
 Compensating the Voltage flickering
Active Power Filters:

8. BLOCK DIAGRAM

9.  Control of Grid Interfacing Inverter:

10. DC-Link Voltage and Power
Control Operation:
Fig: DC-Link equivalent diagram

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

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

13. 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.