Dear Rounak Mohanty,

The main problem of energy quality in a solar power plant is the lack of stability of energy supplies due to changes in the weather and the cyclical nature of the power source, i.e. solar energy in the range of the day (day - night) and changes of seasons in the temperate climate zone. It is therefore necessary to improve the technology of energy storage. In addition, when developing energy storage technology, battery technology should be improved in order to create more environmentally friendly solutions when used batteries are recycled.

Have a nice day, Best wishes,

Dariusz Prokopowicz

https://www.electrical-installation.org/enwiki/Power_quality_-_impact_of_solar_self-consumption

I think we should first of all agree on the defintion of "power quality". To me, the term "voltage quality" or "current quality" would better describe it than "power quality".

To me "power quality" can best be described by starting from a definition of voltage or current having a "perfect quality":

A "perfect voltage" is a three-phase sinusoidal voltage with constant amplitude and frequency, which is perfectly symmetrical with regard to the three phases (for currents analoguously).

Based on this defintion of a "perfect voltage" (or current) "Power quality" issues refer to any devition of voltage (or current) from such a perfect voltage (or current).

More specifically, power quality issues are:

- Distortions, which are deviations from the sinusoidal shape and which can be described by harmonics in the frequency domain.

- Flicker, which describes sinusoidal voltages (or currents) with non-constant amplitude (or frequencey "frequency flicker", which is, however, less relevant)

- Rapid voltage changes: single events leading to a reduced voltage amplitude (e.g. because of switching actions or short-circuits).

- Voltage unbalance: Different voltage magnitudes in the three phases (or angular displacements).

I think, these are the most important power quality aspects.

Additionally, we must ditinguish

- Power quality issues caused by PV inverters and

- Robustnes of PV inverters against power quality issues in the grid.

Power quality issues caused by PV inverters are typically:

- Harmonics (distorted currents)

- Flicker (e.g. from inappropriate converter controls. Cloud effects are typically too slow to cause flicker)

- Voltage unbalance

Besides this, a PV converter should be able to withstand (tolerate) all relevant power quality issues of the grid, as long as it is within permitted limits (as stated in a grid code or defined by relevant standards like the IEC61000-3-x series of standards).

Best Regards,

Markus Pöller

The major problem with the Renewable integration is their inverter control topologies due to overall reduced system inertia. They use active injections to improve weaker grid penetration, which can create large values for THD and voltage flickering in the overall grid conditions.

Various optimal injections techniques are developed in the literature to control this power quality concern. You can visit my paper where I have discussed all the aspects in quite a detail with a noble AI-based technique in the inverter controls.

Hope that helps.

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