Effect of PV on-grid (quality, voltage, stability)

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SUMMARY

The discussion focuses on the effects of on-grid photovoltaic (PV) systems on quality, voltage, and stability. On-grid systems generally enhance stability by utilizing the grid as a backup, although they can introduce voltage losses due to cable resistance. The quality of the PV system can degrade over time due to the intermittent nature of solar energy and the potential wear on components from constant grid interaction. Additionally, issues such as current draw and corrosion of interconnections significantly impact system efficiency and reliability.

PREREQUISITES
  • Understanding of on-grid photovoltaic (PV) systems
  • Knowledge of electrical circuits and current draw
  • Familiarity with voltage stability and losses in power distribution
  • Awareness of corrosion effects on electrical connections
NEXT STEPS
  • Research the impact of current draw on PV system performance
  • Learn about voltage loss calculations in electrical distribution systems
  • Investigate methods to mitigate corrosion in electrical interconnections
  • Explore the principles of distributed generation (DG) and its effects on local grids
USEFUL FOR

Electrical engineers, renewable energy professionals, and anyone involved in the design and maintenance of on-grid PV systems will benefit from this discussion.

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What is the effect of on-grid PV systems, in terms of quality, voltage and stability? I'm not really sure how to answer this.

Stability -- If consumer is tied to a PV power plant, grid stability could potentially be an issue. However, generally speaking, on-grid systems use the grid like a battery back-up, so in some senses they are more stable than off-grid systems.

Voltage -- Can be lossed from grid to home. Voltage lost in cables.

Quality -- The constant need to potentially have energy coming from the grid to the home could wear out the components in the PV system. PV itself is intermittent / variable and depends on weather conditions.

I read something else about reactive power but the concept was a little difficult to understand.

Is there anything I'm missing in terms of the quality, stability and voltage effects of PV on-grid?
 
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Just a few notes;

I would add corrosion of the interconnections over time - quality of cable termination is critical.

Current draw is your main enemy in a system like this. Basically let's say your converter is 120Vac. It should provide this voltage at all times at a very stable value (very little ripple). You can turn on your TV and computer. Maybe a few lights and an alarm clock. Your overall current draw is already 3-4 Amps. Now that's not a big problem for the system. The problem is when you turn on the stove and the dryer. These can add 5-10 amps each on top and will easily exceed small PV installations. At this point, it would be better to farm multiple small installations into a common grid so the intermittent current draws can be normalized.

The battery bank and converter quality along with the type of system used (fixed or rotating) all have an overall impact on system efficiency.
 
PV is a tiny portion of the connected generation in the USA. 0.2% if my memory is correct. Something that small has a negligible effect on the bulk power grid, no matter what it does.

Local power distribution, say on your street, is a different matter. Distributed generation (DG) makes it more difficult to design the protective relaying required to keep the local power supply safe and reliable.

Your questions are all mixed up. You ask about the grid, but then about your own equipment.

Electrical circuits are not worn out by time varying voltages and currents.

Corrosion is not affected by voltages and currents, unless there is a galvanic current leaking to earth. Contaminants in the air are the principle cause of corrosion. I live on a boat in salt water. Salt in the air is a constant enemy of my electrical connections.
 
In some parts of the grid it might not be possible to add more generating capacity because it will increase the local grid voltage too much.

This can happen when too much solar is added to a local grid that wasn't designed for it.
 

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