Voltage drop is a phenomenon whereby electrical current in wires can build up resistance over long distances. This can lead to a drop in voltage due to electrons facing friction carrying a charge.
Voltage drop can lead to your Solar PV system not performing to its desired and advertised capacity. This is a cause for concern when designing a system that results in significant investment from the client.
According to International best practices, a voltage drop of 3% or less is acceptable in designing a solar PV array. An array that has massive voltage drop probabilities will not power the inverters as they should, leading to a drop in efficiency of the whole system.
A solar designer should know all of the intricacies that are involved in designing such a system and minimizing losses. Overall, there are 4 main approaches through which voltage drop across the system can be decreased:
1. Decreasing the length of the wire
According to the rules of nature, there will be more friction if electrons face more surface area for contact which will lead to heat losses. Decreasing the length of the wire will give them less surface and running area which will benefit us to design the system according to the specifications and requirements.
If a wire is under the 100 inches mark lengthwise, it will automatically lead to a voltage drop of less than 3% standard voltage drop-in systems. The components need to pack in a way as to minimize wire length.
2. Inverter Placement in the loop should be optimized
The current that is generated through the panels is Direct (DC Current). The current that is needed by our homes is AC (Alternating Current). The inverter does the job of converting Direct current to alternating current.
The wires that go from the inverter to the service panel are susceptible to higher voltage drops than the high dc voltage wires connecting the inverter and solar panels. The opposite is true sometimes as well.
The wire that is providing a higher voltage will push out more current which will subsequently lead to voltage drop. An inverter should be optimized according to the situation but the rule of thumb indicates inverter placement near the low voltage-end.
For instance, off-grid systems naturally produce low voltages hence there are high voltage charge controllers to control the system.
3. Increase the wire size (Diameter)
If a system can allow for wires for a bigger size, it can really help in decreasing the voltage loss across the wires. The downside is that wires of bigger sizes tend to cost a lot.
The reasoning behind wires of bigger diameters is that electrons will have more space to travel to per square inch hence there will be less friction as compared to wires of smaller diameter.
Investing in wires of bigger size will more than make up the cost of investing in them in the longer run.
4. Using products that warrant high voltage
Instead of using long wires to decrease resistance, we can invest in products that need high voltage to function.
Inverters that are coupled with power optimizers give out a fixed voltage regardless of the number of panel strings they are attached to. For example, 380/400 V will be constantly in the output if the above component is attached to the system.
Inverters that don’t have power optimizers give varying voltages that are in the range of 195-480 V. They vary along the spectrum of 240 V, either increasing in voltage or decreasing. The voltage is directly proportional to the number of string panels that are attached. The voltage drop can be kept in check if larger strings are used.
Voltage drop is a serious concern that can affect the investment one is about to make. Voltage drop leads to a resulting loss in production.
A holistic approach should be undertaken when designing an intricate system such as a solar panel system. Carefully selected equipment should be procured so that an efficient system is laid down with the best possible return on investment. For more information regarding this, see how Ethraa finances its projects.
Ethraa has earned a reputation for hiring the best personnel for its installations. They take a highlevel view of the overall projects following the Industry’s best practices.