What is selective deployment or selective optimization?
In solar PV systems that are not equipped with module-level optimization devices (e.g., DC optimizers or microinverters), having a few shaded modules can negatively affect the production of all the modules connected in the string. This means having even one or two panels affected by shade can result in significant production losses for your whole system. Traditional module-level optimization solutions, such as DC optimizers from SolarEdge and microinverters from Enphase, APsystems, or NEP, have required that you equip all modules in an array with optimization devices, even those that do not necessarily need it. Still, now we have an alternative from Tigo.
Tigo allows for selective deployment or selective optimization, meaning you can select which modules in a PV system get equipped with optimizers. You no longer have to have an all or nothing array; you can simply install optimizers on modules that absolutely need them.
If the site’s shading conditions change over time, for example, if a tree grows larger, you can add optimizers to the newly shaded modules as needed. Since adding optimization to each module results in a higher cost for your system, limiting the number of optimizers means more savings for you.
Selective deployment for mixed orientations
Often due to roof-space limitations, you may not be able to fit all the modules in the same roof plane, facing in the same direction and with the same angle. Having modules in a string facing different orientations or at different angles raises similar performance issues as shading. You can use the same solution here by adding TS4-A-O optimizers to a smaller group of modules in the same string facing a different direction.
Complying with NEC 2017 rapid shutdown requirements
If you need to comply with NEC 2017 rapid shutdown requirements, adding TS4-A-O devices only to the shaded modules will not be enough. The entire array needs to be fitted with module-level rapid shutdown devices. This does not mean you have to install TS4-A-O devices on every module. Instead, you have the option to combine TS4-A-O and TS4-A-S Tigo devices in the same system.
The Tigo TS4-A-S device provides rapid shutdown and module-level monitoring without optimization. It can still communicate with TS4-A-O optimizers in the rest of the array, making your full system rapid shutdown compliant. This will even result in a lower cost than adding optimizers to every module in your system -- something that cannot be avoided using traditional module-level rapid shutdown solutions.
**Please note that you cannot combine TS4-A-O and TS4-A-F devices in the same installation as these have different communication technologies and are not compatible.
The photos below show examples of rapid shutdown compliant systems using a combination of TS4-A-O (yellow) and TS4-A-S (red).
Rules to follow when selectively deploying Tigo MLPE devices:
Ensure the strings meet the minimum/maximum and start-up voltage requirements for your inverter. If you have modules in the same string with some facing a different orientation, assure at least one of the sub-arrays has enough modules to meet the inverter’s start-up and minimum operating voltage.
Selective deployment is meant for a single string going to an individual inverter input or MPPT. If you have two strings in parallel going into the same MPPT, you will need to add optimizers to all the modules on both strings. You cannot have optimizers on only one of the parallel strings. When installing strings in parallel, try to have an equal number of modules on each string. If that is not possible, do not have a difference of over 25% between the two.
Please refer to the image below for some examples of selective deployment with the TS4-A-O optimize.
Similarly, NEC 2017 rapid shutdown compliant systems using both the TS4-A-O and TS4-A-S devices.
The TS4-A-O optimizers can optimize right out of the box without any other communication device. To comply with rapid shutdown requirements when using the TS4-A-O alone or in combination with TS4-A-S devices, you will need the complete Tigo Smart system, which consists of module-level devices, a TAP (communication device) and a CCA (Cloud Connect Kit). Depending on the size and layout of your installation, you may need several TAP communication devices.
If you have any questions about Tigo’s selective deployment or anything Tigo related, please contact the RENVU support team by emailing firstname.lastname@example.org.