In the United States, there are several types of Rapid Shutdown (RSD) solutions that can be adapted to meet the local requirements and codes. Here are some commonly used RSD options:

1.Module-Level RSD: This approach involves the use of power optimizers or microinverters attached to each solar panel. These devices enable individual panel-level shutdown, allowing for rapid de-energization of the system. Module-level RSD offers high granularity and flexibility, as each panel can be independently controlled and shut down. It is commonly used in residential and commercial installations.

2.String-Level RSD: String-level RSD involves the use of rapid shutdown devices (RSDs) installed at the string level of the solar array. These devices are typically installed at the string combiner boxes or near the inverters. When a rapid shutdown signal is triggered, the RSDs shut down the entire string, reducing the voltage and current to a safe level. String-level RSD is commonly used in larger commercial and utility-scale installations.

3.Inverter-Integrated RSD: Some solar inverters have integrated rapid shutdown functionality. These inverters are designed to meet the specific RSD requirements and can be controlled remotely to initiate rapid shutdown. Inverter-integrated RSD simplifies the installation process as it eliminates the need for additional RSD devices. It is commonly used in both residential and commercial installations.

4.Power Line Communication (PLC): PLC-based RSD systems use communication signals transmitted through the power lines to control the rapid shutdown of the PV system. This approach eliminates the need for additional wiring or communication infrastructure, as the power lines are used to transmit the shutdown signal. PLC-based RSD can be implemented with module-level or string-level solutions.

It’s important to note that the specific RSD requirements can vary depending on the local electrical codes and regulations. The National Electrical Code (NEC) in the United States provides guidelines for RSD, and it’s essential to consult with a qualified solar installer or electrical professional to ensure compliance with the appropriate RSD requirements in your area.