DC Surge Protective Devices (SPDs) are specialized components designed to protect direct current (DC) electrical systems from transient voltage surges, such as those caused by lightning strikes or switching events. They work by diverting excess voltage away from sensitive equipment to the ground, thereby preventing damage and ensuring the reliability of the DC system. DC SPDs are commonly used in photovoltaic (solar) systems, battery storage systems, and other applications where DC power is prevalent, safeguarding both the equipment and the overall electrical infrastructure.