What is overvoltage protection or surge protection device (SPD)?

SPD stands for Surge Protective Device, which is also commonly referred to as overvoltage protection or surge protector. SPDs are electrical devices designed to protect electrical and electronic equipment from voltage spikes or surges in power systems. These surges can occur due to various reasons, including lightning strikes, power grid fluctuations, or switching operations in the electrical network. When a surge in voltage occurs, it can potentially damage or degrade sensitive electronic equipment, such as computers, televisions, appliances, and industrial machinery.