Safeguarding Solar Inverters & Sensitive Smart Electronics from Transient Surges
Sri Lanka experiences some of the highest lightning flash densities in South Asia, especially during the inter-monsoon periods. Transient overvoltages generated by lightning strikes and utility grid switching cause catastrophic damage to grid-tied solar inverters, smart home controllers, LED drivers, and CCTV DVRs.
1. The Difference Between Type 1 and Type 2 SPDs
- Type 1 SPDs: Designed to withstand direct lightning discharge currents (10/350 µs waveform). Installed at main service entry points where external lightning protection systems (lightning rods) are present.
- Type 2 SPDs: Engineered to divert indirect lightning-induced surges and switching transients (8/20 µs waveform). Essential for distribution sub-panels, solar combiner boxes, and inverter DC/AC inputs.
2. Protection on Solar PV Installations
Solar arrays act as massive outdoor antenna arrays for induced electromagnetic pulses. A standard PV setup requires Type 2 DC SPDs on the DC string input side (up to 600V or 1000V DC) and Type 2 AC SPDs on the inverter output grid connection side.