The multi-function digital relay can protect a generator from voltage, frequency, reverse power, over current, loss-of-field, and over-excitation (V/Hz) disturbances, while also providing breaker failure/flashover protection. Electrical relays, protective devices used to switch power on or off for parts of a circuit, have been integrated into circuits for nearly two hundred years. The first example of a relay dates back to the mid-nineteenth century, when Joseph Henry used a small electric signal to activate an. Our photovoltaic relays (PVR) are remotely controlled switches (on/off) with complete galvanic isolation from input to output The operating parameters of PVRs are ideal for switching low-level signal loads in instrumentation and data acquisition to medium-power loads in industrial controls and. This transformation introduces critical requirements for protection coordination, fault isolation, and adherence to grid compliance standards. This document serves as a detailed guide to the protection systems employed in solar PV plants. Moreover, the advantages of photovoltaic panels are numerous, both in terms of duration of the installation and in terms of reduced maintenance costs, this ensures that the tr nd and the investments are destined to continue. The function and the ANSI codes for different relays have been discussed for a Line- In- Line- Out (LILO) arrangement and the protection standards in Indian scenario has been briefed.