As per Oman Standard for Solar PV project on grid , the system should meet the bellow technical requirements at the Point of connection (POC ) :

– The frequency at the POC stays within the range of 47,5Hz to 52,5Hz.
-The voltage at the POC stays within the range 85% to 110 % of the rated voltage.
– Total Harmonic distortion (THD) is:  3% at (as per ASPR) ,or as per DISCO
– Short circuit (Is): 6% of Max switch Capacity.

In case that THD exceed the limit, the electrical filter should be applied after submitting the electrical simulation study.

Please refer OES standard in ASPR