Comparative study of Q(U) reactive power control on power control flexibility across IEC and IEEE standards and Thailand’s provincial distribution network grid code

This work evaluates the alignment of PEA grid codes with international DER standards for reactive-power capability and voltage–reactive-power control. PEA 2016 depends on fixed power-factor checks without defining Qmax/Qmin or dynamic response, while the PEA Draft 202X adds Volt–Var voltage windows but keeps the function disabled by default. In comparison with IEEE 1547-2018 and IEC 62786-2017, PEA’s approach remains capability oriented, requiring full reactive support at rated active power without curtailment. This contrasts with international practice, which specifies reactive-power envelopes and mandatory response times. As DER penetration grows, clearer functional requirements and standardized inverter capabilities will be essential for maintaining grid stability.