Genset Problem

Your problem has little to do with the type of excitation system and much to do with the fact that your gen sets' control systems are not interconnected properly. Although you do not supply enough information to determine the exact mode of operation the fact that the two older gen sets are picking up less than the expected portion of the load generally means that there is no coordination between systems. The governors and the AVRs (Automatic Voltage Regulator) need to be set for parallel operation with the proper droop/compensation settings.

actually we setting the governor and AVR of G3(new genset)I want to ask, is the absence of PMG is the cause of this problem Or has no effect

Again, although different types of excitation systems have different operating characteristics and response times, proper tuning accommodates those differences. The absence of a PMG should make no difference if the control systems are properly set up.

I need to know why G3 current reach to 300A at 100 kw this value accepted or no and what is the reasons which cause the reverse power problem in G3 please confirm