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I am using version PSS/E 34.2 to do dynamic simulations of the Poland test system which contains 2000+ buses. I am trying to input the CMLDBLU2 model for every load in the system. When I have greater than approximately 1500 loads with the CMLDBLU2 I get the error: "Return to dynamics terminated--system model requires too many VARS". My system will run successfully when using under 1500 dynamic load models. Then when using greater than 1500 and I get that error and I receive "NaN" in the output results. When loading the dynamic file the output is:

Generator models use: CONS 1- 3924 STATES 1- 1635

Excitation System models use: CONS 3925- 8502 STATES 1636- 2943 VARS 1- 327

Turbine Governor models use: CONS 8503- 10791 STATES 2944- 3924 VARS 328- 654

Shared Load Characteristic models use: CONS 10792-253649 ICONS 1- 3652

Shared Load Relay models use: CONS 253650-290169 ICONS 3653- 5478

Return to Dynamics terminated--system model requires too many VARS

Unshared Load models use: STATES 3925- 50040 VARS 655-249876 ICONS 5479- 87414

SUMMARY OF MODELS READ:

GENS: GENSAL 327

EXSYS: IEEET1 327

GOVS: IEEEG2 327

USER: USRLOD 3652

NEXT AVAILABLE ADDRESSES ARE: CON STATE VAR ICON 290170 50041 249877 87415

Only PSS/E supplied models in case. Compilation is not required

What is the cause of this error? And if there a way to work around it?

Thank you!