Error: Two blocks cannot be connected in series

Block 1: Synchronous machine pu Standard Block 2: Three phase Transformer-2 winding cannot be connected in series

The first block connected as a current source cannot be connected in series with inductive element of the second block

HELP!!!

[Nisar Ahmed]

same problem face can you help me

[e-mail]

[Swathi Vinayagamoorthi]

I am facing the same problem now in IEEE 9 bus system.

Can you please help me??

[e-mail]

Thank you

Answer 1

[Joel Van Sickel]

Hello Susmita,

this is a common problem in specialized power systems (was called simpowersystems a while ago). Essentially, inductors are modelled as current sources, and 2 current sources cannot exist in series. The quick fix for this is to place a three phase snubber resistor on the output terminals of the motor. A common snubber could be a wye connected resistor with resistance of 1e6 and grounded. Making this resistor smaller can improve simulation speed, but eventually it will draw enough power to actually impact the quailty of your simulaiton. Making this larger will improve accuracy but decrease simulation speed.

Alternatively, you could switch to using simscape electrical core components (the blue ones) and then you won't get this issue.

Regards,

Joel