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Error: Two blocks cannot be connected in series

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Susmita on 7 Apr 2013
Answered: Joel Van Sickel on 5 Aug 2020
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

  1 Comment

Nisar Ahmed
Nisar Ahmed on 12 May 2020
same problem face can you help me

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Answers (1)

Joel Van Sickel
Joel Van Sickel on 5 Aug 2020
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.


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