Short-circuit curve - Wound field synchronous machines

The aim of the test “Characterization – Short circuit – Generator – Short-Circuit” is to characterize the behavior of the machine when running in a three-phase short-circuit state and to provide the short-circuit curve by considering several field currents.

The analysis of the machine’s short-circuit characteristics is a first step to evaluate the relevance of the machine design regarding not only parameters such as topology, winding architecture, composition of coils and choice of materials, but also the impact of the applied field current value on the short-circuit characteristics of the machine - including potential non-linear behavior.
Warning: When a delta winding connection is considered, the computation doesn’t consider circulation currents. That can lead to a different result than what was expected in transient computation.

In such a case, it is recommended to perform a transient computation in Flux® environment. The application “Export to Flux” allows exporting the model with the corresponding scenario ready to be solved

  • User inputs

    The maximum field current value (or equivalent maximum field current density) and the rotation speed are the only necessary standard input parameters to run this test. The operating temperature of the field winding and damper bars, if existing, can be defined in the settings “Thermal”.

    Additionally, if the user wants to run a complete short-circuit test for a single point, performing a magneto-transient simulation specified with a field current value, the two concerned inputs are available as standard inputs as well.

  • Computation of non-linear behavior

    Although the short-circuit characteristic is ideally linear, non-linear behavior could become significant if the field current value is high enough, depending on the machine topology. A systematic approach based on small signal modelling is performed to compensate for the linear characteristic with any existing non-linear behavior displayed by the machine according to the maximum field current value provided.



    Characterization - Short circuit – Generator – Short-Circuit - Overview


    Characterization - Short circuit – Generator – Short-circuit – The main outputs