The idea of the initialisation is to preset the internal model signals by the results of an initial load flow.

The key point is to first check for each DSL-model, which inputs/outputs are known and which have to be determined based on the known ones. With this information the initialization sequence of models can then be determined.

PowerFactory does this automatically, but if there is no sequence found (because of dead lock situations) there will be an error message. It is recommended to set all DSL-models out of service and put them in service one by one in the initialisation sequence, so each model can be tested properly.

Some guidelines:

1. Define the initial conditions in the first complex block instead of doing it on each primitive block (like first order time lag).
2. The general initialisation direction is from right to left, i.e. the outputs are normally known and the inputs (or set points) have to be determined.
3. If initial conditions are not defined for a certain variable the simulation equations are used instead. It should be therefore enough to specify the initial conditions of the state variables and input variables.
4. The option Automatic Calculation of Initial Conditions needs some configuration work, but does not require correct initial conditions for each state/input variables. The initial values are only used to initialise the iteration process. The statement incfix can be used to determine the initial values in ambivalent situations (refer to User Manual and DSL tutorial).
5. Use the option Verify Initial Conditions to check if the initial conditions lead to the correct result.
6. The option Verify Initial Conditions is only available for RMS simulations, then before running an EMT simulation verify with a RMS if there are no initialisation problems.