Can a load acceptance followed by a load rejection be modeled by HAMMER? (or the reverse?)
Currently, this cannot be directly modeled in HAMMER. You will need to perform two separate transient simulations (scenarios); one for load acceptance and another for load rejection (or instant load rejection.) If you are concerned about transient effects of a load rejection occurring soon after a load acceptance, consider making conservative assumptions for both of the individual acceptance and rejection simulations. Or, consider using a TCV or GPV to approximate the turbine. For this, you could run a regular load rejection or acceptance scenario with the turbine element, observe the results, then replace the turbine with a TCV and configure the coefficient type, valve type, coefficients and operating rule pattern until the results with the TCV match the results with the turbine. The model still won't be as accurate as using a turbine element, but you would be able to set the pattern on the TCV to close and then reopen (or the reverse) to approximate the turbine load rejection or acceptance.
The addition of load acceptance + load rejection or Load rejection + load acceptance will be considered for future versions of HAMMER. (enhancement # 486154)