According to PSS/E POM documentation (scattered among many doc files inside the source folder), we can summarize an approach to handle Switched Shunts behavior
MODSW == 0: the switched-shunt admittance is locked at BINIT.- A switched shunt connected to a type 3 bus is treated as locked at BINIT, regardless of MODSW.
MODSW == 1: the shunt starts from BINIT, is adjusted during the power-flow solution, and is then moved to the nearest discrete step.MODSW == 2: the shunt is continuously adjusted during the solution. Its effective admittance cannot be reconstructed from the discrete block statuses alone.
Documentation states that BINIT contains the actual solved value only when the case is considered solved (the only way to know this is if it's an exported power flow case from PF.jl), the switched shunt is locked (MODSW = 0), or switched-shunt adjustment is disabled
So we can safely use BINIT when:
- Locked switched shunts (MODSW == 0).
- Switched shunts connected to type 3 buses.
- Continuously controlled switched shunts (MODSW == 2).
- Any RAW file known to have been exported after a converged power flow.
- In case switched shunts connected to type 1/2 buses: (automatic switched-shunt adjustment is allowed)
- With
MODSW = 1, BINIT is only the starting value unless the case is known to be solved. For an unsolved case, the discrete block state should be used to determine the current switched-shunt admittance.
- With
MODSW = 2, BINIT is the starting value unless the case is known to be solved. The effective continuous admittance cannot be reconstructed from the block statuses, so an unsolved RAW file does not contain enough information to determine the actual operating admittance.
For v35 files, the block status fields Sᵢ indicate whether each block is on or off; they are not the number of engaged steps. When reconstructing a discrete switched shunt, the block contribution must include the number of steps Nᵢ:
B = sum(Sᵢ * Nᵢ * Bᵢ)
According to PSS/E POM documentation (scattered among many doc files inside the source folder), we can summarize an approach to handle Switched Shunts behavior
MODSW == 0: the switched-shunt admittance is locked at BINIT.MODSW == 1: the shunt starts from BINIT, is adjusted during the power-flow solution, and is then moved to the nearest discrete step.MODSW == 2: the shunt is continuously adjusted during the solution. Its effective admittance cannot be reconstructed from the discrete block statuses alone.So we can safely use
BINITwhen:MODSW = 1,BINITis only the starting value unless the case is known to be solved. For an unsolved case, the discrete block state should be used to determine the current switched-shunt admittance.MODSW = 2,BINITis the starting value unless the case is known to be solved. The effective continuous admittance cannot be reconstructed from the block statuses, so an unsolved RAW file does not contain enough information to determine the actual operating admittance.For v35 files, the block status fields Sᵢ indicate whether each block is on or off; they are not the number of engaged steps. When reconstructing a discrete switched shunt, the block contribution must include the number of steps Nᵢ: