I had the same issue in version 35.3. This solved the issue for me: import os import sys

Import PSSE_PATH

PSSEPATH = r"C:\Program Files\PTI\PSSE35\35.3\PSSBIN32" os.environ['PATH'] += ';' + PSSEPATH

Import Modules

import psse3503 import psspy

I had the same issue in version 35.3. This solved the issue for me: me:

import os
import sys
 
Import PSSE_PATH
 
PSSEPATH sys
#Import PSSE_PATH
PSSE_PATH = r"C:\Program Files\PTI\PSSE35\35.3\PSSBIN32"
os.environ['PATH'] += ';' + PSSEPATHPSSE_PATH
  
Import Modules
 
#Import Modules
import psse3503
import psspypsspy