Patent ID: 11916367
Assignee: HITACHI ENERGY SWITZERLAND AG
Field: Measurement (Instruments)
Classification: CPC H  G | IPC G  H

Claim 20:
21. The method of claim 1, wherein the one or more transmission lines are two or more transmission lines, including a first transmission line and a second transmission line wherein the disturbance is a fault on the second transmission line, and wherein estimating the source impedance of each equivalent source comprises calculating:, Z
       sM
      
      =
      
       
        
         -
         b
        
        +
        
         
          b
          2
         
        
        -
        
         4
         ⁢
         ac
        
       
       
        2
        ⁢
        a
       
      
     
    
   
   
    
     
      
       Z
       sN
      
      =
      
       
        
         
          (
          
           
            Z
            par
           
           +
           
            Z
            sM
           
          
          )
         
         ⁢
         
          Z
          MF
         
        
        -
        
         
          
           Z
           
            l
            ⁢
            2
           
          
          
           (
           
            
             Z
             sum
            
            
             Z
             l
            
           
           )
          
         
         ⁢
         
          Z
          sM
         
        
       
       
        
         Z
         sM
        
        -
        
         Z
         MF
        
       
      
     
    
   
  
  }
 

 wherein

 
  
   
    
     a
     =
     
      
       Z
       MF
      
      -
      
       Z
       NF
      
      -
      
       
        Z
        
         l
         ⁢
         2
        
       
       
        (
        
         
          Z
          sum
         
         /
         
          Z
          l
         
        
        )
       
      
     
    
   
  
  
   
    
     b
     =
     
      
       
        Z
        par
       
       ⁢
       
        Z
        MF
       
      
      +
      
       
        
         Z
         
          l
          ⁢
          1
         
        
        
         (
         
          
           Z
           sum
          
          /
          
           Z
           l
          
         
         )
        
       
       ⁢
       
        (
        
         
          Z
          MF
         
         -
         
          Z
          NF
         
        
        )
       
      
      -
      
       
        
         Z
         
          l
          ⁢
          1
         
        
        ⁢
        
         Z
         
          l
          ⁢
          2
         
        
       
       
        
         (
         
          
           Z
           sum
          
          /
          
           Z
           l
          
         
         )
        
        2
       
      
     
    
   
  
  
   
    
     c
     =
     
      
       
        Z
        
         l
         ⁢
         1
        
       
       
        (
        
         
          Z
          sum
         
         /
         
          Z
          l
         
        
        )
       
      
      ⁢
      
       Z
       par
      
      ⁢
      
       Z
       MF
      
     
    
   
  
 

and wherein ZsM is the source impedance of the equivalent source associated with a first one of the at least two substations, ZsN is the source impedance of the equivalent source associated with a second one of the at least two substations, ZMF is a bus impedance for the first substation, ZNF is the bus impedance for the second substation, Zl is line impedance on the first transmission line, Zl1 is line impedance on a first section of the second transmission line, Zl2 is line impedance on a second section of the second transmission line, is a Zsum of line impedances, and Zpar is an impedance parameter that is based on the line impedances and Zsum.