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

Claim 21:
22. The method of claim 1, wherein the event is a switching event of a shunt element, and wherein estimating the source impedance of each equivalent source comprises calculating:, Z
       sM
      
      =
      
       
        Z
        MF
       
       
        1
        +
        
         
          
           I
           M
           O
          
          -
          
           I
           M
           I
          
         
         
          I
          inj
         
        
       
      
     
    
   
   
    
     
      
       Z
       sN
      
      =
      
       
        Z
        NF
       
       
        1
        +
        
         
          
           I
           N
           O
          
          -
          
           I
           N
           I
          
         
         
          I
          inj
         
        
       
      
     
    
   
  
  }
 

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, IMO is a steady state value of current at the first substation, IMl is a value of the current at the first substation after the event, INO is a steady state value of current at the second substation, INl is a value of the current at the second substation after the event, and Iinj is injected current.