Patent ID: 11870254
Assignee: TIANJIN UNIVERSITY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. The multi-terminal differential protection setting method for a distributed generator T-connected distribution network according to claim 1, wherein step S7 of solving the optimization problem of the non-convex constraint space comprises the following specific steps:
step S701: inputting data matrixes of İ1.tr-İn.tr, λ1-λn and α1-αn;, [
     
      
       
        
         I
         
          1.
          tr
         
        
       
       
        
         β
         
          1
          ,
          tr
         
        
       
       
        
         λ
         1
        
       
       
        
         α
         1
        
       
      
      
       
        
         I
         
          2.
          tr
         
        
       
       
        
         β
         
          2
          ,
          tr
         
        
       
       
        
         λ
         2
        
       
       
        
         α
         2
        
       
      
      
       
        ⋮
       
       
        ⋮
       
       
        ⋮
       
       
        ⋮
       
      
      
       
        
         I
         
          n
          ,
          tr
         
        
       
       
        
         β
         
          n
          ,
          tr
         
        
       
       
        
         λ
         n
        
       
       
        
         α
         n
        
       
      
     
     ]
    
   
   
    
     (
     28
     )
    
   
  
 

wherein I1.tr-In.tr are amplitudes of İ1.tr-İn.tr, and β1.tr-β1.tr are phases of İ1.tr-İn.tr;
wherein the specific values of λ1-λn and α1-αn can be determined by the type of a current transformer and the data synchronization accuracy of a data synchronization method, and İ1.tr-İn.tr are fault current flowing through primary and secondary fusing intelligent switches when a fault outside the protected area is most severe;
step S702: determining to discretize the constraint space of the optimization problem into (4+2m)n points according to λ1λn and α1-αn;
step S703: generating a discrete point matrix;, [
     
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           -
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           -
           
            α
            1
           
          
          )
         
        
       
       
        
         
          I
          
           2.
           tr
          
         
         ⁢
         
          (
          
           1
           -
           
            λ
            2
           
          
          )
         
         ⁢
         ∠
         ⁢
         
          (
          
           
            β
            
             2.
             tr
            
           
           -
           
            α
            2
           
          
          )
         
        
       
       
        …
       
       
        
         
          I
          
           n
           .
           tr
          
         
         ⁢
         
          (
          
           1
           -
           
            λ
            n
           
          
          )
         
         ⁢
         ∠
         ⁢
         
          (
          
           
            β
            
             n
             .
             tr
            
           
           -
           
            α
            n
           
          
          )
         
        
       
      
      
       
        
         
          I
          
           1.
           tr
          
         
         ⁢
         
          (
          
           1
           -
           
            λ
            1
           
          
          )
         
         ⁢
         ∠
         ⁢
         
          (
          
           
            β
            
             1.
             tr
            
           
           +
           
            α
            1
           
          
          )
         
        
       
       
        
         
          I
          
           2.
           tr
          
         
         ⁢
         
          (
          
           1
           -
           
            λ
            2
           
          
          )
         
         ⁢
         ∠
         ⁢
         
          (
          
           
            β
            
             2.
             tr
            
           
           +
           
            α
            2
           
          
          )
         
        
       
       
        …
       
       
        
         
          I
          
           n
           .
           tr
          
         
         ⁢
         
          (
          
           1
           -
           
            λ
            n
           
          
          )
         
         ⁢
         ∠
         ⁢
         
          (
          
           
            β
            
             n
             .
             tr
            
           
           +
           
            α
            n
           
          
          )
         
        
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           -
           
            α
            1
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           -
           
            α
            2
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           -
           
            α
            n
           
          
          )
         
        
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           +
           
            α
            1
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           +
           
            α
            2
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           +
           
            α
            n
           
          
          )
         
        
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           -
           
            
             α
             1
            
            
             2
             m
            
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           -
           
            
             α
             2
            
            
             2
             m
            
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           -
           
            
             α
             n
            
            
             2
             m
            
           
          
          )
         
        
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           -
           
            
             3
             ⁢
             
              α
              1
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           -
           
            
             3
             ⁢
             
              α
              2
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           -
           
            
             3
             ⁢
             
              α
              n
             
            
            
             2
             m
            
           
          
          )
         
        
       
      
      
       
        ⋮
       
       
        ⋮
       
       
        …
       
       
        ⋮
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           -
           
            
             
              (
              
               
                2
                ⁢
                k
               
               +
               1
              
              )
             
             ⁢
             
              α
              1
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           -
           
            
             
              (
              
               
                2
                ⁢
                k
               
               +
               1
              
              )
             
             ⁢
             
              α
              2
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           -
           
            
             
              (
              
               
                2
                ⁢
                k
               
               +
               1
              
              )
             
             ⁢
             
              α
              n
             
            
            
             2
             m
            
           
          
          )
         
        
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           +
           
            
             α
             1
            
            
             2
             m
            
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           +
           
            
             α
             2
            
            
             2
             m
            
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           +
           
            
             α
             n
            
            
             2
             m
            
           
          
          )
         
        
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           +
           
            
             3
             ⁢
             
              α
              1
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           +
           
            
             3
             ⁢
             
              α
              2
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           +
           
            
             3
             ⁢
             
              α
              n
             
            
            
             2
             m
            
           
          
          )
         
        
       
      
      
       
        ⋮
       
       
        ⋮
       
       
        …
       
       
        ⋮
       
      
      
       
        
         
          
           I
           
            1.
            tr
           
          
          (
          
           1
           +
           
            λ
            1
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             1.
             tr
            
           
           +
           
            
             
              (
              
               
                2
                ⁢
                k
               
               +
               1
              
              )
             
             ⁢
             
              α
              1
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        
         
          
           I
           
            2.
            tr
           
          
          (
          
           1
           +
           
            λ
            2
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             2.
             tr
            
           
           +
           
            
             
              (
              
               
                2
                ⁢
                k
               
               +
               1
              
              )
             
             ⁢
             
              α
              2
             
            
            
             2
             m
            
           
          
          )
         
        
       
       
        …
       
       
        
         
          
           I
           
            n
            .
            tr
           
          
          (
          
           1
           +
           
            λ
            n
           
          
          )
         
         ⁢
         
          ∠
          ⁡
          (
          
           
            β
            
             n
             .
             tr
            
           
           +
           
            
             
              (
              
               
                2
                ⁢
                k
               
               +
               1
              
              )
             
             ⁢
             
              α
              n
             
            
            
             2
             m
            
           
          
          )
         
        
       
      
     
     ]
    
   
   
    
     (
     29
     )
    
   
  
 

wherein k≥1 and 2k−1≤2m−1
step S704: for 1-n columns in the matrix in step S703, performing the following (4+2m)n operations respectively for different points x{dot over (ι)}1,1, x{dot over (ι)}2,2, . . . , x{dot over (ι)}n,n of 4+2m rows;

ΔIΣ=|x{dot over (ι)}1,1+x{dot over (ι)}2,2+ . . . +x{dot over (ι)}n,n|  (30)

wherein 1≤{dot over (ι)}1, {dot over (ι)}2, . . . , {dot over (ι)}n≤4+2m;
step S705: searching for the maximum value in the (4+2m)n results calculated in step S704, i.e., the approximate solution ΔIΣ.max′ of a global optimal solution, and approximately replacing ΔIΣ.max by ΔIΣ.max′ as the protection setting value in formula (9).