Patent ID: 11921170
Assignee: MAHDI DAVARPANAH
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 3:
4. The method of claim 2, wherein performing each iteration of the iterative measurement procedure comprises:
measuring, utilizing the numerical relay, a third voltage phasor of the periodic neutral-to-ground voltage at a third moment in a respective period of the periodic neutral-to-ground voltage, the third voltage phasor comprising a third voltage amplitude and a third voltage phase;
obtaining a third compensated voltage phase by compensating the third voltage phase according to the phase of the positive sequence component;
obtaining a relative voltage change according to an operation defined by the following:, E
    V
  
  =
  
    
      
        
          
            V
            
              NE
              ⁢
              
                
              
              ⁢
              3
            
          
          _
        
        -
        
          
            V
            
              N
              ⁢
              E
              ⁢
              1
            
          
          _
        
      
      
        
          0
          .
          5
        
        ×
        
          (
          
            
              V
              
                N
                ⁢
                E
                ⁢
                1
              
            
            +
            
              V
              
                NE
                ⁢
                
                  
                
                ⁢
                3
              
            
          
          )
        
      
    
    ×
    100
  

 where:
EV is the relative voltage change, and
VNE3=VNE3∠ϕNE3 where VNE3 is the third voltage amplitude and ϕNE3 is the third compensated voltage phase;

measuring, utilizing the numerical relay, a first current phasor of a neutral electric current passing through a neutral conductor of the three-phase distribution transformer at the first moment, the first current phasor comprising a first current amplitude and a first current phase;
measuring, utilizing the numerical relay, a second current phasor of the neutral electric current at the third moment, the second current phasor comprising a second current amplitude and a second current phase;
obtaining a first compensated current phase by compensating the first current phase according to the phase of the positive sequence component;
obtaining a second compensated current phase by compensating the second current phase according to the phase of the positive sequence component;
obtaining a relative current change according to an operation defined by the following:, E
    I
  
  =
  
    
      
        
          
            I
            
              N
              ⁢
              C
              ⁢
              2
            
          
          _
        
        -
        
          
            I
            
              N
              ⁢
              C
              ⁢
              1
            
          
          _
        
      
      
        
          0
          .
          5
        
        ×
        
          (
          
            
              I
              
                N
                ⁢
                C
                ⁢
                1
              
            
            +
            
              I
              
                N
                ⁢
                C
                ⁢
                2
              
            
          
          )
        
      
    
    ×
    100
  

 where
EI is the relative current change,
INC1=INC1∠ϕNC1 where INC1 is the first current amplitude and ϕNC1 is the first compensated current phase, and
INC2=INC2∠ϕNC2 where INC2 is the second current amplitude and ϕNC2 is the second compensated current phase;

obtaining, utilizing the one or more processors, a first amplitude I11 of the positive sequence component at the first moment; and
obtaining, utilizing the one or more processors, a second amplitude I12 of the positive sequence component at the third moment.