Patent ID: 11949234
Assignee: ELECTRIC POWER SCIENCE & RESEARCH INSTITUTE OF STATE GRID TIANJIN ELECTRIC POWER COMPANY
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G | IPC H

Claim 1:
2. The method for making a spatio-temporal combined optimal scheduling strategy of an MES system according to claim 1, wherein step 4 comprises:
establishing the optimal regulation model of the MES system, wherein an objective function of the model is set to a minimum load reduction in a time set [NΔt, T], and is specifically expressed as:, min
          ⁢
          f
        
        =
        
          
            
              ∑
              
                t
                ∈
                T
              
            
            ⁢
            
              
                ∑
                
                  i
                  ∈
                  
                    E
                    n
                  
                
              
              ⁢
              
                
                  P
                  
                    i
                    ,
                    t
                  
                  
                    L
                    ⁢
                    S
                  
                
                ⁢
                Δ
                ⁢
                t
              
            
          
          +
          
            λ
            ⁢
            
              
                ∑
                
                  t
                  ∈
                  T
                
              
              ⁢
              
                
                  ∑
                  
                    
                      i
                      ⁢
                      j
                    
                    ∈
                    
                      E
                      b
                    
                  
                
                ⁢
                
                  
                    r
                    
                      i
                      ⁢
                      j
                    
                  
                  ⁢
                  
                    I
                    
                      ij
                      ,
                      t
                    
                  
                  ⁢
                  Δ
                  ⁢
                  
                    
                  
                  ⁢
                  t
                
              
            
          
        
      
    
    
      
        (
        1
        )
      
    
  

wherein in the formula (1), En and Eb represent a node set and a branch set in a power distribution network respectively, PLS i,t represents a load reduction of a node i at a time point t, rij and Iij,t represent resistance of a branch ij and a square of a current of the branch ij at the time point t respectively, Δt represents the time interval,, ∑
    
      t
      ∈
      T
    
  
  ⁢
  
    
      ∑
      
        
          i
          ⁢
          j
        
        ∈
        
          E
          b
        
      
    
    ⁢
    
      
        P
        
          i
          ,
          t
        
        LS
      
      ⁢
      Δ
      ⁢
      
        
      
      ⁢
      t, represents a load reduction of the power distribution network,, λ
  ⁢
  
    
      ∑
      
        t
        ∈
        T
      
    
    ⁢
    
      
        ∑
        
          
            i
            ⁢
            j
          
          ∈
          
            E
            b
          
        
      
      ⁢
      
        
          r
          
            i
            ⁢
            j
          
        
        ⁢
        
          I
          
            i
            ,
            j
            ,
            t
          
        
        ⁢
        Δ
        ⁢
        t, is used to ensure accuracy of solving the model after second-order cone relaxation optimization, and λ represents a real number greater than 10; and
setting model constraints, comprising a path traffic constraint, an energy storage battery constraint, and a power flow constraint of the power distribution network, wherein
the path traffic constraint is that the MES vehicle needs to complete a traveling process according to the delivered path instruction; pi,s,t is a binary decision variable, indicating whether an MES system s is located on the node i at the time point t; and when pi,s,t=1, it indicates that the MES system s is located on the node i at the time point t;, ∑
              
                i
                ∈
                
                  W
                  n
                
              
            
            ⁢
            
              p
              
                i
                ,
                s
                ,
                t
              
            
          
          ≤
          1
        
        ⁢
        
          

        
        ⁢
        
          
            ∀
            
              s
              ∈
              
                Ω
                s
              
            
          
          ,
          
            t
            ∈
            T
          
        
      
    
    
      
        (
        2
        )
      
    
  

wherein in the formula (2), Wn represents a set of nodes in a traffic network, Ωs represents a set of MES vehicles, and a traveling track of the MES vehicle also needs to meet a constraint of the traffic network to ensure that the MES vehicle can reach an expected position within specified time, as shown below:

  
    
      
        
          
            L
            
              i
              ,
              j
              ,
              t
            
          
          =
          
            round
            ⁢
            
              
            
            ⁢
            
              (
              
                
                  ∑
                  
                    k
                    ∈
                    
                      W
                      ij
                    
                  
                
                ⁢
                
                  
                    d
                    k
                  
                  
                    
                      γ
                      
                        k
                        ,
                        t
                      
                    
                    ·
                    v
                  
                
              
              )
            
            ⁢
            
              ∀
              i
            
          
        
        ,
        
          j
          ∈
          
            W
            n
          
        
        ,
        
          t
          ∈
          T
        
      
    
    
      
        (
        3
        )
      
    
  

pi,s,t+pj,s,t+τ≤1∀i∈Wn,j∈Wn,τ∈[1, . . . ,min{Li,j,t,T−t}],s∈Ωs  (4)

wherein in the formulas (3) and (4), Li,j,t represents time required by the MES vehicle to travel from the node i to a node j at the time point t; Wij represents a set of roads within a least time-consuming path between the node i and the node j, and is obtained based on a floyd algorithm; γk,t represents a congestion coefficient of a road k at the time point t, and is used to measure an actual traffic capacity of the road based on traffic congestion, road construction, and other factors; dk and v represent a length of the road k and the average traveling speed of the MES vehicle respectively; and Pj,s,t+τ represents whether the mobile storage energy system s is located on the node j at the time point t;
the energy storage battery constraint is related to the power instruction, the power instruction indicates active discharging power PM i,s,t and reactive discharging power M i,s,t of the energy storage battery after the MES vehicle reaches a destination and is connected to a power grid, and the energy storage battery constraint comprises capacity constraints represented by formulas (5) and (6) and power constraints represented by formulas (7) to (9), as shown below:, E
            
              s
              ,
              t
            
          
          =
          
            
              E
              
                s
                ,
                
                  t
                  -
                  1
                
              
            
            -
            
              
                ∑
                
                  i
                  ∈
                  
                    E
                    n
                  
                
              
              ⁢
              
                
                  P
                  
                    i
                    ,
                    s
                    ,
                    t
                  
                  M
                
                
                  η
                  
                    d
                    ⁢
                    i
                    ⁢
                    s
                  
                
              
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            ∀
            
              i
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          ,
          
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            ∈
            
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          ,
          
            t
            ∈
            T
          
        
      
    
    
      
        (
        5
        )
      
    
  
  
    
      
        
          
            
              σ
              min
            
            ⁢
            
              E
              s
            
          
          ≤
          
            E
            
              s
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              t
            
          
          ≤
          
            
              σ
              max
            
            ⁢
            
              E
              s
            
          
        
        ⁢
        
          

        
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            ∀
            
              s
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                Ω
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          ,
          
            t
            ∈
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        (
        6
        )
      
    
  
  
    
      
        
          
            
              -
              M
            
            ·
            
              p
              
                sta
                ,
                s
                ,
                t
              
            
            ·
            
              P
              s
              max
            
          
          ≤
          
            P
            
              
                s
                ⁢
                t
                ⁢
                a
              
              ,
              s
              ,
              t
            
            M
          
          ≤
          0
        
        ⁢
        
          

        
        ⁢
        
          
            ∀
            
              s
              ∈
              
                Ω
                s
              
            
          
          ,
          
            t
            ∈
            T
          
        
      
    
    
      
        (
        7
        )
      
    
  
  
    
      
        
          0
          ≤
          
            
              P
              
                i
                ,
                s
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              M
            
            
              η
              dis
            
          
          ≤
          
            
              p
              
                j
                ,
                s
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            ·
            
              P
              s
              max
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            ∀
            
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              ∈
              
                E
                n
              
            
          
          ,
          
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          ,
          
            t
            ∈
            T
          
        
      
    
    
      
        (
        8
        )
      
    
  
  
    
      
        
          
            
              -
              
                p
                
                  j
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                  ,
                  t
                
              
            
            ⁢
            
              Q
              s
              max
            
          
          ≤
          
            Q
            
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          ≤
          
            
              p
              
                j
                ,
                s
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            ⁢
            
              Q
              s
              max
            
          
        
        ⁢
        
          

        
        ⁢
        
          
            ∀
            
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              n
            
          
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              Ω
              s
            
          
          ,
          
            t
            ∈
            T
          
        
      
    
    
      
        (
        9
        )
      
    
  

wherein in the formulas (5) to (9), Es,t represents a battery capacity of the MES system s at the time point t, PM i,s,t and M i,s,t represent active and reactive charging and discharging power of the MES system s on the node i at the time point t respectively, ηdis represents discharging efficiency, Es represents the capacity of the MES battery, σmax and σmin represent the upper and lower capacity limits of the MES battery respectively, Pmax s and max s represent upper limits of active and reactive discharging power of the MES system s respectively, M represents a real number greater than 100, and sta represents a position of a central MES station; and
the power flow constraint of the power distribution network is that a power distribution system needs to meet power balance constraints represented by formulas (10) to (13) and operation safety constraints represented by formulas (14) and (15) after the MES system is orderly connected to the power distribution network in a plug and play manner, as shown below:, ⁢
        
          
            
              
                
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        (
        10
        )
      
    
  
  
    
      
        
          
            
              
                ∑
                
                  
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        (
        11
        )
      
    
  
  
    
      
        
          
        
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                            ⁢
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            =
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          ⁢
          
            

          
          ⁢
          
            
          
          ⁢
          
            
              ∀
              
                i
                ∈
                
                  E
                  n
                
              
            
            ,
            
              j
              ∈
              
                E
                n
              
            
            ,
            
              ij
              ∈
              
                E
                b
              
            
            ,
            
              t
              ∈
              T
            
          
        
      
    
    
      
        (
        12
        )
      
    
  
  
    
      
        
          
        
        ⁢
        
          
            
              
                
                
                  
                    [
                    
                      
                        
                          
                            2
                            ⁢
                            
                              P
                              
                                
                                  i
                                  ⁢
                                  j
                                
                                ,
                                t
                              
                            
                          
                        
                        
                          
                            2
                            ⁢
                            
                              Q
                              
                                
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                                  ⁢
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                            I
                            
                              
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                            -
                            
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                    ]
                  
                  T
                
                
              
              2
            
            ≤
            
              
                I
                
                  
                    i
                    ⁢
                    j
                  
                  ,
                  t
                
              
              +
              
                U
                
                  i
                  ,
                  t
                
              
            
          
          ⁢
          
            

          
          ⁢
          
            
          
          ⁢
          
            
              ∀
              
                i
                ∈
                
                  E
                  n
                
              
            
            ,
            
              ij
              ∈
              
                E
                b
              
            
            ,
            
              t
              ∈
              T
            
          
        
      
    
    
      
        (
        13
        )
      
    
  

wherein in the formulas (10) to (13), xij represents reactance of the branch ij, Pij,t and ij,t represent active power and reactive power flowing from the node i to the node j at the time point t respectively, Ui,t represents a square of a voltage of the node i at the time point t, PL i,t and L i,t represent active power and reactive power of load on the node i at the time point t respectively, PLS i,t and LS i,t respectively represent active power and reactive power that are reduced for the load on the node i at the time point t, and PG i,t and G i,t respectively represent active power and reactive power that are injected by a generator on the node i at the time point t; and

Uimin≤Ui,t≤Uimax∀i∈En,t∈T  (14)

Iij,t≤Iijmax∀ij∈Eb,t∈T  (15)

wherein in the formulas (14) and (15), Umax i and Umin i represent upper and lower limits of a square of a voltage of the node i respectively, and Imax ij represents a square of a maximum allowable current of the branch ij.