Most Economical Loading of Interconnected Stations

Most Economical Loading of Interconnected Stations

• Consider power stations S₁ and S_2. Let
  P_L1 and P_L2 be the local loads of stations S₁ and
  S₂ respectively. Let P_S and P_R be the powers
  sent and received by S₁ and S₂ respectively as shown in
  figure A.

  Let, P_L1 = Power input of station S₁

   = P_L1 + P_S

  P
  ₀₂ = Power output of station S₂

  = P_L2 + P_R

  P_s – P_R
  = Losses in the interconnector

  P = Total power input to status S₁
  and S₂ = P_L1 + P_L2

  For most economical loading the power input should be
  minimum i.e. dP/dP₀₁ should be equal to zero.

  In view of equation (1),

    DP_L1
  / dP₀₁ + dPL2 /dP₀₁ = 0

  Or dP_L1
  / dP₀₁ + dP_L2 / dP₀₁ x dP₀₂ /dP₀₁
  = 0

  From equation (1) and (2) keeping in view that P and P are
  constant,

     DP₀₂ /
  dP₀₁ = d(P_L2 – P_R ) / d(P_L1 + P_s
  )

     = dP_R / dP_S

     = Incremental efficiency (η) of the interconnector.

  Substituting equation (6) in (5), we get

    DP_L1
  / dP₀₁ = dP_L2 /dP₀₂ x dP_R / dP_S

    = η dP_L2
  / dP₀₂

  Thus, for most economical loading the incremental power
  input or rate of power input at station S₁ should be equal to
  interconnector incremental efficiency multiplied by incremental power input to
  station S_2.