A method for measuring imbalances in an electrical grid, comprising the steps of: i) obtaining effective values (V A1, V B1, V C1) and arguments (α A1, α B1, α C1) of the phase voltages at the fundamental frequency, as well as effective values (I A1, I B1, I C1) and arguments (β A1, β B1, β C1) of the phase currents at the fundamental frequency of the electrical grid; ii) calculating the effective value ( V + = V A 1+) and the argument (α + = α A1+) of the positive sequence voltages and the effective values of the negative sequence voltage ( V - = V A 1-) and zero sequence voltage ( V o = V A 1o); iii) determining the active power ( P A 1, P B 1, P C 1) and reactive power ( Q A1, Q B1, Q C1) of each of the phases at the fundamental frequency from the values of the voltages and currents at the fundamental frequency; and iv) calculating the value of the imbalance power vector ( S u) according to the following equation: S ̅ u = V + 2 + 2 δ u 2 + 2 δ A 2 ⋅ P A 1 V A 1 cos α + − α A 1 + j Q ̅ A 1 V A 1 sin α + − α 1 + a 2 P B 1 V B 1 cos α + − α B 1 + + ja 2 Q ̅ B 1 V B 1 sin α + − α B 1 + a P C 1 V C 1 cos α + − α C 1 + ja Q ̅ C 1 V C 1 sin α + − α C 1 ⋅ p ̅ + + V + 2 + 2 δ u 2 + 2 δ A 2 ⋅ j P A 1 V A 1 sin α + − α A 1 + Q ̅ A 1 V A 1 cos α + − α 1 + ja 2 P B 1 V B 1 sin α + − α B 1 + + a 2 Q ̅ B 1 V B 1 cos α + − α B 1 + ja P C 1 V C 1 sin α + − α C 1 + a Q ̅ C 1 V C 1 cos α + − α C 1 ⋅ q ̅ + + V + δ u 2 + δ A 2 ⋅ ∑ x = A, B, C P x 1 V x 1 cos α + − α x 1 + j Q ̅ x 1 V x 1 sin α + − α x 1 + j P x 1 V x 1 sin α + − α x 1 + Q ̅ x 1 V x 1 cos α + − α x 1 ⋅ z ̅ wherein a = 1 ∠ 120 °; j is the imaginary unit; δ U = V - /V + and δ A = V 0 /V + are the degrees of imbalance and asymmetry, respectively, of the phase voltages; and p, q, z are the orthogonal unit vectors defining the space itself of the imbalance power vector. i) obtaining effective values (V A1, V B1, V C1) and arguments (α A1, α B1, α C1) of the phase voltages at the fundamental frequency, as well as effective values (I A1, I B1, I C1) and arguments (β A1, β B1, β C1) of the phase currents at the fundamental frequency of the electrical grid; ii) calculating the effective value ( V + = V A 1+) and the argument (α + = α A1+) of the positive sequence voltages and the effective values of the negative sequence voltage ( V - = V A 1-) and zero sequence voltage ( V o = V A 1o); iii) determining the active power ( P A 1, P B 1, P C 1) and reactive power ( Q A1, Q B1, Q C1) of each of the phases at the fundamental frequency from the values of the voltages and currents at the fundamental frequency; and iv) calculating the value of the imbalance power vector ( S u) according to the following equation: S ̅ u = V + 2 + 2 δ u 2 + 2 δ A 2 ⋅ P A 1 V A 1 cos α + − α A 1 + j Q ̅ A 1 V A 1 sin α + − α 1 + a 2 P B 1 V B 1 cos α + − α B 1 + + ja 2 Q ̅ B 1 V B 1 sin α + − α B 1 + a P C 1 V C 1 cos α + − α C 1 + ja Q ̅ C 1 V C 1 sin α + − α C 1 ⋅ p ̅ + + V + 2 + 2 δ u 2 + 2 δ A 2 ⋅ j P A 1 V A 1 sin α + − α A 1 + Q ̅ A 1 V A 1 cos α + − α 1 + ja 2 P B 1 V B 1 sin α + − α B 1 + + a 2 Q ̅ B 1 V B 1 cos α + − α B 1 + ja P C 1 V C 1 sin α + − α C 1 + a Q ̅ C 1 V C 1 cos α + − α C 1 ⋅ q ̅ + + V + δ u 2 + δ A 2 ⋅ ∑ x = A, B, C P x 1 V x 1 cos α + − α x 1 + j Q ̅ x 1 V x 1 sin α + − α x 1 + j P x 1 V x 1 sin α + − α x 1 + Q ̅ x 1 V x 1 cos α + − α x 1 ⋅ z ̅ wherein a = 1 ∠ 120 °; j is the imaginary unit; δ U = V - /V + and δ A = V 0 /V + are the degrees of imbalance and asymmetry, respectively, of the phase voltages; and p, q, z are the orthogonal unit vectors defining the space itself of the imbalance power vector. a = 1 ∠ 120 °; j is the imaginary unit; δ U = V - /V + and δ A = V 0 /V + are the degrees of imbalance and asymmetry, respectively, of the phase voltages; and p, q, z are the orthogonal unit vectors defining the space itself of the imbalance power vector.