Search

Based on real-time access to response information on wide-area tributaries, in order to assess the system stability more quickly, this paper combines the simplified branch transient transmission capability (sBTTC) index and the largest Lyapunov exponent (MLE). An online identification method for transient power angle stability is proposed. Firstly, the method is based on a two-machine system to study the consistency of the power angle difference between the two ends of the critical branch and the change of the phase difference of the fleet. Secondly, the transient power angle stability problem is transformed into the MLE analysis problem according to the change rule of sBTTC index of the key branch. Then, by combining the characteristics of MLE curve and sBTTC index curve, the transient power angle stability criterion is given. Finally, the proposed method is verified and analysed by simulation examples. The method has strong industrial applicability because it does not need system model, the information source is easy to measure, it has strong anti-noise ability, and it overcomes the defect of the traditional method that needs to set a fixed symbolic observation window. [ABSTRACT FROM AUTHOR]

Let V be an (n + l) -dimensional vector space over the finite field F q with l ≥ n > 0 and W be a fixed l -dimensional subspace of V. We say that an m -dimensional subspace U of V is of type (m , k) if dim (U ∩ W) = k. Denote the set of all subspaces of type (m , k) in V by M (m , k ; n + l , n). The collection of all the subspaces of types (m , 0) in V , where 0 ≤ m ≤ n , is the attenuated space. In this paper, we prove the Hilton–Milner theorem for M (m , 0 ; n + l , n) , where 3 ≤ m ≤ n. [ABSTRACT FROM AUTHOR]