204 citations · 1.1k across the 39 of their papers we have counts for
6 papers · 1 filter
Finding Semi-Analytic Solutions of Power System Differential-Algebraic Equations for Fast Transient Stability Simulation
Nan Duan, Kai Sun
This paper studies the semi-analytic solution (SAS) of a power system's differential-algebraic equation. A SAS is a closed-form function of symbolic variables including time, the i…
Adaptive Optimal PMU Placement Based on Empirical Observability Gramian
Junjian Qi, Kai Sun, Wei Kang
In this paper, we compare four measures of the empirical observability gramian, including the determinant, the trace, the minimum eigenvalue, and the condition number, which can be…
Estimating the Propagation of Interdependent Cascading Outages with Multi-Type Branching Processes
Junjian Qi, Wenyun Ju, Kai Sun
In this paper, the multi-type branching process is applied to describe the statistics and interdependencies of line outages, the load shed, and isolated buses. The offspring mean m…
Power System Dynamic State Estimation by Unscented Kalman Filter with Guaranteed Positive Semidefinite State Covariance
Junjian Qi, Kai Sun
In this paper an unscented Kalman filter with guaranteed positive semidefinite state covariance is proposed by calculating the nearest symmetric positive definite matrix in Frobeni…
Optimal PMU Placement for Power System Dynamic State Estimation by Using Empirical Observability Gramian
Junjian Qi, Kai Sun, Wei Kang
In this paper the empirical observability Gramian calculated around the operating region of a power system is used to quantify the degree of observability of the system states unde…
An Interaction Model for Simulation and Mitigation of Cascading Failures
Junjian Qi, Kai Sun, Shengwei Mei
In this paper the interactions between component failures are quantified and the interaction matrix and interaction network are obtained. The quantified interactions can capture th…