Assessment of Power Quality Adverse Phenomena in Power Systems Using Frequency Dependent Network Equivalent and Companion-Circuit Analysis

This application describe the comparative analysis of two time-domain (TD) methods for power systems analysis under faulty conditions. Compared methods consist of frequency dependent network equivalent (FDNE) and companion-circuit analysis (CCA). The FDNE obtains a reduction of the system through equivalents of a large part of the network, while that the CCA is represented using discrete Norton equivalent models (DNEM) through a nodal analysis. Both methods use trapezoidal rule (TR) numerical integration. The solution of FDNE is obtained by brute force (BF) and CCA uses a sparse matrix factorization: LU decomposition, FDNE TR -BF and CCA TR -LU, respectively. These methods show to be alternatives for power system modeling. Performance can be taken into consideration and some advantages of each other can be demonstrated. The methods are applied to the modified 118-busbar power system for the analysis of power quality disturbances, such as voltage sags/swells. The performance is compared in terms of efficiency, while that in terms of accuracy is carried out through direct comparison against to PSCAD/EMTDC® simulator response.