Structural Analysis of the Differential-algebraic Equation System formulated with the Extended Node Method Analytical Properties of differential-algebraic Equations arising in Circuit Simulation using the Extended Nodal Approach

Differential-algebraic systems of equations (DAE) arise in electric network modelling. The resulting index of DAE restricts the selection of possible solution methods. The index of the DAE can be determined beforehand of the simulation for certain methods of circuit simulations under special requirements on the device models and the topology. The results of these methods are transferred to the extended nodal approach used in electrical power engineering. For this purpose, a structural analysis of the DAE is carried out, formulated with the extended nodal approach. This results in a Hessenberg index-1 system in case of using classical element models and having common electric power system topologies.