This paper presents the development of a real-time digital simulator model for the simulation of arbitrary internal faults in synchronous machines. The model is an extension of the embedded phase-domain model of the synchronous machine . To represent a fault, the winding or windings involved in the
fault are considered as a set of split windings [2,3,4,5] with their terminal nodes connected by a suitable fault impedance (or short circuit), which is switched in when the fault is applied. From the machine and winding geometry, values are calculated for the resulting set of mutually coupled inductances for this new
The proposed method takes into account the actual geometry of the slots and the number of turns in each coil and uses an offline procedure to obtain the magneto-motive force (MMF)
distribution due to each winding for a unit injection of current. This MMF along with the air-gap geometry information is used to calculate the flux linkages, and hence the self and mutual inductances of the windings. Thus in contrast with earlier approaches, it is able to calculate the inductances of the machine when the windings are arbitrary distributed.
Since this model is developed for real-time digital simulator, it has the unique feature of being a tool to test the relays designed to protect the synchronous machines from internal faults.
A. B. Dehkordi, A. M. Gole, T. L. Maguire, Presented at IPST 2007, Lyon France, June 3 - 6, 2007, Session 24 Paper No. 90
KEYWORDS: Internal fault, synchronous machine, real-time simulation, electromagnetic transient simulation, winding distribution.