Technical Spot     This part of our web site contains technical discussions, articles and other information of interest to MicroTran users.  Please note that the material in this page is copyrighted and cannot be reproduced or distributed without explicit permission from Microtran Corporation. Factsheet #1. Subsynchronous resonance, case 1. This test case was prepared by an IEEE Subsynchronous Resonance Task Force in 1976, to benchmark computer programs on their ability to simulate subsynchronous resonance phenomena. The case consists of a turbine-generator connected through a step-up transformer to a 500 kV transmission line with series capacitor compensation. The power system at the receiving end is represented by a Thevenin equivalent circuit (infinite bus behind reactance). Subsynchronous torsional vibrations build up after a three-phase fault of 4.5 cycle duration. Click to download Factsheet #2. Subsynchronous resonance, case 2. An IEEE Subsynchronous Resonance Task Force prepared this second benchmark model for computer simulation of subsynchronous resonance in 1985, after the first benchmark model was published in 1977. The case chosen from the two systems consists of a single turbine-generator connected through a step-up transformer to two parallel transmission lines, one of which is series compensated. The power system at the receiving end is represented by a Thevenin equivalent circuit (infinite bus behind impedance). A three-phase fault is applied on the high side of the generator step-up transformer and the fault clearing time is varied from 1 cycle to 4 cycles. The resultant torques vary greatly with the fault clearing time. Click here to download Factsheet #3. Transformer inrush currents. Former ASEA (now ASEA Brown Boveri) made this test case available to CIGRE Working Group 13.05 in 1976, with the permission of the Swedish State Power Board. It shows the transformer inrush currents in a field test performed by the Swedish State Power Board, which were also described in a CIGRE Report in 1968. Click here to download