This simulator feeds a dual-input critical rack from two complete electrical trains, each made of switchgear, a UPS and a panel and each sized for the entire load. You can disable a whole train and compare the mission survival of one train against the pair.
• A 3D train A and train B, each with switchgear, UPS and panel, separated A and B bus routes and a dual-input critical rack. • Sliders for mission duration (100-3000 h) and component failure rate (0.05-2 per 1000 h), switches to disable complete train A or train B and a motion-marker toggle. • Four live readouts: one three-block train survival, dual-train mission survival, available full-load trains and whether the load is energized. • Two presets: A isolated (B alone supplies the full load) and Both trains isolated (the rack loses both feeds).
Each train has three identical series blocks, so the train survives with R_train = exp(-3 lambda T). Two fully independent trains give R_2N = 1 - (1 - R_train)^2. Because each train is sized for the whole load, any single train can be lost, or taken out for maintenance, without interrupting the dual-input load, whereas N+1 installs only a single spare unit.
The model assumes six independent exponential components, an ideal dual-input load, and no cross-tie, shared utility, transfer delay, maintenance or common-mode dependency. 2N does not automatically remove shared causes such as a common utility, fire zone or control system, so physical and functional dependencies must be examined separately.
The complete required capacity. Each of the two trains can carry the entire load on its own, so either one can fail or be isolated.
No. Shared utilities, physical locations or control systems can still defeat both trains at once, and this model excludes those dependencies.
R_train = exp(-3 lambda T) for three series blocks, then R_2N = 1 - (1 - R_train)^2 for two independent trains.
It does not model cross-ties, a shared utility, transfer delay, maintenance activity or common-mode dependencies between the trains.