To save space, we merely quote the independent variables used during the random sampling of the pre-disturbance states : topology (single or double line (400kV or 225kV) or transformer outages); load level (including randomization of individual HV load distribution, power factors, compensation and voltage sensitivities); regional unit commitment (with variable active power generation levels in Plant 1); reactive support (synchronous condenser; EHV and HV shunt compensation; gas turbines) and secondary voltage control set-points.
Figure 5: Brittany region one-line diagram (225kV + 400kV)
A total of 13,513 random variants were drawn to yield 5000 pre-disturbance states. (The remaining 8,513 variants led to power flow computation divergence or non-convergence.) For each state about 200 attributes were computed, corresponding to key variables such as topological indicators, important EHV power flows, 400kV voltages, numbers of units in operation in power plants, total load demand, reactive shunt compensation reserves in the study region, and reactive generation reserves.
All in all 26 different contingencies were considered in this broad study, corresponding to synchronous condenser, generator or line tripping and busbar faults. Thus, in addition to the pre-contingency LPM, the corresponding 26 post-contingency LPMs were computed for each operating state, yielding a total number of 135,000 LPM computations!