1. Phase 2 Composite Load Model Impact – RS Discussion From Draft Preliminary white paper dated 10/20/11

2. Where we are at Simulations now consider angular stability between generators. Voltage dip to approximate acceptable impact to load busses given static loads. MVWG recommending to consider load behavior in Voltage Dip Criteria (FIDVR). Composite load modeling effort under way, this applies to Phase 2 of that effort.

3. Voltage Swing versus FIDVR

4. Main Objectives TPL-001-2 does not permit non- consequential load loss for range of contingencies. Minimize risk of disturbance cascading due to unexpected control or protection action. Ensure no unsafe over-voltages in the transmission and distribution systems due to loss of load during the event.

5. Modeling Challenges Phase 2 – Residential air conditioner stalling. Fault details – Point-on-wave dependence, 1-phase faults can result in FIDVR, simulation models positive sequence equivalent. Uncertainties in load model composition

6. Power System Issues Power plant ride-thru Power plant reactive limits (OEL, UEL) Static VAR systems (over/under voltage control) HVDC system behavior Switched shunt caps and reactors (voltage supervision) Protective relaying (zone protection)

7. Basic Proposal Define voltage dip as margin above tolerance curves, ITIC, gen ride-thru. Measure at bus where model is represented, e.g. load bus, generator bus. Consider impact to zone 2 relays in studies.