This file describes in detail how the standard IEEE 118 test data was slightly modified in order to perform the studies described in detail in reference [1]. This paper also used the Point of Collapse power flow [2], which requires the creation of a "k" file. The information in this writeup should assist users in the creation of a proper k-file. We have also included a sample k-file in this directory. The intent of this file is to permit anyone seriouly interested in replicating the results in [1] to do so. The studies performed in [1] ignore all line flow limits and all generation active power limits, and concentrate instead on the determination of maximum loadability based on voltage collapse considerations. Reactive power limits. The Q-limits under three operating conditions are described below. The first column refers to those Q-limits that are enforced during an ordinary base case solution of the 118 bus test case "as given." The second column corresponds to a list of those Q-limits that are enforced after the initial load expansion described in [1]. The third set corresponds to those limits in effect at the maximum loadability point. Case as given Loads expanded Point of Collapse Bus Limit Bus Limit Bus Limit 19 Qmin 1 Qmax 1 Qmax 32 Qmin 12 Qmax 6 Qmax 34 Qmin 15 Qmax 12 Qmax 92 Qmin 18 Qmax 15 Qmax 103 Qmax 34 Qmax 18 Qmax 105 Qmin 36 Qmax 19 Qmax 55 Qmax 32 Qmax 56 Qmax 34 Qmax 62 Qmax 36 Qmax 70 Qmax 49 Qmax 74 Qmax 55 Qmax 76 Qmax 56 Qmax 77 Qmax 59 Qmax 85 Qmax 62 Qmax 92 Qmax 70 Qmax 103 Qmax 74 Qmax 104 Qmax 76 Qmax 110 Qmax 77 Qmax 6 Qmax 85 Qmax 19 Qmax 92 Qmax 49 Qmax 103 Qmax 100 Qmax 104 Qmax 105 Qmax 105 Qmax 110 Qmax 8 Qmax 100 Qmax 80 Qmax 65 Qmax 10 Qmax 46 Qmax The Qmax limit of Generator 4 has been increased from the given value to avoid an immediate instability. Area interchanges: The modified case considers inter-area power dispatch, as follows: Main Area to Area 2 -> 102.90 MW Main Area to Area 3 -> 143.80 MW Main Area Total -> 246.70 MW Assumption about load variaton: Bus 1, delta P-> 0.0930946 delta Q-> 0.0492854 Bus 2, delta P-> 0.0365077 delta Q-> 0.0164285 Bus 3, delta P-> 0.07119 delta Q-> 0.0182538 Bus 4, delta P-> 0.0547615 delta Q-> 0.0219046 Bus 6, delta P-> 0.09492 delta Q-> 0.0401584 Bus 7, delta P-> 0.0346823 delta Q-> 0.00365077 Bus 11, delta P-> 0.127777 delta Q-> 0.0419838 Bus 12, delta P-> 0.085793 delta Q-> 0.0182538 Bus 13, delta P-> 0.062063 delta Q-> 0.0292061 Bus 14, delta P-> 0.0255554 delta Q-> 0.00182538 Bus 15, delta P-> 0.164285 delta Q-> 0.0547615 Bus 16, delta P-> 0.0456346 delta Q-> 0.0182538 Bus 17, delta P-> 0.0200792 delta Q-> 0.00547615 Bus 18, delta P-> 0.109523 delta Q-> 0.062063 Bus 19, delta P-> 0.0821423 delta Q-> 0.0456346 Bus 20, delta P-> 0.0328569 delta Q-> 0.00547615 Bus 21, delta P-> 0.0255554 delta Q-> 0.0146031 Bus 22, delta P-> 0.0182538 delta Q-> 0.00912692 Bus 23, delta P-> 0.0127777 delta Q-> 0.00547615 Bus 27, delta P-> 0.113174 delta Q-> 0.02373 Bus 28, delta P-> 0.0310315 delta Q-> 0.0127777 Bus 29, delta P-> 0.0438092 delta Q-> 0.00730154 Bus 31, delta P-> 0.0784915 delta Q-> 0.0492854 Bus 32, delta P-> 0.107698 delta Q-> 0.0419838 Bus 33, delta P-> 0.0419838 delta Q-> 0.0164285 Bus 34, delta P-> 0.107698 delta Q-> 0.04746 Bus 35, delta P-> 0.0602377 delta Q-> 0.0164285 Bus 36, delta P-> 0.0565869 delta Q-> 0.0310315 Bus 39, delta P-> 0.0492854 delta Q-> 0.0200792 Bus 40, delta P-> 0.0365077 delta Q-> 0.0419838 Bus 41, delta P-> 0.0675392 delta Q-> 0.0182538 Bus 42, delta P-> 0.0675392 delta Q-> 0.0419838 Bus 43, delta P-> 0.0328569 delta Q-> 0.0127777 Bus 44, delta P-> 0.0292061 delta Q-> 0.0146031 Bus 45, delta P-> 0.0967453 delta Q-> 0.0401584 Bus 46, delta P-> 0.0511107 delta Q-> 0.0182538 Bus 48, delta P-> 0.0365077 delta Q-> 0.0200792 Bus 49, delta P-> 0.158808 delta Q-> 0.0547615 Bus 50, delta P-> 0.0310315 delta Q-> 0.00730154 Bus 51, delta P-> 0.0310315 delta Q-> 0.0146031 Bus 52, delta P-> 0.0328569 delta Q-> 0.00912692 Bus 53, delta P-> 0.0419838 delta Q-> 0.0200792 Bus 54, delta P-> 0.206268 delta Q-> 0.0584123 Bus 55, delta P-> 0.114999 delta Q-> 0.0401584 Bus 56, delta P-> 0.153332 delta Q-> 0.0328569 Bus 57, delta P-> 0.0219046 delta Q-> 0.00547615 Bus 58, delta P-> 0.0219046 delta Q-> 0.00547615 Bus 59, delta P-> 0.505631 delta Q-> 0.206268 Bus 60, delta P-> 0.14238 delta Q-> 0.00547615 Bus 62, delta P-> 0.140555 delta Q-> 0.0255554 Bus 66, delta P-> 0.07119 delta Q-> 0.0328569 Bus 67, delta P-> 0.0511107 delta Q-> 0.0127777 Bus 70, delta P-> 0.120475 delta Q-> 0.0365077 Bus 74, delta P-> 0.124126 delta Q-> 0.0492854 Bus 75, delta P-> 0.085793 delta Q-> 0.0200792 Bus 76, delta P-> 0.124126 delta Q-> 0.0657138 Bus 77, delta P-> 0.111348 delta Q-> 0.0511107 Bus 78, delta P-> 0.129602 delta Q-> 0.04746 Bus 79, delta P-> 0.07119 delta Q-> 0.0584123 Bus 80, delta P-> 0.2373 delta Q-> 0.04746 Bus 82, delta P-> 0.0985707 delta Q-> 0.0492854 Bus 83, delta P-> 0.0365077 delta Q-> 0.0182538 Bus 84, delta P-> 0.0200792 delta Q-> 0.0127777 Bus 85, delta P-> 0.0438092 delta Q-> 0.0273808 Bus 86, delta P-> 0.0383331 delta Q-> 0.0182538 Bus 88, delta P-> 0.0876184 delta Q-> 0.0182538 Bus 90, delta P-> 0.14238 delta Q-> 0.0766661 Bus 92, delta P-> 0.11865 delta Q-> 0.0182538 Bus 93, delta P-> 0.0219046 delta Q-> 0.0127777 Bus 94, delta P-> 0.0547615 delta Q-> 0.0292061 Bus 95, delta P-> 0.0766661 delta Q-> 0.0565869 Bus 96, delta P-> 0.0693646 delta Q-> 0.0273808 Bus 97, delta P-> 0.0273808 delta Q-> 0.0164285 Bus 98, delta P-> 0.062063 delta Q-> 0.0146031 Bus 100, delta P-> 0.0675392 delta Q-> 0.0328569 Bus 101, delta P-> 0.0401584 delta Q-> 0.0273808 Bus 102, delta P-> 0.00912692 delta Q-> 0.00547615 Bus 103, delta P-> 0.0419838 delta Q-> 0.0292061 Bus 104, delta P-> 0.0693646 delta Q-> 0.0456346 Bus 105, delta P-> 0.0565869 delta Q-> 0.04746 Bus 106, delta P-> 0.0784915 delta Q-> 0.0292061 Bus 107, delta P-> 0.0511107 delta Q-> 0.0219046 Bus 108, delta P-> 0.00365077 delta Q-> 0.00182538 Bus 109, delta P-> 0.0146031 delta Q-> 0.00547615 Bus 110, delta P-> 0.07119 delta Q-> 0.0547615 Bus 112, delta P-> 0.0456346 delta Q-> 0.02373 Bus 114, delta P-> 0.0146031 delta Q-> 0.00547615 Bus 115, delta P-> 0.0401584 delta Q-> 0.0127777 Bus 117, delta P-> 0.0365077 delta Q-> 0.0146031 Bus 118, delta P-> 0.0602377 delta Q-> 0.0273808 Generator Participation by Area: As demands increase, generators particiapate in the following proportions: Area 2, Bus 10 -> 0.420954 Area 2, Bus 12 -> 0.0795136 Area 2, Bus 25 -> 0.2058 Area 2, Bus 26 -> 0.293732 Area 1, Bus 46 -> 0.0100903 Area 1, Bus 49 -> 0.108338 Area 1, Bus 54 -> 0.0254913 Area 1, Bus 59 -> 0.0823154 Area 1, Bus 61 -> 0.0849712 Area 1, Bus 65 -> 0.207648 Area 1, Bus 66 -> 0.208179 Area 1, Bus 69 -> 0.272969 Area 3, Bus 80 -> 0.337819 Area 3, Bus 89 -> 0.429887 Area 3, Bus 100 -> 0.17847 Area 3, Bus 103 -> 0.0283287 Area 3, Bus 111 -> 0.0254957 Modification necessary to the standard 118 bus data include: (1) Increase the loading from the initial loading in the 118 bus test system data file to a total load of 5677 MW in direct proportion to load size. While doing this, enforce all reactive power limits. At this loading, there will be no generators at their minimum limit. (2) Remove the Q max limit at bus 4. If this is not done, an immediate instability results just before voltage collapse. (3) Establish an area interchange control as specified above. Other changes are necessary for some of the sensitivity simulations as a result of the need for model changes required by each sensitivity study. For example, to study the effect of load type the load model themselves change. The paper details these changes. References: [1] S. Greene, I. Dobson and F. Alvarado, "Sensitivity of the loading margin to voltage collapse with respect to arbitrary parameters," ECE Report 95-8, Department of Electrical and Computer Engineering, the University of Wisconsin, Madison, Wisconsin, July 1995. [2] C. Canizares, F. Alvarado et al, "Point of Collapse and Continuation Methods for Large AC/DC Systems," IEEE Transactions on Power Systems, Vol. 7, No. 1, Feb 1993, pp. 1-8.