symbolic dynamic models for highly varying power system loads

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3.5 Test results
ST-A01: The aim of this test is to identify the best index out of five indices
proposed in Chapter 2. In signal 2, δ was varied from 0 to 90 degrees to check the CSI in
each case. Theoretically as phase angle increases, the number of common words in two
signals should decrease, and correspondingly there should be a regular increasing or
decreasing tendency of CSIs. When the program was run to obtain the numerical values,
it was observed that all the CSIs except CSI 3 had the decreasing tendency as the phase
angle increased. For phase angle zero, i.e. when both the signals are same, CSI 1 and CSI 3
has the value 0.5 and 0 respectively. This indicates that CSI 1 has the maximum value of
0.5 and CSI 3 has the minimum value of 0 and these values are for two identical signals. In
all the other indices these maximum values were some arbitrary numbers. Moreover
when all the indices were plotted against phase angle, CSI 1 was found to be the best.
Therefore the other CSIs were discarded for any future analysis.
Numerical results of the test have been tabulated in Table 3.3.
ST-B01: In this test it is obvious that as θ increases signal 2 will rise higher and
higher, as in Figure (3.1). Therefore the common points on the two signals will lie only in
the initial period when θ is small. Comparing the two signals CSI was found to be 0.0462
which is well below 0.5000 and shows a very few common points.