Time Step variability while qrt=1

[PandaRP01]

Dear Dr. Cui

While running a simulation, I was printing time through pert file, I observed unexpected time step printing.
simulation config

ssPV.TDS.config.tstep = 1
ssPV.TDS.config.shrinkt = 1
ssPV.TDS.config.check_conn= 1
ssPV.TDS.config.qrt = 1
ssPV.TDS.config.tf =30
ssPV.TDS.run()

#printing massage

0.0
1.0
0.9
0.81
0.7290000000000001
0.6561000000000001
0.5904900000000002
0.5314410000000002
0.7971615000000003
1.0495959750000003
1.2894087262500005
1.5172308399375005
1.7336618479406256
1.971735956744063
2.1979063601073285
2.446693803806921
2.6830418753215333
2.9430247539876073
3.1900084887203777
3.4616905969264247
3.7197885997221696
3.964981702378127
4.23469411529968
4.4909209075751555
4.734336360236857
5.002093358164729
5.256462506196208
5.536268569030834
5.802084328723729
6.054609300431979
6.294508023554816
6.558396618989938
6.809090784653303
7.084854366883005
7.3468297700012215
7.595706402963527
7.869470699222064
8.129546780667674
8.376619058041003
8.648398563151666
8.906589093006795
9.151870096369167
9.421679200067777
9.677997848581455
9.959948361946502
10.227801349643297
10.482261687955251
10.762168060098402
11.028079113634394
11.280694614493587
11.5585716654387
11.822554863836558
12.073338902314523
12.349201344640283
12.611270664849757
12.860236519048756
13.134098958667655
13.39426827630561
13.641429128061667
13.913306064993328
14.171589155078408
14.416958090659232
14.68686391979814
14.943274457480102
15.225326048930262
15.493275060807912
15.74782662209168
15.989650605311258
16.255656986852795
16.508363049317257
16.786339718028163
17.050417553303525
17.301291496815118
17.57725283467787
17.839416105647487
18.088471213068622
18.36243183123187
18.622694418486955
18.869943876379285
19.14191828006085
19.400293963558337
19.64575086288095
19.91575345213582
20.17225591192795
20.454408617699293
20.722453688182068
20.977096505140704
21.257203603795205
21.52330534751698
21.776102004052667
22.05417832624192
22.318350832321713
22.569314713097516
22.845374981950897
23.10763223736161
23.35677663000179
23.630835461905985
23.89119135221497
24.13852944800851
24.4106013533814
24.669069663485644
24.914614558084676
25.184713942143613
25.441308356999603
25.723562213341193
25.9917033768657
26.246437482213985
26.526644998097098
26.792842138186053
27.04572942127056
27.323905432663523
27.588172643486836
27.839226493768983
28.115385729079343
28.377737002624187
28.626970712491786
28.90112779334615
29.16157702015779
29.40900378562885
29.68117322764702
Simulation to t=30.00 sec completed in 31.3952 seconds.
29.939734197564277
30.0
True

As the time step is 1 second and it is in qrt=1. I was expecting it should be around 0 , 1, 2, 3, 4, 5..
Could you suggest why it is happening or anything I would have to change in the config file to get actual time step?

[cuihantao]

You have shrinkt= 1, which means the step size will be adjusted adaptively when nonconvergence is detected. A step size of t=1 is too large for the electromechanical models.

ANDES cannot guarantee the step size at the set step size, because some disturbances will require smaller step sizes for network equations to solve. Also, in the proximity of the disturbances, two additional steps (i.e., before and after) are inserted to obtain accurate states.

Also, this backtracking does not look right to me. You probably printed more than the timesteps:

0.0
1.0
0.9
0.81
0.7290000000000001
0.6561000000000001
0.5904900000000002
0.5314410000000002
0.7971615000000003

[PandaRP01]

Dear Dr. Cui

Thank you for the response.

Regards
Rakesh