Page 39 - IJEEE-2023-Vol19-ISSUE-1
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Basim T. Kadhem                                                                                                                            | 35

                          a) Without controller.                      This 14th reduced order LQG/LTR controller is capable of
                                                                 efficiently dampening all SSR modes at varying amounts of
               b) With full order controller for 29th            series compensation, ranging from 30% to 90%. Rotor angle
                                                                 oscillations, level compensation, and SVC susceptibility were
                c) With reduce order controller to 3rd.          presented in Fig. 15 for three different levels of level
                                                                 compensation.
               d) With reduce order controller to 14th.
  Fig. 14: (1). Rotor angle oscillations, (2). Terminal voltage        2
generator, (3). Level compensation, and (4). SVC susceptance.
                                                                 1.8
                    At three phase short circuit.
                                                                 1.6                                           Dg(2)  Dg(3)

                                                                 1.4

                                                                 1.2 Dg(1)

                                                                   1
                                                                                                      Level compensation(3)

                                                                 0.8 Level compensation(2)

                                                                 0.6

                                                                 0.4 Level compensation(1)

                                                                 0.2 SVC susceptance (3)  SVC susceptance (2)
                                                                   0

                                                                 -0.2                                                 SVC susceptance (1)  10
                                                                       0 2.5 5                                                 7.5

                                                                 Fig.15: System response for three phase short circuit 0.1sec at
                                                                 time t=1sec, with reduce order controller to 14th. Rotor angle

                                                                   oscillations, level compensation, and SVC susceptance for
                                                                                three cases according the following
                                                                                  1-for level compensation = 50%
                                                                                  2- for level compensation = 60%
                                                                                  3- for level compensation = 70%

                                                                                           VII. CONCLUSION

                                                                      In order to dampen subsynchronous resonance
                                                                 oscillations, this study outlines a design process for LQG
                                                                 control of VSC, TCSC, and excitation system. One feedback
                                                                 signal (angular speed deviation) and three control signals, each
                                                                 of which is capable of dampening all undesired oscillations,
                                                                 are used to create a robust control utilizing LQG. This setup
                                                                 uses a quantity that can be measured, making it both easy to
                                                                 use and practical. The 14th order version of the full-order
                                                                 robust controller displayed the same high performance.

                                                                                               APPENDIX I

                                                                 Generator data
                                                                 Xd=1.869, Xq=1.869, Xs=0.194, X'd=0.3016, X''d=0.2337,
                                                                 X'q=0.2337, Ra=0.0022, Rr=904e-6, R1d=3.688e-3,
                                                                 R1q=0.00108,
                                                                 Transformer data
                                                                 Rt=0.005, Xt=0.12.
                                                                 Excitation system data
                                                                 Kou=-15, K1u=-7.2, Tou=0.09, T1u=0.039, Tp=0.07,
                                                                 Transmission line data
                                                                 RL=0.025, XL=0.5
                                                                 SVC data
                                                                 Kour=-15, K1ur=-10, Tour=0.09, T1ur=0.39, Tpr=0.001,
                                                                 BLo=-0.01, BLmax=-0.0001, BLmin=-0.25;
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