Nt1310 Unit 5

This section discusses the results are obtained from Matlab/Simulink software. The simulation consequences are obtained in two scenarios with taking in account the variation of wind generation. The first scenario examines the test system with SSSC, set on Line 1 and between the buses 1 and 2, but without power oscillation damping (POD) role. This exam is conducted through applying three-phase fault at midpoint of Line 2. The fault is applied at 1.33 second and it takes 10 cycles to clear the fault by the two breakers at the end of Line 2. When the fault happens, the high currents pass though the lines depending on their impedances to provide the fault what needs. As shown in Fig. 3 and Fig. 4, the power flow in all buses (bus 1 is blue, bus 2 is red, bus 3 is black, and bus 4 is green) would be changed after the circuit breakers resulting in change the configuration of the system. The spike of power flow in this test system at clearing time is caused by the switching of circuit breakers of Line 2 to off-line and

After the Simulink runs, the SSSC-controller will work to damp out the power oscillation damping very quickly in condition of the three-phase fault. The change of Vqref, shown in Fig. 6, forces the SSSC to inject the Vqinj to reach it. Compared with previous scenario, the POD makes the variation between the inductive, capacitive, and disturbance conditions gradually. Also, in Fig. 6. and compared with Fig. 5, the power flow at bus 2 would be damped about %10 due to the role of POD of SSSC. Even SSSC decreases the oscillation of damping but it also participates in delivering some active and reactive power during the first few cycles of changes until the POD takes its function. In Fig. 7 and Fig. 8, the impacts SSSC and its POD would be displayed through the reducing the oscillation of power flow for both active and reactive power. The POD of SSSC checks the Vqref and injects voltage to reduce the variation in power