ABSTRACT: This paper presents the performance and comparative analysis of Static Synchronous Compensator (STATCOM) based on 6, 12 and 48-pulse VSC configuration. STATCOM is implemented for regulation of the voltage at the Point of Common Coupling (PCC) bus which has time-variable loads. The dq decoupled current control strategy is used for implementation of STATCOM, where modulation index M and phase angle ø are varied for achieving voltage regulation at the PCC bus. The 6, 12 and 48-pulse configurations are compared and analyzed on the basis of Total Harmonic Distortion (THD) and time response parameters such as rise time, maximum overshoot and settling time. The simulation of various configurations of STATCOM is carried out using power system block-set in MATLAB/Simulink platform.
- Decoupled current control system
- Voltage Sourced Converter
- Total Harmonic Distortion
Fig.1:Single line diagram of STATCOM.
EXPECTED SIMULATION RESULTS:
Fig. 2: PCC bus voltage-VM for 6, 12 and 48 pulse STATCOM respectively.
Fig. 3: q-axis STATCOM current-ishq for PI controller of 6, 12 and 48 pulse STATCOM respectively.
Fig. 4: d-axis STATCOM current-ishd for PI controller of 6, 12 and 48 pulse STATCOM respectively.
a: Dc capacitor voltage-Vdc
b: Active power of loads-PL
c: Reactive power-Qstat
d: Active power-Pstat
Fig. 5: Vdc, PL, Qstat and Pstat for 48 pulse STATCOM respectively.
In this paper, for voltage regulation and dynamic power flow control a 48-pulse ±100 MVA two-level GTO STATCOM has been modeled and simulated using decoupled current control strategy. By varying the modulation index (M) and phase angle (ɸ) between PCC bus voltage and STATCOM voltage, voltage regulation at the PCC bus is achieved. The THD and various time response parameters of 6, 12 and 48 pulse STATCOM are compared. The results show that THD of output voltage of 48 pulse STATCOM is less than 5%, which satisfies the IEEE 519 standard. Hence, there is no need of active filter. Also, 48 pulse STATCOM has better transient response as compared to 6, 12 pulse STATCOM.
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