STATCOM (static synchronous compensator) as a shunt-link flexible AC transmission system(FACTS) controller has shown extensive feasibility in terms of cost-effectiveness in a wide range of problem solving abilities from transmission to distribution levels. Advances in power electronic technologies such as Voltage Source Converter (VSC) improves the reliability and functionality of power electronic based controllers hence resulting in increased applications of STATCOM. In this paper, design and implementation of a Distribution type, Voltage Source Converter (VSC) based static synchronous compensator (DSTATCOM) has been carried out. It presents the enhancement of power quality problems, such as voltage sag and swell using Distribution Static Compensator (D-STATCOM) in distribution system. The model is based on Sinusoidal Pulse Width Modulation (SPWM) technique. The control of the Voltage Source Converter (VSC) is done with the help of SPWM.
The main focus of this paper is to compensate voltage sag and swell in a distribution system. To solve this problem custom power devices are used such as Fixed Compensators (FC, FR), Synchronous Condenser, SVC, SSSC, STATCOM etc. Among these devices Distribution STATCOM (DSTATCOM) is the most efficient and effective modern custom power device used in power distribution networks. DSTATCOM injects a current into the system to mitigate the voltage sag and swell. The work had been carried out in MATLAB environment using Simulink and SIM power system tool boxes. The proposed D-STATCOM model is very effective to enhance the power quality of an isolated distribution system feeding power to crucial equipment in remote areas. The simulations were performed and results were found to be satisfactory using MATLAB/SIMULINK.
- Facts Controllers
- Voltage Source Converter
- Total Harmonic Distortions
Fig.1 Schematic diagram of D-STATCOM
EXPECTED SIMULATION RESULTS:
Fig.2 Three Phase to Ground -Voltage at Load Point is 0.6600 p.u
Fig.3 Double Line to Ground- Voltage at Load Point is 0.7070 p.u
Fig.4 Line to Line- Voltage at Load Point is 0.7585
Fig.5 Single Line to Ground- Voltage at Load Point is 0.8257
Fig.6 The waveforms shows THD (41.31%) results of fixed load and variable inductive load.
Fig.7 The wave forms shows THD (21.28%) results of fixed load and variable capacitive load
Fig.8 Three Phase to Ground-Voltage at Load Point is 0.9367 p.u
Fig.9 Double Line to Ground- Voltage at Load Point is0.9800 p.u
Fig.10 Line to Line- Voltage at Load Point is 1.068
Fig.11 Single Line to Ground – Voltage at Load Point is 0.9837
Fig.12 The waveform for pure inductive,capacitive loads with statcom
Fig.13 The waveform for without filter THD results 41.31%
Fig.14 The above waveform for with filter THD results 1.11%
The simulation results show that the voltage sags can be mitigate by inserting D-STATCOM to the distribution system. By adding LCL Passive filter to D-STATCOM, the THD reduced. The power factors also increase close to unity. Thus, it can be concluded that by adding DSTATCOM with LCL filter the power quality is improved.
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