Research And Implementation Of STATCOM In Distribution System Based On DSP

As an important member of the flexible AC transmission system, static synchronouscompensator(STATCOM) can compensate reactive power of power grid quickly. Due to itsexcellent regulation performance and strong compensation ability, STATCOM has became aresearch hotspot in reactive power compensation device. Static synchronous compensator isinstalled at the proper position of the power system can effectively improve the thephenomenon of power quality decline because of the large impact load brought into powergrid. At present, the studies both home and abroad focue at high voltage and large capacitySTATCOM device. This thesis was aimed at the problem of insufficient reactive powercompensation in low voltage distribution network in China, then studied the technology ofsmall capacity STATCOM. The main work was completed which is that studied the relatedcontrol technology and designed the hardware circuit.At first, this thesis introduced the background and significance of reactive powercompensation, the development and research status at home and abroad of reactive powercompensation device. Detailed the working principle,the main circuit structure and workingcharacteristics of STATCOM.Secondly, briefly analyzed two basic detection methods of thethree phase instantaneous reactive power theory, then put forward one detection method takenin this paper based on the improvement of the instantaneous reactive power theory which isd qmethod. The advantage of using this method is that it can still accurately detect systemreactive current at the distortion status of grid voltage. Then elaborated the control strategy ofSTATCOM. Analysis and balanced the advantages and disadvantages of the direct currentcontrol method and the indirect current control method, discussed the triangular wavecomparison method and comparison of hysteresis current control method which is theuniversal application of the direct current control method.Direct current control methodsuitable for the situation of small power, which is very suitable for small and medium capacitySTATCOM devices due to its fast response, small tracking error, effectively suppress theharmonic characteristics. Next, using MATLAB/Simulink analysis tool to modeling andsimulation for STATCOM. Simulation studied at three siguation that the ideal grid voltage, thedistortion of the voltage and the voltage sag, respectively, the simulation results show that STATCOM had a good compensation affect in the grid voltage distortion or voltage drop.Verified the feasibility of reactive power detection and control method adopted in this thesis.Finally, this thesis designed the hardware circuit of the control system each part ofSTATCOM by taking TMS320F2812as the main controller, which including the main circuit,the synchronous circuit, the current detection circuit and the PWM driving circuit, besidesgiven the various modules of software process.