Research On Detection Method Of STATCOM Compensation Reference Current

Static synchronous compensator(STATCOM) as a new generation of reactive power compensation device with good performance and development prospects, has been widely used at home and abroad. STATCOM compensation reference current detection technology is an important prerequisite for it to compensate reactive power、 restrain harmonic and compensate the imbalance. Therefore, this paper study the traditional STATCOM compensation reference current method based on instantaneous reactive power theory, aims to improve the STATCOM compensation reference current detection method for the accuracy and real-tine performance of detect method.Firstly, the basic structure and working principle of STATCOM is studied deeply, and pointed out the definition of STATCOM compensation reference current, which lays a theoretical foundation for the study of STATCOM compensation reference current detection method.Secondly, the principle of vector coordinate transformation is analyzed. Based on this, the principle of the two classical methods of STATCOM compensation reference current detection p-q and ip-iq detection is further studied. The limitations of the traditional detection methods are discussed, and the improvement of the STATCOM compensation instruction is provided.And then, for the work limitation of cross port STATCOM, a new method for the detection of the cross port STATCOM compensation is proposed. The voltage information is obtained from the point of detection and compensation of the injection point, and the phase compensation angle and the PR controller are improved from two aspects of the voltage phase and amplitude respectively to achieve the purpose of reducing the detection error. The simulation analysis shows that the method can improve the accuracy and response speed of detection in the cross port STATCOM conditions.Finally, for the work limitation of the traditional phase-locked loop, the soft phase locked loop is improved by the method of positive and negative sequence separation, which makes the modified soft phase lock loop has a more superior lock phase property. In order to improve the ability of phase adjustment, a phase modulation module is proposed, which can adjust the feedback operation principle in real time. The improved soft phase lock loop and the phase modulation module are introduced into the traditional ip-iq detection method, and an improved detection method for STATCOM compensating reference current is obtained. Simulation and experimental analysis shows that the proposed method can overcome the detection error caused by the phase difference and greatly improve the accuracy of the compensation instruction current detection.