The Study On The Line Protection For Shunt Compensated Lines Based HHT

Static synchronous compensator(STATCOM)is important member of FACTS and it has been more and more applied in engineering practice. Based on the analysis of the principle of STATCOM, this paper establishes a line model with STATCOM in its mid-point by PSCAD/EMTDC simulation software, focuses on impacts of the harmonics generated by lines with STATCOM and the impacts to the line protection. Because adding STATCOM will cause fault action of the distance protection, it proposes a new method of line distance protection which is suitable to the shunt-compensation line, and it proves the correctness of the new method by simulation. The paper proposes an improving Hilbert–Huang (HHT) algorithm to enhance the validity and accuracy of the traditional HHT algorithm. It studies the spectrum characters of in-zone and out-zone fault in the simulation model. Base on the differences of the spectrum between in-zone and out-zone fault, it proposes a new method of transient protection, the simulation results prove that this new method can effectively district in-zone and out-zone fault in all fault situation.