Notice of RetractionOnline estimation of short circuit ratio for HVDC system

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

Based on the Thevenin equivalent circuit, this paper proposes a method utilizing the covariance characteristic of random vectors to calculate the Thevenin equivalent parameters to obtain short circuit ratio. In order to avoid the parameters drift problem, calculate the average and deviation of the measurement data of the electrical variables of ac side, utilize fluctuations method to estimate the phase angle of voltage, utilize the covariance characteristic of random vectors to simplify the mathematical expression of the Thevenin equivalent impedance, and adopt sliding data window to do an online calculation of the impedance. To obtain real-time short circuit ratio, the short circuit capacity of ac system can be calculated by using the impedance, therefore online estimation of SCR for HVDC system can be achieved. Based on the analyzed results of Deyang-Baoji ±500kV HVDC system, it demonstrates the proposed method is real-time and the result is accuracy.