Investigation On Protection Scheme And Settings During Power System Black-Start

Black-start is an effective measure to restore the power system whenblackout occurs. During black-start, the special switching manipulation and modeof operation in power system have a great effect on the security and dependabilityof protective system. By analyzing the features of power system black-start, theeffects on various types of protective devices and their action during fault in theprocess of black-start are analyzed. The basic principles of how to arrange theprotective devices are presented. The transmission-line protection scheme withzero-sequence current protection and distance protection as the main protection isproposed for the radial system with a single power source during the initial stageof black-start. Based on the analysis of zero-sequence current distribution of earthfaults under different operating conditions, a method to determine the settings ofthe zero-sequence current protection is also presented. A computer program forsetting calculation is developed to meet the needs of black-start.