823 / 2019-04-29 20:09:24

An new solution of adaptive distance protection

Adaptive impedance protection; Transient tolerance; steady-state tolerance; Overreach; Underreach

It is a big challenge for impedance protection to be applied on a very short line, the overreach could be easily occurred due to the comparatively high tolerance, this headache issue confused many power system users when they are required to provide the setting of underreach impedance protection. To reduce the workload of setting engineers, and improve system reliability caused by overreach, this paper proposes a solution of adaptive impedance protection. In this paper the factors that affect the accuracy of steady-state impedance protection and transient impedance protection are analyzed. Finally, based on the characteristics of the tolerance of steady-state impedance measurement and transient impedance measurement, a new solution is proposed by automatically adjusting the range of the underreach instantaneous distance protection and the debounce time for confirmation, which solved the problem how long can it be for a line that the impedance protection could be put into service. In this paper, RTDS simulation is carried out for the system with different voltage levels to simulate various fault positions and fault impedances. The test results prove the effectiveness of this method, which can reliably avoid the overreach for underreach impedance protection.