A New Distance Protection Scheme Based on Improved Virtual Measured Voltage

An Adaptive Protection Scheme for Power Systems Considering the Effects of HVDC Interfaced Distributed Generations

“…To overcome the errors introduced by the fault transition impedance, several improved impedance measurement methods were proposed [1]- [3][11] [12]. In [1], a protection scheme based on improved virtual measured voltage was proposed.…”

“…To overcome the errors introduced by the fault transition impedance, several improved impedance measurement methods were proposed [1]- [3][11] [12]. In [1], a protection scheme based on improved virtual measured voltage was proposed. The main idea of this method was to feedback the voltage of the fault-point, and the virtual measured voltage was proposed by combining the voltage of the faultpoint, local current and the threshold of impedance (Z set ).…”

“…Given that the fault transition resistance can not affect the voltage droop equation, the errors introduced by the fault transition resistance will be eliminated. Compared with [2], the method in [1] and [3] needed to feedback the information of the voltage at fault-point.…”

“…The proposed distance protection scheme only need the local current, voltage and the impedance between the relay to the PCC point (where the distributed generation is connected). Compared with [1] and [2], the proposed method does not need to feedback the information (i.e., voltage and active power) of the fault-point.…”

“…T HE distance protection of high voltage transmission systems is an essential safety measure and plays a vital role to ensure the stability and security of power systems [1]- [5]. In the transmission system of a large-scale power system, the high-voltage long-distance transmission lines are irreplaceable.…”