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Arc grounding over-voltage is one of the worst over-voltages in the neutral isolated system. It is an important factor to be considered when selecting neutral ground mode. At present, system simulation is the main method for the study of the arc grounding over-voltage. Arc extinguish and re-ignition is simulated by controlling the switch on or off. However, the switch opening or closing need to be...
The impedance algorithm in distance protection for high voltage (HV) and extra high voltage (EHV) lines, although neglecting the influence of shunt capacitance, is able to produce satisfactory performance. However, the accuracy of the algorithm is significantly reduced when applying to ultra high voltage (UHV) lines due to the larger P.U. line shunt capacitance and longer transmission radius. Therefore,...
Modeling study provides a more effective and flexible way for research of high impedance fault (HIF) detection. An accurate model which can reveal most features of HIF is very important. In this paper, based on extensive investigation into documented test results, a set of most common and agreeable features of HIF has been summarized: the arc features, the non-linearity, the time-varied resistance...
This paper presents a novel integrated protection scheme for distribution lines based on Transient Polarity Comparison technique. In the proposed scheme, the specially designed interface units are installed at each substation and connected to the CTs on every line associated to the busbar. The unit converts the measured signals to optical format and sends to the central protection relay through a...
The precision of impedance fault location algorithm is deteriorated by the extremely large shunt capacitance in UHV line. And the traditional improved ways are all invalid caused by the nonlinearity of measurement impedance in relay and the frequent variations of operation modes in UHV system. In response to this question, a novel impedance fault location algorithm is proposed for phase faults. It...
The principles of the equivalent circuit principle and the magnetic property theory are not affected by the inrush current and over-excitation, which enable protection to act rapidly and reliably and implement ideas different from differential protection. However, the leakage inductance and resistance of each winding are required as priori parameters. At present, there is no accurate measurement method...
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