Notice: Undefined variable: test in F:\Users\pe2018\WWW\class\engine.php on line 180 Notice: Undefined variable: test in F:\Users\pe2018\WWW\class\engine.php on line 182 Forecasting in Electric Power Engineering PE 2018
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Marciniak L., Piątek M. return

The influence of the network asymmetry on the settings and sensitivity of an earth fault protection using higher harmonics

Detection of high resistance earth faults in medium voltage networks is an important problem due to ineffectiveness of traditional earth fault protections. Such short circuits can be detected by the criterion of reactive power of higher harmonics of zero sequence current and voltage. The main problem in this is determining the power setting value in the protection, which depends on asymmetry of phase-to-earth capacitances and higher harmonics in supply voltages, which are generated by non-linear loads. The intensive tests of the asymmetry of zero sequence currents and voltages for harmonics and their reactive power have been carried out in 15 kV compensated network as a function of all relevant parameters, i.e.: maximum capacitance deviation of the network and protected line, percentage content of harmonics in supply voltages, capacitive current of the network and the line. It has been shown that zero sequence voltage and current for the third harmonic are the best suited for practical use, since the reactive power of asymmetry of these components is the smallest among the considered harmonics and the protection sensitivity will be the highest.

Inserted: 2018-05-02 13:55:21
Modified: 2019-03-27 16:37:49

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