Ground Fault Temporary Overvoltages in MV Networks: Evaluation and Experimental Tests

Cerretti, Alberto; Gatta, Fabio Massimo; Geri, A.; Lauria, S.; Maccioni, M.; Valtorta, Giovanni

doi:10.1109/tpwrd.2012.2192456

Cited by 50 publications

(20 citation statements)

References 11 publications

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“…This is a not uncommon occurrence, as the temporary overvoltages can be substantial: if the network neutral is grounded by means of Petersen coil, also equipped with a parallel high resistance, the Earth-Fault-Factor (EFF) is 1.73 p.u., whereas in networks with ungrounded neutral EFF can attain 2.5-3.5 p.u. [1]. In both cases, the associated switching overvoltages are in the 2.7-4.5 p.u.…”

Section: Introductionmentioning

confidence: 93%

An Equivalent Circuit for the Evaluation of Cross-Country Fault Currents in Medium Voltage (MV) Distribution Networks

et al. 2018

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A Cross-Country Fault (CCF) is the simultaneous occurrence of a couple of Line-to-Ground Faults (LGFs), affecting different phases of same feeder or of two distinct ones, at different fault locations. CCFs are not uncommon in medium voltage (MV) public distribution networks operated with ungrounded or high-impedance neutral: despite the relatively small value of LGF current that is typical of such networks, CCF currents can be comparable to those that are found in Phase-To-Phase Faults, if the affected feeder(s) consists of cables. This occurs because the faulted cables' sheaths/screens provide a continuous, relatively low-impedance metallic return path to the fault currents. An accurate evaluation is in order, since the resulting current magnitudes can overheat sheaths/screens, endangering cable joints and other plastic sheaths. Such evaluation, however, requires the modeling of the whole MV network in the phase domain, simulating cable screens and their connections to the primary and secondary substation earth electrodes by suitable computer programs, such as ATP (which is the acronym for alternative transient program) or EMTP (the acronym for electromagnetic transient program), with substantial input data being involved. This paper presents a simplified yet accurate circuit model of the faulted MV network, taking into account the CCF currents' return path (cable sheaths/screens, ground conductors, and earthing resistances of secondary substations). The proposed CCF model can be implemented in a general-purpose simulation program, and it yields accurate fault currents estimates: for a 20 kV network case study, the comparison with accurate ATP simulations evidences mismatches mostly smaller than 2%, and never exceeding 5%.

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Section: Introductionmentioning

confidence: 93%

An Equivalent Circuit for the Evaluation of Cross-Country Fault Currents in Medium Voltage (MV) Distribution Networks

et al. 2018

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“…Thus, only three cu phase earth faults y dangerous states. icular phase equals Consequently, the between the other te is present on the [16,21,22]. This ctric shock due to henomena such as etc.…”

Section: Converter Operation Without Fourth Legmentioning

confidence: 99%

A novel least norm-based PWM for a four-leg earth fault compensator

Komrska

Peroutka

Matuljak

2014

IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society

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This paper proposes a novel P voltage-source converter operating as an ea compensator in power grids with unearthed earthed neutral. For proper earth fault c converter has to draw zero-sequence curren phase grid. Its control is based on t proportional-resonant controllers. The main modulator is to generate from three outputs control block four modulation signals enter order to minimize a dc-link voltage of the c norm method is used to eliminate high differen the modulation signals. Keywords-four-leg converters; lest norm m compensationI.

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“…Samples -grounding -were carried out at the terminal block of the second phase belonging to the line LES 20 kV (to the pillar No. 1) by mounting a shortcircuit cable with its connection to the pole earth inlet (grounding) [3], [12], [13], [14].…”

Section: Tests For Comparative Analysis Between the Two Treatment Metmentioning

confidence: 99%

Impact analysis of changing the neutral treatment solution in an MV electrical station on the system performance

Mircea

Marin²,

Mircea

et al. 2018

MATEC Web Conf.

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The actual operation of the power distribution systems asks for high standards concerning the performance of the system in terms of continuity and safety in supplying consumers on the one hand and the quality of the delivered energy on the other hand. Thus, the paper aims to present a complete analysis of the impact that the modification of the neutral treatment system in a 110 kV / MV station belonging to Energy Distribution Oltenia (DEO), has on both the number and the type of unwanted events or phenomena as well as on the network parameters and the transient regime which occurs as a result of some defects with the earth. All of these have been analyzed taking into account the new performance standards that distribution systems have to respect.

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Ground Fault Temporary Overvoltages in MV Networks: Evaluation and Experimental Tests

Cited by 50 publications

References 11 publications

An Equivalent Circuit for the Evaluation of Cross-Country Fault Currents in Medium Voltage (MV) Distribution Networks

An Equivalent Circuit for the Evaluation of Cross-Country Fault Currents in Medium Voltage (MV) Distribution Networks

A novel least norm-based PWM for a four-leg earth fault compensator

Impact analysis of changing the neutral treatment solution in an MV electrical station on the system performance

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