Transformîna Yerlendkirina & Konseptên Kabelan Explained
پاشkirina wêzanên û terînolojîya transformasyonan
Cirakî çendî ya barka bûka bi bêdewamî ye, û cirakî rêzikî ya li ser rûpel êk bi xwe da zêdetir e, taybetmendî 100 her û îra yên rêzikî rêzikî rêzikî.
Kapasîna vê reşeyê yên cable 25-50 her û îra yên kapasîna vê reşeyê yên rêzikî rêzikî rêzikî.
Frekança çendîya şopandinê ya ampera capacitif: 300-1500Hz ji bo rêzikî rêzikî rêzikî û 1500-3000Hz ji bo cable.
Talabên performansa ji bo transformasyona grounding externe: Li dema kirina normal ên berzaniyê, dêra nîvenda dîwarî ya we dike ve girîng e, û tenha jorîkî mezîn hatiye ji bo windings; wanî da ku sergazî yên single-phase ground fault di sisteman de dibêje, winding dikare nîvenda dîwarî ya pêwist û negatif bigire, û nîvenda dîwarî ya zero sequence. Rewşên wiring yên ev transformers Y0/Δ an Z-type in.
Ji ber ku parta high-voltage ya transformer Z-type wiring bikar dihê, her phase winding ji du segment dan, ku di navbera core columns yên different phases de ne, û du segmentan ya coil bi polarities opposite hatine hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate......
پاشkirina wêzanên û terînolojîya transformasyonan
Cirakî çendî ya barka bûka bi bêdewamî ye, û cirakî rêzikî ya li ser rûpel êk bi xwe da zêdetir e, taybetmendî 100 her û îra yên rêzikî rêzikî rêzikî.
Kapasîna vê reşeyê yên cable 25-50 her û îra yên kapasîna vê reşeyê yên rêzikî rêzikî rêzikî.
Frekança çendîya şopandinê ya ampera capacitif: 300-1500Hz ji bo rêzikî rêzikî rêzikî û 1500-3000Hz ji bo cable.
Talabên performansa ji bo transformasyona grounding externe: Li dema kirina normal ên berzaniyê, dêra nîvenda dîwarî ya we dike ve girîng e, û tenha jorîkî mezîn hatiye ji bo windings; wanî da ku sergazî yên single-phase ground fault di sisteman de dibêje, winding dikare nîvenda dîwarî ya pêwist û negatif bigire, û nîvenda dîwarî ya zero sequence. Rewşên wiring yên ev transformers Y0/Δ an Z-type in.
Ji ber ku parta high-voltage ya transformer Z-type wiring bikar dihê, her phase winding ji du segment dan, ku di navbera core columns yên different phases de ne, û du segmentan ya coil bi polarities opposite hatine hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate......
Li ser dema kirina grounding transformer da ku hûn dikarin taybetmendî yên secondary load bigire û station transformer bike, li dema kirina secondary loads, kapasîna primary ya grounding transformer dêkere ji herdu kapasîna arc suppression coil û kapasîna secondary load; li dema nekirina secondary loads, kapasîna wê ye kapasîna arc suppression coil.
Amaşeya zêdekirina damping resistor ku di dema vêne kirina series resonance di sisteman de, voltage displacement UN ya neutral point bi 15% ên voltage phase hatine hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate hate............
Li ser dema bikar bûna parallel medium resistance line selection method, hewce ye ku box ya parallel medium resistance bikar bîne, ku di du endan de arc suppression coil. Wanî da ku cihaz dikare ku sergazî permanent single-phase ground fault di sisteman de dibêje, medium resistance dêkere li serkirina active current bike bibe ji bo line selection, û resistance dêkere li vir bi short delay.
Hemî çendî dielectric constant, conductivity zêdetir e.
Transformers yên three-phase yên bikar bûn di sisteman de distribution zêdetir rewşên Dyn11 bikar hin, ku ji ber vê rewşan avantajên mêhêbikin: dikarin harmonic current bikişînin, performansa kirinan bikişînin, zero-sequence impedance kêm e, dikarin single-phase short-circuit current bikerzanin, û dikarin ku sergazî yên single-phase ground fault bikişînin; dikarin kapasîna transformer bikişînin li ser şertên three-phase unbalanced load, û dikarin lossan transformer bikişînin yekdê.
Wave impedance ya line yên connected to primary side ya transformer zêdetir hundreds ohms e, û wave impedance ya line yên connected to low-voltage side zêdetir tens to more than one hundred ohms e.
Power frequency damping rate ya overhead line normal 3%-5% e, ku dikare 10% bike wanî da ku line damp be; power frequency damping rate ya cable line 2%-4% e, ku dikare 10% bike wanî da ku insulation aged be.
Capacitance to ground per phase of 3-35kV overhead lines 5000-6000pF/km e. Capacitive current of overhead lines in double-circuit lines on the same pole Ic=(1.4-1.6)Id (where Id is the capacitive current of one circuit in the double-circuit lines; the coefficient 1.6 corresponds to 35kV lines, and 1.4 corresponds to 10kV lines).
Li ser dema sergazî neutral point resonant grounding system, wanî da ku sergazî single-phase ground fault dibêje, ji ber zero-sequence impedance nîvenda dîwarî girîng e, residual current ne hatine 3rd û integer multiple harmonic currents, zêdetir 5th û 7th harmonic currents.
Li ser dema regulations, wanî da ku arc suppression coil connected to an ordinary transformer, kapasîya wê ne dikare ve 20% ên kapasîya transformer. Transformer Z-type dikare arc suppression coil connected with a capacity of 90%-100%. Li ser dema connected with an arc suppression coil, grounding transformer dikare taybetmendî yên secondary loads bigire û station transformer bike, ji bo saving investment costs.
Li ser dema kirina grounding transformer, wanî da ku zero-sequence current of a certain magnitude passing through, currents flowing through the two single-phase windings on the same core column are opposite in direction and equal in magnitude, so that the magnetomotive forces generated by the zero-sequence current are exactly opposite and cancel each other out, resulting in extremely small zero-sequence impedance. Due to the low zero-sequence impedance of the grounding transformer, when a single-phase ground fault occurs in phase C, the ground current I of phase C flows into the neutral point through the earth and is equally divided into three parts into the grounding transformer; since the three-phase currents flowing into the grounding transformer are equal, the displacement of the neutral point N remains unchanged, and the three-phase line voltages still remain symmetric.
Harmonics in the zero-sequence circuit are mainly caused by the nonlinear characteristics of the transformer core. Since the secondary side of transformers in China's distribution networks mostly adopts delta connection, there are generally no 3rd and integer multiple high-order harmonics in the zero-sequence circuit, so the ground fault current basically does not contain these high-order harmonic components, mainly 5th and 7th harmonic components, whose magnitude will change with the load.
For a single-phase ground fault, the equivalent sequence network is a series connection of positive, negative, and zero sequence networks; for a double-phase ground fault, the equivalent sequence network is a parallel connection of positive, negative, and zero sequence networks; for a double-phase short circuit, the equivalent sequence network is a parallel connection of positive and negative sequence networks; for a three-phase short circuit, the equivalent sequence network only includes the positive sequence network.
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