Prekawzjonijiet għall-installazzjoni ta 'transformer kurrenti ta' sekwenza żero

1. Problemi fl-installazzjoni
(1) Zero-sequence current transformer'>The current transformer should be installed on the bottom plate of the switch cabinet, and should be fixed by a reliable bracket. However, some manufacturers or construction units install the zero-sequence current transformer'>current transformer on the bracket under the bottom plate of the switch cabinet, and even bind the zero-sequence current transformer'>transformer tal-kurrent fuq il-kejbil, li jikser il- Il-prinċipju ta 'switchgear magħluq għal kollox la huwa sigur u lanqas trab, aħseb u ara annimali żgħar, li jħallu ħafna perikli moħbija.

(2) After the cable terminal passes through the external zero-sequence current transformer'>current transformer, the relative position of the cable's metal shielded grounding wire and the external zero-sequence current transformer'>current transformer is incorrect. According to the "Beijing Electrical Engineering Installation Regulations", the metal sheath at the terminal of the three-core power cable must be well grounded; the copper shield of each phase of the plastic cable and the steel armor should be tin-welded with the ground wire (oil-impregnated paper insulated cable lead-clad and armored) The ground wire should be welded), when the cable passes through the zero-sequence current transformer'>transformer tal-kurrent, l-għata tal-metall tal-kejbil u l-wajer ta 'l-art għandhom ikunu iżolati mill-art, u l-punt ta' l-art tal-kejbil (il-punt ta 'l-iwweldjar bejn il-wajer ta' l-art tal-kejbil u l-ilqugħ tal-metall tal-kejbil) huwa taħt it-transformer, il-wajer ta 'l-art għandu jkun ertjat direttament ;

When the grounding point is above the transformer, the grounding wire should pass through the transformer for grounding. The grounding wire must be connected to the special grounding copper bar in the switch cabinet. The grounding wire must be copper stranded wire or tinned copper braided wire. The cross section of the grounding wire must be Meet the requirements of the regulations. During the inspection, it was found that some cable grounding wires should pass through the zero-sequence current transformer'>current transformer, and some cable grounding wires should not pass through the zero-sequence current transformer'>transformer tal-kurrent. Aġixxi dritt.

(3) Due to the relatively large cable terminal, the magnetic circuit of the current transformer'>current transformer is not closed. At present, the commonly used 10kV power cables are three-core XLPE cables. >The current transformer cannot be put on, and the zero-sequence current transformer is disassembled during the construction'>The current transformer interface, the cable is put on, but the interface is forgotten to be restored; some are restored, but the interface is not restored strictly; some terminals The separation of the first three cores is thicker than the zero-sequence current transformer'>current transformer's inner diameter and just stuck in the middle of the zero-sequence current transformer'>current transformer so that the zero-sequence current transformer'>current transformer interface cannot be restored to close, resulting in Zero-sequence current transformer'>Iċ-ċirkwit manjetiku tat-transformer tal-kurrent mhuwiex magħluq u ma jistax jaħdem b'mod normali.

(4) The zero-sequence current transformer'>current transformer's secondary connection was opened during the cable construction, and it was not restored in time after the work was completed, causing the current transformer'>coil sekondarju tat-transformer tal-kurrent biex tiftaħ.

(5) It-tarf ta 'l-ert tal-wajer ta' l-ert tal-għata tal-metall tal-kejbil mhuwiex iwweldjat mat-terminal, u lanqas imqabbad mal-bar tar-ram ta 'l-ert fil-kabinett tas-swiċċ, iżda huwa casually lapped fuq il-boltijiet tal-korp tal-kabinett tas-swiċċ.

2. Metodu ta 'installazzjoni korrett
(1) Għandu jiġi żgurat li t-transformer tal-kurrent ta 'sekwenza żero jintgħażel> id-dijametru ta' ġewwa tat-transformer tal-kurrent huwa akbar mid-dijametru ta 'barra tar-ras tat-terminal tal-kejbil;

(2) Try not to dismantle the zero-sequence current transformer'>transformer tal-kurrent waqt il-kostruzzjoni. Jekk irid jiġi żarmat, għandu jiġi restawrat għall-istat oriġinali tiegħu wara li jitlesta x-xogħol;

(3) The grounding wire must be copper stranded wire or tinned copper braided wire, the cross-section of the grounding wire should not be less than 25mm2, the grounding end should be welded with a terminal, and the grounding wire and the zero-sequence current transformer'>it-transformer tal-kurrent għandu jiġi mmaniġġjat sew Il-pożizzjoni relattiva tal-wajer ta 'l-ert għandha tkun installata fuq il-bar tar-ram ta' l-ert;

(4) Is-sistema ta 'protezzjoni ta' sekwenza żero għandha tiġi aġġustata qabel ma tinxtegħel biex tiżgura li l-protezzjoni taħdem b'mod normali.