Tranzistorên Nîrvend 101: Tiranê Ji Deyş, Regerdanê Heyvî û Yakek Diyar

Dîvên cîhanberên têkewtin û piçeyên sereke yên wan çi ne?

Cîhanberên têkewtin di navbera rêzikên pêşdebiriyê de hejmarên jêrîn din. Wan dibe destnîşanandin ser bincîhîna êndazeyê ya yek phase an sê phase; tipê core an shell ser bincîhîna rastînîna windings û core; û dry-type, air-cooled, forced oil circulation air-cooled, an water-cooled ser bincîhîna rêzikên derdixwaziya. Ser bincîhîna insulation-ya neutral point, cîhanberan dibedestnîşanandin wekî fully insulated an partially insulated. Herweha, insulation classes-ê windings dibedestnîşanandin wekî A, E, B, F, û H ser bincîhîna material type. Her cîhanber tip bikarhatîn operasyonel sereke ye. Piçeyên sereke yên cîhanbera têkewtin dibin navbera core, windings, bushings, oil tank, conservator (oil pillow), radiator, û accessories-ê liyankir.

Inrush current di cîhanberan de çi e û çi ji bo wê çavkaniye?

Inrush current divî bi transient current nîşan bidin ku ji roja voltage-ya vebijarkirina hêla di windings-ê cîhanberan de da. Dibe ji bo lê zanîna residual magnetic flux-ê li ser core bi magnetic flux-ê ku ji bo applied voltage hatine çêkirin, ku ji bo ku total flux ji saturation level-ê core bigire. Ev ji bo ku large inrush current bigire, ku divê 6 an 8 her çî ti reyûl current be. Mîna inrush current bi faktorên wergera voltage phase angle at energization, amount of residual flux li ser core, û source system impedance be. Peak inrush current tenê divê ji bo voltage at zero crossing (ji bo peak flux) bigire. Inrush current divî DC û higher harmonic components bike û li ser time dike decay ji ber circuit resistance û reactance - tenê li ser 5-10 seconds ji bo cîhanberên mezin û 0.2 seconds ji bo unitên biçûk.

Rêzikên voltage regulation di cîhanberan de çi ne?

Di navbera rêzikên voltage regulation de on-load tap changing (OLTC) û off-load tap changing (DETC) hejmarên jêrîn din.On-load voltage regulation dibe tap position adjustments ji bo dema ku cîhanber energized û operating e, ku voltage control continuous biguherîne bi guherandina turns ratio. Configurations-ê common dibin line-end tap û neutral-point tap. Neutral-point tap dibin reduced insulation requirements bike la herwa divê neutral solidly grounded be during operation.
Off-load voltage regulation dibe changing the tap position tenê ji bo dema ku cîhanber de-energized e an during maintenance.

Fully insulated transformer çi ye û partially insulated transformer çi ye?

Fully insulated transformer (ji bo nav fully insulated) dibin consistent insulation levels throughout the winding. Berbi partial insulated transformer (an graded insulation) dibin reduced insulation levels near the neutral point compared to the line ends.

Ji bo voltage transformers û current transformers operasyonel differences çi ne?

Voltage transformers (VTs) dibin primarily used for voltage measurement, while current transformers (CTs) dibin used for current measurement. Key operational differences dibin:

• Secondary side-ê CT must never be open-circuited but can be short-circuited. Conversely, secondary-ê VT must never be short-circuited but can be open-circuited.

• A VT dibin very low primary impedance relative to its secondary load, making it behave like a voltage source. In contrast, a CT dibin high primary impedance û functions as a current source with effectively infinite internal resistance.

• Under normal operation, a VT operates with magnetic flux density near saturation, which may decrease during system faults due to voltage drop. A CT, however, operates at low flux density under normal conditions. During short circuits, the increased primary current can drive the core into deep saturation, increasing measurement errors. Therefore, selecting CTs with high saturation resistance is recommended.