Konfigurasyonê Bîndanê yên Transformatorên Paşîn Ji Bo Dikarinên PV yên Têgihîda Li Sermstiv Rêzgaran

Çavkaniya nûrî ya silsilanî, ku yek jorîn form ûsaya astengê ye, bi qelîlkên nûrî yên dîtina da dîwarên elektrîkî yên taybetandina. Bi serfirazî ji hêsanên malpera, materyal, an çevgotina û herêmseriya wê, li ser dikarinên demokratik a rêşeyên tenê yên silsilanî di navbera cih û herêm de hatine. Di sisteman PV yên destpêkê de, transformatoran (piramîdên bingehîn yên guhertina energî) pêwist in. Transformatoran step-up yên li ser PV ya vê deme ya karî yên SC-series epoxy-insulated dry-type yên 10 kV/35 kV ne, ku divîne bin birin yên two-winding û double-split. Pela yekem jêrîn hilbijartin.

1 Transformatoran Dry-Type Two-Winding

Struktura transformatoran dry-type two-winding yên li ser PV (wêje Fig. 1, referansa asliyê berdest e) ji derketinan traditional yên distribûsyon dry-type yên taybetandin ne, di lîsana, procesa, û biniyandina — ji wan re biguherîne rola step-up a werger. Her em, inverter yek tevî tevî li ser duwêna two-winding ê bikaranîna di dema ku niha ji bo rated output û gerîla grid voltage e.

Di dema ku grounding neutral-point a transformatoran dry-type dikare di dema opereasyon a inverter de veqetande û harmonics ne, kirina wekheviye Dy11 e ku bi tenê xwe amadekirina werger bike.

2 Transformatoran Dry-Type Double-Split

Di salên din de, ji bo piştgiriyên currents a short-circuit û kurtkirina costên sernivîs, transformatoran split (ji bilî yek winding, mîna low-voltage, split bikin le branchên electrically disconnected ²) zêdetir bikaranîn. Ji bo projeyên PV, transformatoran double-split zêdetir ne: du unitên inverter independent bikaranîn le du branchên double-split winding, operable independently or together.Li ser harmonics a inverter, kirina wekheviye D, y11y11 an Y, d11d11 e. Domestically, wan struktural axially-split an radially-split ne.

Wêje Fig. 2 (referansa asliyê), low-voltage winding divîne du branchên axially-distributed le core yek. Branches jî ne electrical but magnetic coupling (degree depends on structure ²), û dikarin segmental an wire-wound be. High-voltage winding divîne du branchên parallel matching le low-voltage ones, bi specs similar û total capacity equaling transformatorean.

2.1 Transformatoran Dry-Type Axial Double-Split

Bi struktur symmetrical û leakage flux uniform, performans bike bi through/half-through operation. Impedance mezin le branchên axially-split currents a short-circuit dikaribike, ji bo amana ku branch yek bike di dema ku yek fail de.

Lê, high-voltage winding (du parallel windings) turns doubled dikare û conductor cross-section halbed vs conventional. Design 35kV D-connected face issues (turn control, low efficiency), ji bo safety/reliability.

Also, upper/lower low-voltage windings (arranged vertically) have ~20K temperature difference (upper hotter due to air convection). So, design/manufacturing needs enhanced temperature-rise checks and proper insulation selection.

2.2 Transformatoran Dry-Type Radial Double-Split

Common radial double-split dry-type transformers (structural layout in Fig. 3) have two radially-distributed low-voltage winding branches (usually wire-wound, due to structural specificity) and a single integral high-voltage winding.

The high-voltage winding, with normally-selected turns and conductor cross-section, boasts better winding process/efficiency than axial double-split types. Its near-perfect symmetry ensures good ampere-turn balance in through/half-through operation, plus uniform low-voltage winding temperature rise.

Yet, radially-split low-voltage windings have small division impedance and large coupling capacitance, increasing inter-winding interference. This impacts output power quality and inverter component reliability, requiring adjustments to the inverter-side control loop and system.

2.3 Special Double-Split Dry-Type Transformers

Fig.4 depicts a hybrid design combining axial (segmental/wire-wound low-voltage) and radial (single high-voltage) splits. This hybrid addresses radial low-voltage and axial high-voltage issues, reducing costs and improving manufacturing efficiency.

However, half-through operation (e.g., due to environmental factors or inverter faults) causes severe ampere-turn imbalance, leading to end-winding leakage flux and overheating. This design is thus high-risk.

3 Conclusion

Grid-connected PV transformers primarily use two-winding (step-up, D, y11) or double-split configurations. Key recommendations for double-split designs:

• Maintain sufficient low-voltage division impedance for power quality.

• Account for axial split temperature differentials in insulation selection.

• Use Y, d11d11 for 35kV applications.

• Avoid special hybrid designs due to half-through operation risks.