Transformatorbank

A transformatorbank, or transformer bank, is an arrangement of electrical transformers designed to transform voltages within power systems. It typically comprises several single‑phase transformers assembled to form a three‑phase unit, providing increased capacity, redundancy, and modularity for substations, industrial facilities, and large renewable energy installations.

Configurations and operation: In a bank, the transformers are connected to form a three‑phase system. The windings on the high‑voltage and low‑voltage sides may be arranged in Delta or Wye, resulting in common vector groups such as Δ–Y, Δ–Δ, or Y–Y. Banks are often designed to operate in parallel to share load and improve reliability, or in series to achieve higher voltage steps. On‑load tap changers (OLTC) may be included to regulate voltage while the system remains energized.

Construction and cooling: Banks can be oil‑filled or dry‑type. Oil‑filled banks require cooling systems such as radiators and pumps, while dry‑type units use air cooling. Insulation, bushings, and structural supports are arranged to handle thermal and electrical stresses. Protective devices, including relays and, for oil‑filled units, Buchholz relays, monitor oil condition and transformer health.

Applications and maintenance: Transformer banks are common in electrical substations, utility networks, data centers, and industrial plants where high reliability and scalable capacity are needed. Maintenance typically includes insulation testing, dissolved gas analysis, thermal imaging, oil condition monitoring, and inspection of connections and cooling equipment to prevent faults.

Safety and reliability: Handling high voltages and energized equipment requires adherence to strict safety procedures, proper clearances, and protective equipment. The redundancy provided by a bank enables continued service during maintenance or individual transformer faults.