Transformer box power generation and energy storage system

How is a transformer energized?

A transformer is energized when an initial inrush of current propagates in either the inner or outer coils. With two-winding or bidirectional transformers, naming conventions mirror the order of energization. Which coil is energized first makes all the difference.

What is a grid-tied PV system without energy storage?

Before untangling more puzzling windings decisions for isolation transformers, transformers with energy storage in microgrid scenarios, or PV systems supplying both three-phase and single-phase dedicated loads, let us consider a common case: a grid-tied PV system without storage. In this scenario, the PV system is exporting power to the grid.

Should a transformer Wye have a neutral?

Importantly, in grid-connected scenarios without storage, a wye with a neutral should be avoided on the transformer’s utility side. Such a choice runs the risk of circulating currents in the neutral, which, in turn, means more energy loss and overheating risk.

Who should choose a transformer for a solar-plus-storage system?

Designers, developers, and EPCs should always consult their relevant local and national electrical codes, the AHJ, and the transformer manufacturer when making any final specification decisions on a given project. In future articles, our SMEs will dig deeper to tackle transformer selection for more involved solar-plus-storage system designs.

What is the winding configuration of a transformer?

The language most of us often use to describe the winding configuration of a transformer is not always straightforward. This is, in part, because transformers have typically only been used for power flow in one direction, say, a 480 V utility line to service with 208 V loads.

Which winding is best for a grid-tied step-down transformer?

The recommended winding choice for this grid-tied step-down transformer is a delta connection on the grid-tied/primary side and a wye with a ground connection on the inverter/secondary side. This is typical for at least two reasons.