A unique solution to power a pumped hydro site

Generally, running any mechanical equipment backwards isn’t recommended. In most cases the process is unproductive and inefficient—if not completely dangerous.

But when undertaken in the correct manner, running mechanical equipment backwards can deliver productive results. This is exactly what Toshiba engineers are doing on one of their current hydro projects.

For pumped hydro projects like this one, motors in typical use drive pumps that push water where it needs to go. But when the situation is reversed, and the pumps are instead used to drive the motors, something extraordinary happens. The motors run in the opposite direction, and become generators that produce electricity.

This principle can be seen in effect in one of the pumped hydro projects in which Toshiba is involved.

Typically, pumped hydro power plants suffer the problem of long generator maintenance periods spanning several months. This causes a plant’s large equipment to remain idle throughout the period. It’s not an ideal situation, and the economics of keeping these large value assets idle for long periods is always a concern for the plant’s management team.

So rather than let the equipment sit idle, the idea of using the dam water’s gravity to turn the pumps and make them the prime movers for the connected motors makes good sense. These motors now become generators, producing electricity to power the site.

But there’s a catch. It’s not as easy as simply reversing the motors. This type of arrangement, although sounding simple in principle, requires precise speed control to operate motors at the optimum point and ensure exact synchronisation of voltage, current, and frequency.

This is where Toshiba’s engineers have an advantage: the Toshiba regenerative MV drive is equipped with features that allows it to do exactly that.

Toshiba MV drives have been controlling motors in Australia and elsewhere in the world for decades, across a broad range of industries. These drives are available up to 120 MVA up to 7 kV with smaller capacities at 11 kV rating, and include features like extensive motor protection, that allow for more precise utilisation. They’re designed to work in tandem with Toshiba HV motors, but their flexibility and adaptability means they can be used with almost any motor brand.



Utilising the backwards drive of a HV motor isn’t an idea that immediately comes to mind when looking for solutions to power a site. But comprehensive solutions are what Toshiba is known for.

Their highly qualified team of engineers and technicians undertake complex engineering design and simulations, as well as testing and commissioning the entire system, to ensure that it meets customer’s specifications and produces desired result. It’s this complete service package – from the feasibility studies through to the commissioning of the project – that is highly valued by customers.

Toshiba has developed a reputation for delivering solutions to complex HV motor and drive problems. And sometimes, it’s as simple as looking at a piece of equipment and seeing if it can be driven differently.