Upgrading a motor protection circuit for Sydney Water

Sydney Water’s Lakemba pump station transfers fresh water to the city. After a 30-year-old motor at the pump station was decommissioned, its 3.3 kV, 224 kW replacement included modern features that its predecessor didn’t have, such as winding and bearing temperature detectors.

This meant that the new motor didn’t interface entirely with the existing motor protection circuit, allowing it to be isolated and protected against overload and short-circuit. The motor protection circuit needed to be upgraded – and to a deadline, as the motor needed to be in service by a certain date.

Designer Steve Overell, Senior Power Engineer in our Primary and Earthing team, started the task by carrying out a desktop and onsite investigation of the existing motor protection circuit and supply, before coming up with a proposal that would suit the new pump and that considered the time constraints.

At a workshop with Sydney Water’s engineers, he discussed his solution and gathered feedback for inclusion in the final design. As an example, with an eye on future needs, Sydney Water asked for one of the system controllers to include an open communication protocol and ethernet connectivity.

Steve says that the engineering solution was turned around for Sydney Water ahead of the proposed schedule, which gave the corporation more than enough time to make necessary modifications before the motor needed to be in service.

According to Paul McParlane, Design Lead (Treatment) for D4C, who managed the project for Sydney Water, the value that Middleton Group brought to the work was providing “design services in a timely manner for a critical pump refurbishment”.