The site includes the world's first circular wave and tidal current test plant, and the ABB package includes servo drives and low-voltage VSDs (variable-speed drives).
Douglas Rogers, of hydrodynamic test equipment contractor Edinburgh Designs, explains that the plant will be used to simulate energetic sea states typically found in British, European and international waters.
It comprises a 25m diameter test tank with a central floor section, 15 m in diameter, which lifts above the water level for testing wave and tidal energy devices and projects, as well as fixed and floating offshore wind structures.
The ABB servo drives and motors and variable-speed drives are used to generate long-crested straight waves and fast currents, and the computer control system combines thousands of sine waves to build a fully controllable 'random sea'.
Down either side of the tank hall 30 m of marshalling cabinets house ABB circuit breakers, contactors, relays, switches, fuses, PLCs, servo-drives and VSDs.
The tank is encircled by a ring of 168 wave maker paddles that create and absorb waves – each paddle having a brushless ac servomotor that drives a belt running over a curved guide on the top of the paddle.
The ABB BSM brushless servo motors are used to provide full torque from zero speed, and were also selected to minimise maintenance implications.
The velocity, position and force feedback of each paddle is controlled by its own ABB MotiFlex e100 servo drive, using Ethernet PowerLink – the controller taking its signals from force transducers on the back of the paddles.
Encoders measure the paddle position and convert the signals to an algorithm that then gives instructions to the amplifiers. Ethernet Powerlink is used to give error free, real-time control from the controller to the amplifiers, with protection of the latter being afforded through safe stop mechanisms.
Each motion control drive is fed from a common dc bus, the voltage of which is generated using an ABB ACSM1 drive linked to the ac mains supply. Rather than use a conventional front end, the amplifier runs as a line regenerative supply, thereby driving the excess energy from the dc bus back into the mains system.
"We chose ABB because we had a long standing relationship with Baldor, a company now owned by ABB," states Rogers.
"ABB has been particularly valuable in providing a wide range of support in helping us with the installation," he continues.
"For instance, when we decided to use a bank of paddles with these amplifiers and tie it in with a front end, ABB mocked it up on their bench in Bristol and checked it would work before we implemented here."