Rotork valve automation improves solar power operation

16 April 2018

Rotork IQ intelligent electric valve actuators with Rotork Pakscan two-wire digital control provide key valve automation functions for two solar power plants in Spain. These plants utilise parabolic trough concentrating technology combined with a molten salt thermal storage system to maximise their power generating capacity.

Rotork Iberia has worked closely with the plants’ owner to integrate an economical and efficient valve control system, leading to the installation of several hundred IQ actuators on each site. The decision to use Rotork’s Pakscan control system was assisted by its extremely long range bus communication capabilities and cost savings. Each Pakscan Master Station can operate a bus loop of up to 20 kilometres in length with no deterioration in communication performance or the need for repeaters, making it ideal for the spacious environment of a solar power plant.

In addition to the actuators installed when the sites were first built, new actuators have subsequently been retrofitted to manually operated valves to increase the scope of automation across the sites. The retrofit projects are being carried out by Rotork Site Services, a dedicated department that supports all actuator operations with a range of activities including retrofitting, maintenance, repair, extended scope projects and asset management.

More than 300 actuators are also being fitted to the outlet valves of the solar field loops on the Heat Transfer Fluid (HTF) pipes that carry the heat transfer oil between the solar concentrating parabolic mirrors, the steam plant and the power generation circuits. The majority of the actuators are IQ3 multi-turn units with Rotork Gears IB gearboxes, providing on/off control.

These actuators will enable individual HTF circuits to be automatically isolated when essential maintenance is required. Automation will enable the open or closed position of each valve to be remotely indicated and monitored via the Pakscan control system, improving the safety and environmental integrity of operations.

Dataloggers within the IQ3 actuators facilitate valve diagnostics by recording historical operating data and valve torque trends. Using Rotork’s Insight 2 software this data can be analysed on a PC to predict any potential operating issues, enabling maintenance to be planned in advance without interruption to normal plant operations.