An electric power plant with five generators, each powered by a gas turbine, is currently being run in Oman. Strict monitoring and assessment of the vibrations from the turbines is necessary to meet the requirements of endurable and efficient operation. The German engineering company Bluhm Partner was awarded the commission and chose INFRA as their measuring system.
Gas turbines and generators sometimes operate at critical speed of rotation. This means a passage of resonances when a turbine is started or stopped. The resonances cause strong vibrations. Even sudden imbalances in a turbine may cause very strong vibrations – many times greater than those that can come from piling outside the building. Specific requirements for dynamic properties of the foundation plinths are made to ensure that turbine and generator can be operated at the intended production output. The main purpose of the measurements is to test that these requirements are met and if not, lead towards corrective measures.
One single data logger for each machine set
Two of the five machine units, each consisting of a gas turbine and a generator, have three measurement points on the concrete foundation, each with a triaxial geophone (V12), and two measurement points on the generator, each with two accelerometers (A10), so both vibration velocity and frequency are measured. The measurements on the generator allow for a professional assessment of its bearing point vibrations and thus a statement of its durability. One single data logger, INFRA Master, serves all the sensors of a machine set. The measurement standard applied is ISO 10816.
The monitoring started in May 2013 and is planned to continue until July 2014. An extensive assessment of the vibrations will then follow with a possible extension of measurements if no concrete decisions can be made. The commitment of Bluhm Partner is triple: to carry out the measurements, to assess measurement data and propose solutions, and to measure the effects of actions taken. The client will receive monthly reports and can continuously follow the measurements via the web presentation.
Reliable monitoring in an EX environment
Project Manager M.Sc. Ján Bluhm sums up some challenges of the project: Specific requirements exist for explosion protection at the measurement points, as the generators are cooled by hydrogen. Moreover the measurement points on the foundations must be screened off from impacts caused by service works carried out in the machine halls.
– Sigicom´s INFRA system offers a time-saving, efficient and correct installation. The system is monitored via a web presentation and is very reliable. That´s why we chose the system – and we are very satisfied with it, says Ján Bluhm.