"in operation phase" is correct and commonly used in written English.
It can be used to describe a phase of a project or process that is currently active. For example, "The new software is currently in operation phase and testing is still underway."
For instance, due to time limit, most building LCA studies estimate the building materials and fuels consumed in construction phase quite roughly, which excludes the choices on a wide range of construction techniques, materials, specialties and machines, no need to mention the energy consumption in operation phase, which is usually estimated in an even bolder manner.
Knock-on delay, which is the key factor in punctuality of railway service, is mainly related to two factors including the quality of timetable in the planning phase and disturbances which may result in unscheduled trains' waiting or meeting in operation phase.
Existing architectural models used in the development phase differ from those used in the operation phase in terms of purpose, abstraction, and content.
Calibrated energy models can be used for several specific tasks in the operation phase, in particular condition monitoring, fault detection and diagnosis, supervisory control and energy management.
Although the traction emissions per passenger-km traveled of Shanghai Metro are competitive at the global level, there is still great energy-saving potential in the operation phase, especially in ornately designed train stations.
Also, Kapur et al. [21] consider that the delay of the fault removal efficiency depends on their criticality and urgency in the software reliability modeling in the operation phase.
Recalling Fig. 2, emissions in the operation phase arise from vehicles, maintenance and idle operation.
Therefore, the urban pipeline network security risks in its operation phase are more and more common.
In the operation phase, the system automatically detects specific behaviors from a video sequence shot by the same camera as the training phase.
In terms of DG, although it is clean and low-carbon, the randomness and intermittency of renewable generation always bring new challenges in the operation phase.
