On May 29th, Di-Hydro project coordinator CERTH has carried out a technical visit to PPC’s Pournari I plant, located at Arta, Greece. The visit focused on discussing with the plant’s technical staff about the Di-Hydro project. Moreover, discussions also included potential pilot activities that the project can carry out in Pournari plant within the project’s framework.

Specifically, Pournari I manager PPC is participating in the Di-Hydro project in use cases-related to digitisation of operations and maintenance. In fact, three different plants, Ilarionas, Thisavros and Pournari will be part of the Di-Hydro Use Cases. In particular, the activities will cover the installation of a sensor node developed by CERTH. This sensor node is able to detect and record acoustic emission activity, vibration, magnetic flux variations, temperature, humidity and crack growth formation for condition monitoring and structural health monitoring purposes on rotating machinery or infrastructure.

Pournari Dam Hydropower plant

Fig.1: Mock-up of water intake tower and bottom outlet unit structure

Fig.2: Bottom outlet unit (front) and control gates for water intake towers (at the back)

Hence, the aim of the visit was to observe the characteristics of Pournari plant, which is the least digitised plant out of the three plants participating in the project. Furthermore, discussions with the technical staff about operational and maintenance issues provided precious insight on what Di-Hydro could do to improve the plant’s operations. Through these discussions, CERTH and PPC will identify the potential locations of where the sensors could be placed in the plant, depending on their specific needs. In addition, underwater inspections using a remotely controlled underwater vehicle can potentially be carried out by CERTH. The vehicle would survey the intake towers and a second outlet tower that allows draining the catchment lake to a lower level (see Figure 1 and Figure 2). Moreover, biofouling issue was also detected in this plant, leading to potential monitoring activities using an ultrasonic probe system. Such system mostly used for prevention of this phenomenon.

Some of the potential locations for sensorisation were the following:

• Shear pins on link rods for controlling the wicket gate of the Francis turbine (see Figure 3)
• Turbine guide and thrust bearings due to lack of vibration sensors

Fig.3: Shear pins and link rods assemblies

Fig.4: (from left to right) Konstantinos Michelis, sub-head of mechanical maintenance of PPC’s Pournari HPP, Alkiviadis Tromaras (CERTH)

Next steps at Pournari I

In the following months, Di-Hydro will define the monitoring at the Pournari hydropower plant. Moreover, the team will also begin the application of its digitalisation strategy. In fact, including digital systems to support plant managers to plan regular maintenance can indeed enhance efficiency and optimise operations. As a result, Pournari’s energy output can considerably improve, while closely monitoring the infrastructure health.

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