The digitalisation of hydroelectric projects (HEPs) including their control systems and associated networks is a promising trend. It is aimed at optimising plant performance and improving asset management. Digital systems such as supervisory control and data acquisition (SCADA), digital governors and excitation systems are the key pillars of a digital power plant. The digitalisation of HEPs helps in cost reduction, increases flexibility of operations, and improves operations and maintenance (O&M) efficiency.
Depending on the grid frequency, hydropower plants ramp generation up or down, injecting reactive power based on the local bus voltage. Digitalisation helps hydropower plants fulfil these new and emerging requirements to balance the intermittent nature of renewable energy sources. Digital hydropower technologies provide better connectivity, ensure accurate asset management and enable predictive maintenance, facilitating efficient operations through data and analytics. Digitalisation also helps in the reduction of the O&M cost as system reliability and stability are improved and predictive maintenance is enabled. Digital solutions reduce unplanned outages and downtime by swiftly detecting the point of failure. This extends asset lifetime, improves the revenue stream and reduces the capex requirement.
One of the key drivers for the digitalisation of HEPs is remote monitoring and operation, especially given that the majority of the HEPs are in remote and difficult terrain. NTPC Limited’s Koldam HEP in Himachal Pradesh was the first of its kind to be operated remotely, from a distance of 400 km. The remote operation of the plant from NTPC’s SCOPE control centre in Delhi began in 2018. Since then, the success of the project has hinged on its comprehensive safety system, a well-trained response procedure, a resilient and robust communication system, and tight cybersecurity measures. At NHPC, operations of all power stations are either semi-or fully automated. The use of information technology has helped in ensuring construction supervision, post-commissioning monitoring and hurdle-free operations. Many of its power stations are equipped with advanced distributed control systems as well as SCADA systems.
On the technology front, computational fluid dynamics (CFD) is a key tool used for digitalising HEPs. CFD is efficient and inexpensive, and is used for making accurate internal flow predictions. It is also good at detecting flow problems, thereby improving the geometry of turbine components. Using CFD, operators can check the efficacy of alternative turbine designs for optimisation before the final experimental testing of selected designs. Apart from this, distributed control system (DCS) is a crucial components of a digital hydropower plant, involving a network of instrumentation comprising sensors, flow switches, transducers, etc. It provides real-time information to operators, allowing complete control of machines and auxiliaries from the control room, often located in a remote location. With this system, no manual intervention is required as numerical relays are able to record and store a large number of events and disturbance records, providing excellent fault diagnosis tools. Typically, HEPs using outdated control and electrical systems are at a greater risk of experiencing operational stoppages and downtime, and the use of modern DCSs can go a long way in mitigating these risks.
Apart from this, programmable logic controllers (PLCs) along with PC-based SCADA systems are used for plant control and data acquisition. A large PLC has enough relays to carry out all the necessary operations of the plant. Since these relays are digitalised, there is minimum damage to the system, and the cost of maintenance is reduced. This makes the system economically viable and, therefore, suitable for many hydropower plants.
New and emerging digital solutions such as machine learning (ML), artificial intelligence (AI), internet of things (IoT) and internet of services are increasingly being adopted in the hydropower segment. These are useful in asset management, plant and fleet enhancement, outage management, and condition monitoring, among other things. Rules-based analysis, advanced pattern recognition, ML and augmented reality can play a pivotal role in optimising the performance of these plants. Various models and algorithms have been developed that use operational data from control systems, sensors and other measuring equipment. Digital twins, AI and ML provide prompt notifications of changes in the performance of power plant equipment. These models and algorithms are also useful in predicting faults, that could have resulted in serious malfunctions.
To conclude, digitalisation is essential for improving the overall performance of hydropower plants as it optimises asset management and reduces O&M costs. Data analytics will continue to play a vital role in achieving further cost reductions and an overall increase in revenues. The performance of turbines, plants and equipment is expected to improve with the use of new digital controls. Digital solutions help HEPs to work more efficiently with other renewable technologies.
Moving forward, raising awareness about the benefits of digitalisation and developing a comprehensive policy framework for digitalisation will go a long way in enhancing the operational efficiency of hydropower plants. Besides, utilities need to raise awareness about cybersecurity and build strong strategies for cyber resilience.