Targeted Maintenance

Digitalising HEPs for improving operational efficiency

Digitalisation of hydroelectric plants (HEPs) is useful in rationalising operations and maintenance (O&M), besides helping in cutting costs and increasing the effectiveness of workforce management. Digitalisation is also useful in the integration of HEP operations with other variable renewable energy sources since digital solutions help in closely monitoring HEP operations. Digitalisation also optimises reservoir management and extends the operating range of existing hydro units. Various 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 equipment, among other things.

Key technologies

A distributed control system (DCS) is a key component of a digital hydropower plant. It involves 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 at a remote location). With a DCS, no manual intervention is required. Numerical relays can record and store a large number of events and disturbance records, providing excellent fault diagnosis tools. They are highly configurable as the setting parameters and operational logic can be changed easily. The latest numerical relays, which are based on open protocols, can communicate on the plant control network, improving ease of access.

Computational fluid dynamics (CFD) is another key tool for a digital HEP. CFD is an efficient and inexpensive tool to make internal flow predictions with good accuracy. It detects any sort of flow problems and makes improvements in the geometry of turbine components. It is used for checking the efficacy of alternative turbine designs for optimisation before the final experimental testing of selected designs. Another emerging trend is allowing for flexibility in turbine design. Today, turbines are available in varying configurations, such as horizontal and vertical, to ensure efficiency and reliability of operations under extreme conditions. This enables longevity, durability, reliability and robustness, and facilitates a wide range of operations.

An emerging digital solution for HEPs is the acoustic monitoring system. In this, microphones are mounted at specified locations in the plant and they record all ambient noise. The final data interpretation is done to understand the performance of the plant. For calibration purposes, the system would record all acoustic signals. The data collected would then be compared to that of other hydropower plants. Owing to its combination with operating data, the application learns which noises correspond to normal machine behaviour. Later, the system can be programmed to identify deviations from the typical noise pattern. Using AI, the system will complement monitoring of the power plant and preventive maintenance undertaken by the personnel and identify potential machine damage in good time. For instance, Voith is installing an acoustic monitoring system in the Budarhals hydropower plant in Iceland, which detects turbine noise that deviates from normal conditions to prevent potential shutdowns in good time.

Asset performance management

With the deployment of analytics and digital solutions, the overall maintenance of HEPs can be improved significantly. Digital solutions reduce O&M costs of HEPs through reduced outage time and also extend the life of the assets. Digitalisation of HEP operations also helps in improving the role of hydropower as a flexible source of energy. It helps in optimising planning and operation of the plants. Digitalisation is useful for modernisation of the existing HEPs and helps improve overall unit efficiency through upgrades to turbines, draught tubes and other associated equipment.

Condition monitoring equipment

Hydropower contributes significantly to grid stability, owing to its large scale of power production and ease of undertaking flexible operations. This is crucial in view of large-scale integration of intermittent renewable energy sources into the grid. For smooth and flexible operations, intelligent condition monitoring and diagnostics is crucial for HEPs. HEP operators look at expanding the time between plant overhauls and shortening the mean time for repair. Digitalisation and use of sensors is useful in this regard. Intelligent monitoring systems allow detection of failures in the power plant even before they actually occur. Internet-enabled condition monitoring systems remotely collect and analyse real-time data, in order to improve diagnostics and prognostics of faults in the plant.

Outage management

Poorly planned and executed outages lead to revenue loss and build-up of expenses for the utility. For successful management of outages, it is necessary to effectively identify, plan, execute and review outage. Digitalisation of HEPs helps in precisely monitoring and recording various plant performance parameters on a real-time basis. This is useful in managing an upcoming outage efficiently to minimise losses.

SCADA in HEPs

Optimised operations is one of the key priorities of HEP developers. One way to achieve this is to remotely control all power production units through a supervisory control and data acquisition (SCADA) system. A SCADA system handles both the software and hardware of a plant through power line communications, remote terminal units, smart sensors, and data communication and transfer devices. For successful operation of a SCADA system, adaptability, data security, reliability and a friendly user interface are essential.

IoT in hydropower

IoT and big data analytics have revolutionised the energy sector. IoT allows undertaking analysis of plant operations’ data to improve performance. The use of sensors provides a continuous, high-rate stream of data on a real-time basis. Developing cognitive machine-to-machine communications is needed to tune hydropower performance as per energy demand and environmental conditions. Data analytics has been useful for forecasting generation and consumption for many years; however, analytics, cognitive computing and IoT are now being used to enhance operational efficiency. Cognitive computing can be useful for managing power plant operations, and continuous analytics provides inputs for active ML. Overall, cognitive computing can aid hydropower operators in increasing their operational efficiency and optimising time and resources.

AI and ML for HEPs

The old hydropower plants operate at low operational efficiency and entail high expenses. However, the high cost can be managed through better planning and targeted maintenance enabled by digitalisation. In the past few years, digitalisation of hydropower plants has entailed development and testing of a variety of algorithms and methods designed to analyse operational data from power plant control systems. Various models and algorithms have been developed that use operational data from control systems, sensors and other measuring equipment installed in the plants. The digital twins, AI and ML, provide prompt notifications of changes in the function or performance of the power plant equipment. These models and algorithms are also useful in identifying faults in the plants in advance, which could have otherwise resulted in a serious malfunction.

Challenges and the way forward

There are a number of challenges in the digitalisation of operations in HEPs. For successful operation of digital solutions in HEPs, networked platform solutions have to combine previously isolated data and information systems. Further, data across all areas should be available locally and centrally to enable rapid analysis. Besides, poor network connectivity between power stations and remote centres poses a major challenge as effective digitalisation depends on strong communications and connectivity. There is also the risk of cyberthreats, which increase with digitalisation. To minimise these threats, utilities need to raise awareness about cybersecurity and build strong strategies for technological and cyber resilience. Another challenge faced in the implementation of digitalisation initiatives is the lack of financial incentives and IT infrastructure with gencos. The industry has raised concerns about the lack of incentivising investments in digital technologies.

Overall, hydropower stations must be encouraged to adopt emerging technologies and innovative approaches in order to improve their operational performance and cope with cybersecurity risks. In addition, there is a need to create greater awareness about the benefits of digitalisation, especially in HEP operations.

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