Moving with the Times

Digitalisation initiatives of key thermal gencos

At a time when the dynamics of the power sector are evolving, digitalisation plays a key role in meeting thermal generators’ goal of improving profitability, reducing emissions, enhancing flexibility and eliminating forced shutdowns. Most coal-based power plants were initially designed for baseload operations and high capacity utilisation factor. The changing fuel mix in power generation with greater integration of renewables is, however, driving gencos to optimise efficiency and operate at partial load. Digitalisation can aid gencos in enhancing flexibility besides reducing operations and maintenance (O&M) costs, enabling better asset management, ensuring compliance with environmental regulations and improving reliability. Indian generation companies are also actively deploying advanced digitalisation solutions such as digital twins and industrial internet of things (IIoT), and have plans to adopt new technologies such as artificial intelligence (AI) and machine learning (ML) in the near future. Power Line presents an overview of the digitalisation initiatives of select gencos…

NTPC Limited

NTPC is harnessing the potential of digital technologies to develop a sustained competitive advantage for the organisation. The utility is taking several digitalisation measures at its 2,000 MW Simhadri super thermal power plant (STPP) in Andhra Pradesh. As a pilot project, new initiatives are under implementation at the Simhadri STPP on a proof of concept basis. These include advanced process control, monitoring of stockyard and asset management.

Advanced process control entails implementation of solutions such as combustion and soot blowing optimisation; model predictive closed loop pressure control and superheater/ reheater temperature control; and adaptive control block. Combustion and soot blowing optimisation is beneficial for the improvement of heat rate while the model predictive closed loop pressure control helps in ramp rate improvement, providing the necessary flexibility to the power plant. The temperature control solution helps enhance the plant’s reliability by reducing excursions from the set parameters and the adaptive control block aids in stabilising the minimum load.

Another digitalisation system, which is under implementation, is the advanced management of stockyard (AMS). AMS supports unmanned automatic operation of stacker reclaimer. It provides 3D profiling of the coal stockyard for volumetric analysis. The plant operator can visualise the exact replica of the coal heap, cross-sectional volume and other details of a particular heap of coal. AMS also provides for hotspot detection, automatic sprinkler operation and identification of temperature zones of the stock yard.

NTPC is also implementing advanced asset management comprising asset information management, asset performance management (APM), application of IIoT in generating units (AIG), and digital worker 3D model at the Simhadri STPP.

APM focuses on reliability-centred maintenance practices as well as condition-based monitoring. It has tremendous benefits such as maintenance optimisation, reduction in forced outages, system driven decision-making, and improved manpower productivity. AIG is another digital tool that can augment today’s handheld-based condition monitoring with permanently mounted portable wireless vibration and temperature sensors on critical equipment, humidity and temperature monitoring in remote equipment, and voltage-level and lux-level sensors in remote pump houses.

NTPC has also introduced the concept of digital worker at the Simhadri STPP, under which smart devices are deployed for field operation rounds, digital helmets are provided for remote assistance/monitoring and real-time tracking facility is available. In addition, a three-dimensional digital twin is being used for training and maintenance planning.

Sembcorp Energy India Limited

Sembcorp Energy India Limited (SEIL) has also undertaken a host of digital initiatives at its TPPs in Andhra Pradesh with an aggregate capacity of 2,640 MW. One of the key measures adopted by the utility is the use of drones for coal inventory management. Through the use of drones for coal stock verification, the company has been able to reduce the cycle time to three days from 10 days. SEIL handles about 10 million tonnes of coal every year. The coal inventory at the yard is physically monitored on a quarterly basis. Earlier, coal stockpile volume computation was carried out with multi-station, handled by a surveyor. Now, with drone technology, photos are obtained from multiple angles, with high degrees of overlap. Photogrammetry software is used to generate high resolution map, point cloud and 3D model integrating. The digital intervention has reduced inspection time, outage time and O&M cost to a greater extent, compared to traditional methods.

The company also utilises a data lake platform that has over 100,000 data tags synchronised to data factory from TPPs. The platform enables real-time data access for performance indicators like turbine heat rate, auxiliary power consumption, boiler efficiency and steam consumption. The platform has helped the genco shift towards data-driven analysis and fact finding with easy data access.

Connected field force is another digital measure adopted by SEIL, which automates field data. It provides integrated data access for field operators while monitoring machine health, location route map, communication with control room, as well as computer-aided programmes to monitor abnormalities such as oil leakage, dust accumulation and flame.

Another significant digital solution deployed by the utility is the lone worker manager platform (LWMP) that connects lone, remote and vulnerable workers via dedicated devices, mobile phones and computer applications to an alarm receiving centre (ARC). A lone worker device is provided to such employees and features an SOS button with two-way audio, and a motion and shock sensor, which can automatically raise an alert if a fall is detected. The device has a fall detection function, which works by registering an impact. The GPS reports the worker’s last known location to the LWMP. An ARC operative will call the worker’s device to make sure he is fine. If one does not answer, they will follow up with the next steps in the escalation procedure, such as contacting a line manager.

Nabha Power Limited

Nabha Power Limited (NPL), a wholly owned subsidiary of L&T Power, which operates a 1,400 MW TPP in Punjab, has been actively undertaking digitalisation initiatives for the past four years. In 2017, it implemented enterprise resource planning (ERP) as well as carried out certain non-ERP enhancements (dashboards for O&M, commercial, fuel sourcing, materials management and procurement, finance, and human resource functions). In the following year, automation of manual processes and business functions was carried out. In 2019, it implemented analytics-based solutions and plans to use cognitive technologies such as AI, ML, IoT and robotic automation in plant processes during 2020.

The genco has also taken steps to improve its digital infrastructure in terms of hardware and servers and network switches for faster communication. Business process automation has been achieved through the use of e-surveillance systems at strategic locations, automation of wagon tippler systems, management information system, and energy management system, among other things.

The utility has also implemented measures for data security. A network attached storage drive has been implemented, which ensures complete data security of NPL staff. On the mobility front, vital plant parameters, purchase order approvals, and statutory compliance details are available on mobile devices.

NPL has also deployed laboratory information management system, which enables automatic data communication between different lab instruments. It results in benefits such as generation of automatic test reports of coal analysis, transparency in the coal testing sequence and on the fly report availability, and improved efficiency and reliability of resources.

The genco has also established wireless communication between the coal handling plant’s control room and stack equipment, which has helped in the removal of expensive and damage-prone cables as well as reliable and fast data transfer with zero maintenance.

Digitalisation for flexibilisation

Digital solutions can help monitor and enhance the flexibility of a TPP. Common software  systems for automatic mill operation (mill scheduler), main steam temperature control, reheat steam temperature control, automated start of fans and pumps, integrated start-up automation, flame detection system, flue gas temperature control, and online coal flow measurement system can be deployed by TPPs to aid flexible operations of a power plant.

The installation of condition monitoring systems is also critical for plants undergoing flexible operations as cyclic operations often lead to fatigue and creep in mechanical components, stresses on turbine shells due to changing pressure and temperature, failure of boiler tubes, overheating of reheater and superheater, and cracking in dissimilar metal welds. Condition monitoring can aid the plant operator to constantly monitor these systems and schedule preventive maintenance whenever necessary.

Net, net, digitalising old TPPs by leveraging latest automation technologies can significantly improve flexibility and operational performance of plants in real time and are a practical alternative to costly retrofits and upgrades. nBased on presentations by G. HariNarayanaRao, NTPC; JiteshPotel, Head, IT, SEIL; Snehesh Banerjee, AGM, NTPC; and R.S. Lall, Head, O&M, NPL, at a Power Line conference

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