Power grid stability: Behind India’s leap forward
To provide 24×7 power for all, India plans on integrating 175 gigawatts of renewable energy into the national grid. Harald Griem, CEO of the Energy Management Division at Siemens Ltd. in India, explains how digitalization and Flexible AC Transmission Systems are helping the country reach their targets and revolutionize their energy sector.
What is your view on the energy transition envisaged by the government of India?
Griem: India is leapfrogging dynamically by driving basic electrification while installing the latest technology for power quality and smart grids, and coping with the integration of large scale renewable energy. We see a mid-term market growth of 7 percent per year under high pressure for affordable products and solutions.
Reliable energy is a quintessential priority for India – a country that is witnessing a leapfrog development in the energy sector versus a conventional and evolutionary development. The various government initiatives from 24×7 reliable power to all with rural electrification and renewable energy focus, are contributing to the digitalization of the Indian grid. These focused efforts are aimed at power quality improvement thereby reducing losses and ensuring efficient transmission and distribution automation.
While we have seen a lot of technology transformations over the last decade, the next two decades will see technology innovations in the energy sector being rolled out at a faster pace than ever before. With the advent of digitalization, smart grid technologies and control centers; the road map for the country’s energy sector manifests a fine balance between delivering electrification for all and improving the quality of power. Ubiquitous digital connectivity in the energy sector has been an underlying factor that is being widely talked about by policymakers and technology experts – the role that digitalization plays to deliver reliable energy is crucial.
What role is Siemens playing in helping India achieve this transition?
Griem: We are a trusted advisor and local partner to meet all challenges. We are seen as very reliable in project execution, where shorter delivery times and high focus on environmental protection, health management and safety (EHS) are requested, and in product quality. For example, we received the reward for best transformer quality from PGCIL for the last two years. We develop, test and validate the latest technology with our customers, from Miniature Circuit Breakers or Fault Passage Indicators for distribution lines to 1200 kV AC Substation components. And we provide ideas and references from the rest of the world for new business models such as Reliability Centered Asset Management or Leasing and digitally enhanced applications.Finally, we are setting up dual vocational training centers for electricians and electronics, supporting skill development in India.
Tell us about some of the prestigious projects in India that Siemens is currently working on?
Griem: Together with Sumitomo Electric Industries Ltd. we recently won the order from Power Grid to supply a high-voltage direct current (HVDC) transmission system. The total size of the order won by the consortium is US $520 million. The about 200-kilometer-long HVDC connection will be India’s first direct current link using voltage-sourced converter (VSC) technology, capable of transmitting 2000MVA at ±320 kilovolt (kV). It will connect Pugalur in the southern state of Tamil Nadu to Trichur in Kerala State in South-West India. The grid-augmentation project will go a long way in delivering reliable, uninterrupted power to the state of Kerala.
Another prestigious project that we are working on is the design, engineering, supply, civil, installation, testing and commissioning of supply static synchronous compensator (STATCOM) solutions to PGCIL. This will be executed across four substation locations of PGCIL: Ranchi, Rourkela, Kishenganj and Jeypore across the states of Bihar, Jharkhand and Odisha. Cutting edge technology from Siemens will result in the installation of one of the world’s largest STATCOM projects at 400 kV level with a dynamic swing range of 2000MVAr and 1250MVAr mechanically switched components. This is the first STATCOM order for Siemens Ltd. and is the latest chapter in the long and successful Flexible AC Transmission Systems (FACTS) journey in India. Siemens Ltd., together with PGCIL, have always been trendsetters in India for FACTS.
" The road map for the country’s energy sector manifests a fine balance between delivering electrification for all and improving the quality of power. "Harald Griem, CEO of the Energy Management Division at Siemens Ltd.
How do technologies like STATCOM and SVC help integrate renewable energy into the grid?
Griem: The task of transporting renewable energy in the transmission grid is becoming increasingly more complex. Since the transmitted load often varies considerably from one hour to the next, the reactive power balance in a grid varies as well, resulting in unacceptable variations in voltage, including voltage depression or even voltage collapse. STATCOM continuously provides variable reactive power in response to voltage variations, supporting the stability of the grid. Operating according to voltage source converter (VSC) principles, STATCOM is a multilevel converter technology. VSC is the latest innovation in HVDC technology, offering a very stable and highly-flexible reactive power control independent of active power control and additional features to support the AC systems like blackstart capability.
By contrast with other self-commutated converter topologies, the voltage wave shape produced is practically sinusoidal by virtue of the multilevel technology. This makes the low-frequency harmonic filters often used in earlier solutions superfluous and substantially reduces the space requirements for the overall unit. STATCOM increases power transfer capability by enhancing voltage stability and maintaining a smooth voltage profile under different network conditions, with the ability to perform active filtering for improvements in power quality. The power converter is based on a modular topology, with each branch consisting of series-connected insulated gate bipolar transistor modules (IGBT power modules). In the rare event of a fault, these would continue to ensure operation at full rated power without a forced shutdown. Replacement of defective components could then be postponed until the next scheduled maintenance.
How important is digitalization for the transmission and distribution grids?
Griem: Without it, the operators could not deal with the complexity and the long distances covered by the grids. Balancing fluctuating generation with demand and managing load intelligently without load shedding requires digital control centers. Maintenance benefits from digitally transmitted signals and diagnostics. Mostly, digital systems can be installed and commissioned much faster.
Smart grids are also essential to reduce losses. The fewer cables are used, the less tampering and theft can occur. Smart metering improves the connectivity and demand side management, where many customers are fine to pay for an uninterrupted power supply.
June 16, 2017
Picture credits: Arush Mayank; Siemens