Why digital substations need to embrace microgrid integration pronto!

Technology experts and substation managers collaboratively discussed the developing trends and technologies that will further us to achieving successful integration of grids and microgrids through efficient and effective designs and operations through digitalisation, energy storage systems, sensors and monitoring products and technologies.

Power substations are critical components of the power grid infrastructure in India, and several aspects of their design, operation, and maintenance have been the subject of discussion and debate. One key aspect is the need for modernisation and upgradation of existing substations to meet the increasing electricity demand and ensure a reliable power supply. This includes adopting smart grids, which can optimise power distribution, reduce losses, and enable better power quality management. The following interaction has a great inclusiveness of optimistic thoughts and experiences that have been advancing our substations performance and reliability in lieu with our long-term agenda for obtaining smart cities and smart grid.

Integrating microgrid to power substations to obtain optimum efficiency
Integrating microgrids with next-generation and modern substations is a cutting-edge approach to achieving a more resilient, efficient, and sustainable power grid. By combining advanced communication technologies and control systems, microgrids can help to balance energy supply and demand while also providing backup power in the event of outages or emergencies. This integration enables utilities to optimise power delivery, improve energy reliability, and reduce operational costs.

According to Ajay Tiwari, Associate Vice President for Projects at Jakson Group, integrating microgrids into power substations can provide several benefits. By incorporating smaller and distributed sources of energy, we can reduce our dependence on large, centralised power plants that are more susceptible to disruptions and outages. During peak demand periods, microgrids can help balance the grid by providing a more stable and predictable source of energy. In the event of a blackout or other disruption, microgrids can operate independently from the main grid and provide power to critical infrastructure, such as hospitals, emergency services, and water treatment plants, thus improving the resiliency of the grid. Tiwari also suggests that using renewable energy sources, such as solar and wind, in microgrids can help to reduce greenhouse gas emissions and mitigate the impacts of climate change. Excess energy generated by the microgrid during periods of low demand can also be stored using battery storage technology and used during peak demand periods or during grid outages.

Therefore, integrating microgrids into power substations can potentially improve the reliability, efficiency, and resiliency of the grid while reducing our reliance on fossil fuels and lowering our carbon footprint.

Rajiv Goel, President of Vivani Consulting Pvt. Ltd., explains that microgrids enable the injection of power into the main grid from the downstream side. However, there can be losses and the potential for overloading when power is transferred from the upper stage. When power is returned to the substation, it helps balance the upstream power flow and reduces the pressure and temperature on the distribution network, thereby mitigating the risk of overloading.

Microgrids also offer other benefits to the power distribution system. By incorporating local sources of renewable energy and energy storage, they can reduce the reliance on energy imported from distant locations, which can be vulnerable to disruptions. In addition, microgrids can operate independently during a power outage, providing a backup power supply to critical infrastructure.

To integrate microgrids effectively into substations, there are some key considerations that need to be taken into account. For example, the microgrid must be designed to operate safely and efficiently with the main grid, and appropriate control and protection systems must be in place. It’s also important to consider the economic viability of the microgrid and how it will be financed and maintained.

Obtaining substation performance efficiency and grid stability with IoT and 5G communication
In the future, substations will incorporate various advanced technologies, not just for conventional generation, but also for renewable energy sources such as solar and wind power, and even hydrogen-based fuel cell storage. Commenting on this Akilur Rahman, the Chief Technology Officer at Hitachi Energy, says “This will require the integration of diverse sensors, controllers, actuators, and communication systems. The traditional deterministic communication system will have to be extended to include cloud computing for asset performance management, additional sensors, data collection to improve predictability and real-time monitoring of power evacuation and predictive maintenance. Communication is crucial in this context, and the new IoT cloud-based communication and 5G technologies must be proven in the substation environment to be reliable and secure.”

The goal is to achieve real-time control that is reliable while accommodating changes in the sources of energy and loads. The system should provide real-time information about the asset operation and system, and predictive and prescriptive maintenance. In addition to augmented reality-based applications, the substation design and real-time data about assets, such as transformers and circuit breakers, should also be taken into account. Communication plays a significant role in ensuring reliable and secure control, and new communication technologies such as 5G and wireless mesh must be integrated to increase reliability.

Rahman emphasises that the technologies are available; it is a matter of implementing them competently and making them reliable.

Piyush Pandya, Sr. VP-South BU, IndiGrid, takes this opportunity to talk about the utility perspective. He stresses that it’s important to look back at how asset management of substations or transmission was traditionally done. It was mostly manual interventions like surveillance inspections and based on that, certain decisions were made. However, with India adopting the one-grid principle, it’s become more challenging to serve the grid in a reliable, secure, and safe manner, while keeping the cost low.

As the country transitions from fossil fuels to renewable energy and with the plan of adding 500GW of renewables to the transmission sector, it’s important to have a more secure and reliable network and asset management practices to meet this growing demand. The foundation block for this will be the digitisation of all the assets, data inspections, and records. On top of that, AI and ML analytics will help convert the data into meaningful information for decision-making.

Regulations and policies in advancing digitalisation for the next-generation substations
When it comes to digitalisation, it’s important to start with guidelines, installers and a pilot program that has been tested and proven reliable. Once that is in place, regulations can be brought in to ensure compliance with grid codes and 62-1850 based standards.

On analysing this, Rahman emphasises the need to keep the core substation automation system, including SCADA and EMS, highly secured, while the asset performance management, IoT and digital twin should be kept as a separate shell. This is necessary to protect the core system from emerging issues and vulnerabilities that may arise due to high connectivity with different devices.

To ensure cybersecurity, they follow a “defence in depth” strategy where the core is created and protected with a shell to keep it safe from any cyber-attacks. The IoT cloud can still be isolated in case of any issue.

Leveraging technology to enhance communication resiliency and reduce outages in rural areas
As far as power losses in the rural areas are concerned, they can be tapped and are already being tapped to a great extent, says Goel. If we are talking about the communication technology available to reduce the RSB Power slab, I believe we have limitations as it will be difficult to do that. As far as technical losses are concerned, today, the modern grid operates on two power transformers are installed in substations with a load capacity of 10 MVA each. These transformers can sense the load condition in the unit balance the load in the power transformers and in the substation. Furthermore, we can use 2-3 transformers with various MVA capacities as it will help us curtail the technical losses.

Elaborating on the technology implementation and their advantages, Rahman emphasises the importance of assessing the existing system or building a new one in rural areas. He suggests carrying out simulation studies to determine if the feeders are radial, if there are losses, and how to create a power mesh network to reduce losses and improve reliability by allowing power feed from multiple points. By studying the lines before or after they are laid out, the system can be enhanced with multiple connections, creating a mesh and parallel path for power flow to ensure minimal losses and uninterrupted power supply to consumers.

The goal is to maintain a reliable system that doesn’t give any surprises in terms of substation tripping or downtime. By implementing these measures, they can create a scalable and secure system that is adaptable to new technologies and advancements in the future.