Digital Substations: Transforming the Connected Grid

As the world moves into a more connected, sustainable, and energy-efficient future, infrastructure plays a crucial role in enabling this transformation. One such transformative innovation – the digital substation - is changing and revolutionizing electrical grids.   

With VPR (Virtualized Protection Relaying) technologies, utilities have the tools they need to optimize grid performance, lower the cost of operations, and get better insights into the grid. This article talks about how digital substations, virtualized protection relaying and testing enhance the reliability and safety of the grid.  

The digital substations market would grow well, and it has a projected compound annual growth rate of 7.7% over the period 2023 to 2033. The market is estimated to reach US$ 15.1 billion by 2033 from US$ 7.23 billion in 2023. All this is basically due to the advancement of technology in grid modernization, the rise in energy demand, and a strong need for reliable, efficient, and smart grids globally.  

(Source: Digital Substations Market Share, Size & Forecast 2033)

Rise of the Digital Substation   

In a digital substation, the various components like smart electronic devices, protection relays, and automated control and monitoring systems are inter-connected. In an integrated setup, optimized electricity flow becomes possible while performance of the grid is continuously being monitored in real time. Traditional substations, on the other hand, have these components operating on their own, increasing the complexity of systems to identify faults in a timely manner. This absence of integration causes delay in troubleshooting and restoration of operations.  

Automation and remote monitoring with digital substations enable faster response times, reduced downtime, and lower probabilities of faults or outages. They utilize advanced diagnostics and predictive analytics for detecting developing issues before they become serious enough to require significant interventions, hence avoiding service disruption.  

With all other industries having already moved to the digital platform, the power sector is also transforming its infrastructure to capitalize on the digital revolution.  

Virtual Protection Relays (VPRs): History and Importance 

A Virtual Protection Relay (VPR) is a software-based system decoupling protection algorithms from the physical relay hardware. The primary goal of VPR is to improve substation operations and maintenance by simplifying the control room setup. 

In the early 2000's, the IEC 61850 set of standards brought in a major boost to multi-vendor IED integration and device-to-device data transfer. Standards were prepared for data exchange between devices (station bus) and current/voltage information from field (process bus).  

As IEC 61850 standards gradually got acceptance across the world, it led to the creation of station level and process level communications networks for the exchange of raw digitized values as well as the processed values/information among the substation's varied devices and other such monitoring systems located outside the substation.   

The below figure shows the IEC 61850 Digital Substation Network model. Merging Unit(s) (MU), circuit breaker controllers (Breaker IED), relay and control devices (IED), and supervisory control and data acquisition (SCADA) systems are connected across three conceptual levels with communication buses. 

Source: VPR Whitepaper   

Implementation of protection for even a single medium-voltage substation requires up to 100 individual IEDs each with its own power supply, case, electronic components, firmware, installation and maintenance guide(s), and configuration tool(s). Each vendor of IEDs has their own design paradigm for their hardware and there is a significant engineering cost to swap one make or model of an IED with an essentially equivalent IED from another vendor.   

Why has VPR become important now? 

VPR eliminates many of these costs, reduces the physical size and complexity of a substation protection and control infrastructure, and opens the market for software-defined innovation where the best-of-breed protection functions and automation algorithms can be deployed with high confidence and reliability but minimum cost.   

Virtual protection relays drastically bring down operational and deployment costs as they do not require a lot of cabling, recurrent maintenance, and physical infrastructure, unlike traditional relays. Additionally, when compared to the long testing cycles of traditional relays along with the time-consuming upgrade cycles, VPRs offer quicker deployment and easier upgrades.   

Moreover, as the integration of Distributed Energy Resources (DERs) continues to increase, these systems will not only have more innovative, flexible, and custom-made control functions but will also be suited to traditional power grid engineering, respectively. Virtual protection relays are more adaptable and provide enhanced cybersecurity that manages dynamic characteristics of modern power grids and complexities in DER systems. This flexibility, along with lower operating costs and quicker implementation, makes virtual protection relays a preferred choice for modern electrical infrastructure.  

Virtual Protection Relays: Challenges in Implementing  

Although VPRs have become increasingly popular, their deployment is still limited to pilot projects that are conducted to test their feasibility. Digitalization has a historical trend of always beginning first with the consumer and e-commerce sectors then, after a certain period, retail, aviation, and banking before settling down finally in the energy and utility domain. The energy sector is very slow in adopting new systems because infrastructure is critical, and security risks are higher. Many a times, the utilities have been found to be under a cyber or a terrorist attack or a black-out, so any transition or upgrade in this industry is a very careful and slow exercise.   

Although private enterprises will probably take the lead in using VPRs, especially for private substations, broader rollout will take several years to materialize as utilities move forward with careful testing and security considerations.  

Virtualization of Relays: An Emerging Future in Grid Protection  

The protection relay forms the core of any given substation's reliability. Protection relays detect faults and irregularities within the network, and automatically initiate safety mechanisms to avert damage to the infrastructure or loss of service. Traditionally, these are hardware-based in that they require physical presence within the substation and the human hand in testing, configuring, and calibrating.  

Operational Benefits of VPR  

Testing and deployment of Virtual Protective Relays (VPRs), however, are changing with virtualization. Some of the key advantages that virtualized protection relays have over hardware-based systems include:  

1. Reduced Hardware Dependence: Virtual protection relays (VPRs) do not need large physical devices since they run on software platforms deployable on standard IT infrastructure. This reduces the cost and complexity of maintaining physical hardware and enables more scalable solutions.  
2. Quicker Testing and Configuration: Virtualization facilitates the very testing of protection relay settings and configurations quite efficiently. It is possible to simulate real field conditions, including fault scenarios, without the need for actual field testing.   
3. Better Adaptability and Flexibility: Virtual VPRs can be updated and reconfigured remotely, thus under better scenarios for the adaptation of changing grid conditions or evolving regulatory requirements.  
4. Cost Efficiency: Since VPRs run on virtualized platforms, their infrastructure cost would be drastically cut for the utilities since they would not have to make expensive procurements to place physical protection devices at every substation. A virtualized system is managed centrally rather than locally, thereby achieving a reduction in personnel on site, and hence operational costs.  
5. Advanced Cybersecurity: Virtual protection relays are hosted on secure IT infrastructure, thus taking advantage of the latest cybersecurity protocols that could always be updated to ward off new threats.  
6. Better integration with the smart grid: VPRs is integrated with the other digital technologies on the grid, such as smart meters, sensors, and advanced data analytics platforms. This offers better decision-making opportunities to utilities regarding the operation of the grid and energy distribution, thus leading to a more efficient and stable grid.  

It is critical to evaluate and ensure that VPRs perform flawlessly under real-world conditions. In this regard, Kalkitech with the support of Intel Corporation established The Advanced Grid Automation Technology Lab at Campbell, CA which offers a unique environment for integrating, evaluating, and promoting the use of advanced computing technologies in the substation for modernizing protection, automation, and control (PAC). Among the key features of the lab is the utilization of Ametek Real-Time Digital Simulator (RTDS) for hardware-in-the-loop (HIL) testing of virtual protection relays (VPRs). The Lab provides a vendor agnostic environment to develop, verify, measure performance and troubleshoot advanced concepts and ideas. 

How Virtualization and Testing of VPR Relays Benefits Utilities  

The virtualization and testing of VPR relays offer utilities operational benefits that include improved asset management, better operational efficiency, and enhanced grid reliability. These are achieved through features like quicker fault detection and response, predictive maintenance through remote monitoring and diagnostics, and improved resilience as they are more resistant to physical damage and allows grid operators to restore service faster for critical operations.  

Conclusion: A Smarter, More Resilient Grid  

Digital substations and virtualized VPR relays are making big strides towards modernizing the electrical infrastructure. These innovations increase the efficiency and reliability of the grid as well as enhance utilities' ability to respond to disruptions, manage complexity, and deliver continuous service to their customers. Urgency now lies in the designing of an adaptive, agile, and resilient grid, especially with the integration of renewable energy sources and electric vehicles on the horizon. It is now that virtualized protection relays-based digital substations can play a pivotal role in the proper implementation of a more intelligent, sustainable, and better-prepared grid for tomorrow's challenges.  

These are not choices but necessities for utilities to stay competitive and resilient in this new landscape. By tapping into the power of a digital substation and virtualization, utilities are transforming not only their operations but also shaping the future of the connected grid.