Claudio Cenci, Andrea Delpozzo, Luca Marcolongo, Stefano Premarini, Marco Riva, Marco Testa, Lorenzo Verniani ABB Electrification, Dalmine, Italy, claudio.cenci@it.abb.com, andrea.delpozzo@it.abb.com, luca.marcolongo@it.abb.com, stefano.premarini@it.abb.com, marco.riva@it.abb.com, marco.testa@it.abb.com, lorenzo.verniani@it.abb.com
Consistent with the emerging smart grid concept in which the flow of energy and communication are bi-directional, the role of the MV CB is evolving. These devices are no longer simply used for protection, they are proactive apparatuses able to interact with the main installation-specific electrical entities and to coordinate operations. The increasingly pressing demand from public utility companies and private industry for greater continuity of service and a better quality of energy supply lead to further requirements: ie, the ability to manage energy flows generated by renewable energy sources of variable input, eg, distributed energy resources (DERs), additional storage and the electrification of transport →02.
Such profound changes in how electricity is generated and distributed parallels notable advances in the development of grid control and protection components, growth in the use of electronic sensor systems for collecting data, and the application of advanced analytics. Combining such innovations could help make the power grid smarter, more robust and reliable, as well as efficient in terms of energy and maintenance while improving safety and protection.
Recognizing the opportunities of this convergence, ABB re-examined their conventional, yet highly successful, VD4 CB. With over 2 million installed units, this vacuum indoor CB with mechanical actuator (spring mechanism) is intended for primary distribution up to 46 kV, 4,000 A, 63 kA. ABB wondered if they could provide end-users with the benefits of new digital and green technologies while continuing to deliver the VD4’s sterling level of safety and protection. The trailblazing VD4 evo CB is ABB’s answer: a smart protection system that builds on the success of the VD4 CB to create a safer, more connective, cyber secure solution that is sustainable.
Diagnostics and protection for the MV smart grid of the future
The new VD4 family is designed to provide protection and control for cables, overhead lines, distribution substations, motors, transformers, generators and capacitor banks. This new generation of CBs considers the state of the electric power supply (voltage, frequency, harmonic components, etc.) and load conditions (current values, displacement, etc.) in the control and execution of commands, thereby allowing for the optimization of current interruption, mechanical and electrical life by adapting their behavior to the power system conditions [1,2].
With up to a 60 percent improvement in efficiency, a 30 percent reduction in unexpected outage and 15 percent increase in compactness, the VD4 evo improves operation thanks to embedded monitoring and diagnostic features. Sensors not only continuously monitor and analyze the operational status but also communicate this status, displayed on an on-premise human machine interface (HMI).
By integrating new components, control and diagnostic functions and introducing new services in life management for VD4, targeted recovery actions can be taken and condition-based and predictive maintenance is possible [3]. Thus, reliability is improved, leading to a longer service life and limiting the impact on the power grid.
Improving MV CB operations
The high-tech integrated sensors embedded in the CB are the “eyes and ears” of the new VD4 evo family of CBs . Sensors devoted to monitor various parameters are available for the first time onboard the apparatus: mechanical, eg, travel curve, vibration; electrical, eg, current, voltage, temperature and other relevant signals. The sensors consistently collect data related to operation consisting of both “continuous” parameters, eg, temperature and, or, primary AC current; and “on event” parameters, eg, vibration during closing or opening of an operation. Moreover, information can be shared with the intelligent device inside the CB control and monitoring unit (CMU) – the core of VD4 evo monitor and diagnostic (M&D) features.
CMU and Maxwell Platform
The CMU in VD4 evo is based upon Maxwell, the ABB proprietary platform specifically designed to support M&D and ABB Ability™. This solution enables the collection, processing and analysis of data from sensors or other smart devices. ABB’s all-important Maxwell architecture is based on a modular design →03:
• System on Module (CPUM), in which the Linux embedded OS and customized analytics and user interfaces have been developed according to specific applications.
• Carrier Board that provides a dedicated enclosure for the proper hardware interfaces for each specific application requirements: power management, upstream/downstream communication interfaces, eg, serial and wireless connectivity, I/O →03a.
03a The schematic illustrates the hardware and software and interfaces for each specific application requirements. 
03b The CMU is based on ABB’s Maxwell, and has a modular structure; it has been designed to support M&D and ABB Ability™.
03 Schematics that indicate the architecture of VD4 evo and CMU and the important interactions and connections are displayed.
With more adept communication capabilities, remote monitoring and a prompt response to critical events is ensured. By communicating with automation and control systems, eg, ABB Ability™ zenon supervisory control and data acquisition system (SCADA), to implement necessary corrective protection, negative impacts to other parts of the smart grid are minimized; efficiency and reliability are ensured, outage time is reduced and power continuity is improved →03b.
The monitor diagnostic concentrator
Because collecting data quickly is not enough, the VD4 evo’s smart concentrator processes the data, aggregating and forwarding information received from the sensors, eg, meters, continuously in real-time, or periodically →04. Using specific algorithms, the device searches for anomalies or problems in the breaker, eg, overtemperature or other anomalous behavior. Based on the processed information, the intelligent device diagnoses the condition of the CB and provides alarm alerts or warnings of any critical situations that would require immediate action.
The digital “heart” of the VD4 evo also enables direct connectivity to the health management system of the CB [3]: CMU offers both a Wi-Fi access point, on mobile phones and tablets via a QR code →05, and direct integration to the SCADA system. Data transfer and storage are completely safe thanks to the application of the latest cyber security standards.
05a By simply accessing the QR code via tablet or smart phone, customers can rapidly access important information. 
05b With the QR code, the latest catalogs, instruction manuals, and the newest test results are obtainable. In addition customer can contact ABB directly and of course access the breaker.
05 The VD4 evo includes a QR code.
Data management – key to cyber security
A CB that enables data collection not only poses technical challenges for advanced monitoring of electrical circuits, the security challenges arising from data availability and sharing can also be significant. Despite offering the benefits of flexibility and efficiency, connectivity increases the attack surface related to M&D features, thereby providing more opportunities for the exploitation of vulnerabilities related to the digital part – the primary function of the breaker is unaffected. Nonetheless, the expanding integration of operational technology (OT) with information technology (IT) drives the creation of more complicated networks and devices that could be prone to encroachment if cyber security is inadequate. Thus, ABB applied best practices to their cyber security approach for VD4 evo.
Establishing cyber security in OT is quite different in scope from cyber security in IT because devices must perform in real-time, outages are prohibited, the technology lifecycle is longer (>20 years compared with five years) and patch updates are more difficult and take longer to be applied. Moreover, security awareness among users is typically lower. And yet, data confidentiality, availability and integrity must be granted, data security risks must be assessed, and a defense-in-depth strategy must be adopted.
For these reasons, ABB’s VD4 evo solution integrates cyber security requirements starting at the development process stage, thereby leveraging threat modeling. This approach was initially defined by Microsoft [4] and the ABB vulnerability handling process [5]; as well as assessing the architecture using a STRIDE approach [6].
Consequently, the product has been hardened by removing unused ports and services; integrating a traffic limiter to prevent Denial-Of-Service attacks from upstream interfaces, including encrypting data over a Transport Layer Security (TLS) channel. The device implements a Role Base Access Control (RBAC) policy that allows the configuration of as many user accounts as there are real product users. For the purposes of security, these users are allocated differing levels of privilege according to the principle of least privileges. The system can be easily updated by connecting to its Web interface. All software updates are signed by using ABB Public Key Infrastructure (PKI) and any non-authentic software is automatically discarded.
For additional security in case of cloud interfacing, the product has been based on a microprocessor with a secure-boot module onboard and includes a secure element (Trusted Platform Model-like device). These VD4 evo security improvements ensure that cyber security meets the necessary standards.
VD4 evo dashboard interface
It is only when extensive information, made possible by analytics and expertise, can be interpreted and conveyed to end-users securely, that failures and outages can be avoided. In the case of VD4 evo, the dashboard is the user’s control cockpit →06. The CB and parameter interfaces show the current flow value and the general health status of the breaker, informing, and holding to peak current limits through the use of embedded electronic sensors, eg, meters. This information reflects physical quantities: thermal, electrical, and mechanical →06a.
06a This dashboard shows the health status of thermal, electrical and mechanical entities of the CB, thereby reflecting the physical quantities. 
06b An example of the opening- and closing times that are used to ascertain if the CB is running properly. 
06c An example of the analytics used to detect criticalities on the primary current path.
06 Examples of some of the VD4 evo dashboards are displayed.
In regard to thermal monitoring, up to 13 thermal sensors can be installed: six sensors are embedded in the contact arms of the CB (close to the interface with the panel), six wireless sensors are added to check the cable and busbar status, and one ambient sensor is added to check environmental temperature and humidity. Here, the analytics detect criticalities on the primary current path, eg, bad, loose, or damaged mechanical and, or, electrical connections →06c.
As for electrical monitoring, the data that arrives from a current sensor, CTs, installed on the panel, are used to estimate the remaining life of the CB vacuum interrupters (VI) by continuously monitoring the primary current, including any breaking currents traveling through the CB →06.
Electrical data is combined with thermal data for an advanced dynamic thermal monitoring that considers electrical load and environmental conditions to display the temperature limits of specific applications; the thermal setup is fully configurable.
Mechanical monitoring is a complex interaction of kinematic parts: tolerances, accessories and spring motion. Here, each mechanical operation is monitored by a magnetic angular sensor, placed precisely on the main shaft of the CB to detect the entire motion (position, speed), and by three Hall-effect sensors that monitor the auxiliary currents that power the opening- and closing coils of the device as well as the closing spring’s charging motor.
Critical parameters, eg, the opening- and closing times and speeds, are analyzed to check if the CB runs within the design prescriptions →06b.
Each resulting parameter is assigned a unique health index. The VD4 evo system translates this information into user-friendly visualizations displayed on the HMI. And if anomalies arise, the users, eg, maintenance manager or operator, can easily access details within the dashboard to determine a possible root cause, or if actions are required. The user even has the ability to contact an ABB expert through service maintenance sup- port. And if errors persist following operations, the user can download the device database and contact service for further support.
Sustainable management and protection of energy distribution
Demonstrating a strong commitment to the environment, ABB aims to reach carbon-neutral operations by 2030 and actively helps customers reduce greenhouse gas (GHG) emissions in their operations. By developing eco-friendly and sustainable technical and digital solutions such as VD4 evo, ABB shows their commitment to helping industry reach their sustainability goals.
Concomitant with these ambitions, ABB considered the environmental impact of VD4 evo throughout all phases of the product’s development [7]. The effects of additional electronic components could be evaluated by benchmarking the Life Cycle Cost and the environmental impact of traditional apparatuses and solutions versus the new generations.
The Life Cycle Assessment method was applied to evaluate environmental performance of VD4 evo by defining, compiling and evaluating the inputs, outputs, and potential environmental impacts for manufacturing, including upstream process (eg, acquisition of raw material, etc.), the main manufacturing and processing steps; distribution; installation, including use preparation [7]. Usage includes the required maintenance steps; the end-of-life stage includes all steps until final disposal or product system recovery.
Based on the resultant models, ABB found that during the first phase of the product’s life, a higher environmental impact results from the additional use of resources and energy but that this can be offset through improved efficiency during the operational phase [7]. Moreover, reliability and life extension through predictive maintenance help VD4 evo reach the lowest possible overall impact.
Building on the success of VD4, ABB’s new digital MV CB, VD4 evo, provides advanced control and diagnostic capabilities, using an algorithm-based prediction model that allows real-time asset assessment. Thus, VD4 evo helps customers meet the pressing demands of an evolving smart power grid efficiently and reliably, yet safely and sustainably with the utmost cyber security →07.
Further information
ABB product website, “IEC indoor vacuum circuit breaker VD4”.
ABB product website, “VD4 evo Evolution that empowers”.
ABB website, “ABB Sustainability Strategy 2030”
References
[1] M. Riva, et al., “The future evolution of medium voltage circuit-breakers: new developments and possible applications” in Proceedings CIGRE, Paris, France, Aug. 2018, pp. 1 – 10
[2] M. Testa, et al., “Towards Smart Digital Circuit Breakers enabling advanced control and diagnostic features.” Proceedings 25th Intl. Conference on Electricity Distribution, Madrid, Spain, 2019, pp. 1 – 5
[3] M. Scarpellini, et al., “Asset assessment method in a MV predictive model to estimate the asset status”, Proceedings 2018 Petroleum and Chemical Industry Conference Europe, Antwerp, Belgium, 2018, pp. 6 – 11
[4] Microsoft Website, “Security Engineering, Microsoft Security Development Lifecyle, Threat Modeling”, Available: https://www.microsoft.com/en-us/securityengineering/sdl/threatmodeling [Accessed Aug. 9, 2023.]
[5] ABB internal document, “ABB’s approach to software vulnerability handling”.
[6] L. Kohnfelder and P. Garg, “The threats to our products” Microsoft Interface, Microsoft Corporation 33, April 1, 1999.
[7] The Norwegian EPD Foundation, "Environmental Product Declaration VD4/P 12/17.12.40", Sept. 5 2022, Available: https://library.abb.com/d/2RDA044481, [Accessed Nov. 17, 2023.].
Figures 04 – 06 are taken from a video about the VD4 evo. Watch the full video here: https://search.abb.com/library/Download.aspx?DocumentID=9AKK108467A4976&LanguageCode=en&DocumentPartId=&Action=Launch
Photo fig. 07: ©Rawpixel.com/stock.adobe.com
