IEC 61850 standards are the global standard for communication in substations. It is gaining popularity in power substation automation and will dominate the future substation automation and protection system design. The standards provide new approaches for protection, control and metering function via communication. The secondary circuits in substation are simplified significantly and the massive hardwired cables are replaced by the high-speed process bus which transmit analogue and binary signals with Ethernet messages. However, the conformity of a device with the standards does not necessarily guarantee the interoperability with devices from different manufacturers. The use of devices compatible with IEC 61850 standards presents a challenge to many system integrators, especially due to lack of familiarity with features such as Generic Object Oriented Substation Event (GOOSE), reporting, Sampled Values and the need for system redundancy. To facilitate a smooth implementation, all the features and the data exchanges between devices need to be tested to ensure the system operates correctly. This project was carried out to study the protection performance of secondary schemes with IEC 61850 process bus architecture in substation. The tests were performed including current differential protection and distance protection on a transmission substation of the type used in the UK on the transmission network. The protection schemes were tested under IEC 61850 environment with multi-vendor IEDs like Alstom MiCOM IEDs, NARI IEDs with the OMICRON test set. More tests were carried out to verify the interoperability and the performance of time-critical messages were evaluated under different network architectures. The impact of the background traffic on these two messages was investigated and the response of the IEDs when the Sampled Values packets were lost or overwritten was recorded and provided to utility as a reference. This project also presented a technique to assess the performance of Merging Units from different manufacturers, when operating with Intelligent Electronic Devices (IEDs) performing a distance protection function. The performance of the process bus with parallel redundancy protocol is evaluated using a closed loop approach involving a Real Time Digital Simulator. The results indicate that protection using process bus communication is feasible, and meets grid code requirements when implemented with commercially available products. It was found that process bus operation is robust, even with network traffic conditions far beyond what would be experienced in an active substation.

Un système de distribution électrique est le cœur de tous types de sites industriels, aussi bien les sites producteurs d'énergie que les sites consommateurs. La sécurité de ce système doit être impérativement assurée par la mise en place des unités assurant plusieurs fonctionnalités de protection contre les dédauts électriques. Parmi ces fonctionalités il existe celles qui se basent sur des échanges d'information entre plusieurs unités de protection. Le standard IEC 61850 guarantit cet échange des informations via des signaux ‘temps réel' échangé via le réseau de communication. Vue l'aspet non deterministe de ces signaux, une étude poussée de leur fiabilité doit être effectuée. Pour ces raisons notre travail de thèse a pour objectif de mettre en place une méthodologie, basée sur une plateforme de Co-Simulation conçue pendant notre étude, qui permet la validation de la fiabilité de ces messages tout au long du cycle de vie d'un système de communication IEC 61850. / From 2004, a new worldwide standard of communication IEC61850 is introduced in the majority of substation automation system carrying out new innovation prospects to the world of substation. One of these feature is that it allows the exchange of security real time communication messages all over the communication network. These messages are used as control information for the Distributed Automation Application 'DAA'. Taking into consideration that DAA have a direct effect on ythe dependability of a smart grid architecture, the fiability of these real time IEC 61850 should be evaluated. For these reasons, our research delas with the development of a Co-Simulation platform that permits the evaluation and validation of an IEC 61850 communication network.

Thesis (MEng (Electrical Engineering)--Cape Peninsula University of Technology, 2019 / The purpose of an electrical power system is to supply electrical energy to the customers. Power transformers are required to transform the system voltage from generation to transmission and distribution levels. Protection and control systems must ensure that power system high voltage equipment such as transformers operate and deliver save, reliable and secure electricity supply. The aim of the project research work is to develop and implement a strategy, methods and algorithms for monitoring, protection and voltage control of parallel power transformers based on IEC 61850-9-2 process bus standard. NamPower is a power utility in Namibia. The IEC 61850 protocol for electrical substation automation system is used for the protection and control of 5 power transformers operated in parallel in an existing substation system. The IEC 61850-9-2 process bus standard is however not used in regards of Sampled Values (SV). Protection and control devices are connected to a substation communication network, routers and switches using fibre optic linked Ethernet. Inductive Current Transformers (CTs) and Voltage Transformers (VTs) secondary circuits are hardwired to Intelligent Electronic Devices (IEDs) and fibre optic links are not used for this purpose at process level communication. The research focuses on the implementation of the IEC 61850 standard with Merging Units (MUs) and sampled values to improve the existing implemented protection and control system at NamPower. This includes substation communication networks and MUs used for transformer protection, voltage regulator control and cooling fan control. At the present the CTs located at the transformer bushings and switchgear and the VTs located at the switchgear are hardwired to the inputs on protection and control IEDs. The research focuses on issues with the copper wires for voltage and currents signals and how these issues can be eliminated by using the MUs and the SV protocol. The MUs which are considered in this Thesis is to improve the voltage regulator control and the control of the cooling fan motors. The voltage regulator control IED is situated at the tap change motor drive of the On-Load Tap Changer (OLTC). The IED of each transformer is required to regulate the voltage level of the secondary side bus bar it is connected to. All the regulating IEDs are required to communicate with each other and collectively to control the bus bar voltage depending on the switching configuration of the parallel transformers. The control circuit for controlling the cooling fan motors is hardwired. Temperature analogue signal input into a programmable automation controller IED can be used for controlling the transformer cooling fans. A strategy, methods and algorithms for transformer protection, voltage regulator control and cooling fan motor control of parallel power transformers need to be developed and implemented based on IEC 61850-9-2 process bus. Power utilities and distributors can benefit from interpretation of the IEC 61850-9-2 standard and implementing MUs and SV in substations. MUs can be included in the power transformer protection, automation and control systems. A cost reduction in high voltage equipment, substation installation and commissioning costs and better performance of protection and control system are anticipated.

Substations are important components for transforming voltage and distributing power in electrical infrastructure. Modern substations are usually automated by substation automation systems, which offload the work of operators and reduce potential human error. The IEC 61850 standard was released in 2003 to address the compatibility of electronic devices with substation automation systems. However, it exposed more attack surfaces with the adoption of Ethernet, the wide use of digital devices, and the connection to the Internet. Therefore, it is necessary to analyze the security threats of modern substations. This master thesis investigated the common design options of IEC 61850 substations, then used the graph-based threat modeling method to explore the security weaknesses of those options and compare the effectiveness of security mechanisms. The construction of threat models is carried out with SecuriCAD and several domain-specific modeling languages that developed from the Meta Attack Language framework. Through the analysis of the results, we conclude that the evaluated security mechanisms can bring security benefits and mitigate security threats in the area of substation automation. / Transformatorstationer är viktiga komponenter för att transformera spänning och distribuera kraft i elektrisk infrastruktur. Moderna transformatorstationer automatiseras vanligtvis av transformatorstationsautomationssystem, som avlastar operatörernas arbete och minskar potentiella mänskliga fel. IEC 61850-standarden släpptes 2003 för att ta itu med kompatibiliteten hos elektroniska enheter med automationssystem för transformatorstationer. Men det exponerade fler attackytor med antagandet av Ethernet, den breda användningen av digitala enheter och anslutningen till Internet. Därför är det nödvändigt att analysera säkerhetshoten för moderna transformatorstationer. Denna masteruppsats undersökte de vanliga designalternativen för IEC 61850-transformatorstationer, och använde sedan den grafbaserade hotmodelleringsmetoden för att utforska säkerhetssvagheterna hos dessa alternativ och jämföra effektiviteten hos säkerhetsmekanismer. Konstruktionen av hotmodeller utförs med SecuriCAD och flera domänspecifika modelleringsspråk som utvecklats från ramverket Meta Attack Language. Genom analysen av resultaten drar vi slutsatsen att de utvärderade säkerhetsmekanismerna kan ge säkerhetsfördelar och mildra säkerhetshot inom området för automatisering av transformatorstationer.

With the advancements in the Industrial Internet of Things (IIoT), new networking requirements and demands are introduced to Substation Automation Systems (SAS) within electrical power grids. The possibility of merging Information Technology (IT) and Operational Technology (OT) traffic on the same network to achieve higher productivity, however, presents new challenges in providing real-time guarantees to OT traffic. Time-Sensitive Networking (TSN) can be a promising solution that allows IT and OT traffic to coexist seamlessly while still providing real-time guarantees for critical applications. Substations act as critical nodes within power grids, and their digitalisation is a crucial element in the energy transition. A digital substation handles International Electrotechnical Commission (IEC) 61850 protocol traffic such as Generic Object Oriented Substation Event (GOOSE), Sampled Values (SV), and Manufacturing Message Specification (MMS), which all have strict timing requirements. The integration of TSN into these substations could improve the handling of this traffic and, consequently, the controllability of power grids. This thesis investigates the use of TSN in an IEC 61850 process bus, typically implemented in an SAS. A series of simulated test scenarios were developed to evaluate the impact of TSN compared to traditional networking methods. These included configurations using Ethernet, Ethernet with priority queuing, and TSN with Time-Aware Shaper (TAS) and Credit-Based Shaper (CBS). The results indicate that TSN can meet critical timing requirements, reduce jitter, and manage sporadic traffic effectively under high traffic loads. While the TAS scheduler may increase End-to-End delay for periodic traffic, CBS can reduce it for event-based traffic. Furthermore, robust timing guarantees are ensured for the TSN scenarios by providing a feasible schedule for Scheduled Traffic (ST) and a worst-case response time analysis for Audio-Video Bridging (AVB) traffic. This research highlights TSN’s potential to improve grid controllability and reliability through enhanced network performance, illustrating its role in the future of resilient grid technologies.