Matthew Carrara

José María Torres

Stewart Flood

This paper focuses on the development of SF6 expertise, ESB's approach in the legislative process, and our strategy for adoption of non-SF6 switchgear. The previous use of SF6 gas and new legislation drove updates to our practices to lower emissions and enforce a circular economy for SF6 gas. With new legislation, ESB took the initiative to collaborate with legislators on a feasible approach to moving away from SF6. The scene is now set for a completely new approach to switchgear and a move to zero emissions in line with ESB’s net zero strategy.

Neil Gwinnutt

The proposed alternatives to SF6 gas, either other halogenated compounds or Gas of Natural Origin, create challenges when it comes to assessing the condition of the gas during the commissioning and on-going maintenance of breakers. This presentation will cover the new technologies (InfraRed) associated with measurement of the new Novec gases and Gas of Natural Origin (Dry/Clean air) along with their breakdown products. This will be referenced to the upcoming release of the new IEC 63360 standard relating to the measurement of insulating gases and the ongoing work of IEC 63359 relating to measurement of SF6 alternative gas breakdown products.

Marco Piga

Some factors that affect GIS equipment life expectancy include SF6 gas leakage, mechanical component deterioration, gas humidity content, and insulation deterioration/breakdown. GIS monitoring can help provide real-time data on the condition and performance of GIS equipment and in turn help optimize maintenance and operation activities by providing historical trends. This paper will discuss the advantages of online GIS monitoring and present real world case studies.

Bruce Pahlavanpour

Ed Casserly

Specifications for the supply of mineral insulating liquids are published and used as a standard by both buyers and suppliers to define their mutual obligations. IEC 60296 is the most widely used standard for insulating liquids. Edition 4 was published in 2012 and underwent a major revision in 2020 to provide one specification for both virgin and recycled oil. As the quality of the insulating liquid and the expectation of the performance in-service has improved, the standards must adapt. New tests, specification limits, and labelling requirements were introduced and will be discussed.

Riccardo Actis

Assessment of the hydration state of cellulosic insulation is not an easy task, because it is impossible to take samples from the transformer active parts and make laboratory tests. The traditional method to determine the water content in the cellulosic insulation is based on measuring the absolute water content in oil and using equilibrium diagrams. Diagnostic methods, such as Frequency Domain Spectroscopy (FDS) and Polarisation Depolarization Current (PDC) measurement, are more expensive and can be difficult to apply but are able to give more reliable results. Online measurements using water probes could be a good compromise between the technical and economical effort to achieve reliable results. This paper gives an overview of the available techniques and methods to determine the water content in cellulosic insulation.

Miguel Ronderos

Pablo Pacheco Ramos

Inna Geramisova

Sergey Snagovskoy

Three-winding core-form transformers with axially stacked windings require a special thermal design approach compared to traditional concentric core-form winding configurations. Windings stacked on top experience a higher oil temperature rise, while those below experience a lower oil temperature rise. The differences are more significant for ONAN and ONAF cooling due to the larger differences between the top and bottom oil rise. Understanding these temperature differences from an experimental point of view, provides an opportunity to optimize the transformer operation. This paper will compare the traditional and special thermal model for a three-phase, 160MVA (ONAF), 400/30/30kV GSU transformer with axially stacked low voltage windings. 

Andrés Tabernero

At an industrial facility, routine DGA measurements collected as part of a predictive maintenance programme detected an unusual rise in the gases in a transformer which was only 7 years old. Investigative works were carried out during scheduled plant maintenance to determine the cause of the irregular DGA pattern. The paper will discuss the unexpected findings of the investigation and the solution; ultimately, the solution led to the DGA results returning to normal levels.

Steve Brauer

Dissolved gas monitors are remarkable machines. To protect electrical assets they need to deliver sensitive and accurate chemical measurements multiple times per day over many years, oftentimes in unforgiving electromagnetic and climatic conditions. In this presentation we will review the different gas-measurement technologies in these products and the trade-offs each presents for measurement performance and cost-of-ownership. We will also describe how other key subsystems contribute to the overall DGA performance. Finally, we will review factors beyond the monitor datasheet that are worth considering to ensure the success of a DGA monitoring program.

Bart Farrell

Inspiring trends for an ever-changing energy scenario. A broad and general vision of the keys to the future of energy, which aims to guide companies and professionals in anticipating challenges and taking advantage of new opportunities for business.

Jimmy Godwin

This paper explores some recent developments in asset health monitoring and inspection, sharing experiences of conceptual methods, illustrates some of the asset management strategies being developed by the Asset Management team to improve the asset health of its equipment. It demonstrates the benefit of proactive seasonal preparedness, conceptual utilisation of Spot the Dog Robot and the centralisation of Asset Health data for easy visualisation within the HVDC converter station. The initial and conceptual outcomes look promising in terms of failure prevention in winter, ease of inspection and detecting incipient failure and creating a one-stop-shop for all the data for quick decision making. However, there are some caveats to one of the strategies at this conceptual stage since there is no published information to date to the deployment of robot technology in an HVDC converter station.

Bryan Gwyn

The rapid emergence of artificial intelligence (AI) capabilities is profoundly transforming operational technology (OT) security in the energy and utility sectors. The rise of advanced machine learning algorithms enables predictive cyber threat detection by identifying anomalies and patterns in massive amounts of OT system data that point to potential attacks. AI's rise is also automating response to cyber intrusions across multiple sites in near real-time. These AI innovations are making OT security more proactive and adaptive. However, the rise of AI also introduces new vulnerabilities that must be managed, including biases, data poisoning attacks, and adversarial sample evasions. Energy and utility companies need to implement responsible AI strategies, promoting transparency, ethics and security in design. With proper governance, the rise of AI can significantly enhance OT security resilience. But securing AI itself is equally crucial as its role in critical infrastructure expands. The right balance can amplify the benefits of AI's rise while minimizing emerging risks.

Tawanda Chitifa

The ongoing energy transition regime has led to the rapid increase in the development of offshore windfarms, among other energy resources. Apart from providing a vast and sustainable source of renewable energy, the offshore environment solves some pertinent hurdles for developers, especially around the issue of public perception. However, it has also created new practical and economic challenges for asset managers whose responsibility it is to maintain maximum availability of the associated assets. This presentation discusses those challenges and shares insights into how innovation has to come fast if asset managers are to adequately address the issues presented by the harsh and often unpredictable offshore environment.

Tony McGrail

Alfredo Ortiz

The EU H2020 funded BIOTRAFO project is generating knowledge on the temperature in the windings of transformers when using biodegradable liquids, which by their nature are more viscous than traditional mineral oils. This temperature is a critical factor for the useful life of the transformer, due to the aging of dielectric solid materials. The aging of these materials immersed in these liquids will also be analysed. The project is not only addressing this question from a theoretical perspective, industrial platforms will also be used to test the generated models.

Rannveig S. J. Loken

In this presentation experience from Statnetts R&D Digital substation will be given. The goal of the project was to develop the next generation protection, automation and control system using IEC 61850 process bus in a transmission substation. The multivendor system combined protection and control from two 420 kV line bays in the same IED. The architecture of the pilot system will be described and discussed. Some experience related to testing of the system will be shared.

The R&D projects "Engineering and Condition monitoring in Digital Substation" and "Power system protection and control in digital substations" from Norway will be shared.

A summary of CIGRE working group B5.53 that discuss Test Strategy for Protection, Automation and Control Functions in a Fully Digital Substation Based on IEC 61850 Applications will be given. In the end the Experience gained and Recommendations for Implementation of Process Bus in Protection, Automation and Control Systems from the ongoing CIGRE WG B5.69 will be summarized.

Imad Kanouni

A transformer bushing is a special insulating device that enables the passage of an energized, current-carrying conductor through the grounded tank of the transformer. Transformer bushing failures are often credited as one of the top causes of transformer breakdowns, so the condition of the bushings is of high interest to transformer asset owners. Typical bushing failure modes include moisture ingress, electrical flashover, and lightning strikes. Room temperature vulcanising (RTV) silicone rubber coating for High Voltage Insulators (HVIC) is essential to preserve the integrity of the bushings under stressed conditions.

Elmer Sorrentino

Juan David Hernández

Carl Johnstone

The trip-time and travel parameters of a population of 400 kV breakers were being used a simple binary monitoring system (ok/alarm). Data was extracted from the online devices for statistical analysis to create a time-travel chart for the breakers. A single ‘cloud’ of results was expected, but, in fact, there were two distinct clouds; an investigation into the variation uncovered a design change which affected the timing. Further analysis showed the two designs corresponded to the two ‘clouds’, except for one point which was ‘in the wrong cloud’. Examination of this anomalous breaker showed that the timing results had been affected by a sheared bolt in the mechanism. The bolt was fixed and an untimely failure avoided. 

Sergio Valle

Carlos Sardá

Condition assessment of transformers through oil analysis has been one of the most efficient ways for many decades. Dissolved gases analysis can detect a latent defect inside a transformer. Some insulating liquids tend to produce certain amounts of gases in service unrelated with a transformer fault, that interfere with DGA diagnostic. However, nowadays there are some resources to overcome this issue. We will discuss the methods to test Stray Gassing, what factors should be considered, and we will make a review of the different tools to interpret the Stray Gassing results.

Allan Lathan

A major connections project was being held up by very high levels of ethylene in a 66kV/22kV grid transformer. The gassing signature seemed to indicate a stray gassing event. However, because the levels of ethylene were something unseen in National Grid’s experience multiple tests and intrusive inspections were conducted to try to investigate the cause of the gassing. The paper will discuss this case study and detail the findings of the investigation.

Roberto Fernández

Kumar Mani

Alan Sbravati

Lance Lewand

A pattern of excessive gassing tendency was identified in different geographies in transformers used as step-up units both in solar and wind generation farms. This presentation is focused on transformers coupled to frequency inverters in solar farms, produced by several different manufacturers and located in the US. A case study of a Duke Energy solar farm will be presented and the evaluation of the proposed solutions and the results of the adopted one summarized.

Anabela Peixoto

DGA (dissolved gas analysis) is the most recognized tool for transformer monitoring. However, some oils, under thermal-oxidative stress at temperatures considered usual for normal operating conditions, can produce gases due to its constituents and are not connected to an internal transformer fault. This phenomenon is called Stray Gassing and the typical gas composition comprises hydrogen, methane and mainly ethane. These same gases in certain concentrations can also arise in the oil as the result of transformer thermal defects at low temperature (<300 °C). This situation creates a diagnostic difficulty: when these individual gases are detected in concentrations above the normal values for the studied transformer population, are we detecting a transformer defect or stray gassing? In this presentation EDP Labelec will show its methodology and how to mitigate this situation.