Estonian engineers and scientists are developing an innovative methodology for assessing the reliability of substations. If implemented effectively, it is possible to reduce electrical system failures and keep the necessary costs under control.
On its way from power plants to buildings, electricity passes through substations. These hubs, important for electricity distribution, contain many different devices: in Estonia alone there are more than 50,000 of them in substations. Here, as in most places in the world, the substations were mostly built several decades ago or even earlier. As equipment ages, faults occur more frequently and the reliability of the electrical system decreases, writes Guido Andreesen, a doctoral student and junior researcher at Tallinn University of Technology.
“We, as in most places in the world, built substations mostly several decades ago or even earlier.”
However, the main challenge of substation management lies in preventing faults that cause power outages. Another important question is how to avoid large-scale equipment replacement. It is generally expensive and therefore should be avoided. Especially in a situation where the additional expenses are actually avoidable. Due to the failures and their consequences, the reputation of the company that operates the substations also suffers.
The ideal solution to the problem would be to use measurement sensors that report the deterioration of the condition of the equipment in real time. At the same time, purchasing the measurement sensors themselves represents a large investment. Furthermore, it is unwise to constantly monitor the condition of equipment, the consequences of which in case of failure are not very extensive. The time-based approach currently used also has several drawbacks and would require large-scale investments in the future. Therefore, it is necessary to find a suitable methodology to improve the efficiency of substation management.
An innovative solution
I develop just such a methodology in my research. In this framework, I will base myself on the importance of substations and their equipment in the electricity system, as well as on the price of different management methodologies. According to the methodology, the highest risk devices are identified first. A cost-effective method is then chosen to reduce the risk. For example, you can use real-time measurement sensors, make preventive replacements, or stock up on a spare device nearby. As a result of the research work, there is an opportunity to extend the effective life of equipment and standardize its replacement.
The development of the methodology is based on the joint research development project of Tallinn and Elering University of Technology. It is therefore planned to implement this result in the Estonian electricity system. In this way, attention and investments can be directed towards the most important substations in terms of reliability. This could avoid failures and avoidable costs.
Numerous bottlenecks
However, it is necessary to take into account that the methodology needs several inputs for its operation, for example, a better view of the changing conditions of the equipment over time and the possibilities of using measurement sensors.
Furthermore, the current problem is the scarcity and imprecision of statistics, which mainly arise from using a time-based approach. In particular, the frequency of periodic inspection can vary depending on the type of equipment and its age, from one to ten years. This may not be detected if the condition of the device deteriorates rapidly between inspections. Therefore it is also difficult to collect statistics and find the right time for preventive repairs.
Inspections may also reveal that the condition of older equipment is actually perfectly good, but this already incurs the cost of the inspection.
My research also helps determine the upper limit on the number of devices for which it is worth reducing risk entirely. Therefore, the costs of different management methodologies must be taken into consideration to discover their profitability points. Based on this you can decide how broadly it is appropriate to move towards risk-based management.
Also important are the price of the measuring sensors and the accuracy of the status information obtained from them. The use of metering sensors is not cost-effective if the cost of the sensors is relatively close to the cost of a failure or exceeds the cost of time-based management.
Obligatory choice
In summary, aging substation equipment is accompanied by numerous problems that are costly, require complex responses, and affect society as a whole with possible power outages. Therefore, innovative methodologies that approach the field from a different perspective are needed.
My research presents a solution based on failure risk, electrical system reliability, and cost-effectiveness. This eliminates unnecessary inspections and replacements of equipment, as well as the installation of numerous measurement sensors. Furthermore, the methodology provides a good basis for the inclusion of modern and intelligent solutions, as the substation management of the future will include more and more of them.
Guido Andreesen, PhD student-junior researcher at Tallinn University of Technology. Author/source: Private collection
The article was published as part of the “Science in 3 Minutes” competition organized by the Estonian Academy of Sciences, the final of which will take place on February 2.
Guido Andreesen has been dealing with electricity for eight years. Andreesen is fascinated by the versatility of the sector, which ranges from electricity system stability to consumption management, energy storage and electric transportation. He has completed his master’s degree as praise and placed in the top three in the national competition with his master’s thesis. He is currently developing a more efficient and economical methodology for substation management in his doctoral studies. In his free time he likes to ride a faster bicycle and take photography.
2024-01-24 11:30:00
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