Abstract The importance of transformers in the SS Margem Direita of Itaipu for supply of power to Paraguay led to the installation of a pilot project for on-line monitoring in November 2006, which…
ABSTRACT
One of the greatest challenges in energy generation is ensuring that assets are always available, exhibit minimal failure rates, and maintain maximum operational output. Power transformers are among the most critical assets in wind farms, as they are particularly vulnerable due to being the connection points to Brazil’s National Interconnected System (SIN).
It is widely known that the performance of power transformers used with renewable energy sources—due to the effects of harmonics, system transients, and power inverters—differs from that of transformers used in traditional generation, transmission, and distribution grids. Although these transformers have evolved over hundreds of years to become reliable in conventional applications, ensuring they serve reliably for forty years in renewable energy applications presents a completely different challenge.
Capacitive bushings, components of these transformers, demand close attention due to their failure rates—they account for 15.6% of failures, according to 2015 statistics from Cigré WG A2.37.
To mitigate risks associated with failures in power transformer bushings, the CPFL approach has involved the use of real-time monitoring tools and inferences. These tools are designed to preempt incipient failures by monitoring operational behavior. Through continuous online measurement, data is relayed to our Asset Monitoring Center (CMA). Here, any emerging risk of potential failure is identified using the potential failure curve (PF), which, if detected, can pose a significant threat—potentially leading to total or catastrophic loss.
This scenario necessitates a Business Impact Analysis (BIA) under ISO 31000 Risk Management and ISO55000 Asset Management standards, as well as increasing both operational costs and security risks.
The monitoring tool installed on high-voltage bushings senses and records several parameters including tangent delta, leakage current, and capacitance. This is part of an integrated asset management system that employs predictive techniques to preemptively address incipient failures. The data collected provides real-time insights into the behavior of capacitive bushings, enabling timely interventions through a Predictive Maintenance Plan. This not only prevents total asset loss but also optimizes maintenance strategies.
Moreover, the tool includes prognostic capabilities that predict future issues based on the progression of measurements over time. This early detection of problems in their incipient phase allows our asset management system to tailor interventions to the specific needs of wind farms in Brazil. The benefits of online monitoring include reduced risk exposure, enhanced operational health data, lower unexpected costs, and improved asset availability.
Each aspect of online monitoring is underscored by real-world cases that demonstrate its impact on the management processes of power transformers and wind farms. This technology significantly boosts productivity indicators and enhances the overall operational reliability of the company.
From these implementations, we have developed criteria for mapping operational risk management, which has resulted in cost savings, risk mitigation, and a more predictive approach to asset lifecycle management.
AUTHORS
Main Author: Afonso Cesar Tavares – afonso.tavares@cpfl.com.br
Daniel Carrijo
Claudio Justi
Lucas Pavan Fritoli
CPFL Renováveis
Universidade de São Paulo – USP
CPFL Renováveis
Treetech Tecnologia
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