At Camlin we’re engineering better futures. We want tomorrow to be better than today. For our customers. For their customers. For our own people. And for the wider world around us.
At Camlin we’re engineering better futures. We want tomorrow to be better than today. For our customers. For their customers. For our own people. And for the wider world around us.
Transformers today experience a wide array of conditions and faults related to what is occurring within the transformer. However, one of the biggest factors comes from external events occurring outside of the transformer. Through fault currents (TFC) pose significant risks which can undermine transformer's health and lifespan.
Through-fault currents occur when faults happen externally in the network but the fault current flows through the transformer, leading to mechanical and thermal stress on the internal winding components. While these events may not immediately lead to transformer failure, the cumulative effects can weaken the mechanical structure and accelerate insulation aging.
By monitoring the repetitive occurrence of through-faults, it’s possible to understand which transformer is in the most critical state. By correlating TFC with other transformer health indicators, such as DGA and PD, operators can take action to improve the health and reliability of their transformer.
Weakening of the transformer’s mechanical integrity The repetitive failure of through-faults can weaken the mechanical integrity of transformers and over time makes the transformer not able to withstand a true fault. A significant percentage can be attributed to stresses caused by bushings failures and winding failures due to through-faults generated by external events through the transformer.
Acceleration of insulation and thermal aging Due to through-faults happening over time, it increases the thermal aging that the transformer's insulation endures. This is typically used to define the transformer's end of life – a direct relation to the transformer's paper condition. The transformer's paper insulation becomes brittle and movements in the transformer winding caused by network disturbances can cause the paper materials to rip or tear, leading to a transformer winding fault.
Increased failures Transformer failures most commonly occur as the result of through-faults. It is typically not a single through fault that leads to failure, but the cumulative effects of a multitude of through faults that the transformer is exposed to during its lifetime. Failures are accelerated if there is no robust maintenance plan in place to prolong the transformer's life.
Impact upon the stability of the network Transformers are exposed to through-faults regularly and overtime can impact the stability of the network through electrical, mechanical and thermal damage. For example, the condition of protective equipment can be damaged by the exposure of through-faults leading to a higher chance of downtime occurring for a longer period of time.
Conclusion
Safeguarding transformers is a critical strategy to ensure reliability is maintained as they are exposed to many risks. The cumulative effects of through-faults can weaken the mechanical structure and accelerate insulation aging and overtime can lead to an increase of failures.
Camlin’s TOTUS online transformer monitoring solution, monitors all key components on the transformer. It can monitor and identify which transformers’ experiencing the most frequent through-faults and by correlating through-fault data with DGA and PD, operators can take action to significantly improve the overall transformer health and reliability.
If you are interested in finding out more about monitoring through-fault current in your transformer, get in touch or download our whitepaper below.
Through-Fault Current Monitoring to Plan Proper Maintenance
A leading cause of power transformer failures in the transmission grid has been linked to unpredictable external events, such as over-voltages, lightning strikes, and through fault currents. Through faults are believed to indirectly lead to winding displacement in autotransformers and electrical failures in transformers connecting HV and MV grids.
To learn more about TFC monitoring and the results from a trail performed on a HV/MV transformer simply fill in the form to download the whitepaper.
