Vaasa Field Tests – High Impedance Earth Faults Located Up To 39 kOhm


Vaasa Field Tests – High Impedance Earth Faults Located Up To 39 kOhm

Vaasa field tests were conducted during two days, 15 – 16.11.2023 at two locations in Vaasa network. In total, there were 17 earth-fault tests using resistors. Fault resistances ranged from 3kΩ to 39kΩ. All the faults were located correctly and with an average locating accuracy of 116m. The test durations were short enough to ensure no trip resulting in an outage would occur during the tests. Since no earth-fault caused any trip, all the earth-faults were classified as ‘Warning’ and were visible on the GridGuardian alerts page.

In addition to earth-faults using resistors, there were earth-faults that were performed using branches of trees in series with a 3kΩ resistance.

Another set of tests that was conducted on both days was partial discharge simulations. Partial discharge tests were conducted using dedicated equipment with an adjustable air gap. They were also located correctly.

Summary of Field Tests

The Vaasa field tests were conducted over two days at two locations within the Vaasa network. The tests included three different types: direct earth fault tests, earth fault tests caused by tree branches, and partial discharge simulations. The tests were executed successfully and safely, without causing any harm to customers through unnecessary trips or outages.

All earth fault tests were accurately located, with an average distance of 116 meters from the test fault locations. Similarly, the partial discharge simulations were correctly found. The tests validated the performance of Safegrid’s monitoring system for Vaasan Sähkö and generated valuable new data for Safegrid.

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