ACTOM Distribution Transformers has achieved the SA Bureau of Standards’ new SANS 780: 2019 Edition 5 standard for single-phase 16 kVA to 3.15 MVA distribution transformers after a sample unit underwent a series of tests at the SABS’ National Electrical Test Facility (NETFA).
Conducting routine testing on a 200 kVA 11 kV/420 V transformer in ACTOM Distribution Transformers’ test facility.
The new standard represents a significant advance as it demands lower no-load and load losses than were required under the SANS 780: 2009 Edition 4 standard that formerly applied to this range.
The transformers to which the newly introduced standard applies are used extensively in the local market by Eskom, municipalities and electrical contractors.
The sample transformer that was put through the required tests at the NETFA during July and August 2020 was a 200 kVA 11 000/420 V oil immersed unit.
ACTOM Distribution Transformers chose to provide a sample from the lower end of the range for testing to ensure the fullest possible battery of tests could be performed by the NETFA on the unit. This enables the division to assure its customers that all the requirements of the new standard have been met.
After a pre-test inspection and full routine tests monitored by a NETFA engineer were carried out on the sample unit at ACTOM Distribution Transformers’ own test facility in Knights, Germiston, the following tests were performed on the unit by NETFA:
- Temperature rise test at the NETFA High Current lab.
- Short circuit withstand test at the NETFA High Current lab.
- Lightning impulse test at the NETFA High Voltage Lab.
Following the successful outcome of the tests, a post-test inspection for mechanical deformation of the windings and full routine tests were conducted at ACTOM Distribution Transformers’ facility, again monitored by a NETFA engineer.
“The reduction in losses will assist our strained electricity generation sector,” commented Lee Mbenge, ACTOM Distribution Transformers’ Projects Manager. “The SANS type and special testing is onerous on the transformer, especially when it comes to demonstrating the ability to withstand short circuit by testing, where 115% of Un is used to calculate the short circuit currents, the total change in inductance does not exceed 4.0% per phase and the successive shorts can be repeated until there is less than 0.25% change,” Mbenge concluded.
For more information visit: www.actom.co.za