A leading supplier of input materials to the electrical motor, transformer repair and manufacturing industries, recently announced that it has been appointed the distributor of the South African-developed Series 8400 Combustible Gas Monitor for the South African and African transformer markets.

Gerhard Streicher, founder of Electronic Measurement Technologies (EMT) has been working on the development of a uniquely South African combustible gas monitor for the transformer market for the past eight years. This monitor detects combustible gasses dissolved in transformer oil.

Preventative maintenance of oil-filled transformers begins with the testing of transformer oil for abnormalities taking place inside the transformer. One of the most critical areas of detection is the measurement of hydrogen and other combustible gasses dissolved in the transformer oil. Particularly high concentrations of the hydrogen gas typically indicate a level of insulation decomposition which, if ignored, could lead to the complete failure of the transformer. The resultant downtime to either repair the transformer (if possible), or to install a replacement, will have an exacting toll on the profitability of that industry deploying the transformer, or have an immense impact on service delivery by the municipal provider. Should the transformer explode due to the non-detection of the extreme concentration of these combustible gasses, damage to peripheral buildings and other machines could escalate financial losses.  

Gerhard originally developed a portable monitor which has been successfully deployed in Israel and other parts of Africa. Eskom then approached Gerhard to develop a monitor that could be placed permanently alongside the transformer to relay real-time data to a control centre.

“The Series 8400 is designed to operate unattended for long periods of time. Gas concentration data as well as status information can be called up via a modem and downloaded to a PC at anytime. All combustible gasses will be detected within the range of 500 to 10 000 ppm. Hydrogen gas can be detected selectively in the range of 50 to 1 000 ppm. The periodical analysis of the transformer oil usually averages at every three months to six months, and the result for dissolved gasses in the oil can take up to three months in a laboratory. Critical transformers do not have that advantage of time,” explains Gerhard.

Wilma Muller, Manager of the Transformer Insulation division at Wilec, a division of the large industrial group, Savcio Holdings (Pty) Ltd, believes that the ingenuity of Gerhard’s monitor has huge applications in South Africa’s present industrial climate whereby predictive and preventative maintenance of transformers is critical.  

“This division at Wilec provides a comprehensive range of insulation products supplies to the transformer industry. Insulation deterioration is a huge concern to the players in this industry. Gerhard’s monitor detects both the dissolved hydrogen and combustible gasses in the transformer oil, and the hydrogen gas levels specifically will detect the trend of insulation deterioration. Early detection will allow our customers to prepare adequately for maintenance thereby avoiding unplanned shutdowns and the resultant cost implications,” says Wilma.

The monitor is programmable to produce real-time gas detection of an oil sample that is processed in about 10 to 20 minutes. The oil sample is about 200ml, and is returned to the transformer. The sample rates can be programmed in days, hours, minutes and seconds. Any changes made to the programmable parameters will be displayed on the print-out, with the old and new values. The gas trend values can be displayed as a graph.

“The beauty of this monitor is that it is a South African development. All components are sourced locally resulting in a 67% overall cost saving to the end-user, compared to equivalent imported monitors. We believe that all critical transformers in this country cannot afford not to operate with the Series 8400 monitor. Wilec intends marketing this monitor to all critical industries and municipalities within the country and to the rest of Africa,” mentions Wilma.