DAC 2021_12

44 n CONTROLGEAR November/December 2021 www.drivesncontrols.com L ast year, North Macedonia faced a potential national disaster when more than 300,000m 3 of water flooded parts of a coal mine that supplies a major thermal power plant, effectively disabling its operations. The event had serious ramifications, because the power plant – managed by the state company ESM- North Macedonia – is an key part of the country’s energy system, with three 233MW generators that produce 70% of its power. The mine needed to be drained quickly and effectively. Extra pressure was added by the approaching arrival of winter, because the lives and well-being of the country’s population would depend on the power plant’s ability to produce electricity using coal from the flooded mine. With such high stakes, ESM turned to Simtech Solution, which specialises in devising automation and Scada systems, as well as power distribution and management installations for environments including manufacturing and water treatment. But a natural disaster on this scale was a first for Simtech. “There were several obstacles that had to be overcome if we were going to succeed,” explains Igor Novevski, who is in charge of projects and business development at the company. “We only had a couple of days for project planning to devise the technical solution and three weeks to execute the entire project. So, there was a very high pressure to complete the draining project on time and a need for a quick response from all our project partners.” Simtech sourced several heavy-duty pumps to remove the sludge from the mine. They included three 110kW pumps made by Tsurumi of Japan, and three 90kW pumps built by Dragflow in Italy. Although the pumps were supplied complete with electrical equipment, they still needed an effective start-stop control system. It was decided that soft-starters would be essential to operate the pump motors quickly, safely and reliably, especially in circumstances as time-critical as the mine drainage project. Simtech chose WEG SSW900 soft-starters for several reasons including their advanced performance, embedded protection and energy-saving capabilities, as well as built-in bypasses which help to extend the starter lifetime and reduce the amount of heat generated. The soft-starters also offer fault history and diagnosis capabilities, time- stamped troubleshooting and network communications. The starters’ digital compatibility helped Simtech to integrate several PT100 thermal protection probes as required by ESM A major challenge that the project had to overcome was the Covid-19 pandemic. How would it be possible to provide the technical know-how to install and commission the soft-starters when travel and face-to-face meetings were being severely limited? WEG solved this conundrum by offering online training by experts located in Brazil, who also provided remote support throughout the project. Despite the challenges of the tight time- frame and the pandemic, the drainage project was completed on time. It underlined the advantages that Scada- enabled soft-starters can offer in such circumstances, and ESM is now planning to integrate Scada facilities into its ERP (enterprise resource planning) system. n When a coal mine flooded in North Macedonia, it threatened the country’s electricity supplies. The race was on to pump out the resulting sludge, and the high-powered pumps brought in to perform the task needed soft-starters to control safely them and reliably. Soft-starters help to save national power system from disaster Powerful pumps were brought in to remove sludge and water from the flooded coal mine which is used to supply a critical power station in North Macedonia