Breakthrough in cleaning the power grid
Mr. Nguyen Van Xuan said that to secure the safety of power grids in Vietnam, periodically after a period of operation, the power units must carry out power cuts and mobilize a large force of manpower to clean the power grids.
The power cut during cleaning the grid has damaged the power system: breaking the reasonable mode of operation, increasing power losses, disrupting power supply to customers, etc. Especially, workers washing every porcelain insulator at the height of 15 - 40m, or even over 50m, are implicitly exposed to occupational dangers.
In 2005, the idea of live – line insulator washing by high pressure water began to grow and started to be studied by Mr. Xuan. It aimed to ensure safety, time and effort saving for workers, especially not interrupting power supply to customers. This technology uses high pressure water injection solutions to power poles, lines, porcelain bowls while the power lines are still energized. Deionized and pure water used in the grid cleaning does not conduct electricity.
The solution has been adopted by many countries, but it is completely new in Vietnam. Therefore, the power sector had to spend a lot of time for researching, calculating efficiency, safety and especially proving that they can master the technology.
In 2010, PTC 3 started applying live line insulator washing technology with high pressure water on 500 kV and 220 kV transmission grids; creating breakthroughs, overcoming deficiencies of the traditionally manual method. Therefore, the research outcomes had been recognized and allowed to put into practice on the transmission network by the Acceptance Council of National Power Transmission Corporation.
Two years later, Vietnam Electricity requested the Research Group to further expand the scope of application on the distribution grid. Because this technology allows cleaning the power grid when energized, workers must strictly follow the safety procedures and no mistakes are tolerable. Therefore, despite great support, EVN’s leaders at that time was very cautious and required pilot implementation on the power grids of all three regions; particularly requiring to master water treatment technology to ensure the safety of workers.
By 2015, after researching and verifying the effectiveness of this solution in practice for 10 years, the live line insulator washing procedure was officially issued by EVN, providing a legal basis for EVN’s subsidiaries to implement. At the same time, EVN requested PTC 3 to train and transfer technology to other power grid operators. So far, this technology has been widely applied nationwide, from the 22 kV to 500 kV grids.
Increasing productivity, reducing power interruption duration
As one of the leading organizations in application of live line washing technology, Mr. Nguyen Duc Hung - Director of the Northwest Transmission Company (under Power Transmission Company No.1) said, previously it took two to three hours for workers to manually clean a tower, but now the implementation time is not more than 3 minutes.
In addition, when the power system of Vietnam has not really met the N-1 criterion, changing the mode of operation due to cutting off an electrical feeder line for insulator washing during a long time is very problematic and likely to make power lines overloaded. Hence the live line insulator washing technology has contributed significantly to increasing the reliability of power supply, improving SAIDI and SAIFI indexes of the entire Electricity.
In the first six months of 2017, the Electro - Mechanical Enterprise under Phu Yen Power Company had carried out 27 times of cleaning grids by live line technology, reducing 5,640 minutes of power interruption; helping to ensure the safe and continuous supply of electricity, reducing power outage duration.
Mr. Bui Xuan Thanh - Deputy Director of Ha Nam Power Company (PC Ha Nam) shared that customers in industrial zones, especially cement manufacturing companies, often have a high failure frequency. To alleviate this situation, in 2016, PC Ha Nam invested in a live line insulator washing and equipment cleaning truck for these companies, which was highly appreciated.
Not only securing the safety of the power system, diminishing power losses, the live line insulator washing technology also contributes to labor safety since workers do not have to hang themselves on tens of meter high towers / poles to clean each porcelain bowls manually.
Its effectiveness has been justified by reality. The application of "live line insulator washing technology" keeps affirming that EVN has been adopting advanced technical solutions in line with the development trend of a modern industry.