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Strict quality requirements for the reliable grid

A reliable supply of electricity largely depends on the reliable operation and condition of the transmission network equipment. The equipment must be subject to regular maintenance and upgrades to ensure consumers safe and reliable access to electricity. As an electricity transmission system operator, Litgrid aims at ensuring safety and quality by taking a responsible approach towards the management of the national infrastructure entrusted to it, including maintenance of the existing grid and planning of its development.
“A high-voltage electricity grid is a complex and hazardous infrastructure. Any works performed in the proximity of such equipment must be undertaken with extreme caution, occupational safety regulations or quality requirements must not be compromised in any way. Compliance with these regulations determines both the safety of workers who reconstruct the grid and the operational reliability of the grid after the works are completed”, said Vidmantas Grušas, Board Member and Director of Litgrid’s Transmission Grid Department.
Every year, Litgrid‘s staff or contractors carry out inspections of the high-voltage overhead power transmission lines. An inspection involves verifying that the line and its equipment (supports, insulators etc.) are intact, not outdated, and not overgrown with trees and bushes. Repair works are planned for the elimination of any problems.
More than half of the Lithuanian transmission grid was built 46 years ago, thus the consistent reconstruction is planned on an annual basis. Five or six grid reconstruction projects are usually launched, and approximately the same number of projects are completed annually. As many as 26 transformer substations and switch-yards are currently under reconstruction, as well as works on the overhead line spans are ongoing.
The specific timing of the reconstruction projects is estimated by Litgrid using a special methodology that accounts for the actual state of equipment. An investment is then allocated to the areas that need the most attention, as well as those that are needed to maintain the reliability of the grid.
All reconstruction and maintenance work on the electricity transmission grid is performed by Litgrid subcontractors – companies that have won public procurement bids. 11 companies are currently engaged in various grid reconstruction works under such contracts, while 12 companies are in charge of the service and maintenance of the grid.
The quality and safety of the contracted works are under regular supervision by Litgrid specialists. 58 occupational safety inspections were conducted in 2014 and throughout the first four months of this year. One third of the inspected sites were free of any violations.
The specialists inspected all the transformer substations and switch-yards under reconstruction, as well as overhead spans under reconstruction and construction. Occupational safety inspections were also carried out during contracted check-ups or repairs of the overhead lines. Some of the structures supervised by contractors were subject to repeated inspection. 62 occupational safety violations were detected during 58 inspections.
The contractors were required to eliminate quality defects found in their construction works. “After a defective foundation laid at one of the reconstructed switch-yard was found, on-site works were terminated until all 208 foundations that had already been laid were replaced with new foundations of certified quality”, said V. Grušas.
During the inspections, violations of work organization were detected, for example, improper instructions related to works on power equipment in operation, inadequate enclosure of the site, works covering a larger area than planned, or the absence of employees in charge on-site.
In other cases, certain technical violations were detected, for example, the workers did not wear any personal protection equipment, performed unsafe work on the mechanisms, or required grounding was not provided for work on power equipment in operation.
Contractors who fail to comply with occupational safety and quality requirements are always subject to disciplinary measures: from warnings to fines. In some cases, Litgrid terminates the contracted works until all violations are eliminated. To avoid the repetition of violations, the top management of the contractor companies are addressed with the requirement to undertake systematic changes in order to avoid the reoccurrence of violations.
The transmission grid is being built and reconstructed to ensure its service for several decades ahead, which means that the work quality must be guaranteed. Strict and effective regulations on occupational safety and quality are important for the contractors as well, as they contribute to the safety of employees working on the hazardous power infrastructure.
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