Maintenance of HV/MV Substations

Ensuring dependable operation, prevention of downtime, and prolongation of equipment lifespan, the maintenance of medium voltage (MV) and high voltage (HV) substations is of paramount importance. To facilitate the proper and secure operation of an HV/MV substation, the following preventive maintenance tasks are conducted on an annual service basis:

The power transformer (T/F) is the core of a substation. High purchase costs and long delivery times lead to capital and income losses. Consequently, the annual maintenance is critical in order to prevent serious faults. Our company utilizes cutting-edge diagnostic equipment to conduct the following proactive diagnostic tests:

• DC winding resistance Primary and secondary side
• Dynamic resistance measurement (DRM) in each TAP position
• Transformer turns ratio in each TAP position
• Insulation resistance measurement
• Winding & Bushing Dissipation and power factor (tanδ)
• Bushing hot-collar test
• Excitation current
• Short-circuit impedance.

Additionally, in order to investigate the internal condition of a power transformer, we execute transformer oil analysis, in cooperation with well-established laboratories.

• Cleaning and lubrication of the moving parts of the cubicle using proper products.
• Mechanical Maintenance inspects mechanical connections, bolts, and busbar joints for tightness and corrosion, and addresses any issues to maintain proper electrical conductivity.
• Circuit breaker timing tests, in order to ensure the proper opening and closing time of the CB.
• Circuit breaker contact resistance test.
• PD Scanning
• Thermal Imaging

Using a secondary injection device, we simulate fault cases in order to verify the proper functioning of the protection relays.