Converter transformers are used for long-distance DC transmission or between power grids

Description of Converter Transformer
The converter transformer is a key interface device between high-voltage direct current (HVDC) transmission systems and AC power grids, with its core function being to realize the conversion and transmission of electrical energy between AC and DC forms. It is mainly used in long-distance DC transmission projects (such as cross-regional power transmission) and scenarios of interconnection between different power grids. Through electrical isolation and voltage adaptation, it converts electrical energy from the AC grid into a form suitable for DC transmission, or conversely converts DC electrical energy back into AC electrical energy for integration into the grid. It is a core device ensuring efficient transmission of large-capacity power across regions.

• Purpose：Used for power conversion in long - distance DC transmission or power grid interconnection.

• Features：In addition to withstanding AC voltage, it also has to endure the DC voltage generated during the AC - to - DC conversion process.

• Scope：Capacity: Below 610 MVA; Voltage: Valve - side below ±1100 kV; Grid - side below 750 kV.

Features of Converter Transformer

• Withstanding composite voltages: It not only needs to withstand high voltages on the AC side but also the DC voltage generated during AC-to-DC conversion. Therefore, its insulation design must meet the dual challenges of both AC and DC voltages, with insulation performance requirements far higher than those of conventional AC transformers.

• Adapting to complex working conditions: Its operating environment involves special electrical stresses such as harmonics and commutation pulsations caused by AC-DC conversion. It must have strong anti-harmonic interference capability and stable electromagnetic compatibility to minimize energy loss during energy conversion.

• Large capacity and wide voltage coverage: It can cover capacities below 610 MVA, with voltage ranges including the valve side below ±1100 kV and the grid side below 750 kV. It can meet the power and voltage requirements of DC transmission projects of different scales, adapting to diverse scenarios from regional interconnection to ultra-high-voltage long-distance transmission.

• High-reliability design: As the "hub" of the DC transmission system, its operational stability directly affects the safety of the entire power grid. Therefore, reinforced designs are adopted in structural strength, cooling systems (such as forced oil circulation), and insulation materials to adapt to long-term heavy-load operation.