Synchronous transformers play a crucial role in the stable operation of the power grid, especially in grid connection operations, voltage regulation, and system protection, which cannot be replaced.

1、 The core function of synchronous transformer:

1. Implement secure grid connection

Phase matching: When connecting two independent power grids or power generation units (such as generator sets, microgrids, energy storage systems) to the grid, transformers help adjust voltage, frequency, and phase angle through electromagnetic coupling to ensure that the amplitude, frequency, and phase of the voltage on both sides are consistent, avoiding surge currents or equipment damage caused by asynchronous grid connection.

Suppressed surge current: If there is a phase difference during grid connection, direct closing may generate surge currents up to 10 times the rated current, and transformers can reduce such risks through transient control.

2. Voltage regulation and isolation

Voltage matching: When establishing connections between power grids of different voltage levels, synchronous transformers adjust the voltage level through variable ratios to achieve energy transfer.

Electrical isolation: provides physical isolation, reduces mutual interference between the two systems, suppresses harmonic transmission and fault propagation (such as preventing short circuits on one side from affecting the other).

3. Frequency and phase synchronization

Soft start grid connection: When distributed power sources (such as photovoltaics, wind power, and energy storage) are integrated into the main grid, transformers can cooperate with the control system to slowly adjust phase and frequency, achieving "soft grid connection" and reducing the impact on the main grid.

Dynamic support: Maintain voltage stability and promote system frequency recovery through excitation regulation during fluctuations in grid frequency (such as sudden load changes).

4. Protection and Control

Fault isolation: When a system fault is detected on one side, the transformer can quickly cut off the faulty side to prevent the fault from spreading to the other side of the power grid.

Power oscillation suppression: By adjusting the excitation current or series impedance, low-frequency power oscillations between power grids are suppressed (such as oscillation problems during regional power grid interconnection).

2、 The importance of synchronous transformers is reflected in:

1. Ensure the safety of grid connection

To avoid equipment damage (such as generator shaft torsional vibration, transformer insulation breakdown) or system collapse caused by asynchronous grid connection.

Ensure seamless connection and improve power supply reliability during microgrid and main grid switching (such as black start scenarios).

2. Improve the stability of the power grid

In weakly interlocked power grids (such as regional interconnected power grids), transformers enhance system damping and reduce the risk of power angle instability through phase synchronization and voltage support.

In the scenario of high penetration rate of new energy, alleviate the frequency fluctuation problem caused by intermittent power grid connection.

3. Optimize power quality

Isolate harmonics and voltage fluctuations to reduce the pollution of nonlinear loads (such as rectification equipment) to the main grid.

Improve voltage qualification rate and reduce network loss through voltage regulation function.

4. Support flexible grid architecture

In multi terminal DC transmission (such as high-voltage DC converter stations), synchronous transformers serve as AC side interfaces to coordinate energy exchange between AC and DC systems.

In the smart grid, dynamic grid connection and power allocation are achieved in conjunction with automated control systems.