High impedance transformers play an important role in limiting system short-circuit currents, and the issue of excitation inrush current has always been a major challenge in the application of high impedance transformers. Therefore, it is very important to effectively control the excitation inrush current of high impedance transformers to ensure the safe and stable operation of the power system.

There are several methods to effectively control the inrush current of high impedance transformers, summarized as follows:

1、 Optimize transformer structure

Optimizing the structure of the transformer core, strengthening the insulation performance of the transformer winding, designing materials with high impedance and high magnetic resistance to optimize the transformer structure can effectively limit the inrush current of the transformer when it is closed.

2、 Transformer series capacitor

Connect capacitors of appropriate capacity in series at the input end of the transformer to provide reactive power compensation excitation current and reduce the peak value of inrush current. Dynamically adjust the parameters of series capacitors according to the actual needs and operating status of the power grid, adapt to different load conditions, and ensure the effectiveness and safety of the equipment.

3、 Control the closing phase

By using a control system to monitor the voltage waveform of the power grid, automatically calculate the optimal closing timing, and accurately control the transformer to close at the zero crossing of the voltage, the occurrence of excitation inrush current can be reduced, achieving intelligent phase control.

4、 Adopting pre excitation technology

Based on the parameters of the transformer and the conditions of the power grid, accurately control the magnitude of the pre excitation current. Before the transformer is officially put into operation, apply a small DC current through the auxiliary circuit to establish a magnetic field in advance and reduce the excitation inrush current during closing.

5、 Install surge current limiter

According to the capacity and closing characteristics of the transformer, install appropriate surge limiters or reactors to limit the excitation inrush current.

6、 Dynamic adjustment of input voltage technology

Real time monitoring of system status, dynamically adjusting the rising speed and amplitude of input voltage based on the actual response of the transformer. By gradually increasing the voltage at the input of the transformer, the excitation inrush current is effectively controlled.

8、 Real time monitoring of transformer status and setting of protection strategies

By utilizing sensors and monitoring systems to monitor the operational status of transformers in real-time, corresponding protection strategies such as overcurrent protection, differential protection, etc. are formulated to prevent damage to transformers caused by excitation inrush currents.

XZT 7111 High Voltage Circuit Breaker Tester