DC Industrial Magnetizer with Direct Resistance Demagnetization

XHXC105

As a special-purpose equipment, the power transformer and mutual inductor demagnetizer eliminates residual magnetism risks left by DC resistance tests on large-scale power transformers and mutual inductors. It is of vital significance for shielding such equipment against excitation inrush current shocks and enabling their safe operation.

Product Features:
Utilizes patented technology – DC variable frequency attenuation principle;
Demagnetization is achieved by demagnetizing only phase B of the three-phase transformer;
Features automatic current stabilization judgment and 16-bit AD data acquisition and processing;
Offers manual/automatic demagnetization modes;
Fast demagnetization speed – reduced from 30 minutes to no more than 4 minutes per cycle;
Significant demagnetization effect – improved from 80% to over 90% per cycle;
Can directly utilize the current lines of the DC resistance test, making it convenient for use with DC resistance testing equipment;
Suitable for eliminating residual magnetism in large power transformers and instrument transformers of 35kV and above before commissioning; especially for large-capacity transformers of 330kV and above;
The product is small in size and light in weight, making it very suitable for field use.

Technical Parameters
Demagnetizing Current: 5A
Demagnetization Method: Manual, Automatic
Demagnetization Time: Manual 3 min/cycle, Automatic 9 min/cycle
Demagnetization Efficiency: Greater than 90%/cycle
Demagnetization Progress: 0-100%
Operating Power Supply: AC 220V±10%
Power Frequency: 50Hz±1Hz
Ambient Temperature: -25℃～50℃
Ambient Humidity: ≤90%

The dangers of residual magnetism:
It can cause the transformer's relay protection device to malfunction, leading to frequent failures in transformer operation;
The voltage surge generated when a short-circuit fault is cleared in the transformer's output can trigger false tripping of the transformer protection, causing a complete power outage on all sides of the transformer;
The inrush current generated when a transformer in power station A is connected to the power supply under no-load conditions can induce "sympathetic inrush" in other transformers operating in nearby power stations B and C, leading to false tripping and large-scale power outages;
The inrush current can cause damage to transformers and circuit breakers due to excessive electromagnetic forces;
It can induce switching overvoltage, damaging electrical equipment;
The DC component in the inrush current causes the magnetic circuit of the current transformer to be excessively magnetized, significantly reducing measurement accuracy and the correct operation rate of the relay protection device;
The large amount of harmonics in the inrush current causes serious pollution to the power quality of the power grid;
It can cause sudden increases or decreases in grid voltage, affecting the normal operation of other electrical equipment.