At present, 220kV-330kV power supply is mostly used for the voltage regulating rectifier transformer used in the electrolytic aluminum industry, with an annual output of 400,000 tons to 500,000 tons, and 500kA and 600kA series are mostly used for the electrolytic cell.The rated DC voltage is about 800-1700V, and the capacity of a single voltage regulating rectifier transformer can reach 190MVA. Generally, N+1 or N+2 standby mode is adopted.
Generally, the oil tank of the voltage regulating transformer and the rectifier transformer are separated in structure. Most of them are forced oil and air cooling, and some are self-cooling.The secondary voltage regulation of the voltage regulating transformer is divided into step-down voltage regulation or auto-coupled voltage regulation. Generally, the voltage regulation is continuous, and the stages are 79, 95 or 107(max).On-load tap changers mostly use vacuum changers produced by German MR company (some also use domestic changers).
The voltage regulating transformer is equipped with filter compensation winding. The primary side of the rectifier transformer is connected with the secondary side of the voltage regulating transformer through the oil-in-oil bushing outside the oil tank.The primary side of the rectifier transformer is phase-shifting, and the phase-shifting angle is calculated according to the total pulse number of 12N. The single unit group forms 12 pulses, and the phase-shifting angle difference in the single unit group is 30 °. The valve side adopts the bridge in-phase inverse parallel structure.
The rectifier cabinet uses silicon control or secondary tube with saturated reactor to adjust or stabilize the current. Therefore, the rectifier transformer with secondary tube in the rectifier cabinet needs to add a saturated reactor, which is generally about 60V DC.At present, there are still 110KV voltage regulating rectifier transformers in operation in the electrolytic aluminum plant built in the early stage. Our company is fully capable of producing voltage regulating rectifier transformers that meet the above requirements in terms of design, production equipment and industrial workers.
