Jiugang electrolytic aluminum direct power supply technology has reached the domestic leading level

After Jiugang's 900,000-ton electrolytic aluminum project was launched in the Jiabei Industrial Park, the direct power supply system that was matched with it was born on the uninhabited Gobi Desert. This is a long-term development of the JISCO, which is of great significance for the survival of the aluminum industry. In order to implement a low-cost strategy and pursue economies of scale, Jiuquan Steel worked with Shandong Electric Power Engineering Consulting Institute Co., Ltd. and Guodian NARI Technology Co., Ltd. to overcome the problems affecting the safe and stable operation of the direct power supply system and creatively developed electrolytic aluminum direct power supply technology. And reached the leading domestic level.

In recent years, facing the severe situation of the steel industry, in order to accelerate the integration of resources and optimize the industrial layout, Jiuquan has vigorously promoted 900,000 tons of electrolytic aluminum projects and determined to find a new path for the survival and development of enterprises. However, the establishment of an internal direct power supply grid, safe and stable operation is an imminent problem. Jiugang's 900,000-ton electrolytic aluminum direct power supply system consists of six 350MW generator sets, four energy-saving small units, three 330kV substations, one 330kV switch station and two 110kV substations. It is a relatively independent power supply system. In order to reduce the cost of electrolytic aluminum, Jiuquan Steel has no domestic mature experience and precedents can learn from it. Under the premise of conforming to the national industrial policy, it has introduced external technical forces and put forward a power supply mode of large power supply to a single heavy load.

However, Jiuquan has established a 900,000-ton electrolytic aluminum direct power supply grid, which is extremely risky. Because of the small capacity of the power grid, the number of units is small, and the frequency regulation capacity is limited. The fluctuation of the load can easily cause the frequency and voltage amplitude of the direct power supply system to be excessively large and the rate is too fast, which may cause damage to the unit equipment and even the frequency of the power grid. In addition, the direct power supply system is a large power source and a large load type, and there is no precedent in the country. The Jiuzhai Iron and Steel Technology Research Group determined the technical parameters applicable to large power supply and large load type direct power supply systems through simulation calculations and field test methods to ensure the stability of the frequency of the direct power supply power grid system.

Faced with various problems in reality, Jiuzhai Electric Power's professional technicians vigorously carried out technological innovations. The first time they used the load frequency modulation function to solve the technical problems of frequency control of the direct power supply grid; for the first time, the smoothing control technology was adopted for electrolytic aluminum pressure Accuracy of the load-reducing operation of the safety and stability control system in the case of a fault in the case of a direct power supply grid fault; for the first time, the SCR rectification feature was used to realize the “AC offset, DC juxtaposition” power supply method, and the direct power supply grid was solved due to the weak grid. The electrolyzed aluminum enterprise's shutdown problem caused by serious grid failure. At the same time, it provides a technical reference for the domestic coal and electricity joint ventures, the development of large-scale industrial and mining companies, and the establishment of local grids in remote areas.

The successful exploration of the Jiugang direct electrolytic power supply technology has exerted a far-reaching impact on the regional energy advantages and competitiveness of Jiuquan. Among them, the 12 patented technologies developed and researched have been implemented in Jiuquan's 900,000-ton electrolytic aluminum direct power system power plant and electrolytic aluminum control system, all achieving the expected results, and the technical conversion rate is 100%. The successful application of this technology has ensured the safe and stable operation of Jiugang's 900,000-ton electrolytic aluminum direct power supply system, creating the conditions for the direct operation of the direct power supply system and reducing the cost of electricity for the enterprise.