INVT GD5000 MV VFD for Cement Plant Retrofit Project in Yancheng

Background
As a key foundational industry, the cement industry is an indispensable supplier of primary raw materials for the construction sector and plays an irreplaceable role in the development of the national economy. In recent years, due to saturation in the real estate market, the cement industry has also shown some new development trends. Against this backdrop, cement enterprises are placing greater emphasis on industrial upgrading and structural adjustment, while increasing investment in technological innovation and R&D to enhance market competitiveness.

Customer Needs
In this wave of industry transformation, Variable Frequency Drives (VFDs), as critical equipment in cement production lines, are crucial for the production efficiency and environmental compliance of cement enterprises. A cement enterprise in Yancheng City faced issues with its medium-voltage VFDs, such as aging equipment and frequent failures, due to increasing years of service. This led to a gradual increase in equipment downtime. Particularly, the spare parts for the blast furnace circulating fans used in the cement production line were completely out of production, severely impacting normal operations. Consequently, the enterprise decided to undertake a retrofit project utilizing the existing equipment framework, with the following specific requirements:

- Retain the original medium-voltage VFD's automatic bypass cabinet, transformer, and the entire medium-voltage VFD cabinet structure to fully utilize existing resources and reduce retrofit costs.
- Upgrade the VFD unit cabinets, control cabinet, overall control system, VFD cabinet top fans, transformer cabinet bottom fans, and the automatic bypass cabinet control system to improve equipment performance and stability.
- Require completion of the retrofit within a short timeframe to minimize production losses caused by equipment downtime.

Solution
Based on the customer's retrofit requirements utilizing existing equipment, INVT employed its self-developed GD5000-A1400-10-L series medium-voltage VFD system, matched with the customer's 900kW asynchronous motor. The specific retrofit plan was as follows:

1. Retained the original unit cabinet structure with 9 units per phase in series, using a front-4 rear-5 unit arrangement. The cabinets were hollowed out and the backplanes were replaced. The main cables from the transformer secondary side to the units were also replaced.

2. The input/output voltage detection resistor boards were installed in a centralized manner.

3. For input current detection, a sheet metal component installation method was used at the transformer incoming line end. Output current detection used a sheet metal component installation method within the original VFD unit cabinet.

4. All transformer cabinet bottom fans and VFD cabinet top fans were replaced. The fan control system was made compatible with the retrofitted main control system.

5. The control panel was installed using an embedded method.

Customer Benefits

1. Significant Economic Benefits: Through the retrofit approach utilizing existing equipment, the customer achieved substantial savings in equipment procurement and installation costs, effectively reducing operational expenses and enhancing the enterprise's economic efficiency and industry competitiveness.

2. Reduced Production Losses: Precise speed control and optimized operation significantly improved system energy utilization efficiency, leading to a noticeable reduction in energy consumption.

3. System Synergy and Optimization: The system features comprehensive protection with multiple software-based protection functions. The VFD control system perfectly interfaces with the customer's DCS system, enabling automated control and optimized management of the production process, thereby improving production efficiency and reducing manual intervention costs.

4. Stable Equipment Operation: The new GD5000 system components eliminate the risk of downtime and production stoppages associated with aging equipment, enhancing equipment reliability and stability, and ensuring production continuity.

Although the cement industry faces certain challenges, its future development prospects remain broad. The INVT GD5000 series medium-voltage VFD retrofit solution addressed the customer's concerns, and the rapid retrofit cycle minimized losses associated with production stoppages. This retrofit not only enhanced the cement enterprise's production efficiency and competitiveness but also accumulated valuable experience for INVT in the field of medium-voltage VFD retrofits within the cement industry. 

As the cement industry continuously develops towards environmental protection, sustainable development, high-end production, intelligence, green practices, and full industry chain integration, INVT will continue to uphold the philosophy of "Pursuing Excellence with Sincerity and Ambition" to provide high-quality VFD retrofit solutions for more cement enterprises, assisting the cement industry in achieving transformation, upgrading, and sustainable development.