INVT GD5000 VFD for Long-Distance Mining Conveyor in Xinjiang

1. Background

The Xinjiang Zhundong Coal Power Base is a crucial coal-producing region in China. It relies on the Zhundong-East China ±1100 kV UHVDC transmission project (the fourth channel of "Xinjiang Power Outbound Transmission") to export electricity, supplying power to dozens of nearby large-scale thermal power plants. However, coal transportation from mining sites to power plants primarily depends on trucking, which incurs high logistics costs and is heavily affected by weather conditions. Extreme weather often leads to inefficiencies and instability in transportation. To address these issues—ensuring efficient, eco-friendly, cost-effective, and reliable coal transportation—the establishment of a long-distance coal conveyor system from mines to power plants has become imperative.

2. Project Requirements

The newly constructed belt conveyor system spans approximately 45 kilometers, with a belt width of B = 1200 mm and a transport capacity of Q = 800 t/h. The system consists of seven belt conveyors (300, 301, 302, 303, 304, 305, 306), each configured with the following drive setups:

* Conveyors 300, 305, 306: Each equipped with one low-voltage permanent magnet synchronous motor and one low-voltage frequency converter, adopting a single-drive configuration.

* Conveyor 301 (~5 km): Adopts a dual-drive setup at the head, paired with two medium voltage permanent magnet synchronous motors and two medium voltage frequency converters.

* Conveyors 302, 303, 304 (~13 km each): Use a two-head-one-tail drive configuration, each equipped with three medium voltage permanent magnet synchronous motors and three medium voltage frequency converters.

3. Customer Issues

* Synchronous Control: The frequency converters must ensure synchronized operation to prevent belt tension imbalance caused by uneven power distribution.

* High Starting Torque: Due to the large inertia of long-distance conveyors, the converters must provide high starting torque (typically ≥150% of rated torque) at low speeds to prevent belt slippage or mechanical shock.

* Controlled Deceleration Stop: Sudden power cuts (free-stop) could lead to belt slippage, material pile-ups, or mechanical damage. A deceleration stop ensures smooth speed reduction, minimizes mechanical stress, and enhances safety.

4. INVT Solution
To meet the demands of long-distance heavy-duty conveyance, INVT designed a tailored solution featuring GD5000 medium voltage frequency converters and GD350 low-voltage frequency converters for the seven conveyors:

* Conveyors 300, 305, 306: Each driven by a standalone GD350 low-voltage converter.

* Conveyor 301: Equipped with GD5000 converters in a dual-drive setup, connected via a 15-meter multi-mode fiber-optic ring for master-slave communication.

* Conveyors 302, 303, 304: Use GD5000 converters in a two-head-one-tail configuration, with fiber-optic links ensuring signal stability and real-time PLC communication for power balancing.

5. Advantages

* Energy Efficiency & Cost Reduction: Speed adjustment (0–100%) optimizes operation for varying demands (e.g., low-speed maintenance or high-speed transport), reducing idle energy consumption.

* Soft Start/Stop: S-curve acceleration/deceleration minimizes mechanical shock, prolonging equipment lifespan. Controlled stops maintain belt tension, preventing slippage or material spillage.

* Precision & Stability: 
High torque during heavy-load starts prevents stalling, vibration, or reversal.
Master-slave fiber-optic synchronization ensures even power distribution across ultra-long conveyors (e.g., 13 km between drives).

* Smart Remote Management: Modbus485 communication with PLCs enables real-time monitoring of voltage, current, torque, temperature, and other parameters via a central control platform.

The successful deployment of GD5000 medium voltage converters in this project demonstrates INVT’s technical prowess in overcoming industry challenges, such as synchronous motor stalling during heavy-load starts and stable long-distance signal transmission (up to 13 km). Recognized by the client, this solution sets a benchmark for smart mine innovation.

Moving forward, INVT remains committed to advancing industry-specific technologies, leveraging its comprehensive high/medium/low-voltage product lines and robust R&D capabilities. By collaborating with strategic partners, INVT aims to drive the energy sector toward greater efficiency, intelligence, and sustainability.