Cement Rotary Kiln in India - INVT CHV100 Series Inverters
Abstract: This paper mainly introduces the application of INVT CHV100 medium-voltage inverters to rotary kiln and describes detailed information involving the process of cement production, control structure and principle of electrical system, and the process of control system commissioning. The practical application shows good speed control performance and stability of INVT CHV100 690V voltage inverters and it is worth promotion. Keywords: Rotary kiln, CHV100, 690V, 2000kW
1. Brief introduction So far, DC drive has been used in most rotary kilns in India. To overcome the disadvantages of DC drive, one cement plant of northern India takes the lead in introducing AC inverters for rotary kilns. INVT CHV100 series inverter has the following features which suitable for this application: a) DSP control system, multiple control mode: Close-loop, open-loop and V/F control; b) High speed control accuracy, fast torque response, high torque at low speed c) Plenty of control function: speed trace, fixed length control, flying starting etc. d) Multiple extension card: communication card, I/O card, many kinds of PG card.
2. Cement process introduction Cement process flow chart is as below:
And the cement process description is as follows: 1) Crushing and Pre-homogenization Crush all the material like limestone, clay, iron ore and coal, and then pre-homogenization 2) Raw material preparation Prepare the raw materials: fuel, clinker, mixture and gypsum 3) Raw material homogenizing 4) Preheating and calcinations 5) Formation of cement clinker 6) Cement grinding Cement grinding is the last and power-consuming step in cement process, which will grind cement clinker to proper grain size. 7) Cement packaging The cement is delivered in two ways of bag and bulk.
3. Kiln information and system solution 1) Kiln information Rotary kiln: diameter 4.6m, length 30m; parameters of drive motor: 930kW, 60Hz, 1194rpm, 996A, 690V;
2) System solution Considering motor parameters, controller requirements and overload capacity (250% overload 1 minute), INVT CHV100-2000G-6(F) can meet the requirement.
The wiring diagram of the inverter is shown below:
4. System commissioning Step 1: motor auto-tuning Set motor parameters for motor auto-tuning several times and take the average. Step 2: basic parameters setting (For detailed information, refer to parameter settings.) Set P0 to basic function group, P5 to input terminals group and P6 to output terminals group Step 3: pre-operation Carry out pre-operation at low-speed 5Hz and observe running situations of the rotary kiln, output current, voltage and frequency of the inverter; if normal, operate at high speed.
Output wave form
After commissioning, the rotary kiln runs normally and meets the requirements of customers.
5. Conclusion As a well-known cement manufacturer in India, the cement plant has successfully replaced DC drive for the kiln system of the old production line with AC drive for the new production line. The commissioning is so satisfactory that the plant will use INVT AC drive all the time. References:  Operation Manual of CHV100 Vector Inverter, Shenzhen INVT Electric Co., Ltd., [M], 2013.  Operation Manual of GD300 Inverter, Shenzhen INVT Electric Co., Ltd., [M], 2013.  Operation Manual of GD35 Inverter, Shenzhen INVT Electric Co., Ltd., [M], 2013.