Summary: In this case，through introducing INVT GD5000 medium voltage variable frequency drive(VFD) applied to SKS fan in the India to illustrate variable frequency drive transformation of the feasibility and economy. Especially can optimize process control and significantly energy saving.
Keyword: GD5000 medium voltage drive, SKS fan, energy saving.
1. Project introduction and analysis
Ultratech Cement Co Ltd is the biggest cement manufacturer in India. The capacity of production is about 96,500,000 tons/year. The company belongs to Aditya Birla Group.
There is one plant Aligarh Cement has SKS fan used baffle to control air speed and air flow. This is the old technology speed control method, through this way has below disadvantages:
1)Narrow adjusted speed range.
Due to baffle control method can’t be elaboration and sensitive, so the system adjusted speed range is narrow.
2)High maintenance costs for pipe network of air.
There is lots of big and long pipe network of air in the main materials milling process. Because of air is high pressure, those pipes need much maintenance work and costs during whole plant maintenance period.
3)High power loss.
Because of baffle control method is old and outmoded speed control technology, there is much power consumption during speed adjust period.
2. System Configuration
2.1 Motor introduction.
Detailed motor parameters are list as follow:
Figure 1.The SKS fan motor nameplate
2.2 System solution.
Based on INVT experience on cement industry VFD renovation project, INVT can supply whole solution for the customer.
According to customer demand, the variable frequency drive (VFD) consists of transformer cabinet, power cell cabinet and control cabinet. The GD5000 MVD has function of local/remote button and emergency stop button on control cabinet.
INVT suggest VFD solution:
Main systme diagram:
Figure 2.The system diagram
Figure 3.The SKS fan VFD
3. Application and Advantage
After using VFD, there are some major advantages as follow:
1.Wide range speed adjusted.
Because VFD is a step-less speed regulation, the SKS fan can be run smoothly with wide speed range. It means that the speed adjusted can be elaboration and sensitive.
2.Increase powder selection efficiency.
The fineness of the material production can be flexibly adjusted and controlled according to the specific process requirements. The grading effect of material particles is improved and the powder selecting efficiency is improved based on production granularity.
3.Increase grid line power factor.
The grid line power factor is over 0.97. It can increase efficiency of the grid.
The SKS fan and it’s system is running at optimal situation and can save energy. From the site real running situation, the energy saving ratio is about 35% by roughly calculate.
5.Perfect output waveform.
Output waveform is perfect, less than 2% of distortion.
6.Prolong motor working life time.
VFD can keep motor running at optimal situation.
Compared with old technology, the VFD driven method has many advantages. Especially increase powder selection efficiency and significant energy saving. The energy saving ratio can reach 35%. The transformational VFD system works very well, customers are satisfied with INVT solution and INVT VFDs met with customer’s requirements.
 GD5000 Series Medium-voltage Variable Frequency Speed Control System Manual. Shenzhen INVT Electric CO., LTD.