A thermoelectric project invested and built by a thermoelectric company in Xinjiang,China

In this EPC engineering renovation project that equipped with 2×315MW unit induced draft fan installed with the inverter ,the original induced draft fan is a centrifugal induced draft fan, driven by a 1000kW/6kV motor (the relevant parameters of the motor are shown in Table 1).Adjusting and controlling equipment of the operation by using fluid coupling device.

Table1. Field motor rated parameter table

The rated voltage of the system of the on-site power supply network is 6.3kv, the maximum voltage is 7.2kv, the rated frequency is 50Hz. The power supply system adopts the way of neutral non-grounding. Electrical equipment is installed in the electrical room.

Now, four sets fan motors are equipped with frequency conversion speed control devices, and the original fluid coupling is adjusted to frequency conversion to save energy. Each set fan is driven by one set frequency device. In this project, the fan frequency conversion device uses the ACS580MV medium voltage frequency converter manufactured by ABB.  ABB partner completes the civil construction, installation and commissioning of the equipment. All materials required for the construction are solved by ABB partners.

ABB solution

In this project, the clients request as follows:

1. Reducing operating costs and achieving partial energy saving on the original basis;

2. Reducing maintenance time of devices and service time when equipment fails;

3. Reducing the inventory and maintenance costs of spare parts, especially various costs of the fluid coupling during production and use;

4. When the hydraulic coupling device fails, the system can also continue to run automatically without stopping.

ABB partners have the following solutions for the requirements of customers in this project:

1. Four sets fan motors are equipped with frequency conversion speed control devices, and the original hydraulic coupling adjustment is changed to frequency conversion adjustment to save energy.

2. Each fan machine is driven and controlled by one set frequency converter device to meet the capacity requirements of customers in production and reduce the inventory requirements of spare parts required by customers for product operation;

3. As ABB medium voltage inverter ACS580MV adopts modular structure design, the modules of 4pcs inverters can be universal, reducing the inventory of spare parts required for product operation;

4.In order to realize the unattended and faulty equipment proposed by the customer, the system can automatically switch the function of continuing operation. Each inverter adds automatic switching bypass cabinet system to realize this function.The system constitution of the inverter and the automatic bypass switch cabinet is shown in Figure 1.

Figure1.inverter and motor one to one automatic bypass switch cabinet system structure

When the inverter fails or is faulty,and alarm is issued the PLC control system performs logical operations and judgment. According to different faults or error alarms of the inverter, the PLC controls different levels of alarm information and gives different control commands. For example, when the inverter fails, the inverter stops, and the PLC control system issues a control command. First, the high-voltage contactor or the high-voltage circuit breaker at the output end of the inverter is disconnected, and then the high-voltage contactor on the incoming side of the automatic bypass switching cabinet is closed. The high-voltage contactor on the output side of the inverter and the high-voltage contactor on the incoming side of the automatic bypass switch cabinet need to be mechanically interlocked to prevent a short circuit at the same time and damage the inverter.

Project feature

1、The success of the project transformation affects the stable operation of the power plant, and is even closely related to the power supply and economic development of the local area;

2、The first use of the newly medium voltage transmission product ACS580MV on the induced draft fan of the power plant;

3、The control method of replacing the fluid coupling with the inverter has a major impact on the operating cost;

4、The combination of inverter control and automatic switching cabinet system improves the safety and reliability of the system,and reduces the operating cost of the enterprise.

Customer benefit

• Through the transformation of the inverter fan installed in the power plant, the operating cost is reduced for the customer, and energy saving and consumption reduction are further realized on the original basis.

•Reduced customer maintenance costs for fluid couplings, including maintenance time, maintenance of spare parts, etc. 

•The automatic bypass switching cabinet system matched with the inverter facilitates the unattended operation of the customer and effectively ensures the stable operation of the customer system.