Taking Rudong Xiexin Environmental Protection Thermal Power Co.
, Ltd. as an example, this paper expounds the control application strategies of three Woodward controllers, 505 E, 2301E, in small thermal power units, and makes a comprehensive comparison.
With the development of electric power technology, for Turbogenerator units, the requirements for coal consumption, heating coal consumption, heating parameters and power supply quality of power plant are getting higher and higher, while various digital electro-hydraulic controllers (DEH) of steam turbines are more flexible and convenient in configuration, and various control application strategies meet the requirements of steam turbine control system, dynamic response and so on. It should be faster, with higher control accuracy, more convenient for automation operation, and provide better user needs. Woodward Corporation is one of the leading producers of Digital Electro-hydraulic Controller (DEH). Its main products are Woodward 505, Woodward 505E, Woodward 505C, Peak 150, 2301 series controllers, etc. For example, Dongxixin has selected three main control products: Woodward 505, Woodward 505E and 2301E, which are respectively applied to No. 1 back pressure unit, No. 2 condensing steam turbine unit and No. 4 steam-driven feed water pump drive. Their control mode is representative in our group and even in small thermal power plants nationwide. 505E control system. 505E is a 32-bit microprocessor-based control system. It was successfully applied to No.
1 15MW condenser generator and No. 2 15MW condenser generator in 2004. 505E has three independent control loops: speed/load PID control loop, auxiliary series PID control loop and steam extraction PID control loop. It can drive two independent control loops simultaneously. The executive unit loop, commonly known as high-regulation HP and low-regulation LP, controls the speed/power of steam turbine and the first stage extraction of steam turbine respectively. The extraction pressure is controlled from 0.
98 MPa to 1.27 MPa, which is supplied to the heat users of the external network. Because “cascade” is a secondary speed setting function, speed PID must control 505 LSS bus in order to make “cascade” play a control role. 2301E control system. 2301E controller is a new generation of Woodward digital governor. It completely replaces the old 2301A and 2301D governors. It has the function of dynamic speed control and is compatible with most load distribution speed control systems. It is used for remote control of driving pumps or compressors to provide constant load.
It is also called digital load distribution and speed controller for small steam turbines. 。 In November 2016, 15MW pumping unit No. 1 of our company was transformed into back pressure unit, which was successfully applied to the control of steam feed pump No. 1 of our company. The company’s control strategy is speed PID control regulation, regulating the speed of steam-driven feed water pump.
Under normal conditions, the actual speed and speed setting values are equal. When the external disturbance changes the speed of feed water pump, there will be a deviation between the speed setting values. After 2301E control system enlargement and PID operation, the feed water pump will be transported. The output command signal, through a “low selector” low selector protection output, thermostatic element directly controls the actuator of the intake valve of the steam feed pump, thus promoting the steam feed pump, which has the characteristics of fast response and high reliability. It has single function and simple structure.
It is generally used to control the speed or load of steam turbines. It is only suitable for pure condensing units or back pressure steam turbines. The 505E controller can drive a single or two independent actuators at the same time. It has special proportional amplification restriction logic and implicated decoupling algorithm. It can control two interacting parameters of power and extraction steam at the same time. Therefore, 505E is suitable for extraction steam turbines. 2301E controller provides digital load distribution and speed control for small steam turbines. It is widely used in the speed/load control of diesel engines, steam-driven traction equipment or generators in enterprises. Woodward controller has high modularity and comprehensive functions.
All of them adopt the way of setting parameters, that is, to debug according to the parameters provided by the manufacturer. After putting into operation, the system is maintained normally. It is easy to master and use. It has strong operability and can realize the special functions required by various users. In terms of hardware. The core processors of 505, 505E and 2301E are 32-bit microprocessors. The number of input and output channels is limited and cannot be expanded. Some channels have fixed their functions, while others can be configured according to user’s requirements. In terms of software. The program of 505E and 505E controllers is relatively solidified, and can only be configured by menu form, that is, input parameter values through the controller panel, or use “YES/NO” to configure the program. Although the configuration of Chinese version is more convenient, it has no expansion function. The 2301E controller loaded software, the software program is relatively solidified, and also through the use of form-filling configuration. In terms of operation mode. 505, 505E and 2301E control systems have two operation modes: programming mode and operation mode.
The programming mode is used to select the internal configuration and operation mode of the controller, while the operation mode is controlled according to the set program. These configurations and dynamic settings can be set, changed, adjusted and stored. Aspect. All three controllers can be operated on the controller panel. Operators need basic professional skills. They can also connect with DCS through hard wiring to achieve remote control. Our company’s 505, 505E, 2301E controllers are connected with Hollysys DCS system through hard wiring. The graphics configuration and database communication are carried out. Most of the remote control functions of steam turbine are realized, and the man-machine interface is friendly. From the above practical application and comparison, we can see that the mainstream controllers of WOODWARD Company: 505, 505E, 2301E basically meet the requirements of automatic control of small steam turbine units in our company. Moreover, these three controllers have fast dynamic response, high control accuracy, convenient automation operation, stable performance, different functions, and different prices. Users can choose different products according to the actual application needs of the project, in order to achieve the optimal allocation of cost-performance ratio.