On The Closed-loop Control And Protection System Of V94.3A Combined Cycle Steam Turbine

Combined cycle generator units is a kind of commercial dynamoelectric devices with mature technology and low pollution, which is progressively recognized and well developed in the world nowadays. It shows some nice features, such as high efficiency, low wastage, fast startup and flexible adjusting etc. Because SIEMENS V94.3A is one of the heavy duty dynamoelectric devices with the most advanced technology and the best running time, it is introduced from as the main type units by Shanghai Electric Group Turbine Workshops. According to the domestically produced requirement of technical indraught of our company, we must absorb all of the key technology of SIEMENS V94.3A and then improve it. Therefore, it is necessary and meaningful to develop the control system of SIEMENS V94.3A in this background.Based on the project of Shanghai Electric Group Turbine Workshops for combustion turbine power plant Phase I in the east of Xia men - construction and operation of V94.3A single shaft combined cycle units, the control and protection strategies for combined cycle units were designed by absorbing the key design of control system of SIEMENS V94.3A single shaft combined cycle units.Firstly, by analyzing the process and principle of combined cycle turbine units, control requirement and performance target of the heat recovery boiler and turbine sets were proposed from the processing point of view. These formed the firm bases for the control scheme and architecture of control system.Secondly, according to the control requirement and technological process, the control principle of the combined cycle turbine units was analyzed. Its control function was mainly divided into speed control, steam inflow control, main steam pressure and so on by the modular design method then. In different conditions, these designed control modular worked together to complete the parameterized coordinate control for speed-up, breaker closer and safeguard the control requirement and running safety of the turbine. What's more, in terms of the practical control requirement, SPPA-T3000 software platform was adopted to complete the configuration of control system hardware and software.Protection function and strategy of the combined cycle units were analyzed from the viewpoint of safety, reliability and economic status. Two types of the important protection scheme were put forward. One was the trip protection at abnormal condition, including the protection of overspeed,axial shift and vibration and so on. The other was the trip protection at the aspect of thermal stress, that is, the condition of heat expanding and heat stress of the cylinder and valves was monitored in the running process and corresponding maintenance method was adopted. Furthermore, the design and realization of turbine trip protection at abnormal operation condition and turbine thermal stress protection were mainly discussed.Finally, the simulation scheme for the control and protection strategies was analyzed. By establishing the simulation software platform of control system, validity and rationality of the control and protection strategy of combined cycle turbine units were proven by testing.