Active Fault Diagnosis for Gas-Steam Combined Cycle Power Plant Considering Variable Working Conditions

The gas-steam combined cycle power plant (CCPP) is one of the important energy conversion equipment in iron and steel energy systems., which can utilize the by-product gas to supply power in industrial parks. Due to the complexity of the environment in which the equipment is located., the components of the equipment., including actuators., compressors and combustion chambers., are prone to fault. Especially., the fault information contained in the data is not sufficient when the early fault occurs., it is difficult to fault diagnosis. For this problem., this paper proposes an active fault diagnosis (AFD) method for CCPP considering variable working conditions. Firstly., the system state is estimated by the zonotopic observer., and then the state output set affected by the unknown disturbance is described by the zonotopes. Finally., in order to realize the application of AFD under variable working conditions of the equipment., the auxiliary signal is designed to sperate the state set of the normal model and the fault model under variable working conditions. The experimental results show that the proposed method has good fault diagnosis ability under variable working conditions.

I. Introduction

Due to the advantages of short construction period, high operation reliability and high energy conversion efficiency [1], the installed capacity of CCPP in China has been growing rapidly as well as the capacity of single equipment. The proportion of CCPP in iron and steel industry and power generation industry has been expanding year by year. However, the external complex natural environment and the internal extreme high temperature and pressure environment lead to performance degradation or damage of the internal components of the equipment with the increase of operating time, which is easy to cause various faults [2]. Therefore, it is of great significance to carry out fault diagnosis for CCPP.