Comparison of different models of conduit system on results of power system transient stability

In the previous studies on modeling conduit systems, the conduit system is often regarded as a single conduit with rigid water hammer, the effect of elasticity of the conduit system and the interaction of the complex conduit system are neglected. In this paper, a versatile complex conduit system model is proposed and implemented by the program interface function of PSASP (developed by CHINA EPRI). The model is based on the characteristic method combining with numbering the conduit system according to its topological structure. Thus, the model can be applied in any complex conduit systems. On the basis of the above work, the effect of different conduit system models on power system transient stability is studied through three test cases. The simulation results show that when the conduit is relatively short, the difference of simulation results between the rigid water hammer model and the elastic water hammer model is small. But to a complex conduit system, the difference of simulation results between the complex elastic hammer model and the simplified single conduit rigid hammer model is relatively large. It is suggested that in the extended term stability study of power systems the complex conduit system model should be used.