Intelligent Adaptive Protection Of Applied Research

The thesis comprises two parts. The first one includes chapter 2 and chapter 3, which is the network-based adaptive current protection principle;the second one includes chapter 4 to chapter 6, which Is the study of single-phase reclosing based on Intelligent control.When the power system becomes more complicated,the probability of system problem's emergence is bigger than before. As the most important one in all kinds of security measures,relay protection has been concerned widely by power system's personnel. Adaptive relay protection based on intelligent control is a new sort of protection principle which develops with the advancement of power system technology and the progress of intelligent control theory. It is presented to satisfy the higher request for power system relay protection.Chapter 2 expounds basic concept and normal principles of current protection and indicates the defect that current protection is influenced deeply and directly by the electric power networks connection mode and system's running mode, so current protection is only applied in the electric power network of 35kV of under 35kV. In Chapter 3 the principle of a new network-based adaptive current protection is proposed. Using the combination of communication technology with adaptive setting of current protection, the selectivity of tripping can be ensured and the problem which is difficult to be solve, i.e., the selectivity and the protection region of traditional three-step current protection are influenced by failure modes in distribution network, is solved.Chapter 4 introduces the concept of automatic reclosing and single-phase automatic reclosing,explains their advantages and shortcomings. Their common shortcoming is that they act blindly entirely before reclosing and can not distinguish instantaneous fault from permanent fault. Aiming at this shortcoming,the concept and theory of an adaptive single-phase reclosing scenario based on intelligent control was presented in Chapter 5. It's core is that it can distinguish instantaneous fault frompermanent fault definitely, avoid the blindness of traditional automatic reclosing and eliminate the harm when reclosing on permanent fault. But in some cases, adaptive reclosing can confound instantaneous fault with permanent fault, so it has fault too. In Chapter 6 an adaptive single2phase reclosing scheme based on wavelet neural network is presented to overcome the fault of voltage criteria of adaptive single2phase reclosing in distinguishing the instantaneous fault s from permanent fault. And a scheme based on three21ayer wavelet neural network has been put forward. The simu21ated result s of electric magic transient program( EMTP) and MATLAB show the feasibility of this method.