Research On Fault Diagnosis Of 750kV Substation Based On Coloured Petri Net

The 750 kV interconnection is an extra-high voltage power transmission and transformation project with the characteristics of large scale,long line,high voltage,large units,close networking and so on,which is the key part of transportation forms of electric power in the northwest region.As the role of core and link,intelligent degree of 750 kV substation is getting higher and higher,and there are more and more monitoring devices,which adopt double networks and protection configuration,being more complex and complicated than the general substation and transmission in topological structure and protection configuration.In the event of failure,a lot of alarm information will be poured into the substation,with the peculiarity of various kinds,interference of redundant information and uncertainty which will cause great difficulties for the people charging for the operation in the analysis and judgement.So the research of the substation fault diagnosis model and system has an important significance in the rapid diagnosis of fault for operation personnel,providing a basis for fault recovery and ensuring the efficient operation of the safety of the network engineering.The main contents of the thesis are as follows.(1)In this thesis,a new type of 750 kV substation fault diagnosis based on Colored Petri net combined with double networks and protection configuration is proposed aiming at the problem of large model complex logic and weak versatility in view of the existing Petri nets in the study of 750 kV substation fault diagnosis model.Places with the same type are folded in the direction of horizontal.Transitions with the same structure are longitudinally compressed.While the protection and circuit breakers are represented with a single and composite color,so that the component protection and circuit breaker information are classified and the process is clear.The idea of stratification and subnetting is adopted in the model and reasoning,which is divided into four layers: transformation layer,comparison layer,diagnosis layer and integration layer,making the model establishment and reasoning simple and clear.The model is finally applied to the main and the redundant network to get the coupling net.The simulation results show that this method can obtain the correct result for both single and multiple faults of 750 kV substation.Besides the simple model and fast reasoning,its structure is not changed by the protection configuration and voltage level and the versatility is strong.(2)The error may occur when complete information cannot be proved and the decline of reliability of the diagnosis cannot be realized when the protection acted incorrectly and rejected.A fault diagnosis based on improved colored Petri net method is proposed,focusing on the classification of protection information and the internal logic of the circuit breakers with the relationship between the real representations of the circuit breaker status information.Finally comprehensive diagnosis is applied with the protection information directly identifying the fault.At the same time,the fuzzy factor λ is introduced into the Colored Petri net,and the confidence attribute w is included in the corresponding color attribute to solve the problem of the decrease of the diagnostic credibility and the uncertainty of the symptom information.The entire improved Color Petri net are hierarchically represented by the classification of the change and the identification of the status and it is accurate layer by layer to solve the main network and redundant network diagnosis results,and through the coupling to get the final diagnosis.Through the simulation of single and multiple faults,it is proved that the fault symptom information of the method is clear,the model is simple in structure,small in scale,strong in applicability,and can solve the problem of uncertainty such as missing information and ambiguity.