Information Transmission Security And Relay Protection Strategy Of Distributed Power Distribution Network

The worsening global energy and environmental problems promote the implementation of China’s "double carbon" policy.At the same time,it also further stimulates the rapid development of distributed power generation technology such as wind and solar.But,the structure and function of the new intelligent distribution network are different from the traditional distribution network.New energy distributed power generation system and traditional power generation system are completely different.All these bring unprecedented challenges to the distribution network.Moreover,China’s distribution network has a complex network topology.The types and quantities of electrical equipment are relatively large.These characteristics lead to the intelligent terminal can not cover every corner of the distribution network.Nevertheless therefore,it is urgent to design a safe and efficient transmission network that can accommodate a large number of dynamic fluctuation power data.In addition,the output of distributed power system has the characteristics of intermittence,randomness and diversity.The requirement of intelligentization enables the matching of power processing and load in different time and space scales to be completed in real time.This will inevitably lead to the traditional relay protection device is no longer applicable.Even the new distribution network has put forward higher requirements on the flexibility and reliability of relay protection action.Considering the above factors,this dissertation studies the following two aspects: power data transmission system and security transmission strategy based on mobile network,and new relay protection strategy.At the same time,some innovative research results have also been obtained.1.This dissertation points out the application prospect and problems of the current power data transmission system.And a kind of power data information transmission system which is suitable for distributed power system is studied and designed.The sharing model adopted by the system can accommodate massive power data information.The accuracy of transmission information,exchange rate and packet loss rate also meet the requirements.Then,calculation examples are analyzed by Chariot network performance testing software to verify the practicality and effectiveness of the system designed.2.This dissertation designs an efficient and simple key distribution protocol.On this basis,the secure transmission strategy of power data transmission system based on secure coding technology is constructed.It has solved the problem that the power data transmission system is vulnerable to network attack and the transmitted power data information is easy to be wiretapped or maliciously modified and forged.Finally,the necessity and effectiveness of the security strategy are verified by simulation.3.The new adaptive current protection algorithm is designed after deeply analyzing the influence of single distributed power system is connected to the grid.And it adopts positive sequence fault component method and Fourier algorithm,based on 5G mobile network communication technology,the adaptive current protection.The proposed protection scheme can adjust the current action value setting according to the real-time operation of the distribution network.It effectively integrates the low delay and high reliability characteristics of 5G mobile network closely with the adaptive current protection of a single distributed power grid-connected distribution network.Finally,the effectiveness of the new self-use current protection is verified by simulation.4.This dissertation proposes a new adaptive protection,which measures the impedance changes at both ends of the transmission line combined with 5G communication technology,in view of the actual operation of the multi-distributed power system integrated into the distribution network.The protection can obtain real-time and high-precision operation parameters through 5G communication data acquisition system combined with iterative calculation and correction algorithm.The constructed modulus and phase angle criteria can effectively and accurately distinguish the internal and external faults within the protection range.Finally,PSCAD was used to build a model,and simulation analysis was carried out to verify the effectiveness and applicability of the adaptive protection.In short,this dissertation studies the above key technologies in view of the development status and technical problems of grid-connected distribution network operation with distributed power system.In order to solve the problems existing in its operation.The purpose is to improve the performance and reliability of the grid-connected distribution network with distributed power system,and the relay protection strategies are also more applicable.