| The increasing scale of power grid has put forward higher and higher requirements for real-time fault information collection,accurate fault location and scientific fault decision-making,so as to restore the normal operation of the system as soon as possible.Relay protection information system emerges as the times require.By connecting relay protection,wave recording and safety automatic device,it collects and manages the feedback information of the device in real time.It has become an important basis for protection and fault information collection and processing,power grid fault analysis and decision-making.Since the relay protection information system of China Southern Power Grid UHV Transmission Company was put into operation,it has met the different needs of various professionals and made outstanding contributions to the stable operation and scientific management of the main grid of West-to-East Power Transmission.However,in operation,a large number of data transmission failures and distortions have gradually appeared,resulting in poor system performance.It restricts the ability of various professional support systems to carry out fault analysis.In this paper,some typical sub-stations are selected according to the equipment manufacturers,and the communication status of the system is investigated comprehensively by means of test according to the relevant standards.The main business is tested on the spot,and the research results are analyzed and analyzed,and the investigation and analysis report of the operation status of the system is compiled.This paper expounds the concept and evaluation index of the reliability of communication system,and the requirements and influencing factors of the reliability of electric power communication network.The communication principle and existing communication problems of relay protection information system of EHV transmission company are mainly discussed,and the reliability calculation method of complex electric power communication network is given.Reliability analysis and calculation are carried out based on operation data.On the basis of in-depth analysis of the test results of main station and sub-station,determination of abnormal causes and analysis of communication problems,a scheme for improving the reliability of relay protection telegram is worked out.The scheme includes the optical transmission protection technology to improve the reliability of physical layer,the error handling and conflict arbitration mechanism to improve the reliability of link layer,and the application of IEC 61850 protocol to improve the reliability of application layer.Optical transmission network protection technology can solve the crux of fiber optic cable frequent interruption and restore communication in a very short time after failure.This paper verifies that the technology can effectively improve network availability.CAN technology designs automatic error detection,error automatic retransmission and non-destructive collision arbitration mechanism to ensure data consistency and effectively alleviate network data congestion.Therefore,in the link layer,CAN bus transmission system is upgraded as a way of dispatching data network information transmission.Based on OPNET platform,two different protocols,103 and IEC61850,are tested in substation communication network simulation.The simulation results show that IEC61850 can significantly improve the reliability of guaranteed transmission compared with 103.Finally,an on-line monitoring system for IEC61850 is designed and developed.Through real-time monitoring and analysis of message transmission process between stations,the abnormal message situation is statistically analyzed and the cause of abnormal message is judged,which can be used as a reference for operation and maintenance personnel.The system can enhance the perception,judgement and anomaly detection ability of the guaranteed network.This scheme can fundamentally eliminate the existing defects,enhance the stability of the system,and comprehensively improve the reliability of relay protection telegram. |
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