Research On Non-fault Triping Criterion Of High-voltage Transmission Line Based On Local Electrical Measurements

With the rapid development of power grid construction, EHV/UHV projects have been put into operation, the size and complexity of the grid have greatly increased the requirements to the security and stability of the grid control system have become more sophisticated, non-fault triping maloperation or refuse to move when the accident occurred make a huge threat to the security and stability of the syetem, this paper is in-depth analysis and research on non-fault triping criterion based on the volume of single-ended electrical, around the problems of the traditional non-fault triping criterion, proposing a new criterion that are theoretically feasible, aimed at resolving the the lack of discrimination principle of the current non-fault triping criterion of the stability control system.The sampling algorithm of the stability control devices is related to the change of the electrical characteristics that the criterion used. In this paper, using a algorithm that sampling three phase value at the same time to get the RMS-related electrical quantities. A prerequisite for the correct identification of the follow-up criterion is accurate and reliable components to start the launch, if the component error to start, that will be negative to the follow-up criterion, the paper is constructed based on negative sequence and zero sequence components of the integrated high-performance components to start, through enlarging the failure characteristics to enhance the sensitive and reliability. Using the threshold value through different to curb misuse of the process to start oscillating.Criteria for non-fault triping is the key part of the core criteria. This paper analyzes the shortcomings inherent in the traditional criterion, as well as difficult to determine the actual operating conditions, what's more, study the power system non-fault triping with the other dynamic process of change in the electrical characteristics of the difference between the first side to seize the measurement of amplitude factors and the characteristics of impedance measurement, and based on this proposed new criterion for non-fault triping, the new criterion is a good solution to the traditional criterion and the refusal to move maloperation problem and have good adaptability.Compared to using only the criterion of frequency in terms of volume, volume-based criterion for transient fault will have a more comprehensive grasp. How to determine which extraction of the beneficial characteristics of the transient is the key, for the theory of wavelet transform in time domain and frequency domain to distinguish well and in the areas of power systems have been a wide range of research and application. This paper introduces the wavelet transform the basic concepts of the relevant theory, and do a comparison of Fourier transform analysis of the specific advantage. Discussed for the analysis of power system transient wavelet function, the sampling frequency and data window and select the scale transform the principles and methods. On this basis, the study will be applied to the wavelet transform trip trouble-free start components and determine the feasibility criterion, combined with the principle of wavelet analysis and non-fault tripping discrimination principle, proposed the relevant criterion.