The Countermeasures' Research To Solve The CT Saturation In Typical Micro Computer Relays

Massive research show that CT saturation of modern high-voltage grade , high-capacity, long-distance transmission network may have many adverse effects on the relay protection. furthermore,it may even direct threat to the safe operation of power grids. The problem that various voltage current transformer saturation in System have become increasingly prominent,along with the dramatic increase in short-circuit current and new systems of a large number of relay devices,especially in the agro-power grid transformation.It already impact on the correctness movement of relay devices. Therefore, the papers provided the algorithms and theoretical basis which may solve the problem of saturation by development needs and characteristics of the running relay in our network. By test of the dynamic simulation, digital-analog tests and the establishment of related models, We find the identification saturation criterion of CT saturation in order to identify Comparative analysis of various criteria and presente CT saturation solutions.The paper study on the focal point that anti-CT saturation of all kinds of typical microprocessor-based protection, on the basis of clarifying issues need of CT saturation, it contants the principal tasks include the following:1. In this part ,we depth analysis the causes of the mechanism of CT saturation, characteristics and related measurable indicators.At the same time, we establish the CT saturation mathematical model under a variety of circumstances, then we get the current and secondary current of the excitation waveform of saturated TA on TA transient and steady-state saturation. After that, we summed up the excitation current and secondary current waveform characteristics when comparing CT saturation with the actual recorded waveform. And, we recognize it as a basis for analysis power-CT saturation may have harmful effects on correctness of protective actions.2. The Research of PC protection CT saturation discriminant analysis method and algorithm for CT Saturation Theory, it shows that the algorithm is the key, as well as we use the "wavelet theory" analysising CT saturation is feasible; CT saturation accurate discriminant analysis is the key to whether CT saturation and find the point of saturation The relay then can combine both theory to analyze the impact of power-relay. Papers in the wavelet analysis, adaptive impedance than harmonic, CT Saturation continuous angle on the basis of theoretical models. China's power grid situation, the pan-wavelet algorithm theory, and the completion of the related theory, the digital algorithm work.3. CT saturation in the network algorithm based on China's Software Network's "pan-wavelet theory," a new type of algorithm, and some other algorithm which development with DELPH language, the preparation of the "CT saturation analysis software," The software brings new ideas to address these problems, the CT saturation to achieve rapid, accurate analysis. CT saturation analysis of the software is the basic tool.4. CT saturation-use development of simulation,we analysis CT saturation withMATLAB software, and establish CT saturation using MATLAB Simulink simulation model protection tripping caused by the saturation of the accident simulation. Jincheng Beizhuang 110kV substation and the examples of its CT saturation problem for the simulation analysis, examples of simulation results show that the method of calculating CT saturation research grid is feasible, effective, and the case against anti-CT saturation strategy.5. Numerous appeals combining the results of this thesis from the soft, explore two aspects of the hardware solution to protect current transformer saturation resulting in the misuse of rejecting action, and tried to seek a breakthrough in the theoretical research and production, protection of the right moves to raise rates further, safe and stable operation of power grids to raise the level. In addition, the authors also collected two excellent computer protection abroad since the transformation of the operating conditions in this paper, and combine large amount of accurate first-hand information, a full analysis of system failures, and as a basis. It made a "comprehensive report about Jincheng Power Network Control CT saturation", then gives a comprehensive solution to the problem of regional networks.Among the conclusion, we carried out the research work, and prospected follow-up work.