Ouyang Sen

Application of Improved Mathematical Morphology Method in the Power Quality Monitoring

By means of the mathematical morphology (MM) method, the power quality (PQ) disturbance signals can be monitored quickly and effective. However, the signal under investigation is often corrupted by noises, and the MM filter formed by fixed structure elements of can not handle this very well. In this paper, the theory and shortage of traditional MM theory are analyzed at first. And an improved MM (IMM) method is proposed. In this method, appropriate structural elements are selected and different structural elements and their self-adaptive weighted combinations are used to deal with perturbation signals. Also, the threshold method was used for reference, and it can improve the de-noising capability of the IMM method. In this way, the IMM method can carry out the de-noising and disturbance location task. Simulated results and practical application show that the proposed IMM method is practicable and possessed the advantages of simplicity, high calculation speed and easy hardware implementation.

The analysis of power meters' performance under nonsinusoidal conditions

The conventional definition for power measurement becomes contentious under nonsinusoidal conditions. This paper discusses the measurement principle and error analysis of induction watt-hour meter in the cases of non-harmonics and a variety of harmonics. In contrast with non-harmonics, the measuring process and the complexity of the measurement errors are analyzed under nonsinusoidal conditions. Then, the laws of measurement errors are summed up and a model of power measurement is proposed.

Research of fuzzy synthetic evaluation method of power quality based on improved membership function

The establishment of membership function in synthetic evaluation of power quality is taken to discussion. This paper proposes an improved membership function for power quality fuzzy synthetic evaluation. First, the weight of power quality indicators and the confirmation of indicator limit of membership function as well as the division of quality level are deeply analyzed. Then, on the basic of evaluation indicators quality level, the traditional ridge-shaped function is improved to construct the membership function. At the same time, the fuzzy model of power quality indicators is built on this foundation. In the end, an example is given to evaluate the quality of 33 feed lines belongs to Guangzhou power grid; the result demonstrates the practicability and effectiveness of this method.

Research of the impact of voltage quality and reactive power configuration for shock loads connected into distribution network

This paper proposes three dimensions of characteristics to describe the shock load, including reactive power, time, rate of change, then established the simulation model to did deep analysis on the impact of the voltage quality problem for shock loads connected into distribution network, it focuses on comparing the different dimension characteristic due to the difference of the impact of the voltage quality problem, finally proposed the basic principle and advices for shock load access, and it plays a guiding role in reactive power configuration for shock loads connected into distribution network.

An Autonomous Decision-Making Based Method for Comprehensive Evaluation of Power Quality and Its Application

This paper proposed an new autonomous decision-making based method for comprehensive evaluation of power quality in regional power network. Using the proposed method, the intercomparison between comprehensive power quality evaluation results of different objects to be evaluated in the same region can be implemented while the problem of the subjectivity of index weights is solved. Firstly, a competition principle of strengthening self-advantage and weakening rivals advantage for the objects to be evaluated is adopted in the proposed algorithm, then by use of autonomous decision-making, the competitive interval and view of power quality evaluation objects are analyzed and an evaluation model with the property of competition is built, finally rational sorting results of evaluated objects are obtained. Results of concrete calculation example show that the proposed method can incarnate the autonomous action of evaluated objects and both fairness and effectiveness of evaluation results can be ensured.