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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...
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...
This paper presents an algorithm of new fuzzy membership function for power quality evaluation. Firstly, the six membership functions are presented in this paper to show the main characters as well as the differences. Then, the six functions are applied in the power quality evaluation in Gl method. Thirdly, a new fuzzy membership functions is constructed through weighting and combining six common...
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,...
Based on the research subject of harmonic pollution of Nanhai in Foshan, a harmonics survey in Nanhai gird is presented in this paper, on which a large number of statistical analysis have been worked. This survey takes almost a year and includes 490 enterprises, 772 distribution transformers at 12 towns. According to inspecting results, it shows that the harmonic pollution in Nanhai city is more severe...
In this paper a novel hysteresis current controller for APF(active power filter) with low switching losses is suggested. The controller adjusts the switching frequency with the output current of APF to reduce the switching losses effectively with the same control precision, utilizing the characteristic of APF that the sum of absolute value of three-phase output current of APF would greatly fluctuate...
The switching losses of Active Power Filter (APF) is one of the important factors that influence the performance-price ratio of APF. In this paper, a novel method is suggested. Under this new method, each phase output reference current of APF is compared to adjust hysteresis of each phase, so that the switching number of the phase that has greater switching losses is decreased, meanwhile the switching...
In order to evaluate power quality more accurately, this paper presents a three-layer distributed online power quality monitoring system (PQMS), which uses the General Packet Radio Service (GPRS) wireless network as its communication channel. This PQMS consists of three parts: the power quality monitor (PQM), the monitoring software (MS) in upper computer and the web platform (WP). The PQM which is...
This paper presents an Improved Catastrophic Genetic Algorithm (ICGA) for optimal reactive power optimization. Firstly, a new catastrophic operator to enhance the genetic algorithms' convergence stability is proposed. Then, a new probability algorithm of crossover depending on the number of generations, and a new probability algorithm of mutation depending on the fitness value are designed to solving...
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)...
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