Load-shedding strategy using a zero-sequence power supply scheme for distribution networks in a modern home or building

2018 ◽  
Vol 159 ◽  
pp. 179-190 ◽  
Author(s):  
Rih-Neng Liao ◽  
Nien-Che Yang
2015 ◽  
Vol 9 (1) ◽  
pp. 253-262
Author(s):  
Liu Zhongfu ◽  
Zhang Junxing ◽  
Shi Lixin ◽  
Yang Yaning

As for the wide application of arc suppression coil to the grounding in neutral point of mine high voltage grid, grid leakage fault rules and harmonic characteristics of the neutral point grounding system through arc suppression coil are analyzed, the selective leakage protection program “zero-sequence voltage starts, fifth harmonics of grid zerosequence voltage and zero-sequence current are extracted for phase comparison” is proposed, and corresponding fifth harmonic extraction circuit and power direction discrimination circuit are designed. The experimental results show that the protective principle applies not only to the neutral point insulated power supply system, but also to the power supply system in which neutral point passes arc suppression coil, which can solve selective leakage protection problems under different neutral grounding ways, improving the reliability of selective leakage and guaranteeing the stability of the action value.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1978 ◽  
Author(s):  
Sanna Uski ◽  
Erkka Rinne ◽  
Janne Sarsama

Microgrids can be used for securing the supply of power during network outages. Underground cabling of distribution networks is another effective but conventional and expensive alternative to enhance the reliability of the power supply. This paper first presents an analysis method for the determination of microgrid power supply adequacy during islanded operation and, second, presents a comparison method for the overall cost calculation of microgrids versus underground cabling. The microgrid power adequacy during a rather long network outage is required in order to indicate high level of reliability of the supply. The overall cost calculation considers the economic benefits and costs incurred, combined for both the distribution network company and the consumer. Whereas the microgrid setup determines the islanded-operation power adequacy and thus the reliability of the supply, the economic feasibility results from the normal operations and services. The methods are illustrated by two typical, and even critical, case studies in rural distribution networks: an electric-heated detached house and a dairy farm. These case studies show that even in the case of a single consumer, a microgrid option could be more economical than network renovation by underground cabling of a branch in order to increase the reliability.


Author(s):  
Xin Shen ◽  
Hongchun Shu ◽  
Min Cao ◽  
Nan Pan ◽  
Junbin Qian

In distribution networks with distributed power supplies, distributed power supplies can also be used as backup power sources to support the grid. If a distribution network contains multiple distributed power sources, the distribution network becomes a complex power grid with multiple power supplies. When a short-circuit fault occurs at a certain point on the power distribution network, the size, direction and duration of the short-circuit current are no longer single due to the existence of distributed power, and will vary with the location and capacity of the distributed power supply system. The change, in turn, affects the current in the grid, resulting in the generation and propagation of additional current. This power grid of power electronics will cause problems such as excessive standard mis-operation, abnormal heating of the converter and component burnout, and communication system failure. It is of great and practical significance to study the influence of distributed power in distributed power distribution networks.


Author(s):  
Y. A. Sekretarev ◽  
D. A. Menyaikin

Reliability of power supply of consumers is an important task in the process of transmission and distribution of electric energy. The paper proposes a method for assessing the consequences of power failures of monoconsumers of electric energy on the example of an oil company and an adjacent power grid company. The uniqueness of the developed technique lies in the possibility of reliable calculation of reliability of power supply of complex branched electric networks without taking into account the specific scheme of power supply. The accuracy of calculations is increased due to the use of data directly studied power system, taking into account the specifics and operating conditions of specific equipment, instead of the average information. Classification of failures on the main reasons in electric networks of the oilproducing enterprise of the far North that allowed to develop actions for increase of level of reliability of power supply is made.


2021 ◽  
Vol 9 ◽  
Author(s):  
Liu Shengli ◽  
Wu Jun ◽  
Xue Longjiang ◽  
Wu Di ◽  
Lu Haiqing ◽  
...  

Aiming at the problems of low power supply reliability, poor transfer capacity between stations, and low line utilization in the current distribution network, this paper proposes a diamond-shaped distribution network structure with a clear structure. First, we investigated the typical wiring patterns of medium-voltage distribution networks in Tokyo, Japan, Paris, France, and China’s developed cities, and summarized experience and shortcomings. Secondly, combining the typical wiring patterns of distribution networks in China and abroad, construct a diamond-shaped distribution network structure, and study its adaptability, safety and flexibility, power supply reliability, and economy. Finally, take the transformation of the wiring mode of a regional distribution network in a certain city as an example, compare the use of the diamond-shaped distribution network structure in this article with the use of cable double-ring network wiring, cable “double petal” wiring, and Shanghai diamond-type wiring distribution network grid reconstruction The effect verifies the superiority of the diamond-shaped distribution network structure in this paper.


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