scholarly journals The automatic phase-selective photovoltaic grid-connection system used to control three-phase imbalance of low voltage power grid

2021 ◽  
Vol 645 ◽  
pp. 012066
Author(s):  
Peng Yi-wen ◽  
Zhu Si-tong ◽  
Miao Yi-lin ◽  
Wang Xinyao ◽  
Wang Li-di
Keyword(s):  
Low Voltage ◽  
Power Grid ◽  
Grid Connection ◽  
Automatic Phase ◽  
Three Phase ◽  
Connection System

Analytical Study on the Effect of Coordinated Application of Distributed Grid Connection and SVG on Wind Farms to Increase Power Quality in Fuxin Rural Power Grid

2014 ◽  
Vol 651-653 ◽  
pp. 1028-1032
Author(s):  
Cun Guo Liu ◽  
Yu Peng Wang ◽  
Qing Ye ◽  
Tao Liu ◽  
Bai Chao Shu ◽  
...  
Keyword(s):  
Wind Power ◽  
Power Quality ◽  
Wind Farm ◽  
Low Voltage ◽  
Transmission Loss ◽  
Power Grid ◽  
Load Flow ◽  
Utilization Rate ◽  
Grid Connection ◽  
The Impact

power quality problems such as high line loss, low voltage exist commonly in rural power grid of China due to few supply points, long power transmission and distribution line. Huge fund is required to increase the quantity of supply points in rural power grid; installation of var compensators on line nodes could not solve power quality problems on the whole line. At the same time, as distributed power supply, wind power is also restricted by peak regulation, insufficient line output capacity and other factors in large scale centralized grid-connected output, wind curtailment often occurs. In order to solve the above-mentioned two problems simultaneously, electric power of wind farm may be output via nearby rural power grid line, thus not only utilization rate of wind power is increased, but also power quality of rural power grid is improved.This paper takes an example of a district in Fuxin City, summarizes power quality change data of relevant rural power grid before and after the distributed grid connection of wind farm is made, the analysis shows that distributed grid connection of wind power could improve load flow distribution of the power system, reduce system transmission loss in this district obviously, increase economical efficiency of the system operation effectively. At the same time, effectiveness of static var generator in substation to overcome the impact of such grid connection mode on power grid is verified.

scholarly journals Multi-Mode Voltage Sag/Swell Generator Based on Three-Phase Inverter Circuit

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6520
Author(s):  
Qiguo Han ◽  
Xing Wang ◽  
Pengfei Hu ◽  
Maolin Wang ◽  
Xu Luo ◽  
...  
Keyword(s):  
Low Voltage ◽  
Power Grid ◽  
Thermal Power ◽  
Voltage Sag ◽  
Phase Inverter ◽  
Grid Voltage ◽  
Three Phase ◽  
Inverter Circuit ◽  
Three Phase Inverter ◽  
Multi Mode

The voltage ride through capability of the major auxiliary variable-frequency drive (VFD) in large thermal power plants is the key technical issue of power grid and source coordination. In order to test the high voltage ride through (HVRT) and low voltage ride through (LVRT) capability of the auxiliary VFD, it is necessary to develop a power supply to simulate different grid voltage sag and swell accurately. In this paper, a generator (VSSG) based on the common three-phase inverter circuit that can simulate multi-mode voltage sag/swell is proposed. The designed main circuit consisting of transformer, rectifier, DC split capacitors, three-phase inverter, and LC-filter can generate single-phase and three-phase voltage sag, swell, and phase angle jumping flexibly. The developed control strategies composed of the double closed-loop control and the neutral voltage balance control achieve accurate output, fast dynamic response, and step-less adjustment. Simulation and experiment results verify the multi-mode voltage simulation performances of the proposed VSSG, which can be effectively used to emulate power grid voltage sag and swell phenomena under the IEEE 1159 and IEC standards.

A Phase Locked Loop Method for Low Voltage Ride-Through Control in Three-Phase Three-Wire Photovoltaic Grid System

2013 ◽  
Vol 415 ◽  
pp. 174-179
Author(s):  
Bao Ding ◽  
Gong Zhang ◽  
Yong Ming Zhang ◽  
Liang Zhao
Keyword(s):  
Phase Angle ◽  
Low Voltage ◽  
Phase Locked Loop ◽  
Grid System ◽  
Line Voltage ◽  
Low Voltage Ride Through ◽  
Loop Method ◽  
Synchronous Reference Frame ◽  
Automatic Phase ◽  
Three Phase

Low voltage ride through (LVRT) is regarded as one of the biggest challenges in photovoltaic grid equipments designing, manufacturing and control technology. The fast and accurate automatic phase locked control is the premise to achieve photovoltaic grid low voltage ride through. Considering that the traditional phase locked loop method is difficult to adapt the performance requirements of low voltage ride through (LVRT) in three-phase three-wire photovoltaic grid system, this paper presents a new three-phase unbalanced phase locked loop method. Improved second order generalized integral orthogonal signal generator (SOGI-OSG) is used for line voltage detection; Synchronous reference frame for phase locked loop (SRF-PLL) is used for line voltage phase locked and phase angle detection; Heron formula and Sine theorem is adopted to calculate the three-phase phase voltage amplitude and phase angle. Research results show that when grid voltage dips, this phase locked loop method can detect the fault signal accurately. It provides a technical support for photovoltaic grid low voltage ride through system.

Renovating the View of Cost Sharing for the Underground Low Voltage Cable Projects in Hanoi

2019 ◽  
Vol 35 (5E) ◽  
Author(s):  
Pham Thi Thu Ha ◽  
Phan Dieu Huong
Keyword(s):  
Willingness To Pay ◽  
Cost Sharing ◽  
Low Voltage ◽  
Power Grid ◽  
Field Studies ◽  
Power Industry ◽  
Well Field ◽  
The Subject ◽  
Sharing Responsibility ◽  
The Cost

Underground power grid projects in Hanoi is so urgent that it requires immediate implementation. To synchronously and quickly implement the underground power grid projects, people in charge should not follow the outdated perspectives of just including the power industry, but also need to call for the support and cost sharing responsibility from consumers. This paper aims at approaching the subject both from the producers and consumers’ perspectives to together sharing the cost of putting the power grid underground not only in Hanoi but other metropolitans in Vietnam as well. Field studies (including 104 families) at Hoan Kiem District, Hanoi and CBA method were applied to investigate the willingness to pay (WTP) level of consumers to share the cost with the power industry for the underground power grid projects in Hanoi. The overview of the results shows that cost for the underground power grid in Hoan Kiem District ranging from 30,000 VND/household/month to 46,000VND/household/month. On the other hand, the willingness to pay of a typical household of four people within Hoan Kiem District ranges from 17,000VND/month to 24,000VND/month, with the most favorable method of annual payment within a detailed timeline.

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