Features of Application of the «Open Triangle» Scheme in the Rural Low-Voltage Structure Distribution Network

Author(s):  
Ivan Nadtoka ◽  
◽  
Pyotr Osadchiy ◽  
Vladimir Tropin ◽  
◽  
...  

The features of applying the «open triangle» scheme in the structure of a rural low-voltage distribution network with a voltage of 220 V are studied from the standpoint of achieving a certain energy efficiency. The energy effect is estimated by the criterion of the relative value of the additional power losses in the conductors of a three-wire line of a 220 V network caused by reactive power and load asymmetry. The load is modeled by two power receivers connected to the phase-to-phase voltage, the general output of the power receivers is grounded, which forms the «open triangle» circuit. The energy characteristics of the active load, active load with capacitive corrective element, active load with capacitive and inductive corrective elements are analyzed; and also the most practical case – active-inductive load with various values of reactive power factors -0,1; 0,2; 0,3 and capacitive corrective element. An important feature of applying the «open triangle» scheme in the structure of a rural low-voltage distribution network with a voltage of 220 V, from the standpoint of achieving practically necessary and sufficient energy efficiency - not exceeding 10 % of the additional power losses, is the ability to compensate for reactive power and balancing the phase currents of the network line using only one corrective capacitor of relatively low power - about 50 % of the active power of one power receiver.

2021 ◽  
Vol 4 (S2) ◽  
Author(s):  
Marika Nakamura ◽  
Shinya Yoshizawa ◽  
Hideo Ishii ◽  
Yasuhiro Hayashi

AbstractAs the number of photovoltaic (PV) power generators connected to the distribution grid increases, applications of on-load tap changers (OLTCs), power conditioning systems, and static reactive power compensators are being considered to mitigate the problem of voltage violation in low voltage distribution systems. The reactive power control by power conditioning systems and static reactive power compensators can mitigate steep voltage fluctuations. However, it creates losses in generation opportunities. On the other hand, OLTCs are installed at the bases of distribution lines and can collectively manage the entire system. However, the conventional voltage control method, i.e., the line drop compensation (LDC) method, is not designed for the case in which a large number of PV systems are installed in the distribution network, which results in voltage violations above the limit of the acceptable range. This study proposes a method to determine the optimal LDC control parameters of the voltage regulator, considering the power factor of PV systems to minimize the magnitude of voltage violations based on the voltage profile analysis of low-voltage (LV) distribution networks. Specifically, during a measurement period of several days, the voltages at some LV consumers and pole transformers were measured, and the optimal parameters were determined by analyzing the collected data. The effectiveness of the proposed method was verified through a numerical simulation study using the actual distribution system model under several scenarios of PV penetration rates. Additionally, the difference in the effectiveness of voltage violation reduction was verified in the case where all the LV consumer’s consumer voltage data measured per minute were used as well as in the case where only the maximum and minimum values of the data within the measurement period were used. The results reveal that the proposed method, which operates within the parameters determined by the voltage analysis of the LV distribution network, is superior to the conventional method. Furthermore, it was found that even if only the maximum and minimum values of the measurement data were used, an effective voltage violation reduction could be expected.


Author(s):  
Weifang Zhai ◽  
Yongli Liu ◽  
Yiran Jiang

In order to ensure the safe operation of the distribution network and to understand the operation of the distribution network, it is necessary to monitor the various operating parameters of the distribution network in real time and to send the various measurement parameters to the dispatching and monitoring center in time. So the low-voltage distribution network integrated parameter measurement and control has been widely used. This paper introduces a design method of combining two sets of reactive power compensator and distribution network measuring and controlling device into one part. The distribution network measurement and control, power factor correction and reactive power compensation are realized. In a word, the system has simple structure, high precision, and strong anti-interference ability, among other advantages, with great market potential.


2013 ◽  
Vol 448-453 ◽  
pp. 2097-2104
Author(s):  
Jun Li ◽  
Lin Zhang ◽  
Mei Juan Liu ◽  
Ge Xin Xing ◽  
Wei Wei Li ◽  
...  

SVG can compensate reactive power deficiency, suppress harmonics, improve three-phase imbalance and power quality more flexibly. There are very few small volume SVG products available for low voltage distribution network in the past. The generic SVG products are very expansive, thus not suitable for low voltage distribution network. Therefore, it is an urgent task to design a new generation distribution network SVG product that offers good value for money. This paper studied a SVG digital controller based on TMS320F28335 DSP chip. The fast and powerful computing and parallel operation capability of TMS320F28335 can satisfy the real-time, multifunction and multiple objective coordination control of SVG. Applied the instantaneous reactive power theory and adopted current direct control mode, an enhanced filtering algorithm to filter instantaneous sampling value is proposed. Automatic bi-directional compensation control strategy effectively reduced voltage variation at the user side. Its effectiveness is verified by an engineering project.


Inventions ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 25
Author(s):  
Ahmed F. Ebrahim ◽  
Ahmed A. Saad ◽  
Osama Mohammed

The fast development of the residential sector regarding the additional integration of renewable distributed energy sources and the modern expansion usage of essential DC electrical equipment may cause severe power quality problems. For example, the integration of rooftop photovoltaic (PV) may cause unbalance, and voltage fluctuation, which can add constraints for further PV integrations to the network, and the deployment of DC native loads with their nonlinear behavior adds harmonics to the network. This paper demonstrates the smart integration of a DC microgrid to the neighborhood low-voltage distribution network (NLVDN). The DC microgrid is connected to the NLVDN through a three-phase voltage source inverter (VSI), in which the VSI works as a distribution static compensator (DSTATCOM). Unlike previous STATCOM work in the literature, the proposed controller of the VSI of the DC smart building allows for many functions: (a) it enables bidirectional active/reactive power flow between the DC building and the AC grid at point of common coupling (PCC); (b) it compensates for the legacy unbalance in the distribution network, providing harmonics elimination and power factor correction capability at PCC; and (c) it provides voltage support at PCC. The proposed controller was validated by Matlab/Simulink and by experimental implementation at the lab.


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