scholarly journals Coordinated Control of Active and Reactive Power Compensation for Voltage Regulation with Enhanced Disturbance Rejection Using Repetitive Vector-Control

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2812 ◽  
Author(s):  
Felipe J. Zimann ◽  
Eduardo V. Stangler ◽  
Francisco A. S. Neves ◽  
Alessandro L. Batschauer ◽  
Marcello Mezaroba

Voltage profile is one of many aspects that affect power quality in low-voltage distribution feeders. Weak grids have a typically high line impedance which results in remarkable voltage drops. Distribution grids generally have a high R/X ratio, which makes voltage regulation with reactive power compensation less effective than in high-voltage grids. Moreover, these networks are more susceptible to unbalance and harmonic voltage disturbances. This paper proposes an enhanced coordinated control of active and reactive power injected in a distribution grid for voltage regulation. Voltage drop mitigation was evaluated with power injection based on local features, such loads and disturbances of each connection. In order to ensure disturbances rejection like harmonic components in the grid voltages, a repetitive vector-control scheme was used. The injection of coordinated active and reactive power with the proposed control algorithm was verified through simulations and experiments, demonstrating that it is a promising alternative for voltage regulation in weak and low-voltage networks subject to inherent harmonic distortion.

Author(s):  
Majid Abdulhameed Abdulhy Al-Ali ◽  
V. Yu. Kornilov ◽  
A. G. Gorodnov

Annotation: There are various types of electrical equipment used in the extraction of oil at the Rumaila field, with an average voltage of 11 kV and a low voltage of 0.4 kV. The most common elements in this class are transformers and reactors, engines and gas discharge lamps. All of this equipment consumes reactive power and reduces the value of the power factor. (Power factor is the ratio of kW to kVA). The closer the power factor to the maximum possible value of 1, the greater the benefit for the consumer and supplier. In case of low power factor, the current will be increased, and this high current will lead to (large line losses, an increase in the nominal total power of kVA and overhaul dimensions of electrical equipment, deterioration in voltage regulation process and an increase in voltage drop, a decrease in efficiency).Power factor improvement allows the use of smaller transformers, switchgear and cables, etc. as well as reducing power losses and voltage drop in an installation. Improving the power factor of an installation requires a bank of capacitors which acts as a source of reactive energy. These arrangements provide reactive energy compensation. In Rumila, An improvement of the power factor of an installation presents several technical and economic advantages, notably in the reduction of electricity bills, we save (685.854.007 Iraqi Dinar= 550.000 $) for one month . All this work takes 6 to 12 month.


2021 ◽  
Vol 13 (4) ◽  
pp. 267-272
Author(s):  
M. M. Sultanov ◽  
A. V. Strizhichenko ◽  
I. A. Boldyrev ◽  
O. I. Zhelyaskova ◽  
E. A. Voloshin ◽  
...  

Reactive power in the power system negatively affects the operating mode of the electric network, additionally loading high-voltage lines and transformers, which leads to an increase in power losses, as well as to an increase in voltage drops. The influence of active and reactive power components of voltage in the network nodes is different and is overwhelmingly determined by the ratio of active and reactive components of the resistance elements of the electric system. In high-voltage networks, the reactive component of the resistance significantly exceeds the active component, and therefore the flow of reactive current through the network leads to a greater voltage drop than the flow of the active component of the current. The transfer of reactive power can lead to exceeding the normalized voltage range in the load nodes. To reduce power losses and voltage drop in the elements of the electric network, synchronous compensators (SC), static capacitor banks (SCB), static thyristor compensators (STC), controlled shunt reactors (CSR) can be used. The cost of production and transmission of active and reactive power are different, and when choosing the power of reactive power compensation means, it is necessary to take into account the costs and compare them with the resulting effect, which differs for large and small values of reactive power when this is reduced by the same amount. To assess the feasibility of application of compensatory devices, and to choose their type and locations of installation, relevant calculations are required. An empirical criterion is proposed for preliminary assessment of the technical feasibility of reactive power compensation. It enables to identify the network sections and nodes, which require reactive power compensation and should be considered in greater detail.


Author(s):  
Waleed Khalid Shakir Al-Jubori ◽  
Ali Nasser Hussain

The distribution system represents the connection between consumers and the entire power network. The radial structure is preferred for distribution system due to its simple design and low cost. The electrical distribution system suffers from problems of rising power losses higher than the transmission system and voltage drop. One of the important solutions to improve the voltage profile and to reduce the electrical distribution system losses is the reactive power compensation which is based on the optimum choice of position and capacitor size in the network. In this paper, different models of electrical loads such as constant power(P), constant current(I), constant impedance(Z), and composite (ZIP) model are implemented with comparisons between them in order to identify the most effective load type that produces the optimal settlement for alleged loss reduction ,enhancement of the voltage profile, and cost savings. To minimize search space, Dolphin Optimization Algorithm (DOA) is applied for selecting the size and location of capacitors. Two case studies (IEEE 16- bus and 33- bus) are employed to evaluate the different load models with optimal reactive power compensation. The results of comparison between the different load models show that ZIP model is the best to produce the optimum solution for capacitor position and size. In addition, comparison of results with literature works are done and showed that DOA is the most robust among other algorithms to achieve the optimum solution for voltage profile enhancement significant reduction of losses, and saving cost.


2013 ◽  
Vol 385-386 ◽  
pp. 799-802
Author(s):  
Qiang Guo ◽  
Xiao Lan Xie ◽  
Yang Li ◽  
Xin Yu Chen

This paper is for the problems of the 400V low voltage power capacitor reactive power compensation and for the problems existing in the transient process, resuming the principle of low-voltage capacitor intelligent technology and its implementation briefly. Propose a synchronization of reactive compensation capacitor switching on-off control system based on the micro controller and adaptive control. Real-time monitoring system is used to access system active and reactive power changes in order to extract the zero voltage signals; intelligent control algorithm is used to realize the intelligence of capacitor reactive power compensation on-spot and cutting, which greatly reduce the over-voltage and flow phenomenon produced by the capacitor in the cutting process. The result checked by actual measured shows that the device is stable, reliable, and can be effective to on-site system reactive power compensation and realize intelligent cutting.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak

The paper includes the analysis of the operation of low-voltage prosumer installation consisting of receivers and electricity sources and equipped with a 3-phase energy storage system. The aim of the storage application is the management of active power within the installation to decrease the total power exchanged with the supplying network and thus reduce energy costs borne by the prosumer. A solution for the effective implementation of the storage system is presented. Apart from the active power management performed according to the prosumer’s needs, the storage inverter provides the ancillary service of voltage regulation in the network according to the requirements of the network operator. A control strategy involving algorithms for voltage regulation without prejudice to the prosumer’s interest is described in the paper. Reactive power is used first as a control signal and if the required voltage effect cannot be reached, then the active power in the controlled phase is additionally changed and the Energy Storage System (ESS) loading is redistributed in phases in such a way that the total active power set by the prosumer program remains unchanged. The efficiency of the control strategy was tested by means of a simulation model in the PSCAD/EMTDC program. The results of the simulations are presented.


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