scholarly journals Assessment for Voltage Violations considering Reactive Power Compensation Provided by Smart Inverters in Distribution Network

2021 ◽  
Vol 9 ◽  
Author(s):  
Jindi Hu ◽  
Weibin Yin ◽  
Chengjin Ye ◽  
Weidong Bao ◽  
Jiajia Wu ◽  
...  
Keyword(s):  
Reactive Power ◽  
Low Cost ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Reactive Power Compensation ◽  
Slice Sampling ◽  
Voltage Deviation ◽  
Regulation Model ◽  
Smart Inverters ◽  
Voltage Violation

Due to the high proportion of renewable energies, traditional voltage regulation methods such as on-load tap changers (OLTCs) and switching capacitors (SCs) are currently facing the challenge of providing fast, step-less, and low-cost reactive power to reduce the increasing risks of voltage violations in distribution networks (DNs). To meet such increasing demand for voltage regulation, smart inverters, including photovoltaics (PVs) and electric vehicle (EV) chargers, stand out as a feasible approach for reactive power compensation. This paper aims to assess the voltage violation risks in DNs considering the reactive power response of smart inverters. Firstly, reactive power compensation models of PVs and EV chargers are investigated and voltage deviation indexes of the regulation results are proposed. Moreover, kernel density estimation (KDE) and slice sampling are adopted to provide the PV output and EV charging demand samples. Then, the risk assessment is carried out with a voltage regulation model utilizing OLTCs, SCs, and available smart inverters. Numerical studies demonstrate that the reactive power support from smart inverters can significantly mitigate the voltage violation risks and reduce the switching and cost of OLTCs and capacitors in DNs.

scholarly journals Efficient Reactive Power Compensation Algorithm for Distribution Network

2017 ◽  
Vol 20 (3&4) ◽  
pp. 373-384
Author(s):  
J. Jerome
Keyword(s):  
Reactive Power ◽  
Supply Voltage ◽  
Distribution Networks ◽  
Reactive Power Compensation ◽  
Load Flow ◽  
Solution Technique ◽  
Distribution Automation ◽  
Automation System ◽  
Voltage Deviation ◽  
Propagation Technique

The use of automation and energy efficient equipment with electronic control would greatly improve industrial production.  These new devices are more sensitive to supply voltage deviation and the characteristics of the power system that was previously ignored are now very important. Hence the benefits of distribution automation have been widely acknowledged in recent years. This paper proposes an efficient load flow solution technique extended to find optimum location for reactive power compensation and network reconfiguration for planning and day-to-day operation of distribution networks.  This is required as a part of the distribution automation system (DAS) for taking various control and operation decisions.  The method exploits the radial nature of the network and uses forward and backward propagation technique to calculate branch currents and node voltages.  The proposed method has been tested to analyze several practical distribution networks of various voltage levels and also having high R/X ratio.

scholarly journals Stochastic Analysis-Based Volt–Var Curve of Smart Inverters for Combined Voltage Regulation in Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2785
Author(s):  
Dongwon Lee ◽  
Changhee Han ◽  
Gilsoo Jang
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Flow Analysis ◽  
Voltage Control ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Load Flow ◽  
Renewable Energy Resources ◽  
Voltage Profile ◽  
Smart Inverters

The proliferation of renewable energy resources (RES), especially solar photovoltaic (PV) generation resources, causes overvoltage and line overloading in distribution networks. This study proposes a two-level volt–var control method based on multiple timescales. The on-load tap changer (OLTC) operates on an hourly timescale, to regulate the voltage on the secondary winding. In the 15-minutes timescale, PV-connected smart inverters and static var compensators (SVCs) are obliged to compensate the reactive power for the voltage control at the point of common coupling. In the multi-timescale voltage control framework, this study proposes a new multi-sectional volt–var curve (MSVVC) of a PV inverter. The objective of the MSVVC is to minimize the energy loss in the network, improve the voltage profile, and obtain the operational margin of other reactive power compensation devices. In the process of determining the optimal parameters of the MSVVC, stochastic modeling-based load flow analysis is utilized to consider the intermittency and uncertainty of RES generation. The effectiveness of the proposed method is verified on the IEEE 33-bus system in comparison with the conventional volt–var curve cases.

scholarly journals Using Energy Storage Inverters of Prosumer Installations for Voltage Control in Low-Voltage Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Storage System ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Active Power ◽  
Total Power

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.

Identification of the best topology of delta configured three phase induction generator for distributed generation through experimental investigations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vanka Bala Murali Krishna ◽  
Sandeep Vuddanti
Keyword(s):  
Distributed Generation ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Reactive Power Compensation ◽  
Induction Generator ◽  
Experimental Investigations ◽  
Small Scale ◽  
Empirical Formulas ◽  
Simple Method ◽  
Main Challenge

Abstract Research on Self –excited induction generator (SEIG) brings a lot of attentions in the last three decades as a promising solution in distributed generation systems with low cost investment. There are two important fixations to attend in the operation of SEIG based systems, a) excitation and b) voltage regulation. Many procedures are reported regarding selection of excitation capacitance in the literature, based on state-state analysis, dynamic modeling, empirical formulas and machine parameters which involve various levels of complexity in findings. Moreover, the voltage regulation is the main challenge in implementation of SEIG based isolated systems. To address this problem, many power electronic-based schemes are proposed in the literature and but these solutions have few demerits importantly that additional cost of equipment and troubles due to failure of protection schemes. In particular, the installation of SEIG takes place at small scale in kW range in remote/rural communities which should not face such shortcomings. Further in case of off-grid systems, the maximum loading is fixed based on connected rating of the generator. This paper presents the various methods to find excitation capacitance and illustrates an experimental investigation on different possible reactive power compensation methods of delta connected SEIG and aimed to identify a simple method for terminal voltage control without power electronics. In this experimental work, the prime-mover of the generator is a constant speed turbine, which is the emulation of a micro/pico hydro turbine. From the results, it is found that a simple delta connected excitation and delta configured reactive power compensation limits voltage regulation within ±6% while maintaining the frequency of ±1%, which make feasible of the operation successfully in remote electrification systems.

Research of Large-Capacity Low-Cost DC Deicer With Reactive Power Compensation

2018 ◽  
Vol 33 (6) ◽  
pp. 3036-3044 ◽  
Author(s):  
Jiazheng Lu ◽  
Chuanping Wu ◽  
Yanjun Tan ◽  
Siguo Zhu ◽  
Yicheng Sun
Keyword(s):  
Reactive Power ◽  
Low Cost ◽  
Reactive Power Compensation ◽  
Large Capacity

A Procedure of Drawing up Integral Indicators for Comprehensively Estimating the Properties of Electric Power System Nodes

Vestnik MEI ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 11-18
Author(s):  
Nailia Sh. Chemborisova ◽  
◽  
Ivan D. Chernenkov ◽  
Keyword(s):  
Power System ◽  
Electric Power ◽  
Reactive Power ◽  
Voltage Regulation ◽  
Reactive Power Compensation ◽  
Electric Power System ◽  
Power Losses ◽  
System Operation ◽  
Active Power Losses ◽  
System Nodes

The problem of selecting the electric power system control nodes is studied. By performing control of these modes, matters concerned with providing reliable power supply of the required quality to consumers can be settled in the most efficient manner. As an example, a fragment of the electric power system mathematical model used in the Finist mode-setting simulator for a power system dispatch control center operator is considered, which represents a highly branched electrical network consisting of eleven 110 kV nodes, three 220 kV nodes connected with the system, and two generator nodes. A new procedure for selecting the control nodes is proposed, which takes into account a combination of different indicators having different measurement units, dimensions and scales is proposed. These indicators characterize the following properties of power system nodes: the reactive power fraction absorbed at a node, the sensitivity of voltage to reactive load variations, the number of connected power lines, and statistical indicators characterizing the change of voltage at the nodes and reactive power flows for different options of installing the reactive power compensation devices. For combined use of these indicators, they were ranked according to the efficiency of installing reactive power compensation devices in the system. For each indicator, a scale of five ranks (intervals) is set, which determine the preferences (qualitative judgments) of the researcher in evaluating the reactive power compensation devices installation efficiency at the system nodes. The highest rank (5) corresponds to the maximum efficiency, and the lowest rank (1) corresponds to the minimum efficiency. To calculate the individual (integral) priority indicator of installing reactive power compensation devices, the ranks of indicators are added together, and their sum is divided by the product of the number of ranks by the number of the used indicators (features). Based on the calculation results, the rating (location) of each node is determined, and the nodes for installing the reactive power compensation devices are selected according to their effect on ensuring the electric power system operation reliability, active power losses in the network, and voltage regulation. Thus, a new procedure is presented for determining the integral indicators for comprehensively estimating the properties of complex electric power system nodes and selecting the controlled nodes using a system of various indicators. These indicators characterize the studied nodes in terms of the efficiency of installing reactive power compensation devices to reduce active power losses in the network, voltage regulation, and ensuring the electric power system operational reliability. The validity of the results obtained in the study is confirmed by their comparison with the indicators of the balance-conductivity method, which has proven itself in solving problems connected with determining the nodes for controlling electric power system operation modes.

STATCOM Based Solid State Voltage Regulation for Isolated Self-Excited Induction Generator

2016 ◽  
pp. 147-183
Author(s):  
Pallavi Thakkur ◽  
Smita Shandilya
Keyword(s):  
Solid State ◽  
Reactive Power ◽  
Low Cost ◽  
Voltage Regulation ◽  
Induction Generator ◽  
Terminal Voltage ◽  
Resistive Loads ◽  
Static Compensator ◽  
Self Protection ◽  
Generating System

Self-Excited Induction Generator (SEIG) offers many advantages such as low cost, simplicity, robust construction, self-protection against faults and maintenance free in today's renewable energy industry. However, the SEIG demands an external supply of reactive power to maintain the constant terminal voltage under the varying loading conditions, which limits the application of SEIG as a standalone power generator. The regulation of speed and voltage does not result in a satisfactory improvement although several studies have been emphasized on this topic in the past. To improve the performance of the SEIG system in isolated areas and to regulate the terminal voltage STATic COMpensator (STATCOM) has been modelled and developed in this dissertation. The STATCOM consists of AC inductors, a DC bus capacitor and solid-state self-commutating devices. The ratings of these components are quite important for designing and controlling of STATCOM to maintain the constant terminal voltage. The proposed generating system is modelled and simulated in MATLAB along with Simulink and sim power system block set toolboxes. The simulated results are presented to demonstrate the capability of an isolated power generating system for feeding three-phase resistive loads.

scholarly journals Power factor control of PV generators in local distribution networks using fuzzy logic concept

2018 ◽  
Vol 7 (2.28) ◽  
pp. 362
Author(s):  
Raed A. Shalwala
Keyword(s):  
Fuzzy Logic ◽  
Control System ◽  
Power Factor ◽  
Fuzzy Logic Control ◽  
Reactive Power ◽  
Distribution Network ◽  
Voltage Control ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Logic Control

One of the most important operational requirements for any electrical power network for both distribution and transmission level is voltage control. Many studies have been carried out to improve or develop new voltage control techniques to facilitate safe connection of distributed generation. In Saudi Arabia, due to environmental, economic and development perspectives, a wide integration of photovoltaic (PV) genera-tion in distribution network is expected in the near future. This development in the network may cause voltage regulation problems due to the interaction with the existing conventional control system. In a previous paper, a control system has been described using a fuzzy logic control to set the on-line tap changer for the primary substation. In this paper a new control system is proposed for controlling the power factor of individual PV invertors based on observed correlation between net active and reactive power at each connection. A fuzzy logic control has been designed to alter the power factor for the remote invertors from the secondary substation to keep the feeder voltage within the permissible limits. In order to confirm the validity of the proposed method, simulations are carried out for a realistic distribution network with real data for load and solar radiation. Results showing the performance of the new control method are presented and discussed.  

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