Impact on Voltage Stability Conditions under Inadequate Voltage Control Actions

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Oscar Cuaresma Zevallos ◽  
Marcos Vinicius Pimentel Teixeira ◽  
Ricardo Bernardo Prada
Keyword(s):  
Voltage Stability ◽  
Voltage Control ◽  
Control Device ◽  
Stability Conditions ◽  
System Control ◽  
Sensitivity Matrix ◽  
Special Situation ◽  
Voltage Level ◽  
Control Actions ◽  
The Relationship

Abstract Inadequate voltage control occurs when the controlling variable and controlled voltage of a control device are inversely related (i. e., not related in the usual way), potentially adversely affecting the system voltage level. This special situation can be identified by analyzing the elements of a sensitivity matrix constructed to show the relationship between the system control variables. Analysis of these elements not only allows the adequacy or otherwise of voltage control actions to be determined, but also helps to identify any conflict between controls that could, if not addressed, limit the possibilities for voltage control in the system. Furthermore, once the problem of the inadequacy of voltage control actions for a particular operating point has been identified, its impact on voltage stability conditions can be determined by calculating assessment indexes.

RTDS-Based Simulate Analysis of AC Filters Switch Method in HVDC Converter for Voltage Stability

2013 ◽  
Vol 756-759 ◽  
pp. 4250-4253
Author(s):  
Xiao Jun Zhu ◽  
Tao Chen ◽  
Wei Fang ◽  
Luo Jiang Qian ◽  
Yi Yu Wen
Keyword(s):  
Voltage Stability ◽  
Power Transmission ◽  
Voltage Control ◽  
Salient Feature ◽  
Fast Response ◽  
Control Mode ◽  
Reactive Control ◽  
Voltage Level ◽  
Action Sequence ◽  
Voltage Control Mode

In most of the AC-DC hybrid power transmission system AC filters is widely applied to stabilize voltage level in addition to filter harmonic. However, the voltage stability of AC bus is greatly influenced by action sequence of switching AC filters in group. The paper presents the concept of reactive characteristics of the convertor and AC filters, using reactive and voltage control mode to switch them. The modeling, control, and principle of operation for the AC-side switching filters are described. The voltage level is controlled via regulating action of switching filters by step. The salient feature of the proposed control modes is that voltage control contributes to keep the voltage level, and reactive control has no fast response on guaranteeing voltage stability, but two methods can apply to different occasions based on the requirements of voltage stability. All analysis and control system designs are verified through building a RTDS model in a typical ±500kV power system.

Model of a neural network adaptive system for a digital control loop of an electric drive

2021 ◽  
Author(s):  
O.V. Nepomnyashchiy ◽  
A.V. Tarasov ◽  
Yu.V. Krasnobaev ◽  
V.N. Khaidukova ◽  
D.O. Nepomnyashchiy
Keyword(s):  
Neural Network ◽  
Intelligent Control ◽  
Electric Drive ◽  
Electric Motor ◽  
Control Device ◽  
System Control ◽  
Electric Transport ◽  
Control Loop ◽  
Software Environment ◽  
Power System Control

The problem of increasing the efficiency of power units of autonomous electric transport vehicles is considered. The task of creating a promising power system control device has been singled out. It is determined that in creating such devices, significant results can be obtained by using an intelligent module in the control loop of the electric drive. Goal. It is necessary to develop a power plant model with intelligent control, allowing to obtain data sets about currents, voltages and engine speeds in different modes of operation. The architecture of an intelligent control device, a PID controller based on a neural network, has been proposed; it has been proposed to exclude rotor angular velocity sensors from the classical feedback loop. The type and architecture of the neural network is defined. In the software environment MatLab the model of neuroemulator of the engine for formation of a training sample of a neural network by a method of Levenberg – Marquardt is developed. The trained neural network is implemented in the developed model of the electric motor control loop. The results of simulation of the intelligent control device showed a good convergence of the output influences generated by the neuroemulator with the actual parameters of the electric motor.

scholarly journals Transmission Expansion Planning for the Optimization of Renewable Energy Integration in the Sulawesi Electricity System

2021 ◽  
Vol 13 (18) ◽  
pp. 10477
Author(s):  
Tumiran ◽  
Lesnanto Multa Putranto ◽  
Roni Irnawan ◽  
Sarjiya ◽  
Adi Priyanto ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Voltage Stability ◽  
Energy Integration ◽  
Voltage Level ◽  
Renewable Energy Integration ◽  
Expansion Planning ◽  
Transmission Expansion Planning ◽  
North Sulawesi ◽  
Electricity System ◽  
Transmission Expansion

In order to meet the growth in demand and the renewable energy integration target, the Sulawesi Electricity System (SES) should be expanded. Currently, the SES is divided into two systems, namely South and North Sulawesi. These two systems have different characteristics, such as the system size, reliability and operational cost. North Sulawesi is smaller, weaker and more expensive than the South System. In order to improve the system reliability, generation and transmission expansion planning should be executed simultaneously to meet the economical investment cost and satisfy the reliability standard. For this purpose, the necessity of a backbone system with a higher voltage level than the existing 150 kV system should be considered, including the interconnection option between the two existing systems in Sulawesi. A methodology based on economic and technical criteria was developed to determine the backbone voltage level. Two voltage level options were considered, namely 275 and 500 kV. Several criteria were considered in order to determine the backbone voltage level, including the economic voltage, the line-loading limit, N-1 contingency, short circuiting, transient stability, voltage stability and small signal stability. The backbone voltage candidates should fulfil all of the criteria. The simulation was conducted in base- and high-demand scenarios, considering the fluctuation of future economic growth. The load flow and the dynamic analysis were simulated in a DIgSILENT Power Factory environment. The results showed that the 275 kV backbone, which was built in 2022, would violate three criteria: the economic voltage, N-1 contingency and voltage stability. On the other hand, the 500 kV backbone voltage level fulfills all of the criteria. The result of this research was considered in the electricity planning documents in Sulawesi. From a technical and economical perspective, the 500 kV backbone was chosen for the SES.

scholarly journals Electricity market efficiency and voltage stability

2021 ◽  
Author(s):  
Ayman Helmy Mostafa Elkasrawy
Keyword(s):  
Power System ◽  
Market Efficiency ◽  
Electricity Markets ◽  
Electricity Market ◽  
Voltage Stability ◽  
Electric Power System ◽  
Maximum Efficiency ◽  
Best Interest ◽  
The Relationship ◽  
System Layout

Several electricity markets were created in the last two decades by deregulation and restructuring vertically integrated utilities. In order to serve the best interest of participating entities, it is important to operate electricity markets at their maximum efficiency. In most cases, electricity markets were formed to operate on existing physical power systems that had evolved over several decades as vertically integrated utilities. Location of generating stations, large urban load centers and enabling transmission systems were unique to every power system and followed the 'lay of the land'. Depending upon a power system layout, voltage stability and margin to voltage collapse are unique to it. While an electricity market is to be operated efficiently, its optimal generation schedule to supply energy through an electric power system has to be reliable and meet the strict standards including those that relate to voltage stability. This work elicits the relationship between market efficiency and voltage stability. To this end, a formulation and a solution algorithm are presented. Two contrasting 5-bus cases illustrate how the transmission system layout influences the relationship between voltage stability and market efficiency. The IEEE 118-bus system is also used to illustrate this relationship.

Dynamic Voltage Stability of Distribution Systems in the Presence of High Penetration of Photovoltaic Plants Using PSS/E Software

2021 ◽  
Vol 52 ◽  
pp. 11-29
Author(s):  
Sahar M. Sadek ◽  
Amal A. Hassan ◽  
Faten H. Fahmy ◽  
Amgad A. El-Deib ◽  
Hosam K.M. Yousef
Keyword(s):  
Distribution Systems ◽  
Voltage Stability ◽  
Voltage Control ◽  
Distribution Networks ◽  
Normal Operation ◽  
High Penetration ◽  
Comparison Results ◽  
Dynamic Voltage ◽  
Dynamic Voltage Stability ◽  
Control Methodology

The intermittent nature of photovoltaic (PV) generation causes the voltage to fluctuate and may lead to instability, especially, in case of high penetration. In this paper, a methodology is proposed to control the reactive power generation of PV-inverters. The objective is to mitigate the voltage fluctuations at the point of common coupling (PCC) resulted from increasing or decreasing the active power output of PV plants which is dependent on solar radiation level. The generic PV-inverter models developed and recommended by the Renewable Energy Modeling Task Force (REMTF) of the Western Electricity Coordinating Council (WECC) is used to analyze the effect of high PV penetration on the dynamic voltage stability of distribution networks. Then, the tested distribution network with the embedded PV plants is modeled and simulated using PSS/E software. Levels of control that are built-in PV-inverters are tested in the case of normal operation and during disturbances. Comparison results show that the most suitable control methodology in case of disturbances and after fault clearance is the local voltage control. While the plant voltage control with coordinated V/Q control is the most preferable control methodology during normal operation.

The Migrant Workers Convention: Its Place in Human Rights Law

1991 ◽  
Vol 25 (4) ◽  
pp. 771-799 ◽  
Author(s):  
James A. R. Nafziger ◽  
Barry C. Bartel
Keyword(s):  
Human Rights ◽  
Migrant Workers ◽  
Human Rights Law ◽  
Undocumented Workers ◽  
Special Situation ◽  
The Relationship ◽  
Measure Of Uncertainty

This article summarizes the relationship between the Migrant Workers Convention and the principal general instruments of human rights law. The Convention's vocabulary and complexity invite a measure of uncertainty. Responses to the special situation of undocumented workers are questionable. To initiate a better understanding of the Convention's prospective place in human rights law, the authors have prepared a chart that correlates the Convention's provisions with those in other instruments. The article then cites several examples to clarify four basic relationships between the Convention and corresponding provisions in other instruments: overlapping, extension of existing rights, creation of new rights, and limitation of existing rights. A concluding section acknowledges the possible effectiveness of the Convention, but raises additional issues. The authors suggest several alternatives for supplementing existing instruments in order to extend their protections more simply and explicitly to migrant workers.

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