Impact of cyber dependencies in critical infrastructures: The reliability of grid splitting in power systems

2018 ◽  
Vol 232 (5) ◽  
pp. 491-504 ◽  
Author(s):  
Di-An Tian ◽  
Giovanni Sansavini
Keyword(s):  
Communication Network ◽  
Power System ◽  
Test System ◽  
System Stability ◽  
Critical Infrastructures ◽  
Delay Model ◽  
Critical Transition ◽  
Open Communication ◽  
Transition Range ◽  
Traffic Uncertainty

The growing presence of cyber interdependencies in critical infrastructures can be exemplified by grid splitting, which is an application in power system stability and control dependent on communication services. It involves the controlled separation of a power system into islands in reaction to an imminent instability. Communication is necessary for gathering system-wide synchronized measurements for state estimation as well as for the dispatch of line switch-opening signals. However, grid splitting may become ineffective due to a degradation in communication, which is accrued by the use of non-dedicated, open communication networks. To address this issue, this article aims to quantify the reliability of grid splitting under degraded communication conditions. A simulation framework is developed that allows the integration of a transient electrical model and a stochastic communication delay model that captures the effects of congestion and traffic uncertainty. The application to the IEEE 39-Bus Test System shows that the reliability of grid splitting is reduced under the influence of degraded communication leading to increased time delays. Furthermore, the results identify a critical transition range in the grid splitting reliability for a very narrow range of external interfering traffic and network data rate. Finally, the interdependency of the electric and the communication network is quantified by the expected efficiency of the communication network subject to degraded communication following the grid splitting action. The decrease in the expected communication efficiency under degraded communication is driven by increased congestion levels and by failures of electrical and co-located communication nodes and is related to the critical transition range for reliability. The developed methodology allows identifying the communication requirements for a reliable grid splitting execution under traffic uncertainty and congestion.

scholarly journals Probabilistic small-signal stability analysis of power system with solar farm integration

2019 ◽  
pp. 1276-1289 ◽  
Author(s):  
SAMUNDRA GURUNG ◽  
SUMATE NAETILADDANON ◽  
ANAWACH SANGSWANG
Keyword(s):  
Power System ◽  
Density Function ◽  
Forecast Error ◽  
Low Frequency ◽  
Test System ◽  
System Stability ◽  
Small Signal ◽  
Small Signal Stability ◽  
Oscillatory Dynamics ◽  
Signal Stability

Currently, large-scale solar farms are being rapidly integrated in electrical grids all over the world. However, the photovoltaic (PV) output power is highly intermittent in nature and can also be correlated with other solar farms located at different places. Moreover, the increasing PV penetration also results in large solar forecast error and its impact on power system stability should be estimated. The effects of these quantities on small-signal stability are difficult to quantify using deterministic techniques but can be conveniently estimated using probabilistic methods. For this purpose, the authors have developed a method of probabilistic analysis based on combined cumulant and Gram– Charlier expansion technique. The output from the proposed method provides the probability density function and cumulative density function of the real part of the critical eigenvalue, from which information concerning the stability of low-frequency oscillatory dynamics can be inferred. The proposed method gives accurate results in less computation time compared to conventional techniques. The test system is a large modified IEEE 16-machine, 68-bus system, which is a benchmark system to study low-frequency oscillatory dynamics in power systems. The results show that the PV power fluctuation has the potential to cause oscillatory instability. Furthermore, the system is more prone to small-signal instability when the PV farms are correlated as well as when large PV forecast error exists.

scholarly journals Performance of Communication Network for Monitoring Utility Scale Photovoltaic Power Plants

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5527
Author(s):  
Ali M. Eltamaly ◽  
Mohamed A. Ahmed ◽  
Majed A. Alotaibi ◽  
Abdulrahman I. Alolah ◽  
Young-Chon Kim
Keyword(s):  
Communication Network ◽  
Power System ◽  
Remote Monitoring ◽  
Network Architecture ◽  
Power Plants ◽  
Large Scale ◽  
Meteorological Data ◽  
System Stability ◽  
Critical Parameters ◽  
Accurate Information

The grid integration of large scale photovoltaic (PV) power plants represents many challenging tasks for system stability, reliability and power quality due to the intermittent nature of solar radiation and the site accessibility issues where most PV power plants are located over a wide area. In order to enable real-time monitoring and control of large scale PV power plants, reliable two-way communications with low latency are required which provide accurate information for the electrical and environmental parameters as well as enabling the system operator to evaluate the overall performance and identify any abnormal conditions and faults. This work aims to design a communication network architecture for the remote monitoring of large-scale PV power plants based on the IEC 61850 Standard. The proposed architecture consists of three layers: the PV power system layer, the communication network layer, and the application layer. The PV power system layer consists of solar arrays, inverters, feeders, buses, a substation, and a control center. Monitoring parameters are classified into different categories including electrical measurements, status information, and meteorological data. This work considers the future plan of PV power plants in Saudi Arabia. In order to evaluate the performance of the communication network for local and remote monitoring, the OPNET Modeler is used for network modeling and simulation, and critical parameters such as network topology, link capacity, and latency are investigated and discussed. This work contributes to the design of reliable monitoring and communication of large-scale PV power plants.

Symbiotic Organisms Search Technique for SVC Installation in Voltage Control

2017 ◽  
Vol 6 (2) ◽  
pp. 318 ◽  
Author(s):  
Mohamad Khairuzzaman Mohamad Zamani ◽  
Ismail Musirin ◽  
Saiful Izwan Suliman
Keyword(s):  
Power System ◽  
Voltage Control ◽  
Test System ◽  
Real System ◽  
System Stability ◽  
System Implementation ◽  
Voltage Profile ◽  
Symbiotic Organisms Search ◽  
Symbiotic Organisms ◽  
Control Study

<p>Increasing demand experienced by electric utilities in many parts of the world involving developing country is a normal phenomenon. This can be due to the urbanization process of a system network, which may lead to possible voltage decay at the receiving buses if no proper offline study is conducted. Unplanned load increment can push the system to operate closes to its instability point. Various compensation schemes have been popularly invented and proposed in power system operation and planning. This would require offline studies, prior to real system implementation. This paper presents the implementation of Symbiotic Organisms Search (SOS) algorithm for solving optimal static VAr compensator (SVC) installation problem in power transmission systems. In this study, SOS was employed to perform voltage control study in a transmission system under several scenarios via the SVC installation scheme. This realizes the feasibility of SOS applications in addressing the compensating scheme for the voltage control study. Minimum and maximum bound of the voltage at all buses have been considered as the inequality constraints as one of the aspects. A validation process conducted on IEEE 26-Bus RTS realizes the feasibility of SOS in performing compensation scheme without violating system stability. Results obtained from the optimization process demonstrated that the proposed SOS optimization algorithm has successfully reduced the total voltage deviation index and improve the voltage profile in the test system. Comparative studies have been performed with respect to the established evolutionary programming (EP) and artificial immune system (AIS) algorithms, resulting in good agreement and has demonstrated its superiority. Results from this study could be beneficial to the power system community in the planning and operation departments in terms of giving offline information prior to real system implementation of the corresponding power system utility.</p>

Investigation of Modified Generalized Interline Power Flow Controller (GIPFC) and Performance Analysis

2014 ◽  
Vol 622 ◽  
pp. 111-120
Author(s):  
Ananthavel Saraswathi ◽  
S. Sutha
Keyword(s):  
Power System ◽  
Power Flow ◽  
Test System ◽  
Transmission System ◽  
System Stability ◽  
Flexible Ac Transmission ◽  
Flexible Ac Transmission System ◽  
Flow Controller ◽  
Ac Transmission ◽  
Power Flow Controller

Nowadays in the restructured scenario, the main challenging objective of the modern power system is to avoid blackouts and provide uninterrupted quality power supply with dynamic response during emergency to improve power system security and stability. In this sense the convertible static compensator (CSC) that is the Generalized Inter line power flow controller (GIPFC), can control and optimize power flow in multi-line transmission system instead of controlling single line like its forerunner FACTS (Flexible AC Transmission System) controller. By adding a STATCOM (Static synchronous Shunt Converter) at the front end of the test power system and connecting to the common DC link of the IPFC, it is possible to bring the power factor to higher level and harmonics to the lower level and this arrangement is popularly known as Generalized Inter line power flow controller (GIPFC). In this paper a new concept of GIPFC based on incorporating a voltage source converter with zero sequence injection SPWM technique is presented for reinforcement of system stability margin. A detailed circuit model of modified GIPFC is developed and its performance is validated for a standard test system. Simulation is done using MATLAB Simulink.Index Terms—Convertible static controller, Flexible AC Transmission System (FACTS), Generalized Interline Power Flow Controller (GIPFC),STATCOM, SSSC, Reactive power compensation.

PowSysGUI: A new educational software package for power system stability studies using MATLAB/Simulink

2017 ◽  
Vol 54 (4) ◽  
pp. 283-298 ◽  
Author(s):  
Serdar Ekinci ◽  
Aysen Demiroren ◽  
Hatice Lale Zeynelgil
Keyword(s):  
Power System ◽  
User Interfaces ◽  
Software Package ◽  
Educational Software ◽  
Software Tool ◽  
Power System Stability ◽  
Test System ◽  
Engineering Problem ◽  
Graphical User Interfaces ◽  
System Stability

Graphical user interfaces have been progressively used in the classrooms to provide users of computer simulations with a friendly and visual approach to specify all input parameters with enhanced configuration flexibility. In this paper, an educational software package called PowSysGUI (Power System GUI), which runs on MATLAB and uses graphical user interfaces, has been developed for analysis and simulation of small to large size electric power systems. PowSysGUI is open-source software and anyone can see the inner structure of the program to figure out how to code a power engineering problem. It is designed as a simulation tool for researchers and educators, as it is simple to use and modify. PowSysGUI has algorithms for solving power flow, small signal stability analysis, and time-domain simulation. In the case studies, IEEE 16-machine 68-bus test system is given to show the features of the developed software tool. Moreover, classroom experience has shown that the developed software package helps in consolidating a better understanding of power system stability phenomena.

scholarly journals A FACTS Devices Allocation Procedure Attending to Load Share

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1976 ◽  
Author(s):  
Samuel Marrero Vera ◽  
Ignacio Nuez ◽  
Mario Hernandez-Tejera
Keyword(s):  
Power System ◽  
Test System ◽  
System Stability ◽  
Objective Functions ◽  
Flexible Ac Transmission ◽  
Facts Devices ◽  
Allocation Procedure ◽  
Variable Generation ◽  
Electrical Demand ◽  
Ac Transmission

Power system stability is a topic which is attracting considerable interest due to the increase of both electrical demand and distributed variable generation. Since Flexible AC Transmission Systems (FACTS) devices are an increasingly widespread solution to these issues, it is important to study how their allocation procedure should be done. This paper seeks to assess the influence of load share in FACTS devices allocation. Despite this interest, researchers, as well as system planners, have mainly focused on studying single power system configuration rather than using a wider approach. Keeping this in mind, we have iteratively created several load share scenarios based on an IEEE 14-bus test system. Subsequently, we have applied an heuristic procedure in order to demonstrate how load share may affect the results of the FACTS devices allocation procedure. Additionally, we have compared results from two different objective functions so as to evaluate our proposal. Finally, we have proposed a solution to FACTS allocation which takes load share into account. Our tests have revealed that, depending on the distribution of load within the power system, the optimal location for a FACTS device may change. Furthermore, we have also found some discrepancies and similarities between results from distinct objective functions.

Superconducting Magnetic Energy Storage Control Strategy for Power System Stability Improvement

2005 ◽  
Vol 4 (1) ◽  
Author(s):  
Antonio Griffo ◽  
Davide Lauria
Keyword(s):  
Energy Storage ◽  
Power System ◽  
Control Strategy ◽  
Transient Stability ◽  
Magnetic Energy ◽  
Relevant Literature ◽  
Test System ◽  
System Stability ◽  
Superconducting Magnetic Energy Storage ◽  
Magnetic Energy Storage

Transient stability is recognized as a critical problem for modern electrical power systems, since the deregulation could involve more and more restricted margins. Continuous improvements in power electronics technology gives the possibility to improve significantly the dynamic behaviour. Recently, a great attention in the relevant literature has been paid to Superconducting Magnetic Energy Storage (SMES) devices, showing their intrinsic ability to improve power transmission capability. In the paper, a control strategy for these devices is derived starting from a Control Lyapunov function, thus determining reference values for SMES active and reactive powers injections, able to counteract the effects of large disturbances. Hence, a new topology of the power conditioning system for interfacing SMES device with a power system is proposed. Finally, a control law based upon quasi-sliding technique is employed for tracking the required active and reactive powers. In the last part of the paper an application is presented, with reference to a test system, allowing to outline the flexibility and the goodness of the proposed control strategy.

Effect of Advanced Static VAR Compensator on Control of Power System Load Shedding

2011 ◽  
Vol 403-408 ◽  
pp. 4867-4872
Author(s):  
B. Venkateswara Rao ◽  
G. V. Nagesh Kumar ◽  
R. V. S. Lakshmi Kumari ◽  
M. Vinay Kumar
Keyword(s):  
Power System ◽  
Power Flow ◽  
Test System ◽  
Load Shedding ◽  
System Stability ◽  
Static Var Compensator ◽  
System Load ◽  
Flow Solution ◽  
Newton Raphson ◽  
Raphson Method

This paper investigates the effect of Static VAR Compensator (SVC) on power system load shedding. SVC is mainly used in power system stability improvement. This paper proposes a new use of SVC to reduce load shedding. An algorithm of Newton Raphson method (NR) to reduce the load shedding for installing SVC in the system is proposed in this paper. 5 bus test system example is used to demonstrate the effect on load shedding. The test results show that the effect of SVC is significant, in this Static VAR compensator (SVC) is incorporated in Newton Raphson method in which Power Flow Solution is a solution of the network under steady state conditions subjected to certain constraints under which the system operates. The power flow solution gives the nodal voltages and phase angles given a set of power injections at buses and specified voltages at a few, the model of SVC i.e. SVC Susceptance model is discussed. It is also shown that the power system losses are decreased after incorporating the SVC in this N-R method. The results are generated for 5-Bus system. By incorporating the SVC the amount of load shedding is reduced to get the voltages in their limits.

scholarly journals A Comparative Study of the UPFC System by Simulation with PI-D and (NEWELM and NIMC) Controllers Based on the Adaptive Control for the Compensation of Power

2020 ◽  
Vol 11 ◽  
pp. 22-32
Author(s):  
Bouanane Abdelkrim ◽  
Yahiaoui Merzoug ◽  
Benyahia Khaled ◽  
Chaker Abdelkader
Keyword(s):  
Adaptive Control ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Fast Response ◽  
Test System ◽  
System Stability ◽  
Unified Power Flow Controller ◽  
Model Control ◽  
Elman Recurrent Neural Network

-Flexible Alternating Current Transmission System devices (FACTS) are power electronic components. Their fast response offers potential benefits for power system stability enhancement and allows utilities to operate their transmission systems even closer to their physical limitations, more efficiently, with improved reliability, greater stability and security than traditional mechanical switching technology. The unified Power Flow Controller (UPFC) is the most comprehensive multivariable device among the FACTS controllers. According to high importance of power flow control in transmission lines, new controllers are designed based on the Elman Recurrent Neural Network (NEWELM) and Neural Inverse Model Control (NIMC) with adaptive control. The Main purpose of this paper is to design a controller which enables a power system to track reference signals precisely and to be robust in the presence of uncertainty of system parameters and disturbances. The performances of the proposed controllers (NEWELM and NIMC) are based neural adaptive control and simulated on a two bus test system and compared with a conventional PI controller with decoupling (PI-D). The studies are performed based on well known software package MATLAB/Simulink tool box.

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