Power System Analysis Toolbox Research Articles

Large scale penetration impact of PMS-WTGS on voltage profile and power loss for 5-bus, 330kV system of the Nigerian grid

In recent times, adverse environmental changes and the gradual reduction in fossil fuel deposits is making integration of renewable energy secure global attention. This paper therefore investigates the effect of high penetration of wind power on power loss and voltage profile of 52-bus, 330kV Nigerian grid. Modeling and simulation of the study were successfully done using the Continuation Power Flow method and Power System Analysis Toolbox in the Matrix Laboratory environment. The Ant Colony Optimization (ACO) technique codes were used to determine the best sites and sizes of Permanent Magnet Synchronous-based Wind Turbine Generators (PMS-WTGs) on the grid as nonoptimal placement and size of PMS-WTGs will result into active power losses and poor voltage profile. The ACO and power flow analysis indicated two load buses, Aladja bus and Yola bus as best sites for PMS-WTGs with optimal sizes of 100MW and 197MW respectively. The result shows a decrease in the system's active (42.1%) and reactive (43.9%) power losses while heightening voltage magnitudes of critical buses to statutory values and enhancing the grid power quality. The overall results indicate that integrating 297MW PMS-WTGs improves voltage stability and power loss reduction by maximizing system loadability and reducing line losses.

Application of SSSC for Voltage Stability Improvement in the Nigerian 330 kV Transmission System using Particle Swarm Optimization Technique

Load imbalance has always been a major cause of voltage instability of the power system network and increase in voltage instability affects the power system reliability. In this paper, static synchronous series capacitor (SSSC) FACTS device was implemented to improve the voltage stability in the Nigerian 330 kV transmission network using particle swarm optimization (PSO) technique. Modelled power system network in the power system analysis toolbox (PSAT) is simulated to determine the existing power flow analysis and the level of instability in the power system generation plants situated in the Northern region. The outcome of the power flow is thereafter, optimized with PSO by generating the relationship with a high prediction accuracy between voltage at each location and an inter-linked transmission line distance of the 330kV. The model was generated with least square method and the high prediction accuracy determination was carried out with R-square value of the polynomial order. The best model was optimized and the entire computations were carried out in MatLab resulting in the determination of the optimal location which was between Jebba transmission and Shiroro generation stations. SSSC FACTS controller was implemented on the optimized transmission line and the simulation results showed that the introduction of SSSC improved the voltage stability of the power system network.

Impact study of flexible alternating current transmission system on power flow and power loss in power systems using MATLAB and PSAT

The work presented in this paper is to study the impact of FACTS (flexible alternating current transmission system) on the power flow and power losses of a multi-machine electrical system. In this work, we have calculated the power flow and the active and reactive power losses for a 6-bus 3-machine network system, in the first case where there are no FACTS, and in the second case where there are FACTS (SVC). So, and in the second case we used an SVC ((Static Var Compensator) because it is one of the elements of FACTS, to see their influence on power flow and power losses in electrical systems using MATLAB software (we used the Newton-Raphson method) and using PSAT software (Power System Analysis Toolbox), we calculated the power flow and the active and reactive power losses in the lines, respectively. Finally, we compare the results obtained by the simulation programs MATLAB and PSAT, and see what effect FACTS (SVC) has on the power flow and power loss in our electrical system that we are studying.

Real Time Voltage Stability Estimation under Contingencies by Generalized Curve Fit Method using PMU

An accurate voltage stability monitoring scheme is necessary to take possible remedial action. Recent developments in Phasor Measurement Units (PMUs) technology provide the foundation for online voltage stability monitoring of a power system network. In this paper, the generalized curve fit method using PMUs in the system has been used to access voltage stability of the system and a sensitivity based approach has been used to identify critical buses of the system. Voltage stability margin has been obtained and compared using generalized curve fit method and continuation power flow method using PMUs in the system. Variations in voltage stability margin caused by changing load patterns have also been considered while estimating voltage stability under contingencies. Nose curves obtained using generalized curve fit and continuation power flow methods are also compared. Case studies have been performed on a standard IEEE 14-bus system and practical 246-bus Northern Regional Power Grid (NRPG) system representing power network of nine states of India, with the help of Real Time Digital Simulation (RTDS) and Power System Analysis Toolbox (PSAT) software.

A unified power flow controller-based robust damping controller considering time delay in electrical power systems

Nowadays, different power systems are connected to each other due to technical and economic reasons and form a complex developed network. Such networks measure and send system data to decision-making centers for control and protection. This information transmission is accompanied by a delay and causes the performance of the system’s damping controllers to be affected. To improve power system dynamic stability, the supplementary controller in flexible alternating current transmission system (FACTS) devices is designed to account for information transmission delays. In these methods, to increase the controllability and observability of the inter-area mode, the remote signals extracted from the wide area measurement system (WAMS) are used as the input of the modulator. WAMS systems’ time delay reduces power system stability and even causes instability, so it’s crucial to find the maximum delay margin that ensures stability. Therefore, it is necessary to carefully study the role of FACTS tools in stabilizing the power system and damping interregional fluctuations, considering the delay. This research shows that supplementary controller design can dampen frequency and load angle fluctuations in multi-zone power systems despite information transmission delays. The method works in power system analysis toolbox (PSAT) simulation and MATLAB programming.

Small signal stability and dynamic performance investigation on multi-machines power system including DFIG wind farm

<p>The boundless potential of wind power in augmenting global energy production is a promising prospect. The efficient design and cost-effectiveness of doubly fed induction generator (DFIG) wind systems make them an optimistic solution for incorporating wind power on a massive scale. However, integrating these systems into power grids poses several challenges, including power system stability. This study examines the small signal stability and dynamic performance of a modified Western System Coordinating Council (WSCC) 9-bus system including a DFIG wind farm using load flow analysis, and both electromechanical oscillations and eigenvalue analysis. Three case studies were conducted based on the DFIG location and power increment.The simulation is carried out with the aid of the power system analysis toolbox (PSAT) that operates within the MATLAB environment. The study’s findings suggest that the perturbation and location of the DFIG relative to the system’s load have a minimal influence on the overall system’s stability and efficiency. However, when considering damping ratio, power angle, and rotor speed deviations, generators 1 and 2 with the perturbed DFIG installed on bus 8 are the most sensitive units to instability. Hence, larger perturbations and different DFIG’s location influence on power systems necessitates further analysis.</p>

Investigation of the impact of PSO, ABC, BFO and Cuckoo search optimization techniques on UPFC device for sustainable voltage stability margin improvement

This paper investigates the enhancement of voltage stability margin using Unified Power Flow Control (UPFC) device tuned with Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC), Bacterial Foraging Optimization (BFO) and Cuckoo Search techniques (CS) on Nigerian 330 kV 56-bus practical network. In order to have a voltage stable power system, it is good to keep voltages within the acceptable limits. This is achieved using continuation power flow embedded in Power System Analysis Toolbox (PSAT). The optimal location and tuning of the UPFC device is determined using line stability index and the met-heuristics techniques. The effects of UPFC and the proposed optimizing techniques on voltage stability margin are examined. The results so obtained for tuning PSO, ABC, BFO and Cuckoo Search with UPFC device are compared to know the technique that yields the best loading parameter for Nigerian 56- bus power system for voltage stability margin enhancement. It is found that UPFC tuned with Cuckoo Search outperforms the other techniques in terms of the increased loading parameter of the Nigerian power system with margin improvement of 86.6%, 90% and 88.6% for Adiabor (Bus 45), Jalingo (Bus 34) and Jos (Bus 13). The tuned UPFC device has proved beyond reasonable doubt that it can improve voltage stability margin of the entire Nigerian 330 kV Network as envisaged from results before and after optimization.

Improvement of power system stability in wind connected generator by using PSAT

Voltage stability in power systems is a major problem that receives international attention. An open and free source piece of software, Power System Analysis Toolbox (PSAT) is used in this study to create a model of modified IEEE 14 bus system. Models of two recently created wind turbines—the Squirrel Cage Induction Generator (SCIG) and Doubly Fed Induction Generator (DFIG)—are connected to a modified IEEE 14 bus system. The stability of the power system is examined in this work in relation to the effects of Squirrel Cage Induction Generator (SCIG) and Doubly Fed Induction Generators (DFIG). Here, both DFIG and SCIG, which have variable speeds, are regarded as wind generators. In this work, a small signal stability investigation using SCIG and DFIG wind turbine systems was carried out on a modified IEEE 14 bus system. The results of their simulation were analysed.

Optimal Placement of PMUs in Smart Grid for Voltage Stability Monitoring using AMPSO and PSAT

Efficient energy use is critical for a growing nation like India. The smart grid (SG) idea enables the creation of a highly dependable electricity system that optimizes existing resources. The Indian electricity grid as it now exists needs fundamental modifications to satisfy increasing demand and to make the system more intelligent and dependable. Since the past several decades, power system stability has been seen as a significant challenge to power system researchers and utilities. With a not many strategically placed Phasor Measurement Units (PMUs), it may be feasible to observe the power system stability of the network. This article suggests an optimum location for PMUs, considering the effect of power system stability-related serious situations. The disturbances have been prioritized according to their voltage stability boundary (the gap among the stand case working and nose points). Changes in the voltage stability tolerance due to shifting load conditions were also considered in the crucial contingency determination. PMUs were inserted in the system based on Adaptive Mutated Particle Swarm Optimization (AMPSO) findings for the intact system and crucial contingency scenarios on the basis of voltage stability. The effectiveness of the suggested PMUs placement strategy was determined by examining nose curves produced with PMUs data and pseudo-observations under increasing demands to nose curves calculated offline using continuation power flow data. Using the software tool Power-System Analysis Toolbox (PSAT), case studies were conducted on a conventional IEEE14 bus system and a realistic 246 bus Indian Power Grid system.

An An Optimal Placement of STATCOM Controller on 14-Bus IEEE Standard Test Transmission Network Using Particle Swarm Optimization

The bulk transport of electrical energy from a generating station to an electrical substation is facilitated by transmission network. Transmission network suffered from unavoidable power loss and there is need to minimize the loss so as to improve the overall efficiency of the network. By strategically placing Static Synchronous Compensator (STATCOM) controller into appropriate location, power loss can be reduced. Factually, one of the most crucial Flexible Alternating Current Transmissions (FACTS) device that control electrical power and increase system power transfer capability is considered as STATCOM. STATCOM is typically installed on the transmission network to reduce power losses and improve the voltage profile of the system. To significantly reduce power losses and improve the system voltage profile, which will ensure the security and dependability of the power system, this research looks into the optimal placement of STATCOM controller on transmission system using Particle Swarm Optimization (PSO) technique. A steady state mathematical model of STATCOM-based Power Injection Mode (PIM) through voltage source representation was derived. The mathematical model was implemented into Newton-Raphson (NR) load flow and PSO technique was used to optimize the exact location of STATCOM in objective to minimize power losses, improve voltage magnitude profile and provide adequate voltage stability to the power system. The voltage magnitude, active and reactive power loss were achieved for load flow solution on 14-bus IEEE test system using Power System Analysis Toolbox (PSAT) in MATLAB Simulink. Results revealed that, all the terminal voltages are within the voltage limits of 1.040 p.u and 1.035 p.u., respectively. The total active and reactive power losses were able to reduce by 6.90 % and 9.13 % respectively. The STATCOM based PSO optimal placement gave a stronger compensatory impact because it helped to reduce power losses and improved the overall network STATCOM-based profile.

Generation dispatch with large-scale photovoltaic systems

ABSTRACT The objective of this paper is to explore the role of generation dispatch strategy and spinning and non-spinning reserve methods in solving challenges posed by grid-connected large-scale PV systems as opposed to the commonly used approaches such as voltage, rotor angle and frequency control methods. The investigation covers the issues associated with the inherent intermittent of PV output, which results in additional operational challenges such as load-following requirements, spinning reserve requirements, load frequency excursions and system stability. A detailed performance evaluation of generation dispatch with large-scale PV systems is carried out in this research work based on the IEEE 14-bus test system using the MATLAB-based Power System Analysis Toolbox (PSAT). An analysis is conducted by using the power flow analysis methods such as power flow (PF), continuation power flow (CPF) and time domain (TD) analysis to gain an understanding of the influence that large-scale PV systems have on sub-transmission and transmission networks. The outputs of the study can be used to work out the appropriate penetration level of large-scale PV systems that can minimize their negative impacts on sub-transmission and transmission systems.

The Role of Distributed Generation on The Performance of Electrical Radial Distribution Network

Purpose: This article provides available information on the role of distributed generation (DG) in the performance of a power distribution network. 
 Design/methodology/approach: The study reviewed articles about available methods for reducing technical losses in electrical distribution networks. The second step involved studying various researchers' views on renewable energy in some developing countries for introducing DG into a distribution network. The influence of DG on the economic performance of a distribution network. Finally, the study scouted for available information on the implementation of a demand response (DR) program on the performance of a distribution network in the presence of DG.
 Findings: Available information reveals that the reliability of DG for reducing the technical losses in a distribution network is higher than relying on alternating current controllers. There are indications of renewable energies in developing countries for introducing DG into a distribution network. According to the articles reviewed, the approach for the optimal location of DG did not include the combination of the voltage stability index and power loss reduction index. It is also worth considering using the power system analysis toolbox (PSAT) for DG sitting. The economic influence of DG on a distribution network's performance has not been evaluated based on the technical loss, generation cost, emission cost and reliability. It is also worth considering the benefits of demand response programs in the presence of DG.
 Research limitation: The review concentrated mainly on DG's influence in reducing technical loss. Articles relating to the effect of DG on other distribution network technical issues such as voltage stability, harmonics etc. also require attention
 Practical implications: Distribution network performance is essential for the operation of electrical gadgets. Therefore, improved distribution network performance will result in the economic development of a country.
 Originality/Value: This paper provides the platform that stimulates interest in using DG to improve the distribution network performance.

Continuation Power Flow Analysis of Power System Voltage Stability with Unified Power Flow Controller

The rising power demand has forced power systems all over the world to operate very close to their stability limits. When power systems are overloaded, faulty, or in lack of reactive power, voltage collapses would ensue. The capacity of a power system to keep the voltage of every bus constant under disturbances is called voltage stability. This dynamic phenomenon hinges on the load features. It is commonly known that flexible AC transmission systems (FACTS) can improve voltage stability. This paper puts forward a load flow model with the unified power flow controller (UPFC), and relies on the model to investigate the voltage stability of a power system through continuation power flow (CPF) method. The validity of the model was verified through a simulation, using the power system analysis toolbox (PSAT) in MATLAB/Simulink environment.

Dynamic Stability Control of Sudan National Grid Using Power System Stabilizer

Application of power system stabilizers (PSS), as supplementary control signals for the excitation system in order to damp the low frequency, generator angle, speed variation, generator power, voltage magnitude and power flow oscillations. This paper presents the application of robust decentralized power system stabilizer (PSS) design approaches, for Sudan power system which consists of 41 machines with 167 buses. The paper mainly focus on operator testing of robust decentralized control techniques for power systems, and the optimal control approach to robust control design. Results of robust decentralized control design approaches are defined by using state space model equations. Also for testing dynamic stability Lyapunov theorem is used. The simulations were carried out using symmetrical fault and results presented by Power System Analysis Toolbox, MATLAB.

Improved security and stability of grid connected the wind energy conversion system by unified power flow controller

The stability and security improvements of the grid-connected to the wind energy conversion system (WECS) can be made by optimizing the placement of a flexible alternating current transmission system (FACTS). This study discusses the optimal placement of one type of WECS, namely the doubly-fed induction generator (DFIG) with a series and a shunt-FACTS control device called unified power flow controller (UPFC). The DFIG and UPFC connected grid dynamic perfor mance improvement with a maximum load bus system scenario. The optimal placement of DFIG and UPFC on the grid is formulated as a multi - objective problem, namely maximizing load bus system (Max. LBS) while minimizing active power loss (Min. P loss ) by pleasi ng numerous security and stability constraints. The non-dominated sorting genetic algorithm II (NSGA-II) have been utilized to settle this opposed bi-objective enhancement problem. The validity of the suggested method was examined on a modified IEEE 14-bus and a utilitarian examine system connected to DFIG with UPFC in power system analysis toolbox ( PSAT ) software. The optimal placement of DFIG and UPFC on the grid has increased the system's dynamic performance, with all the specified particular constraints being encountered.

Voltage Stability Assessments and Their Improvement Using Optimal Placed Static Synchronous Compensator (STATCOM)

In this paper, static voltage stability assessments and their improvement using analytical and optimization techniques with different loading scenarios are described. In this study, the 400 kV, 230 kV, and 132 kV Ethiopian electric power networks are modeled using Power System Analysis Toolbox (PSAT), and the load flow analysis is carried out using MATLAB source code. Then, different voltage stability indices, such as the user-defined advanced voltage stability index (AVSI), modified voltage stability index (MVSI), and fast voltage stability index (FVSI), are used to identify the voltage unstable buses. Besides this, particle swarm optimization (PSO) is also used to find the optimal size and placement of the Static Synchronous Compensator (STATCOM) for the most severe buses identified by voltage stability indices. The result presents three special arguments: whether the most severe buses that are ranked at the top based on the voltage stability indices are optimal buses for compensation placement or not, the voltage stability improvement, and power loss reduction with the introduction of STATCOM. Accordingly, it is observed that the weakest bus that is identified through the stability indices may not be the optimal placement of the compensation device. It is also indicated that, with the introduction of STATCOM to the optimal selected bus, the network power loss is reduced from 46.65 MW to 33.32 MW and its voltage magnitude in all buses is also improved. All bus voltages are within the IEEE standard acceptable limit.

A UPFC‐based robust damping controller for optimal use of renewable energy sources in modern renewable integrated power systems

This paper proposes coordinated design of wide-area damping controller (WADC) in the presence of renewable energy resources in a large-scale power system. To tackle with constant and time-varying delays in wide-area system, a robust criterion based on H∞ has been used for the coordinated WADC design. By using an auxiliary function in Lyapunov function, conservatism of linear inequality matrix (LMI) is reduced, such that larger delay margin and larger feasibility region is obtained in the presence of delays. The wind farms here are composed of doubly-fed induction generator (DFIG) and squirrel-cage induction generator (SCIG), which are connected to common bus of photovoltaic (PV) system by using unified power flow controller (UPFC). Then, the renewable energy units are integrated with 10 and 16-machine power systems. Afterwards, by identifying oscillating modes, the coordinated design of WADC is carried out for rotor-side-converter (RSC) in DFIG, DC/AC converter in the PV units, shunt converter (SHC) in UPFC, and power system stabilizer (PSS). Different scenarios of power system operating conditions are considered to evaluate performance of the proposed approach. The simulations in power system analysis toolbox (PSAT) and programming in MATLAB demonstrate effectiveness of the conducted method.

Sparse Dictionary Learning for Transient Stability Assessment

Transient stability assessment (TSA) has always been a fundamental and challenging problem for ensuring the security and operation of power systems. With more power electronic interface resources integrated into the grid and large renewable energies, the stability of the power system is jeopardized. Therefore, TSA of the power system should be considered in advance to keep the system running stable. In recent years, with the development of artificial intelligence (AI) technologies such as artificial neural network (ANN), support vector machine (SVM), and Markov decision process, TSA has improved dramatically. In this study, a sparse dictionary learning approach is proposed to improve the precision of the classification accuracy of transient stability assessment in power systems. Case studies of TSA using multi-layer support vector machine (ML-SVM) and long short-term memory network–based recurrent neural network (LSTM-RNN) are discussed as benchmarks to validate the proposed method. The stable and unstable dictionary learnings are designed based on datasets obtained by simulating thousands of different time-domain simulation (TDS) scenarios performed on the New-England 39-bus system in the PSAT (power system analysis toolbox) toolbox. Stable and unstable dictionaries are developed based on the K-SVD approach. The testing dataset contains both stable and unstable samples which steps into the sparse coding process to obtain the indexes. Compared with the indexes, the system’s final TSA is targeted. The proposed method exhibits satisfactory classification accuracy in transient stability prediction and provides the ability to reduce false alarms both in positives and negatives of the power system.

Power supply enhancement in Onitsha distribution network using distribution generations

The research explored ways in which power supplied in Onitsha distribution line network would be enhanced using distributed generation. The problem of insufficient power supply in densely populated metropolis which is characterised by frequent load shedding was solved using optimal placement and sizing of multiple distributed generation. A gas plant was optimally placed at 33 kV injection substations at Awada and General Cotton Mill (GCM). The generators were optimally placed using voltage sensitivity index factor, while their optimum capacities were sized using step method. Simulations were done by power system analysis toolbox (PSAT) 2.1.11 simulation tool in MATLAB 2018a environment and the result of the findings revealed that 32 buses out of 34 buses were violated. The result of the simulation also showed that the optimal operating power output of the generators at Awada and GCM of 12.5 MW and 2.5 MW respectively could only clear 29 out of the 32 bus voltage violations. Overloading of Fegge injection substation transformer was identified as the cause and its upgrade from 7.5 MVA to 15.0 MVA cleared all the voltage violations. The system active loss and reactive loss were 1.82 MW and 35.03 MVar and the research was able to reduce them by 23.30% and 23.80% respectively. The statutory bus voltage limits of ±5% and the requirement that distributed generators installed must be less than the maximum demanded had been achieved in the research. The power supply in Onitsha distribution network was enhanced using distribution generations and the usage of optimal placement and sizing of multiple distributed generation is therefore recommended for problematic distribution networks not only for loss reduction also for better performance.

Design of Digital Reverse Power Relay Model for Generator Protection

Abstract: Generators are one of the most important parts of the power system. Faults at the generator lead to severe failures and fatal accidents. Hence, generators’ protection is a major concern, especially from faults – voltage and current fluctuations, short circuit faults, frequency variations, over-fluxing, flow of reverse power, etc. In this project, a protection scheme is presented for power flow in opposite direction that is flow of power from grid to the generator, due to which the generator starts consuming and acts as a load. Modelling tools are important to have a basic idea of power system. These tools aid an engineer to modify the system under all circumstances. This paper contains the simulation and modelling of digital reverse power relay in MATLAB/ Simulink®. The libraries in MATLAB offer Power System Analysis Toolbox which are simulation based, for power system engineering projects. Keywords: Reverse power relays, Relay Modelling, Digital relays.