Power System Stability Enhancement Research Articles

Enhancement of Power System Stability Utilizing UPFC Based Hybrid Optimized Technique in IEEE-14 Bus System

A wind turbine, battery energy storage system, and photo-voltaic system are the three main sources included in this work as hybrid renewable energy systems (HRESs). To alleviate power quality (PQ) issues, i.e., swell, sag, harmonics, interruption, and fluctuation, a unified power flow controller (UPFC) is utilized in this paper. The major goal of this research is to compensate the load demand, mitigate the PQ issues, and reduction of cost as well as power flow along with IEEE-14 bus system. In HRESs, the PQ issues are mitigated by utilizing a novel hybrid optimized technique called GWO-CS approach-based UPFC. By utilizing the hybrid optimized technique, the PID controller is employed to drive the pulse width modulation of this UPFC. Numerous PQ issues like fluctuations, interruptions, estimation of harmonics, sags, and swells are evaluated in this paper by validating the enactment of the presented methodology, and also this technique is simulated in MATLAB/Simulink to analyze the outcomes. Moreover, to validate the efficacy of the proposed method, the presented technique is compared with the conventional approaches, i.e., GWO, PSO, and hybrid PSO-based GWO.

Stability Enhancement of Power System by Cooperative Virtual Synchronous Generator Control between ASSC and LFC Hydro Power Plant

Stability Enhancement of Power System by Cooperative Virtual Synchronous Generator Control between ASSC and LFC Hydro Power Plant

Power System Stability Enhancement Using a Novel Hybrid Algorithm Based on the Water Cycle Moth-Flame Optimization

Poor control of the power grid can lead to a total system collapse, causing significant economic losses and possible damage to security and social peace. Therefore, improving power system stability, particularly transient stability, has become one of the major research topics. This paper proposes a developed modeling approach that provides the optimal stabilizer parameters of the control devices, aiming at improving the electrical network stability by minimizing the angular speed deviation in the presence of a severe disturbance event using a novel hybrid algorithm called Water Cycle-Moth Flame Optimization (WCMFO). The main advantages of the proposed method are the speed of response and its efficient exploration and exploitation ability to attain the best solution quality. This is achieved by imposing a thermodynamic incident (an abrupt change in mechanical torque) on the well-known test model (SMIB), Single Machine Infinite Bus. To test the effectiveness of the proposed method, Power System Stabilizer (PSS), Proportional-Integral-Derivative (PID-based PSS), and Fractional Order-PID (FOPID-based PSS) are implemented to control and ensure the system’s ability to return to a stable state in the presence of this fault. The achieved experimental outcomes have proven the superiority, and efficiency of the developed approach (WCMFO) in terms of damping the oscillations and reducing the overshot, with an improvement of 44% over the Water Cycle Algorithm (WCA), Moth-Flame Optimization (MFO), and Artificial Ecosystem Optimization (AEO). It is envisaged that the proposed method could be very useful in the design of a practical high-performance power system stabilizer.

A novel grid-forming technology for transient stability enhancement of power system with high penetration of renewable energy

Owing to the limited inertia and voltage support of traditional grid-following inverters, grid-forming (GFM) technologies with voltage source characteristics, such as droop and virtual synchronous generator (VSG) control, have been proposed recently. However, it is difficult to achieve the same transient performance as that of traditional synchronous generators (SGs) because of the inherent current tolerance of power electronic devices. In this paper, a novel GFM technology with improved speed-power feedback control, defined as a motor-generator pair (MGP), is proposed. In addition, a state-space model is established to illustrate the control stability of the proposed GFM technology. The models and power angle characteristics of four GFM methods, namely droop, VSG, SG, and MGP, are first compared theoretically. Then, considering the current limitations and control delays, the transient response and interactions of the above GFM technologies are simulated in an IEEE 3-generator 9-bus system. The results show that the current saturations may limit the transient support of GFM inverters significantly and may also result in forced overcurrent and imbalanced power in the transient process, because of the slow response of SG governor in the system. Furthermore, compared with GFM inverters, MGP has more satisfactory transient stability because of its spontaneous inertia and faster response in primary frequency regulation than SGs owing to its similar response speed to inverters. Finally, an experimental platform including a 5 kW MGP prototype is established, and the transient performance of the proposed GFM is verified and compared.

Enhancement of power system stability by real-time prediction of instability and early activation of steam turbine fast valving

Turbine FV is a stability enhancing method used to protect power systems against the loss of synchronism after extreme contingency events. To avoid unnecessary FV action, smart control schemes can be used based on real-time instability prediction. In the last decade, several WAMS-based instability prediction methods have been developed. However, relatively long cumulative latencies in WAMS structures significantly reduce the efficiency of preventive control and can lead to system instability. To speed up FV action initiated by smart control scheme, this paper proposes a fast stability prediction method which is completely different from other methods described in literature. It uses only local measurements and requires performing simple mathematical operations. The basis of this method is the prediction of the magnitude of the power-angle characteristic. Just after the fault clearance, the method allows to predict transient instability and initiate MFV action. Based on the magnitude of the power-angle characteristic, the steady-state stability margin can be also computed. When this margin is too small, SFV action can be initiated as well. The validity of the proposed method has been verified by simulations performed for a large-scale real power system and detailed models of power system elements.

Analysis of Synthetic Inertia Strategies from Wind Turbines for Large System Stability

In this article, two different strategies to enhance power system stability exploiting synthetic inertia are presented and compared to assess the possibility of increasing the penetration of converter-based generation in power systems, keeping a suitable stability margin. Synthetic inertia is the emulation, carried out by converted-based generation, of the inertial response provided by rotating generators during frequency events. Two approaches are hence described, focusing on wind power. In the first approach, the primary power source is connected to the grid by a grid-following converter, and it exploits the energy content of the direct current link, suitably sized (or, with the same concept, of a suitable energy buffer available). The second approach uses a grid-forming converter model, whose features resemble more a traditional synchronous machine. The article aims at assessing the contribution to frequency stability that can be provided by converter-based generation. The simulation results demonstrate that converter-based generation can efficiently guarantee frequency stability, thus proving that future power systems will be able to manage ever-increasing renewable energy source converter-based generation.

Investigation of Multiple Resonances and Stability Enhancement in Multi-Source DC Distribution Power Systems

This paper addresses the resonance problem in a multi-source DC distribution power system (DPS). Unlike in a single-source DC DPS where the resonance frequency is almost fixed by the LC filter of the single voltage-controlled converter, line impedances between multiple source converters and DC bus will incur complex bus voltage oscillations at a wide frequency range, and thus may lead to an unstable system. This paper systemically investigates the impact of line impedance on multiple resonances and stability issues of multi-source DC DPSs. Multiple resonance frequencies and magnitude peaks are derived theoretically and then the design boundary of cut-off frequencies of load converters is also given to improve the system stability. With the unavoidable intersection by impedance-based stability criterion, this paper also proposes stability enhancement methods by inserting series virtual impedance (SVI) or parallel virtual impedance (PVI) in load converter, where a double-loop control scheme is suggested to diminish the magnitude dip and avoid the intersection at high frequency range. Finally, a two-source DC DPS is built and verifies the above analysis.

Stability Enhancement of Electric Power Systems by Employing Variable Frequency Transformer

Economical and technical advantages inherent in the coordinated operation of power systems resulted in large-scale grid interconnection. The major concern regarding the interconnection of the neighbouring power systems with relatively weak tie-lines is the appearance of poorly damped electromechanical oscillations. Inter-area (IA) oscillations reduce system stability and transmission capacity, and without an efficient damping mechanism, these oscillations can cause system failure and even lead to large-scale blackouts. In this work, the impact of variable frequency transformer (VFT) on the IA oscillations of a two-area power system connected in series with the tie-line is investigated. The VFT is a recent power transmission technology that offers continuous control over bi-directional power flow with no harmonic injection. The VFT is made up of a rotary transformer for continuously regulated phase shift, as well as a drive system and control that regulates the power flow through the VFT by adjusting the angle and speed of the rotary transformer. The VFT is controlled to increase system damping, and consequently suppress inter-area oscillations. A comprehensive model of the interconnected power system including VFT is developed in the MATLAB/Simulink environment to study the efficacy of the proposed scheme.

An Extreme Learning Machine Based Adaptive VISMA for Stability Enhancement of Renewable Rich Power Systems

Maintaining power system stability in renewable-rich power systems can be a challenging task. Generally, the renewable-rich power systems suffer from low and no inertia due to the integration of power electronics devices in renewable-based power plants. Power system oscillatory stability can also be affected due to the low and no inertia. To overcome this problem, additional devices that can emulate inertia without adding synchronous machines can be used. These devices are referred to as virtual synchronous machines (VISMA). In this paper, the enhancement of oscillatory stability of a realistic representative power system using VISMA is proposed. A battery energy storage system (BESS) is used as the VISMA by adding an additional controller to emulate the inertia. The VISMA is designed by using Fruit Fly Optimization. Moreover, to handle the uncertainty of renewable-based power plants, the VISMA parameters are designed to be adaptive using the extreme learning machine method. Java Indonesian Power Grid has been used as the test system to investigate the efficacy of the proposed method against the conventional POD method and VISMA tuning using other methods. The simulation results show that the proposed method can enhance the oscillatory stability of the power system under various operating conditions.

Frequency Stability Enhancement of Low-Inertia Large-Scale Power System Based on Grey Wolf Optimization

The high penetration of converter-based distributed generations (DGs) to power system can give rise to the lack of rotational inertia while replacing the conventional synchronous generators (SGs), which provide the primary frequency reserve (PFR) in power systems. As the result, the decrease in PFR aggravates the frequency stability. To overcome this problem, the droop coefficients of governors in the remaining conventional SGs must be re-determined newly and properly. This paper proposes a new solution based on the grey wolf optimization (GWO) method to optimally select the droop coefficients of SG governors in the low-inertia large-scale power system due to the high penetration of renewables. The proposed solution is very effective for reducing the computational effort significantly, and it is able to recover not only the steady-state but also the transient frequency stability. To verify the effectiveness of proposed optimization solution based on the GWO method, several case studies are carried out on the practical Korea electric power system with the penetration of wind power plants of 4 GW.

Fully Adaptive Recurrent Neuro-Fuzzy Control for Power System Stability Enhancement in Multi Machine System

Voltage instability in a power system produces low-frequency oscillations (LFOs), causing adverse effects in power distribution. Intelligent control schemes can overcome the limitations of fixed-parameter structures in power system stabilizers (PSS). Flexible alternating current transmission system (FACTS) control along with some supplementary control have remarkable potential in damping the oscillations. This paper proposes an adaptive neurofuzzy based recurrent wavelet control (ANRWC) scheme to enhance the power system stability. The proposed scheme utilizes recurrent Gaussian as antecedent part’s membership function and recurrent wavelet function in consequent parts. Our scheme uses gradient descent, adadelta, adaptive moment estimation (ADAM) and proximal gradient descent algorithms for optimization in which parameters of the scheme are updated using a back-propagation algorithm. A multi-machine power system is used for testing the controller. We evaluate the proposed control scheme in comparison to conventional lead-lag control and an adaptive neurofuzzy takagi sugeno kang (ANFTSK) control scheme. For comparison, we calculate the performance indices (PIs) for different controllers. Both quantitative and qualitative evaluations assert the effectiveness of the proposed control as compared to other schemes.

Optimal hybrid control of interarea oscillation in power system using energy storage systems

AbstractUnmanaged renewables integration into the power system will raise the possibility of small‐signal instability due to higher load deviations in the transmission lines. In power grids with a higher penetration level of the renewables, the load deviation can cause interarea oscillation in the grid. Meanwhile, large‐scale battery energy storage systems are promising solutions to enhance power system stability by smoothening the load profile and their fast response. To damp the interarea oscillations without compromising the voltage stability, we need to consider the battery's dynamic model in axis. The battery's dynamic model in axis allows us to integrate the battery into the power system and simulate both the battery's active and reactive power injection/absorption. In this paper, we model the battery energy storage on axis. Then, the battery model is augmented into the two‐area four‐machine power system. An optimum hybrid controller using linear quadratic regulator techniques is designed to damp generators' frequency deviations. The results show that the interarea oscillations are damped without losing the voltage stability of the system.

Stability enhancement of power system based on HHO-TSA control scheme

ABSTRACT In this article, an efficient control scheme is proposed to enhance the voltage regulation and stability of the power system. The proposed control scheme is the combination of both the Harris Hawks Optimization Algorithm (HHOA) and the Tabu Search Algorithm (TSA). The HHOA searching process is improved by utilising the TSA algorithm based on the minimal error objective function and named the HHO-TSA control scheme. The proposed HHO-TSA ensures adequate swing damping through minimising the mutual influence during transient stability with voltage regulation. An optimisation complex for tuning the parameters of power system stabilisers (PSSs) is designed to increase the damping ratio of electro-mechanical systems and the HHO-TSA control system has been employed for searching optimum parameters. The analysis of the Eigenvalue investigates the dynamic behaviour of the power system at dissimilar characteristic frequencies by utilising the HHO-TSA control scheme. The proposed technique is activated in the MATLAB/Simulink site and the performance is assessed using other existing techniques. The Eigen value for two area systems using the proposed technique achieves −1.31 ± 2.18i, −1.42 ± 1.36i, −1.61 ± 1.53i, −4.50 ± .027i, −10.4 ± 12.6i, −13.7 ± 25.1i and −14.5 ± 55.6i. The Eigen value for nine bus systems using the proposed technique achieves −1.2 ± 2.41i, −2.5 ± 2.62i, −2.11 ± 2.68i, −2.15 ± .2.71i, −4.4 ± 3.76i, −4.7 ± 3.94i and −5.5 ± 6.99i.

Stability enhancement of power system with the implementation of power system stabilizer PSS and excitation system IEEE Type-1

Stability of power system is an ability of an electric power system that reaches its stable condition after fault happens in its network. The system is unstable when one generator loses its stable synchronism performance. This paper investigates the transient stability of an IEEE 9-bus system during faults that happen in different bus locations. Additionally, the analysis contributes to the integration of the exciter IEEE type-1 for synchronous generator and integration of power system stabilizer (PSS) to improve the power angle stability in the power system. The fault at bus 4 has the highest amplitude in which it increases to 77.58 degrees for the power angle of Synchronous Generators (SGs). The absence of PSS showed that the existing system oscillated and it is unstable. However, the integration of PSS enables the system to damp the oscillations of power angle and reduce the settling time to 5.69 seconds during the fault at bus 4. Moreover, the PSS is connected to SGs through the excitation system to improve the stability of the system in relative power angle of SGs, speed deviation, and electrical power of SGs. Hence, the integration of PSS and excitation system enhances the transient stability of the power system.

Small signal stability enhancement of a large scale power system using a bio-inspired whale optimization algorithm

A whale optimization algorithm (WOA)-based power system stabilizer (PSS) design methodology on modified single machine infinite bus (MSMIB) and multi-machine systems to enhance the small-signal stability (SSS) of the power system is presented. The PSS design methodology is implemented using an eigenvalue (EV)-based objective function. The performance of the WOA is tested with several CEC14 and CEC17 test functions to investigate its potential in optimizing the complex mathematical equations. The New England 10-generator 39-bus system and the MSMIB system operating at various loading conditions are considered as the test systems to examine the proposed method. Extensive simulation results are obtained which validate the effectiveness of the proposed WOA method when compared with other algorithms.

Performance assessment of the two metaheuristic techniques and their Hybrid for power system stability enhancement with PV-STATCOM

Performance assessment of the two metaheuristic techniques and their Hybrid for power system stability enhancement with PV-STATCOM

A Converter-Based Power System Stabilizer for Stability Enhancement of Droop-Controlled Islanded Microgrids

To facilitate the transformation from conventional power systems towards smart grids, the concept of microgrids has been widely applied in practice, serving as the medium to accommodate renewable generators. One crucial problem is the stability associated with microgrids. This paper proposes a converter-based power system stabilizer (CBPSS), acting as a supplementary control loop, to enhance the stability of the islanded microgrids. The goal of the proposed CBPSS is to stabilize the critical microgrid mode with the generation of a damping torque, and it is achieved with the identification of the forward loop from the CBPSS to the microgrid. Then, the parameters of the proposed CBPSS can be designed accordingly to compensate the phase lag of the identified forward loop. Besides, an eigenvalue-mobility-based method is presented to identify the optimal installation location of the CBPSS in microgrids. As a consequence, the maximum stabilizing effect can be realized with the least control effort. Finally, modal analysis and time-domain simulations as well as hardware experimental results confirm the effectiveness of the proposed method.

An improved Rao algorithm for frequency stability enhancement of nonlinear power system interconnected by AC/DC links with high renewables penetration

An improved Rao algorithm for frequency stability enhancement of nonlinear power system interconnected by AC/DC links with high renewables penetration

Improvement of Dynamic Stability of a Single Machine Infinite-Bus Power System using MPC based Power System Stabilizer

Abstract— Power system stabilizers (PSSs) are used to enhance the damping during low frequency oscillations. This paper presents a study of power system stabilizer using fuzzy logic to enhance the stability of single machine infinite bus system. In this paper the problem of conventional power system stabilizer for stability enhancement is presented which is traditionally used as well as, an effective techniques using Artificial Intelligence (AI) based on fuzzy logic and Model Predictive Control (MPC) is used in designing the control system for PSS in order to achieve recognized improvement in Dynamic Stability. In the last few years fuzzy logic and MPC are used in power system applications as a powerful tool and shows recognized improvement in the stability performance This paper presents a solution for enhancing the improvement in the performance of single machine infinite bus system with fuzzy power system stabilizer of triangular membership function. Speed deviation (w) and acceleration are taken as an input variable. The performance of conventional, fuzzy based power system stabilizer with triangular membership function and MPC responses are studied and compared with conventional lead-lag compensator. The simulations are implemented using MATLAB - SIMULINK as a simulation program tool.

Adaptive decentralized fuzzy logic‐based underfrequency load shedding to enhance power system stability

Adaptive decentralized fuzzy logic‐based underfrequency load shedding to enhance power system stability