Power system frequency stabiliser for modern power systems

2018 ◽  
Vol 12 (9) ◽  
pp. 1961-1969 ◽  
Author(s):  
Dushyant Sharma ◽  
Sukumar Mishra
Keyword(s):  
Power Systems ◽  
Power System ◽  
System Frequency

Under Frequency Load Shedding Techniques for Future Smart Power Systems

2019 ◽  
pp. 188-202
Author(s):  
H. H. Alhelou
Keyword(s):  
Power Systems ◽  
Power System ◽  
Active Power ◽  
Load Shedding ◽  
System Stability ◽  
Special Focus ◽  
Power Demand ◽  
Synchronous Generators ◽  
Smart Power ◽  
System Frequency

It is critical for today's power system to remain in a state of equilibrium under normal conditions and severe disturbances. Power imbalance between the load and the generation can severely affect system stability. Therefore, it is necessary that these imbalance conditions be addressed in the minimum time possible. It is well known that power system frequency is directly proportional to the speed of rotation of synchronous machines and is also a function of the active power demand. As a consequence, when active power demand is greater than the generation, synchronous generators tends to slow down and the frequency decreases to even below threshold if not quickly addressed. One of the most common methods of restoring frequency is the use of under frequency load shedding (UFLS) techniques. In this chapter, load shedding techniques are presented in general but with special focus on UFLS.

scholarly journals An approach for a multi-stage under-frequency based load shedding scheme for a power system network

2020 ◽  
Vol 10 (6) ◽  
pp. 6071
Author(s):  
Mkhululi Elvis Siyanda Mnguni ◽  
Yohan Darcy Mfoumboulou
Keyword(s):  
Decision Making ◽  
Power Systems ◽  
Power System ◽  
New England ◽  
Operating Conditions ◽  
Load Shedding ◽  
Power Network ◽  
Load Demand ◽  
Multi Stage ◽  
System Frequency

The integration of load shedding schemes with mainstream protection in power system networks is vital. The traditional power system network incorporates different protection schemes to protect its components. Once the power network reaches its maximum limits, and the load demand continue to increase the whole system will experience power system instability. The system frequency usually drops due to the loss of substantial generation creating imbalance. The best method to recover the system from instability is by introducing an under-frequency load shedding (UFLS) scheme in parallel with the protection schemes. This paper proposed a new UFLS scheme used in power systems and industry to maintain stability. Three case studies were implemented in this paper. Multi-stage decision-making algorithms load shedding in the environment of the DIgSILENT power factory platform is developed. The proposed algorithm speeds-up the operation of the UFLS scheme. The load shedding algorithm of the proposed scheme is implemented as a systematic process to achieve stability of the power network which is exposed to different operating conditions. The flexibility of the proposed scheme is validated with the modified IEEE 39-bus New England model. The application of the proposed novel UFLS schemes will contribute further to the development of new types of engineers.

scholarly journals WAMS-Based Online Disturbance Estimation in Interconnected Power Systems Using Disturbance Observer

2019 ◽  
Vol 9 (5) ◽  
pp. 990 ◽  
Author(s):  
Hassan Haes Alhelou ◽  
Mohamad Hamedani Golshan ◽  
Takawira Njenda ◽  
Pierluigi Siano
Keyword(s):  
Power Systems ◽  
Power System ◽  
Disturbance Observer ◽  
Load Shedding ◽  
System Stability ◽  
Main Stage ◽  
Estimation Errors ◽  
Disturbance Estimation ◽  
System Frequency ◽  
Swing Equation

In the event of a generator loss or disturbance, the power system frequency declines quickly and overall system stability is at risk. During these scenarios, under frequency load shedding is triggered to restore the power system frequency. The main stage of modern adaptive under frequency load shedding techniques is disturbance estimation. However, the swing equation is widely used in disturbance estimation but has some critical estimation errors. In this paper, instead of using the swing equation we proposed the use of a disturbance observer to estimate the curtailed power. By making use of wide area measurements, a system frequency response model, which is a representative of the whole power system, can be realized in real time. Using different power system states of the developed model, a disturbance observer can be designed as well. The main advantage of the disturbance observer is that it can accurately estimate the disturbance magnitude and its location in a very short time. Further investigations show that by using the disturbance observer disturbances, which occur at the same time or at different times in different areas regardless of the magnitude or size, accurate estimations can be made. To ascertain the efficiency of the proposed scheme, simulations are done for a four-area power system using Matlab/Simulink.

scholarly journals Optimization of Two Area AGC based Power System Using PSO Tuned Fuzzy PID Controller and PSO Trained SSSC And TCPS

2018 ◽  
Vol 7 (4.10) ◽  
pp. 163 ◽  
Author(s):  
Geoffrey Eappen ◽  
T. Shankar
Keyword(s):  
Power Systems ◽  
Power System ◽  
Pid Controller ◽  
Fuzzy Logic Controller ◽  
Minimum Cost ◽  
Automatic Generation ◽  
Control Area ◽  
Fuzzy Pid ◽  
Particle Swarm Optimizer ◽  
System Frequency

Automatic generation control or AGC system is significant controlling system that operates efficiently to balance the load and generation in power system at minimum cost for economical operation. System frequency will vary from nominal value if there is mismatch occurs between generation and demand. Due to this high frequency deviation system may breakdown. A very fast, reliable and accurate controller is needed to maintain the system frequency within the range to maintain stability. In this paper the proposed model consisting of PID controller whose parameters have been optimized using PSO tuned Fuzzy Logic Controller and it’s been compared with conventional PSO-PID controller. Each control area in power systems includes the dynamics response of the systems. The results contained in this paper present the strength of the particle swarm optimizer for tuning the Fuzzy based PID controller parameter for two area power system network, for better performance PSO trained SSSC and TCPS has been introduced to the system. The enhancement in the dynamic response of the power system network is verified. The output response of the proposed work is compared with conventional PSO-PID & PSO Fuzzy-PID based AGC system. Simulation experiments so conducted in MATLAB showed that the proposed system outperformed the conventional one by achieving better response.  

A DSE-Based Power System Frequency Restoration Strategy for PV-Integrated Power Systems Considering Solar Irradiance Variations

2017 ◽  
Vol 13 (5) ◽  
pp. 2511-2518 ◽  
Author(s):  
Shenglong Yu ◽  
Lijun Zhang ◽  
Herbert Ho-Ching Lu ◽  
Tyrone Fernando ◽  
Kit Po Wong
Keyword(s):  
Power Systems ◽  
Power System ◽  
Solar Irradiance ◽  
System Frequency ◽  
Integrated Power Systems

scholarly journals Common-Mode Frequency in Inverter-Penetrated Power Systems: Definition, Analysis, and Quantitative Evaluation

2022 ◽  
Author(s):  
Huisheng Gao ◽  
Huanhai Xin ◽  
Linbin Huang ◽  
Zhiyi Li ◽  
Wei Huang ◽  
...  
Keyword(s):  
Power Systems ◽  
Power System ◽  
Test System ◽  
Mode Frequency ◽  
Rate Of Change ◽  
Synchronous Generators ◽  
Common Mode ◽  
Response Characteristics ◽  
Frequency Drop ◽  
System Frequency

<p>As synchronous generators (SGs) are extensively replaced by inverter-based generators (IBGs), modern power systems are facing complicated frequency stability problems. Conventionally, the frequency nadir and the rate of change of frequency (RoCoF) are the two main factors concerned by power system operators. However, these two factors heavily rely on simulations or experiments, especially in a power system with high-penetration IBGs, which offer limited theoretical insight into how the frequency response characteristics are affected by the devices. This paper aims at filling this gap. Firstly, we derive a formulation of the global frequency for an IBG-penetrated power system, referred to as common-mode frequency (CMF). The derived CMF is demonstrated to be more accurate than existing frequency definitions, e.g., the average system frequency (ASF). Then, a unified transfer function structure (UTFS) is proposed to approximate the frequency responses of different types of devices by focusing on three key parameters<a>, which dramatically reduces the complexity of frequency analysis. </a>On this basis, we introduce two evaluation indices, i.e., frequency drop depth coefficient (FDDC) and frequency drop slope coefficient (FDSC), to theoretically quantify the frequency nadir and the average RoCoF, respectively. Instead of relying on simulations or experiments, our method rigorously links the system’s frequency characteristics to the characteristics of heterogeneous devices, which enables an in-depth understanding regarding how devices affect the system frequency. Finally, the proposed indices are verified through simulations on a modified IEEE 39-bus test system. </p>

scholarly journals Modeling the Impact of Modified Inertia Coefficient (H) due to ESS in Power System Frequency Response Analysis

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 902 ◽  
Author(s):  
Muhammad Saeed Uz Zaman ◽  
Muhammad Irfan ◽  
Muhammad Ahmad ◽  
Manuel Mazzara ◽  
Chul-Hwan Kim
Keyword(s):  
Power Systems ◽  
Power System ◽  
Frequency Response ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Response Analysis ◽  
Model And Simulation ◽  
Virtual Inertia ◽  
System Frequency ◽  
The Impact

The advantages of increased penetration of distributed generation are also accompanied by several challenges, low inertia being one of them, which threatens the grid stability. An emerging approach to confront this problem is the introduction of so-called virtual inertia (VI) provided by energy storage systems (ESS). In contrast to the already available literature which considers a conventional load frequency control (LFC) model, this work concentrates on a modified LFC model as the integration of a large portion of ESS changes the inertia constant ( H ) of a power system. A sensitivity function is derived that shows the effects of changes in H on the power system’s frequency response. With the help of the developed mathematical model and simulation results, it is shown that a difference in the actual and calculated values of H can deteriorate the system performance and economy. As one of the reasons for this difference is improper modeling of ESS in the LFC model, therefore, the study signifies the accurate calculation of H in the power systems having enlarged penetration of ESS.

scholarly journals Efficient Model for Accurate Assessment of Frequency Support by Large Populations of Plug-in Electric Vehicles

Inventions ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 89
Author(s):  
Michail Dakanalis ◽  
Fotios D. Kanellos
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Vehicles ◽  
Cost Optimization ◽  
Optimal Operation ◽  
Energy Storage Devices ◽  
Distributed Energy Storage ◽  
Large Populations ◽  
Safety And Reliability ◽  
System Frequency

In recent years, plug-in electric vehicles (PEVs) have gained immense popularity and are on a trajectory of constant growth. As a result, power systems are confronted with new issues and challenges, threatening their safety and reliability. PEVs are currently treated as simple loads due to their low penetration. However, as their numbers are growing, PEVs could potentially be exploited as distributed energy storage devices providing ancillary services to the network. Batteries used in PEVs are developed to deliver instantaneously active power, making them an excellent solution for system frequency support. This paper proposes a detailed dynamic model that is able to simulate frequency support capability from a large number of PEVs, using an innovative aggregate battery model that takes into account the most significant constraints at PEV and aggregate battery levels. The cost optimization algorithm, which is the most time-consuming process of the problem, is executed only at the aggregate battery level, thereby reducing the computational requirements of the model without compromising the obtained accuracy. The proposed method is applied to the power system of Crete exploiting detailed statistical data of EV mobility. It is proven that PEVs can effectively support power system frequency fluctuations without any significant deviation from their optimal operation.

scholarly journals Inter-Area Oscillation Damping in Large-Scale Power Systems Using Decentralized Control

2018 ◽  
Author(s):  
Roghieh A. Biroon ◽  
Pierluigi Pisu ◽  
David Schoenwald
Keyword(s):  
Power Systems ◽  
Power System ◽  
Large Scale ◽  
Order System ◽  
Small Signal Stability ◽  
Large Scale System ◽  
Signal Stability ◽  
Oscillation Damping ◽  
System Frequency ◽  
Lower Order System

Inter-area oscillation is one of the main concerns in power system small signal stability. It involves wide area in power system, therefore identifying the causes and damping these oscillations are challenging. Undamped inter-area oscillations may cause severe problems in power systems including large-scale blackouts. Designing a proper controller for power systems also is a challenging problem due to the complexity of the system. Moreover, for a large-scale system it is impractical to collect all system information in one location to design a centralized controller. Decentralized controller will be more desirable for large scale systems to minimize the inter area oscillations by using local information. In this paper, we consider a large-scale power system consisting of three areas. After decomposing the system into three subsystems, each subsystem is modeled with a lower order system. Finally, a decentralized controller is designed for each subsystem to maintain the large-scale system frequency at the desired level even in the presence of disturbances.

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