scholarly journals Load shedding scheme based metaheuristic technique for power system controlled islanding

2021 ◽  
Vol 23 (3) ◽  
pp. 1306
Author(s):  
N. Z. Saharuddin ◽  
I. Zainal Abidin ◽  
H. Mokhlis ◽  
E. F. Shair
Keyword(s):  
Power System ◽  
Evolutionary Programming ◽  
Exhaustive Search ◽  
Load Shedding ◽  
Computational Time ◽  
Power Balance ◽  
Optimal Amount ◽  
Search Techniques ◽  
Controlled Islanding ◽  
Mitigation Techniques

<p>Power system-controlled islanding is one of the mitigation techniques taken to prevent blackouts during severe outage. The implementation of controlled islanding will lead to the formation of few islands, that can operate as a stand-alone island. However, some of these islands may not be balanced in terms of generation and load after the islanding execution. Therefore, a good load shedding scheme is required to meet the power balance criterion so that it can operate as a balanced stand-alone island. Thus, this paper developed a load shedding scheme-based metaheuristics technique namely modified discrete evolutionary programming (MDEP) technique to determine the optimal amount of load to be shed in order to produce balanced stand-alone islands. The developed load shedding scheme is evaluated and validated with two other load shedding techniques which are conventional EP and exhaustive search techniques. The IEEE 30-bus and 39-bus test systems were utilized for this purpose. The results proves that the load shedding based MDEP technique produces the optimal amount of loads to be shed with shortest computational time as compared with the conventional EP and exhaustive search techniques.</p>

scholarly journals A Three-Stage Procedure for Controlled Islanding to Prevent Wide-Area Blackouts

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3066 ◽  
Author(s):  
Hongbo Shao ◽  
Yubin Mao ◽  
Yongmin Liu ◽  
Wanxun Liu ◽  
Sipei Sun ◽  
...  
Keyword(s):  
Power System ◽  
Dynamic Stability ◽  
Power Flow ◽  
Transient Stability ◽  
Load Shedding ◽  
Area Measurement ◽  
Wide Area ◽  
Measurement Systems ◽  
Controlled Islanding ◽  
Three Stages

Controlled islanding has been proposed as a last resort action to stop blackouts from happening when all standard methods have failed. Successful controlled islanding has to deal with three important issues: when, and where to island, and the evaluation of the dynamic stability in each island after islanding. This paper provides a framework for preventing wide-area blackouts using wide area measurement systems (WAMS), which consists of three stages to execute a successful islanding strategy. Normally, power system collapses and blackouts occur shortly after a cascading outage stage. Using such circumstances, an adapted single machine equivalent (SIME) method was used online to determine transient stability before blackout was imminent, and was then employed to determine when to island based on transient instability. In addition, SIME was adopted to assess the dynamic stability in each island after islanding, and to confirm that the chosen candidate island cutsets were stable before controlled islanding was undertaken. To decide where to island, all possible islanding cutsets were provided using the power flow (PF) tracing method. SIME helped to find the best candidate islanding cutset with the minimal PF imbalance, which is also a transiently stable islanding strategy. In case no possible island cutset existed, corresponding corrective actions such as load shedding and critical generator tripping, were performed in each formed island. Finally, an IEEE 39-bus power system with 10 units was employed to test this framework for a three-stage controlled islanding strategy to prevent imminent blackouts.

scholarly journals Stochastic Optimization for Network-Constrained Power System Scheduling Problem

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
D. F. Teshome ◽  
P. F. Correia ◽  
K. L. Lian
Keyword(s):  
Power System ◽  
Load Shedding ◽  
Mixed Integer ◽  
Piecewise Linear Approximation ◽  
Computational Time ◽  
Forecast Errors ◽  
Scheduling Problem ◽  
Generation System ◽  
Network Constraints ◽  
The Impact

The stochastic nature of demand and wind generation has a considerable effect on solving the scheduling problem of a modern power system. Network constraints such as power flow equations and transmission capacities also need to be considered for a comprehensive approach to model renewable energy integration and analyze generation system flexibility. Firstly, this paper accounts for the stochastic inputs in such a way that the uncertainties are modeled as normally distributed forecast errors. The forecast errors are then superimposed on the outputs of load and wind forecasting tools. Secondly, it efficiently models the network constraints and tests an iterative algorithm and a piecewise linear approximation for representing transmission losses in mixed integer linear programming (MILP). It also integrates load shedding according to priority factors set by the system operator. Moreover, the different interactions among stochastic programming, network constraints, and prioritized load shedding are thoroughly investigated in the paper. The stochastic model is tested on a power system adopted from Jeju Island, South Korea. Results demonstrate the impact of wind speed variability and network constraints on the flexibility of the generation system. Further analysis shows the effect of loss modeling approaches on total cost, accuracy, computational time, and memory requirement.

scholarly journals WAMS-Supported Power Mismatch Optimization for Secure Intentional Islanding

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2790
Author(s):  
Jovancho Grozdanovski ◽  
Rafael Mihalic ◽  
Urban Rudez
Keyword(s):  
Power System ◽  
Real World ◽  
Electric Power System ◽  
Load Shedding ◽  
Fine Tuning ◽  
System Stability ◽  
Mixed Integer ◽  
Programming Approach ◽  
Controlled Islanding ◽  
System Integrity

It is expected that a coordinated operation of several system integrity protection schemes will become a necessity in the future. This research represents an innovative strategy for coordinating under-frequency load shedding and intentional controlled islanding schemes for improving electric power system stability and resilience. In the great majority of real-world cases, both approaches follow conventional tactics, i.e., disconnecting a fixed number of feeders at predefined frequency thresholds and isolating a predefined area of a power system regardless of the actual conditions. Under the newly arisen network conditions in which weather-dependent distributed energy sources introduce a significant level of intermittency, conventional approaches need to be upgraded in order to retain a high level of power system operation security. In this paper, a mixed-integer linear programming approach is used to adjust the island size, including/excluding additional substations according to the available amount of generation in the region. The fine-tuning of the power rebalancing is achieved by potentially blocking selected load shedding stages. This minimizes the power imbalance of the newly formed islands, which helps to reduce the number of partial or even total blackouts and also accelerates the power system’s restoration process. The optimization approach was tested on a generic IEEE 39-bus network and shows promising results along with the capability of coping with real-world applications using wide-area monitoring systems as a source of real-time measurements. The results also indicated the importance of appropriate load modelling since both voltage and frequency dependence are recognized to have a significant effect on intentional controlled islanding.

scholarly journals Identification of Optimal Path in Power System Network Using Bellman Ford Algorithm

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
S. Hemalatha ◽  
P. Valsalal
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Shortest Path ◽  
Voltage Stability ◽  
Optimal Path ◽  
Power Balance ◽  
Line Voltage ◽  
System Components ◽  
Path Search ◽  
Search Guidance

Power system network can undergo outages during which there may be a partial or total blackout in the system. In that condition, transmission of power through the optimal path is an important problem in the process of reconfiguration of power system components. For a given set of generation, load pair, there could be many possible paths to transmit the power. The optimal path needs to consider the shortest path (minimum losses), capacity of the transmission line, voltage stability, priority of loads, and power balance between the generation and demand. In this paper, the Bellman Ford Algorithm (BFA) is applied to find out the optimal path and also the several alternative paths by considering all the constraints. In order to demonstrate the capability of BFA, it has been applied to a practical 230 kV network. This restorative path search guidance tool is quite efficient in finding the optimal and also the alternate paths for transmitting the power from a generating station to demand.

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