scholarly journals Coupling of Reactive Power Planning for Operation and Voltage Stability Enhancement

2020 ◽  
Author(s):  
Stefanie Samaan ◽  
Markus Knittel ◽  
Spyridon Iason Dizes ◽  
Albert Moser
Keyword(s):  
Steady State ◽  
Power Plants ◽  
Voltage Stability ◽  
Reactive Power ◽  
Stability Margin ◽  
Voltage Control ◽  
Mixed Integer ◽  
Separate Determination ◽  
Reactive Power Planning

The ongoing decommissioning of conventional power plants decreases the installed reactive power reserves for voltage control in transmission grids. Hence, an efficient planning of compensation devices substituting this lack of reactive power is required. Grid operators must allocate these devices for steady-state voltage control and for dynamic voltage control ensuring voltage stability. A separate determination of this static and dynamic VAR demand, however, fails to exploit synergies and disregards that VAR compensation in steady-state reduces the reserves for dynamic compensation. This paper proposes a coupled determination of the system static and dynamic VAR demand. An optimisation method applying mixed-integer programming identifies an efficient allocation and portfolio consisting of different compensation technologies. It includes constraints for voltage limits during steady-state and contingencies as well as for long-term voltage stability. Results emphasise that the method identifies an efficient portfolio for various operation and fault scenarios, while providing the required voltage stability margin.

scholarly journals Coupling of Reactive Power Planning for Operation and Voltage Stability Enhancement

2020 ◽  
Author(s):  
Stefanie Samaan ◽  
Markus Knittel ◽  
Spyridon Iason Dizes ◽  
Albert Moser
Keyword(s):  
Steady State ◽  
Power Plants ◽  
Voltage Stability ◽  
Reactive Power ◽  
Stability Margin ◽  
Voltage Control ◽  
Mixed Integer ◽  
Separate Determination ◽  
Reactive Power Planning

The ongoing decommissioning of conventional power plants decreases the installed reactive power reserves for voltage control in transmission grids. Hence, an efficient planning of compensation devices substituting this lack of reactive power is required. Grid operators must allocate these devices for steady-state voltage control and for dynamic voltage control ensuring voltage stability. A separate determination of this static and dynamic VAR demand, however, fails to exploit synergies and disregards that VAR compensation in steady-state reduces the reserves for dynamic compensation. This paper proposes a coupled determination of the system static and dynamic VAR demand. An optimisation method applying mixed-integer programming identifies an efficient allocation and portfolio consisting of different compensation technologies. It includes constraints for voltage limits during steady-state and contingencies as well as for long-term voltage stability. Results emphasise that the method identifies an efficient portfolio for various operation and fault scenarios, while providing the required voltage stability margin.

scholarly journals Maximum Loadability Enhancement with a Hybrid Optimization Method

2018 ◽  
Vol 7 (3) ◽  
pp. 323-330
Author(s):  
E. E. Hassan ◽  
T. K. A. Rahman ◽  
Z. Zakaria ◽  
N. Bahaman ◽  
M. H. Jifri
Keyword(s):  
Transmission Lines ◽  
Power Plants ◽  
Voltage Stability ◽  
Reactive Power ◽  
Optimization Technique ◽  
Optimization Method ◽  
Stressed Condition ◽  
Bacterial Foraging ◽  
Reactive Power Planning ◽  
The Cost

Nowadays, a power system is operating in a stressed condition due to the increase in demand in addition to constraint in building new power plants. The economics and environmental constraints to build new power plants and transmission lines have led the system to operate very close to its stability limits. Hence, more researches are required to study the important requirements to maintain stable voltage condition and hence develop new techniques in order to address the voltage stability problem. As an action, most Reactive Power Planning (RPP) objective is to minimize the cost of new reactive resources while satisfying the voltage stability constraints and labeled as Secured Reactive Power Planning (SCRPP). The new alternative optimization technique called Adaptive Tumbling Bacterial Foraging (ATBFO) was introduced to solve the RPP problems in the IEEE 57 bus system. The comparison common optimization Meta-Heuristic Evolutionary Programming and original Bacterial Foraging techniques were chosen to verify the performance using the proposed ATBFO method. As a result, the ATBFO method is confirmed as the best suitable solution in solving the identified RPP objective functions.

Differential Evolution Technique for the Optimization of Reactive Power Reserves

2017 ◽  
Vol 26 (10) ◽  
pp. 1750155 ◽  
Author(s):  
Biplab Bhattacharyya ◽  
Saurav Raj
Keyword(s):  
Differential Evolution ◽  
Modal Analysis ◽  
Voltage Stability ◽  
Reactive Power ◽  
Stability Margin ◽  
Optimization Techniques ◽  
Planning Problem ◽  
Power Sources ◽  
Voltage Stability Margin ◽  
Reactive Power Planning

In the present work, reactive power planning problem along with voltage stability margin is addressed by effective co-ordination of reactive power sources. Modal analysis and L-index methods are used to detect weak nodes of the system accordingly. Differential Evolution (DE) and Genetic Algorithm (GA)-based optimization techniques are applied for the proper co-ordination of Var sources under base and increased loading conditions maintaining voltage stability of the connected power network. The problem is multi-objective and IEEE 30 bus system is taken as the standard system. It is observed that modal analysis based detection of weak nodes are more effective than the L-index-based detection. Moreover, the DE-based optimization algorithm gives better result compared to GA-based approach in maximizing reactive power reserves.

Configuration of Jacobian Matrix in Steady-State Voltage Stability Analysis Based on Rotor Flux Dynamics of Rotating Machines

2013 ◽  
Vol 14 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Shenghu Li
Keyword(s):  
Steady State ◽  
Voltage Stability ◽  
Static Load ◽  
Reactive Power ◽  
Jacobian Matrix ◽  
Stability Margin ◽  
Active Power ◽  
Rotating Machines ◽  
Flux Dynamics ◽  
Rotor Flux

Abstract In the existing literatures, modal analysis for steady-state voltage stability is based on the reduced Jacobian matrix, i.e. active power equations are eliminated, and reactive power equations of the constant power/voltage buses (PV buses) are ignored in the polar coordinate expression, which is actually designed for voltage controllability, but questionable for voltage stability.In this article, power outputs of the rotating machines are newly decomposed to the steady-state and dynamic components, with the latter proportional to derivative of the rotor flux. Therefore, neither the active nor the reactive power equations of the rotating machines may be eliminated or ignored in the Jacobian matrix. Only the static buses with constant load impedance should be eliminated. Numerical results show that elimination of active power equations or ignorance of reactive power equations of the rotating machines will yield optimistic stability margins, while including power equations of static load buses yields pessimistic stability margin. It is also find that more static load component yields larger stability margin.

Fuzzy-Logic-Based Reactive Power and Voltage Control in Grid-Connected Wind Farms to Improve Steady State Voltage Stability

2018 ◽  
pp. 1-54
Author(s):  
Tukaram Moger ◽  
Thukaram Dhadbanjan
Keyword(s):  
Fuzzy Logic ◽  
Steady State ◽  
Voltage Stability ◽  
Reactive Power ◽  
Optimization Technique ◽  
Voltage Control ◽  
Wind Farms ◽  
Wind System ◽  
Fuzzy Logic Approach ◽  
Voltage Deviation

This chapter presents a fuzzy logic approach for reactive power and voltage control in grid-connected wind farms with different types of wind generator units to improve steady state voltage stability of power systems. The load buses' voltage deviation is minimized by changing the reactive power controllers according to their sensitivity using fuzzy set theory. The proposed approach uses only a few high sensitivity controllers to achieve the desired objectives. A 297-bus-equivalent grid-connected wind system and a 417-bus-equivalent grid-connected wind system are considered to present the simulation results. To prove the effectiveness of the proposed approach, a comparative analysis is also carried out with the conventional linear-programming-based reactive power optimization technique. Results demonstrated that the proposed approach is more effective in improving the system performance as compared with the conventional existing techniques.

Optimization of Real Power Loss and Voltage Stability Index for Distribution Systems with Distributed Generation

2017 ◽  
Vol 33 ◽  
pp. 100-114 ◽  
Author(s):  
Mostafa Elshahed ◽  
Mahmoud Dawod ◽  
Zeinab H. Osman
Keyword(s):  
Genetic Algorithm ◽  
Distributed Generation ◽  
Distribution Systems ◽  
Voltage Stability ◽  
Reactive Power ◽  
Optimization Problems ◽  
Stability Index ◽  
Mixed Integer ◽  
Voltage Profile ◽  
Voltage Stability Index

Integrating Distributed Generation (DG) units into distribution systems can have an impact on the voltage profile, power flow, power losses, and voltage stability. In this paper, a new methodology for DG location and sizing are developed to minimize system losses and maximize voltage stability index (VSI). A proper allocation of DG has to be determined using the fuzzy ranking method to verify best compromised solutions and achieve maximum benefits. Synchronous machines are utilized and its power factor is optimally determined via genetic optimization to inject reactive power to decrease system losses and improve voltage profile and VSI. The Augmented Lagrangian Genetic Algorithm with nonlinear mixed-integer variables and Non-dominated Sorting Genetic Algorithm have been implemented to solve both single/multi-objective function optimization problems. For proposed methodology effectiveness verification, it is tested on 33-bus and 69-bus radial distribution systems then compared with previous works.

Reactive Power Loss Index for Identification of Weak Nodes and Reactive Compensation Analysis to Improve Steady State Voltage Stability

2020 ◽  
pp. 177-237
Author(s):  
Tukaram Moger ◽  
Thukaram Dhadbanjan
Keyword(s):  
Steady State ◽  
Power Loss ◽  
Voltage Stability ◽  
Reactive Power ◽  
Power Grid ◽  
Southern Region ◽  
Equivalent System ◽  
Reactive Compensation ◽  
Simulation Results ◽  
Loss Index

This chapter presents a new reactive power loss index for identification of weak buses in the system. This index can be used for identification of weak buses in the systems. The new reactive power loss index is illustrated on sample 5-bus system, and tested on sample 10-bus equivalent system and 72-bus equivalent system of Indian southern region power grid. The validation of the weak buses identification from the reactive power loss index with that from other existing methods in the literature is carried out to demonstrate the effectiveness of the index. Simulation results show that the identification of weak buses in the system from the new reactive power loss index is completely non-iterative, and thus requires minimal computational efforts as compared with other existing methods in the literature.

scholarly journals Multiobjective Reactive Power Optimization of Renewable Energy Power Plants Based on Time-and-Space Grouping Method

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3556
Author(s):  
Linan Qu ◽  
Shujie Zhang ◽  
Hsiung-Cheng Lin ◽  
Ning Chen ◽  
Lingling Li
Keyword(s):  
Renewable Energy ◽  
Power Plants ◽  
Large Scale ◽  
Reactive Power ◽  
Power Optimization ◽  
Reactive Power Compensation ◽  
Mixed Integer ◽  
Reactive Power Optimization ◽  
Time And Space ◽  
Bus Voltage

The large-scale renewable energy power plants connected to a weak grid may cause bus voltage fluctuations in the renewable energy power plant and even power grid. Therefore, reactive power compensation is demanded to stabilize the bus voltage and reduce network loss. For this purpose, time-series characteristics of renewable energy power plants are firstly reflected using K-means++ clustering method. The time group behaviors of renewable energy power plants, spatial behaviors of renewable energy generation units, and a time-and-space grouping model of renewable energy power plants are thus established. Then, a mixed-integer optimization method for reactive power compensation in renewable energy power plants is developed based on the second-order cone programming (SOCP). Accordingly, power flow constraints can be simplified to achieve reactive power optimization more efficiently and quickly. Finally, the feasibility and economy for the proposed method are verified by actual renewable energy power plants.

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