Reactive Power Voltage Control Research Articles

Operating capability as a PQ/PV node of a direct-drive wind turbine based on a permanent magnet synchronous generator

This paper describes the modelling and control system of a direct-drive PMSG wind turbine for effective active and reactive power generation control and voltage control at the grid connection point. This study focuses on the maximum power capability of the wind turbine, which is limited by its generator and power converter. The ability of this model and control strategy are assessed by means of simulations and discussed at length. The results of our study show that a PMSG wind turbine is able to actively participate in grid operation because it can independently control active and reactive power production (operating as a PQ node) or the active power and voltage at the connection node (operating as a PV node).

Voltage Reactive Power Control with Multi Objective Particle Swarm Optimization

The purpose of this research is to minimize a transmission loss and the number of times of VAR devices motions in power system. We formulate Voltage Reactive Power Control (VQC) with Particle Swarm Optimization (PSO) on this problem, and propose Multi Objective PSO (MOPSO) whose objective functions are a transmission loss and the number of times of VAR devices motions.

A pooled-neighbor swarm intelligence approach to optimal reactive power dispatch

This paper presents a pooled-neighbor swarm intelligence approach (PNSIA) to optimal reactive power dispatch and voltage control of power systems. The proposed approach uses more particles℉ information to control the mutation operation. The proposed PNSIA algorithm is also extended to handle mixed variables, such as transformer taps and reactive power source installation, using a simple scheme. PNSIA applied for optimal power system reactive power dispatch is evaluated on an IEEE 30-bus power system and a practical 118-bus power system in which the control of bus voltages, tap position of transformers and reactive power sources are involved to minimize the transmission loss of the power system. Simulation results showed that the proposed approach is superior to current methods for finding the optimal solution, in terms of both solution quality and algorithm robustness.

Ant colony search algorithm for optimal reactive power optimization

The paper presents an (ACSA) Ant colony search Algorithm for Optimal Reactive Power Optimization and voltage control of power systems. ACSA is a new co-operative agents? approach, which is inspired by the observation of the behavior of real ant colonies on the topic of ant trial formation and foraging methods. Hence, in the ACSA a set of co-operative agents called "Ants" co-operates to find good solution for Reactive Power Optimization problem. The ACSA is applied for optimal reactive power optimization is evaluated on standard IEEE, 30, 57, 191 (practical) test bus system. The proposed approach is tested and compared to genetic algorithm (GA), Adaptive Genetic Algorithm (AGA).

Reactive power optimization and voltage control in the Western Algerian transmission system: a hybrid approach : Khiat, M. et al. Electric Power Systems Research, 2003, 64, (1), 3–10

Reactive power optimization and voltage control in the Western Algerian transmission system: a hybrid approach : Khiat, M. et al. Electric Power Systems Research, 2003, 64, (1), 3–10

Reactive power optimization and voltage control in the Western Algerian transmission system: a hybrid approach

This paper describes the methodology adopted to deal with the reactive power dispatch and voltage control problem in the Western Algerian system. A hybrid approach, combining heuristic and numerical techniques, has chosen in view of its successful application to the Spanish transmission network. Details are provided on how for implementations have been modified to cope with the critical situations frequently found in the Algerian case. Finally, field results corresponding to the worst case reported up to date are analyzed to show the validity of the proposed procedure.

Reactive power pricing: a conceptual framework for remuneration and charging procedures

A new electrical sector regulation is being implemented in different countries all over the world. The new regulation stresses the role of competitive markets for the procurement and remuneration of ancillary services. Among these services stand the ones associated with reactive power supply and transmission network voltage control in order to maintain the required system security levels. The object of this paper is twofold. On one hand, reactive power supply and voltage control services, which today are bundled, are decomposed in two types: (i) voltage profile management and reactive dispatch, and (ii) voltage regulation. A theoretical approach based on marginal pricing is proposed in order to clarify the principles to remunerate the suppliers and to charge the consumers of these services. On the other hand, a practical organization of reactive supply and voltage service markets is presented to be implemented in a competitive environment.

配電系統における電圧安定性の向上を目的としたNAS電池の最適配置および最適PQ出力比

In recent years, many studies have been made on allocating Na-S batteries in distribution substations to make good use of power facilities and improve the load factor. Besides, it has also been a hope to utilize Na-S batteries for controls such as AFC (automatic frequency control) or VQC (voltage reactive-power control), because Na-S batteries can respond faster than existing generator units and can control active and reactive power outputs independently by the function of AC-DC converter systems. In this paper, the authors propose a method for determining the optimal allocation and PQ output ratio of Na-S batteries in order to improve voltage stability. The proposed method combines a sensitivity method with an optimal power flow calculation method to determine the allocation and PQ output ratio efficiently and optimally. Simulations are carried out for a 73-bus distribution system to illustrate and verify the proposed method.

VOLTAGE/REACTIVE POWER CONTROL VIA FUZZY LINEAR PROGRAMMING APPROACH

This research presents a fuzzy linear programming method, which employs various membership functions pertaining to constraints and cost functions of system models for voltage reactive power control. Though the problem can be solved by the conventional linear programming approach, the solution from this approach lies on the boundary of the feasible region; hence only a small disturbance is enough to cause the solution to fall outside the constraints. In this research, we develop a fuzzy linear programming model which uses fuzzy set technique to help reach a solution. Because of employment of fuzzy technique, constraints of the system model can be treated lightly such that the presented method is able to consider both cost and security combined. Accordingly, its solution is relatively better compared to that of satisfying hard constraints. A modified IEEE 14-bus test system is used to demonstrate the application of the proposed approach. Computational results show that the proposed method is fairly effective and has the advantage of flexibility.

Optimal reactive power dispatch using an adaptive genetic algorithm

This paper presents an adaptive genetic algorithm (AGA) for optimal reactive power dispatch and voltage control of power systems. In the adaptive genetic algorithm, the probabilities of crossover and mutation, p c and p m, are varied depending on the fitness values of the solutions and the normalized fitness distances between the solutions in the evolution process to prevent premature convergence and refine the convergence performance of genetic algorithms. The AGA applied for optimal power system reactive power dispatch is evaluated on an IEEE 30-bus power system in which the control of bus voltages, tap position of transformers and reactive power sources are involved to minimize the transmission loss of the power system.

Feasibility study of a feed-forwarding voltage-reactive power control method based on linear programming for a central control facility

Voltage–reactive power control (VVC) on power systems becomes difficult when a load increases or decreases rapidly, especially in the morning and at noon. This is caused mainly by two problems. One is delayed operation and the other is noncooperative operation of facilities. To solve these problems, an advanced method and algorithms for a centralized feed-forwarding control system are presented. They are based on two main steps: forecasting the power system state for several minutes and dispatching reactive power sources optimally based on stepwise linear programming. The proposed method is evaluated and tested for data of a large-scale power system. The results show that the proposed method keeps the voltage constraints well and reduces redundant operation of facilities. © 1998 Scripta Technica, Electr Eng Jpn, 125(1): 18–26, 1998

An interactive procedure for the coordination of decoupled var/volt control in radial distribution systems

AbstractThis paper deals with mutually connected problems of reactive power compensation and voltage control in radial distribution systems. The paper presents a simple iterative procedure for optimal coordination of actions of main means for reactive compensation (shunt capacitors) and voltage control (variable turn ratio transformers), within the decoupled solution of these two subproblems. The procedure is based on the static optimization, specified as a non‐linear programming‐type problem. The paper presents the derivation of a method for the solution of specified control problems and gives an illustrative application of this method on the test example of a one‐source radial distribution system, consisting of 53 nodes and 52 branches.

LP法を用いた基幹系統への予測先行型電圧無効電力制御方式

LP法を用いた基幹系統への予測先行型電圧無効電力制御方式

96/01611 Application of a neural network and heuristic model for voltage-reactive power control

96/01611 Application of a neural network and heuristic model for voltage-reactive power control

96/01613 Application of Hopt bifurcation theory for determining critical value of generator contol or load parameter

This paper presents a new approach based on a neural network and heuristic model for voltage-reactive power control. The idea is to combine the learning and parallel-processing characteristics of a neural network as well as the fuzzy reasoning of a heuristic model to simplify the problem and improve the efficiency of calculation. The control variables are determined using a neural network type knowledge base and the quantities of the control actions are calculated with the heuristic model. The modified IEEE 30-bus test system is used to demonstrate the application of the proposed approach.

A new fuzzy control approach to voltage profile enhancement for power systems

This paper presents a new approach using fuzzy set theory for voltage and reactive power control of power systems. The purpose is to enhance voltage security of an electric power system. The violation bus voltage and the controlling variables are translated into fuzzy set notations to formulate the relation between voltage violation level and controlling ability of controlling devices. A feasible solution set is first attained using the minimum operation of fuzzy sets, then the optimal solution is quickly determined employing the maximum operation. A modified IEEE 30-bus test system is used to demonstrate the application of the proposed approach. Simulation results show that the approach is efficient and has good flexibility and adaptability for voltage-reactive power control.

Application of a neural network and heuristic model for voltage-reactive power control

This paper presents a new approach based on a neural network and heuristic model for voltage-reactive power control. The idea is to combine the learning and parallel-processing characteristics of a neural network as well as the fuzzy reasoning of a heuristic model to simplify the problem and improve the efficiency of calculation. The control variables are determined using a neural network type knowledge base and the quantities of the control actions are calculated with the heuristic model. The modified IEEE 30-bus test system is used to demonstrate the application of the proposed approach.

Power system optimal reactive power dispatch using evolutionary programming

This paper is concerned with application of evolutionary programming (EP) to optimal reactive power dispatch and voltage control of power systems. Practical implementation of the EP for global optimization problems of large-scale power systems has been considered. The proposed EP method has been evaluated on the IEEE 30-bus system. Simulation results, compared with those obtained using a conventional gradient-based optimization method, are presented to show the potential of application of the proposed method to power system economical operations. >

Large system interaction characteristics of superconducting generators

Differences between superconducting generators and conventional machines are identified, and ways in which superconducting machines will offer both advantages and problems are shown. Superconducting generators will have system interaction characteristics, somewhat different from those of their conventional counterparts. In general, superconducting machines will improve characteristics of the power system; their low reactances and long time constants will improve transient stability and voltage regulation. However, these also produce large fault currents and torques. If care is not taken, these machines may product interesting and perhaps destructive resonant effects on shaft lines. The author builds simple models that allow several important system integration characteristics of synchronous machines, including the differences between conventional and superconducting machines, to be discussed and understood. These include reactive power capability, transient stability, damping, voltage control, fault currents, and torques. >

Application of the probabilistic method to determine active power voltage control coefficients

Abstract The active method of determining the effect of voltage control on power in an electric power system can seriously disturb the consumers and organization. A passive approach, based on the probabilistic method, and using microprocessing equipment, has been used to determine the active and reactive power voltage control coefficients. The values of the active power voltage control coefficient estimated using the probabilistic method compare favourably with those obtained using the active method.