Arthit Sode-Yome

Adaptive Hopfield neural networks for economic load dispatch

A large number of iterations and oscillations are those of the major concern in solving the economic load dispatch problem using the Hopfield neural network. This paper develops two different methods, the slope adjustment and bias adjustment methods, in order to speed up the convergence of the Hopfield neural network system. Algorithms of economic load dispatch for piecewise quadratic cost functions using the Hopfield neural network have been developed for the two approaches. The results are compared with those of a numerical approach and the traditional Hopfield neural network approach. To guarantee and for faster convergence, adaptive learning rates are also developed by using energy functions and applied to the slope and bias adjustment methods. The results of the traditional, fixed learning rate and adaptive learning rate methods are compared in economic load dispatch problems.

Comparison of shunt capacitor, SVC and STATCOM in static voltage stability margin enhancement

This paper compares the shunt capacitor, SVC and STATCOM in static voltage stability improvement. Various performance measures are compared under different operating system conditions for the IEEE 14 bus test system. Important issues related to shunt compensation, namely sizing and installation location, for exclusive load margin improvement are addressed. A methodology is also proposed to alleviate voltage control problems due to shunt capacitor compensation during lightly and heavily loaded conditions.

A maximum loading margin method for static voltage stability in power systems

In this paper, the maximum loading margin (MLM) approach is proposed in finding generation directions to maximize the static voltage stability margin, where the MLM is evaluated at various possible generation directions in the generation direction space. An approximate and simple model representing the relationship between the generation direction and the LM is used to obtain the MLM point. The proposed method is validated in the modified IEEE 14-bus test system and applied to the Thailand power system. LMs of the system with the generation directions are compared for different generator combinations using the proposed technique.

Static Voltage Stability Margin Enhancement Using STATCOM, TCSC and SSSC

In this paper, voltage stability assessment with appropriate representations of STATCOM, TCSC and SSSC is investigated and compared in the modified IEEE 14-bus test system. AC and DC representations of STATCOM, TCSC and SSSC are used in the continuation power flow process in static voltage stability study. The appropriate representation provides more practical solutions in the DC parts of these devices. Static voltage stability margin enhancement using STATCOM, TCSC and SSSC is compared in the modified IEEE 14-bus test system

A Comprehensive Comparison of FACTS Devices for Enhancing Static Voltage Stability

This paper presents a comparison of FACTS devices for static voltage stability study. Various performance measures including PV curves, voltage profiles, and power losses are compared under normal and contingency conditions. Placement and sizing techniques of series FACTS devices and UPFC are proposed for loading margin enhancement. The paper provides a guide for utilities to have an appropriate choice of FACTS device for enhancing loading margin and static voltage stability.

Impact of large-scale PV penetration on power system oscillatory stability

This paper presents the impact of large-scale photovoltaic (PV) generation on power system oscillatory instability. Two models of PV generation systems, namely detailed dynamic and simplified models, have been studied in IEEE-14 bus test system typically used for power system oscillatory instability studies. Influence of radiation pattern, and size and location of PV generating system on the power system stability issue is thoroughly investigated. In PV generation penetration, two scenarios, namely concentrated and scattered are examined. Simulation shows that the increased penetration of PV system enhances power system oscillatory stability.

Maximizing Static Voltage Stability Margin in Power Systems Using a New Generation Pattern

Abstract In this paper, the maximum loading margin approach for generation directions in static voltage stability margin is proposed based on the maximum loading margin at various possible generation directions in the generation direction space. An equation representing the relationship between generation directions and loading margin is used to obtain the maximum loading margin point. The proposed method is validated in the modified IEEE 14-bus test system. Loading margins of the system with the generation directions are compared for different generator combination using the proposed technique.

Voltage stability in power network when connected wind farm generators

This paper presents voltage stability in power systems when connected by wind farm generators. Two models of wind generator, namely squirrel cage induction generator and doubly fed induction generator are used and based on steady-state model. P-V curve is used to express maximum loading factor in power system when wind farm was installed. The test IEEE 14 bus system is selected to show proposed performance. The results of this paper can be shown that maximum loading factor before install wind farm generator is 0.70398 p.u. The weakest bus is bus no.14. Therefore, loading factor of system that connects two types of wind turbine with 7 m/s wind speed are 0.8688 p.u and 0.7997 p.u respectively. To improve the voltage stability, FACTS device is selected. The results show that STATCOM can improve maximum loading factor better SVC for both types of wind farm generator. Maximum loading factor increased when setting STATCOM up to 56.33% and 53.28% in systems that connected squirrel cage induction generator and doubly fed induction generator wind turbine respectively. Therefore, this methodology can give direct advantage for organization that are responsible to built convincing of power system in study the respond of setting wind turbine generator on voltage stability.

Economic generation direction for power system static voltage stability

This paper compares various generation direction methods in static voltage stability study in power systems. A new approach, namely economic generation direction (EGD) approach, is proposed to find the generation direction that minimizes the total operating cost. The proposed method is compared with conventional and the most recent generation direction methods, namely maximum loading margin and optimal generation direction methods, in terms of voltage stability margin and total operating cost. PV curve, loading margin and total operating cost are compared in the modified IEEE 14-bus test system. The study provides an idea for independent system operator about what kind of generation directions could be adopted in different power system scenario

Effect of Realistic Load Direction in Static Voltage Stability Study

In this paper, effect of realistic load direction based on a practical load variation is investigated in static voltage stability study. A practical load variation is represented by actual daily load curves of a practical power system, namely, Thailand power system, which are used to identify the realistic load direction. The use of the realistic load direction provides a more practical solution in terms of loading margin or voltage stability margin in static voltage stability study. The practical load direction is validated and compared with conventional load direction in the IEEE 14-bus test system under various system conditions