Voltage stability constrained multi-objective optimal reactive power dispatch under load and wind power uncertainties: A stochastic approach

Genetic algorithm based reactive power dispatch for voltage stability improvement

Optimal reactive power flow incorporating static voltage stability based on multi-objective adaptive immune algorithm

Subsynchronous control interaction (SSCI) associated with wind farms has become one of the major challenges for maintaining the stability and reliability of modern power systems. SSCI is mainly caused by the active participation of fast-acting wind turbine converter (WTC) controls in the phenomenon. It can damage the system equipment, reduce the amount of power generation, and degrade the power quality. Thus, it is urgent to develop practical mitigation techniques for the SSCI in order to achieve a smooth and reliable operation of grid interfaced wind farms. This study presents an overview of potential SSCI mitigation techniques at various stages of the power system, including system planning, operation, control, and protection phases at both network and generation sides. In particular, this paper reviews the active damping controls utilizing flexible ac transmission systems (FACTS) and WTC controls. Finally, it outlines the challenges and future work in studying SSCI mitigation techniques in practical wind power systems.

Mitigating subsynchronous control interaction in wind power systems: Existing techniques and open challenges

Chaotic improved PSO-based multi-objective optimization for minimization of power losses and L index in power systems

Effect of iron core loss nonlinearity on chaotic ferroresonance in power transformers

This paper investigates the effect of a metal oxide arrester on the ferroresonance behaviour of a transformer connected in parallel. It is known that the arresters may in some cases cause ferroresonance ‘dropout’. This aspect is examined in detail here by proper modelling of the nonlinear characteristics such as arrester characteristics and transformer saturation. Time-domain simulation has been carried out using a fourth-order Runge–Kutta method and the results were corroborated using EMTP. The results reveal that the presence of the arrester has a mitigating effect on ferroresonant overvoltages. Extensive simulations have been carried out to analyse the sensitivity with respect to arrester parameters, transformer saturation characteristics and the amplitude of the voltage source occurring in the Thevenin equivalent of the circuit. The presence of the arrester has a significant effect on the onset of chaos, the range of parameter values for which chaos persists and the magnitude of ferroresonant over voltages.

Analysis of nonlinear phenomena in MOV connected transformer

A new and fast technique for voltage stability analysis of a grid network using system voltage space

From the viewpoint of operational planning, this paper focuses on the evaluation of the impact of FACTS devices on control of voltage profile and line flows. This paper presents modeling and interfacing techniques of static VAr compensator (SVC) and thyristor controlled series capacitor (TCSC) for real time long term simulation. The proposed models are shown to be effective both for maintaining the voltage at load bus and real power flow through a typically selected line. The effectiveness of the controls are demonstrated for a standard nine bus system

Modeling of SVC and TCSC for power system dynamic simulation

The main responsibility of resource and delivery managers at Hewlett-Packard HP Enterprise Services HPES involves matching resources skilled professionals with jobs that project opportunities require. The previous Solution Opportunity Approval and Review SOAR process at HPES addressed uncertainty by producing decentralized project staffing decisions. This often led to many last-minute subjective, sometimes costly, resource allocation decisions. Based on our research, we developed a decision support tool for resource planning RP to enhance the SOAR process. It optimizes matching professionals who have diverse delivery roles and skills to jobs and projects across geographical locations while explicitly accounting for both demand and supply uncertainties. It also embeds capabilities for managers to incorporate tacit human knowledge and judgment information into the decision-making process. With its 2009 deployment in Best Shore, Bangalore operations of HPES, the RP tool’s significant benefits include reduced service delivery costs, increased workforce utilization, and profitability.

R. Ramanujam

Papers

Effect of iron core loss nonlinearity on chaotic ferroresonance in power transformers

Analysis of nonlinear phenomena in MOV connected transformer

A new and fast technique for voltage stability analysis of a grid network using system voltage space

Modeling of SVC and TCSC for power system dynamic simulation

HP Enterprise Services Uses Optimization for Resource Planning