As a consequence of technological progress, wind power has emerged as one of the most promising renewable energy sources. Currently, the penetration level of wind energy in power systems has led to the modification of several aspects of power system behaviour including stability. Due to this large penetration, transmission system operators have established some special grid codes for wind farms connection. These grid codes require wind farms to provide ancillary services to the grid such as frequency regulation and reactive power regulation. In the near future, the capability of damping system oscillations will be required. For this reason, the influence of grid-connected wind farms on system oscillations is reviewed in this paper, focusing on the contribution or damping of power system oscillations, and on inner wind turbine oscillations.

Power oscillation damping supported by wind power: A review

The deep penetration of renewable energy sources is on the cutting edge of smart grid vision. However, the variability and limited predictability of these sources have brought many technical challenges to grids. Many regulatory communities and system operators in the power sector have established grid codes to ensure proper connection of these renewable sources. This paper investigates the up-to-date methods used to enhance power system performance in the presence of a large share of renewable energy generation. In particular, two areas are addressed; the first is the techniques used for improving the wind and photovoltaic low-voltage ride-through capabilities to meet the required grid codes. The second is the contribution of these sources to the small signal stability of the power system in terms of inter-area oscillation damping.

Challenges of integrating renewable energy sources to smart grids: A review

Multi-machine power system stabilizers design using chaotic optimization algorithm

A honeybee mating optimization technique is used to tune the power system stabilizer PSS parameters and find optimal location of PSSs in this article. The PSS parameters and placement are computed to assure maximum damping performance under different operating conditions. One of the main advantages of the proposed approach is its robustness to the initial parameter settings. The effectiveness of the proposed method is demonstrated on two case studies as; 10-machine 39-buses New England NE power system in comparison with Tabu Search TS and 16 machines and 68 buses-modified reduced order model of the NE New York interconnected system by genetic algorithm through some performance indices under different operating condition. The proposed method of tuning the PSS is an attractive alternative to conventional fixed gain stabilizer design as it retains the simplicity of the conventional PSS and at the same time guarantees a robust acceptable performance over a wide range of operating and system condition. © 2014 Wiley Periodicals, Inc. Complexity 21: 242-258, 2015

Optimal location and optimized parameters for robust power system stabilizer using honeybee mating optimization

This paper details a new coordinated design between power system stabilizers (PSSs) and a unified power flow controller (UPFC) using genetic algorithms (GAs). A GA scheme determines the optimal location for a UPFC while tuning its control parameters, resulting in the optimization of the quantity, parameters, and locations of PSSs under different operating conditions. The problem is formulated as a multiobjective optimization problem in order to maximize the damping ratio(s) of electromechanical modes, matching different numbers of PSSs with a UPFC. The approach is successfully tested on the New England-New York interconnected system (a 16-machine and 68-bus system), proving its effectiveness in damping local and interarea modes of oscillations.

A Coordinated Design of PSSs and UPFC-based Stabilizer Using Genetic Algorithm

This paper discusses the causes of power system instability and the importance of fast fault clearing. The k-constant model is used to explain the relationships among the following: small signal stability, high impedance transmission lines, line loading and high gain, fast acting excitation systems. Various types of power system instability, utilizing both mathematical and practical approaches, are covered. Transient stability is discussed, including synchronizing and damping torques. The power angle curve is used to illustrate how fault clearing time and high initial response excitation systems can affect transient stability. In the past number of years, "power system stability" has become an increasingly popular term used in generation and transmission. The sudden requirement for power system stabilizers for use with new and existing excitation equipment has created much confusion about their applicability, purpose, and benefit to the power system. This paper will discuss the fundamentals of the power system stabilizer and its effectiveness in the system. An explanation will be provided concerning the various types of power system stabilizers and the benefit of some types over others. Lastly, the paper will address regulatory commission guidelines identified by NERC that will impact generation connected to the transmission system.

Understanding power system stability

This paper discusses power system instability and the importance of fast fault clearing performance to aid in reliable production of power. Explanation is provided regarding small signal stability, high impedance transmission lines, line loading, and high gain, fast acting excitation systems. Transient stability is discussed, including synchronizing and damping torques. The power angle curve is used to illustrate how fault clearing time and high initial response excitation systems can affect transient stability. The term, "power system stability" has become increasingly popular in generation and transmission. The sudden requirement for power system stabilizers has created confusion about their applicability, purpose, and benefit to the system. This paper discusses the fundamentals of the power system stabilizer and its effectiveness. In today's paper industry, power system stabilizers are being applied on larger machines in the Northwest United States and Canada.

R.C. Schaefer

Papers

Understanding power system stability

Understanding Power System Stability