Small signal stability analysis of typical power system and its improvement using power system stabilizer

Giriprasad Ambati; G. Anjali Devi; T. Sudhakar; VENU YARLAGADDA; Raja Reddy Duvvuru; B. Ganesh Babu; Ch. Rami Reddy

doi:10.32397/tesea.vol7.n1.726

Authors

Giriprasad Ambati Department of Electrical and Electronics Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad – 500090, India
G. Anjali Devi Department of Electrical and Electronics Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad – 500090, India
T. Sudhakar Department of Electrical and Electronics Engineering, Narasaraopeta Engineering College, Narasaraopeta - 522601, India
Venu Yarlagadda Department of Electrical and Electronics Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad – 500090, India https://orcid.org/0000-0002-5504-2326
Raja Reddy Duvvuru Department of Electrical and Electronics Engineering, Malla Reddy Deemed to be University, Secunderabad – 500100, India
B. Ganesh Babu Department of Electrical and Electronics Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad – 500090, India
Ch. Rami Reddy Department of Electrical and Electronics Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad – 500090, India

DOI:

https://doi.org/10.32397/tesea.vol7.n1.726

Keywords:

small signal stability, power system stabilizer, modelling of a typical power system, small signal model of PSS, small signal stability improvement

Abstract

The modern power network is composed of a huge number of transmission lines and generators. The synchronous generator modelling and its stability analysis are crucial in a power system network. The single machine is analyzed with Phillips Heffron or K1 to K6 model, usually all constants are positive in the general case. In a few cases, the constants K4 and K5 are negative; for high values of external system reactance and high generator outputs, K5 becomes negative. With a negative K5 value automatic voltage regulator action introduces a positive synchronizing torque and negative damping torque. The classical system usually has a positive K4 value; as long as it is positive, it introduces positive damping torque. In some special situations, it can become negative; hence, this article aims to show that typical power systems lead to negative K4 values and their effects on system small-signal stability. The two typical power systems lead to negative K4 values being realized and modeled for stability study in this article, and the improvement of small signal stability is achieved with the design and implementation of a PID controller and power system stabilizer. Finally, comparison is performed without any controller, with a PID controller, and with power system stabilizers on small signal stability; the results prove the effectiveness of the PSS on SSS improvement.