Generation Rate Constraints Physical Identification and Modeling in AGC of Multi-Area Power Systems

Abstract

In this article, generation rate constraints (GRCs) of power generating units are modeled accurately in transfer function modeling of automatic generation control (AGC) system. Typically, GRCs are used to restrict the rate of change of plant generating unit’s power output in order to mimic the realistic dynamic behavior of AGC system. Though, this practice of limiting plant generating unit’s response using GRCs was inferred from the IEEE committee report published in 1967. IEEE working group named as “power plant response” carried out investigations to study the maximum allowable rates of load changes for thermal, hydro and gas based power generating units. In this investigation, it was clearly stated that study is not intended to analyze the ability of plant generating units to cope with changing power system load. However, this study was misinterpreted and researchers started to use GRCs to restrict the rate of change of generating unit’s power outputs. This article rectifies the aforementioned anomaly and presents the accurate placement of GRCs in AGC transfer function model. The study is validated with the dynamic responses of actual 500 MW thermal generating unit and from the tripping tests performed by IEEE working groups in 2001.

Keywords:

• automatic generation control
• generation rate constraints
• supplementary control
• particle swarm optimization

Appendix

• Typical Values of Power System Model Parameters $$P_{r1}=2000\text{MW},\hspace{0.5em}{P}_{r2}=4000\text{MW},\hspace{0.5em}{P}_{r3}=8000\text{MW},a_{12\mathrm{\hspace{0.17em}}}=-1/2,\hspace{0.5em}{a}_{23\mathrm{\hspace{0.17em}}}=-1/2,\hspace{0.5em}{a}_{13\mathrm{\hspace{0.17em}}}=-1/4,B=0.425 \mathrm{Hz}/{\mathrm{MW}}_{p.u.},\hspace{0.5em}R\hspace{0.17em}=2.4 \mathrm{Hz}/{\mathrm{MW}}_{\mathit{pu}},T_p=\mathrm{20\; sec,}\hspace{0.5em}{K}_p=120\mathrm{Hz}/{\mathrm{MW}}_{\mathit{pu}},$$ $$2\pi T_{12}\mathrm{=\; 0.545,}\mathrm{ }2\pi T_{23} \mathrm{=0.545,}2\pi T_{13} \mathrm{=0.545,}{P}_{\mathit{tiemax}} \mathrm{=200\; MW.}$$

• Thermal and Hydro Power System Model Parameters Values $$T_t\hspace{0.17em}=\text{\hspace{0.17em}0.3\hspace{0.5em}sec,}{T}_r\hspace{0.17em}=\text{\hspace{0.17em}10\hspace{0.5em}sec,}{K}_r=\text{\hspace{0.17em}0.5,}{T}_g=\text{\hspace{0.17em}0.03\hspace{0.5em}sec,}{T}_w=\text{\hspace{0.17em}0.5\hspace{0.5em}sec,\hspace{0.5em}}{K}_p,\hspace{0.5em}{K}_i\text{\hspace{0.5em}and\hspace{0.5em}}{K}_d=\text{See\hspace{0.5em}Table\hspace{0.5em}5.}$$

TABLE 7(b) Phase margins comparison of AGC models based on GRC locations-1 & 2.

Additional information

Notes on contributors

Nikhil Pathak

Nikhil Pathak received the Ph.D. degree in “Power System Operation and Control” from Center for Energy Studies, Indian Institute of Technology Delhi in 2018, M.Tech degree in Electrical Power System & Management from Jamia Millia Islamia University, New Delhi in 2014. Currently, he is working as Post Doctoral Fellow in Department of Electrical Engineering, Tsinghua University, Beijing, China. His research interest focuses on power system operation and control, power system modeling and optimization, offshore wind farms operation and control.

Ashu Verma

Ashu Verma received the M.Tech degree in power systems in 2002 and the Ph.D. degree in transmission expansion planning in 2010, both from Indian Institute of Technology Delhi, New Delhi, India. She is currently an Associate Professor with the Center for Energy Studies, Indian Institute of Technology, New Delhi. She also worked as an Assistant Engineer in Nathpa Jhakri Hydro Electric Project, H.P. Her current research interests include power system planning, operation and control aspects of integrated renewable energy systems, policy and regulatory framework for enabling large scale integration of renewable energy sources in India.

Terlochan Singh Bhatti

Terlochan Singh Bhatti received the Ph.D. degree in “Power System Operation and Control” from the Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, India, in 1985. He is currently a Professor with the Center for Energy Studies, Indian Institute of Technology Delhi. He has been involved in teaching and research at Indian Institute of Technology Delhi since 1980. During 1987, he was a Postdoctoral Fellow at the University of Newcastle, Callaghan, NSW, Australia. His research interests include reactive power control, automatic generation control, wind energy conversion systems and small-hydropower systems.

Ibraheem Nasiruddin

Ibraheem Nasiruddin received the Ph.D. degree in power systems from the Department of Electrical Engineering, Aligarh Muslim University (AMU), Aligarh, India, in 2000. He is currently working in the Department of Electrical Engineering, Qassim Engineering College, Qassim University, Kingdom of Saudi Arabia, as a Full Professor. Before taking this assignment, he worked at Jamia Millia Islamia, New Delhi, India, for more than 25 years as teaching faculty and in various other positions. His research interests include power system operation and control, optimal control theory applications in power systems, application of intelligent controls in deregulated power systems and renewable energy systems.

Haocheng Luo

Haocheng Luo received the B.S. degree in electrical engineering from Tsinghua University, Beijing, China, in 2015, where he is currently working toward the Ph.D. degree. His current research interests include wind power generation, energy storage systems, and power systems stability and operation.

Zechun Hu

Zechun Hu received the B.S. degree and Ph.D. degree from Xian Jiao Tong University, Xi’an, China, in 2000 and 2006, respectively. He worked in Shanghai Jiao Tong University after graduation and also worked in University of Bath as a research officer from 2009 to 2010. He joined the Department of Electrical Engineering at Tsinghua University in 2010 where he is now an associate professor. He has published more than 150 peer-reviewed papers and two book chapters. He serves as an associate editor of IEEE Transactions on Transportation Electrification. His major research interests include vehicle to grid techniques, applications of energy storage in power systems, optimal planning and operation of power systems and power markets.