RESEARCH ARTICLE Maiden application of cascade tilt-integral-derivative controller in load frequency control of deregulated power system Sandhya Kumari | Gauri Shankar Department of Electrical Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, India Correspondence Sandhya Kumari and Gauri Shankar, Department of Electrical Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India. Email: sandhya.16dr000226@ee.ism.ac.in; gaurishankar@iitism.ac.in Peer Review The peer review history for this article is available at https://publons.com/publon/ 10.1002/2050-7038.12257. Summary The present work primarily addresses a maiden application of fractional order calculus-based cascade tilt-integral–tilt-integral-derivative (CC-TI-TID) controller in load frequency control of deregulated power systems. Simultaneously, an effi- ciency test of a recently introduced water cycle algorithm (WCA) in obtaining optimal setting of CC-TI-TID controller is also investigated. In the proposed con- troller, TID controller acts as a slave controller, while TI controller played a role of master controller. Performance test of the proposed controller in stabilizing system frequency of a deregulated four-area power system is carried out. In view of the above, firstly, superiority of WCA over other studied algorithms such as genetic algorithm, differential evolution, and teaching-learning–based optimization tech- niques is established considering the proposed CC-TI-TID controller-assisted four- area power system. Secondly, comparative performance among WCA tuned pro- posed CC-TI-TID, CC-PI-TD, and PID controllers are explored in terms of chosen objective function, performance indices, settling time, and peak deviations. The comparative results obtained reveal that WCA tuned CC-TI-TID controller outper- forms the others. Further, to check the robustness of the CC-TI-TID controller, sen- sitivity analysis is performed by varying Disco participation matrix. KEYWORDS cascade controller, deregulated power system, load frequency control, water cycle algorithm 1 | INTRODUCTION Nowadays, power utilities are restructured from vertically integrated utilities to form generation companies (GENCOs), distribution companies (DISCOs), transmission companies, and an independent system operator (ISO). 1 There are List of Abbreviations and Symbols: CC-PI-TD, cascade proportional-integral-tilt-derivative; CC-TI-TID, cascade tilt-integral–tilt-integral-derivative; DISCOs, distribution companies; DPS, deregulated power system; DPM, DISCO participation matrix; FO, fractional order; FOD, figure of demerit; GENCOs, generation companies; GRC, generation rate constraint; IAE, integral absolute error; ISE, integral square error; ISO, independent system operator; LFC, load frequency control; ITAE, integral time absolute error; ITSE, integral time square error; TRANSCOs, transmission companies; apf, area participation factor; cpf, contract participation factor; B i , frequency bias factor of ith area; P ri , power rating of ith area; R i , governor speed regulation parameter of area i; T ij , synchronizing coefficients between area i and area j; T GT , governor time constant of thermal unit; T t , turbine time constant of thermal unit; T psi , power system time constant of area i; Δf i , frequency deviation in ith area; ΔP di , total load demand of the ith control area; ΔP gi , the contracted power supplied by the ith GENCO; ΔP lm , load demand of the mth DISCO. Received: 10 December 2018 Revised: 10 September 2019 Accepted: 23 October 2019 DOI: 10.1002/2050-7038.12257 Int Trans Electr Energ Syst. 2019;1–23. wileyonlinelibrary.com/journal/etep © 2019 John Wiley & Sons, Ltd. 1