This paper addresses robust combined frequency and voltage regulation in a highly nonlinear, amphibious (aquatic and terrestrial), two-area hybrid power system (AHPS). The AHPS comprises multiple sources—thermal, dish–Stirling solar thermal (DSTS), hydro, pumped hydro, and gravity hydro units—connected to a 50-Hz grid. During operation, solar radiation fluctuations and load changes lead to significant variations in key model parameters <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$({e.g., K}_{p},{T}_{p},{T}_{sc},{T}_{rh},{T}_{w},{T}_{1},{T}_{2})$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo stretchy="false">(</mo> <msub> <mrow> <mi>e</mi> <mo>.</mo> <mi>g</mi> <mo>.</mo> <mo>,</mo> <mi>K</mi> </mrow> <mi>p</mi> </msub> <mo>,</mo> <msub> <mi>T</mi> <mi>p</mi> </msub> <mo>,</mo> <msub> <mi>T</mi> <mrow> <mi mathvariant="italic">sc</mi> </mrow> </msub> <mo>,</mo> <msub> <mi>T</mi> <mrow> <mi mathvariant="italic">rh</mi> </mrow> </msub> <mo>,</mo> <msub> <mi>T</mi> <mi>w</mi> </msub> <mo>,</mo> <msub> <mi>T</mi> <mn>1</mn> </msub> <mo>,</mo> <msub> <mi>T</mi> <mn>2</mn> </msub> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>, which can cause undesirable frequency and voltage deviations. To tackle this challenge, a dynamic parameter-based modelling framework is developed for the AHPS, and a new fractional-order tilt-integral sliding mode controller (FOTI-SMC) is proposed for coordinated frequency–voltage regulation. The proposed FOTI-SMC is systematically compared with five benchmark controllers—classical PID, fractional TID, FOPID, FOTID, and nonlinear FOPISMC—whose parameters are tuned using five optimization classes (evolutionary, swarm-based, physics-based, human-inspired) and the bio-inspired Tasmanian Devil Optimization (TDO) algorithm. The TDO-tuned FOTI-SMC achieves a peak overshoot of only 1.18 for frequency deviation in area-1 (∆f1), significantly outperforming the GA-tuned PID. The proposed scheme also realizes faster recovery, with settling times reduced to 15.787s for ∆f1 and 12.052s for ∆f2, voltage deviations (∆V1 & ∆V2), and tie-line power (∆Ptie). Under realistic operating scenarios involving simultaneous variations in load, solar insolation, and modelling parameters, the TDO-FOTI-SMC maintains superior robustness, restricting overshoots to 1.517 for ∆f1 and 0.931 for ∆f2. Real-time validation on an OPAL-RT OP4510 platform confirms that the proposed TDO-optimized FOTI-SMC offers the most effective frequency–voltage regulation and disturbance rejection among all tested configurations.

Combined Voltage and Frequency Containment of Amphibious Hybrid Power System Using FOTI-SMC

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发表日期：

2026年6月25日

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Kothalanka Kameswara Pavan Kumar,
Dulal Chandra Das,
Nirmala Soren

摘要

This paper addresses robust combined frequency and voltage regulation in a highly nonlinear, amphibious (aquatic and terrestrial), two-area hybrid power system (AHPS). The AHPS comprises multiple sources—thermal, dish–Stirling solar thermal (DSTS), hydro, pumped hydro, and gravity hydro units—connected to a 50-Hz grid. During operation, solar radiation fluctuations and load changes lead to significant variations in key model parameters $({e.g., K}_{p},{T}_{p},{T}_{sc},{T}_{rh},{T}_{w},{T}_{1},{T}_{2})$ $({e . g ., K}_{p}, T_{p}, T_{sc}, T_{rh}, T_{w}, T_{1}, T_{2})$ , which can cause undesirable frequency and voltage deviations. To tackle this challenge, a dynamic parameter-based modelling framework is developed for the AHPS, and a new fractional-order tilt-integral sliding mode controller (FOTI-SMC) is proposed for coordinated frequency–voltage regulation. The proposed FOTI-SMC is systematically compared with five benchmark controllers—classical PID, fractional TID, FOPID, FOTID, and nonlinear FOPISMC—whose parameters are tuned using five optimization classes (evolutionary, swarm-based, physics-based, human-inspired) and the bio-inspired Tasmanian Devil Optimization (TDO) algorithm. The TDO-tuned FOTI-SMC achieves a peak overshoot of only 1.18 for frequency deviation in area-1 (∆f₁), significantly outperforming the GA-tuned PID. The proposed scheme also realizes faster recovery, with settling times reduced to 15.787s for ∆f₁ and 12.052s for ∆f₂, voltage deviations (∆V₁ & ∆V₂), and tie-line power (∆P_tie). Under realistic operating scenarios involving simultaneous variations in load, solar insolation, and modelling parameters, the TDO-FOTI-SMC maintains superior robustness, restricting overshoots to 1.517 for ∆f₁ and 0.931 for ∆f₂. Real-time validation on an OPAL-RT OP4510 platform confirms that the proposed TDO-optimized FOTI-SMC offers the most effective frequency–voltage regulation and disturbance rejection among all tested configurations.