HYDROKINETIC TURBINE INTEGRATION INTO MICRO-HEPP TAILWATER: NON-DETRIMENTAL GRID IMPACT ANALYSIS BASED ON O'ZDST 3181:2017

Abstract

This paper presents the first quantitative non-detrimental grid impact study of a horizontal-axis hydrokinetic turbine (HKT) installed in the tailwater discharge of the Marhаmat micro-hydroelectric power plant (HEPP) in Andijan Region, Uzbekistan. The tailwater channel delivers a mean velocity of 3.16 m/s (Re = 4.74×10⁶), making it a technically viable resource for a D = 1.5 m, Z = 3-blade HKT rated at P_el = 11.0 kW. A complete 36-equation differential-algebraic equation (DAE) model with a seven-component state vector is developed, coupling hydraulic-mechanical turbine dynamics, permanent magnet synchronous generator (PMSG) d–q equations, back-to-back voltage source converter (B2B-VSC), and grid equations. All nine criteria of the national grid-interconnection standard O'zDST 3181:2017 are evaluated analytically: voltage deviation ΔV = 0.023% (limit ±5%), harmonic distortion THD_grid = 0.008% (limit 8%), frequency deviation |Δf| = 0.034 Hz (limit 0.2 Hz), and unity power factor (cos φ = 1.000). Eight of nine criteria are satisfied with the existing design; a capacitor upgrade from 6 mF to 24.4 mF addresses the low-voltage ride-through (LVRT) shortfall analytically. Annual energy production is estimated at AEP = 79.0 MWh/year, displacing an equivalent of 67 tonnes CO₂. The methodology provides a replicable framework for HKT integration into the extensive micro-HEPP infrastructure of Central Asia.