A two-level control strategy with fuzzy logic for large-scale photovoltaic farms to support grid frequency regulation

Nguyen Gia Minh Thao, Kenko Uchida

    Research output: Contribution to journalArticle

    8 Citations (Scopus)

    Abstract

    This study proposes a two-level coordinated control strategy with fuzzy logic for appropriately adjusting the total active power supplied to a grid by large-scale photovoltaic (PV) farms in order to regulate grid frequency. For a solar farm, the strategy includes a central coordinating controller and many local controllers at PV power assemblies, treated as agents. In detail, the central controller uses a frequency regulation module based on a new automatic-tuning fuzzy-logic controller scheme to compute the appropriate reference values according to the total power needed. Then, the individual reference value for each local controller is determined. Each local controller governs all power-electronic converters installed at the PV agent to inject power into the grid according to the individual reference value received. Additionally, each local controller uses an algorithm to manage the state-of-charge of the battery bank installed at the agent so that it remains in the safe range of 20–80% while operating and close to the desired idle value of 50% at the steady state. Besides, a special control mode is developed and integrated into the overall strategy to aid rapid recovery of the grid frequency under emergency conditions. Numerical simulations demonstrate that the suggested strategy has the good response in terms of injecting an appropriate amount of power into the grid to regulate the frequency deviation into acceptable ranges of ±0.2 (Hz) in the transient state and ±0.05 (Hz) at the steady state, even when the weather conditions (solar radiation, air temperature), AC system load, and important control parameters of the grid suddenly change. Furthermore, the effectiveness in improving the grid-frequency stabilization by using the proposed strategy is validated within a four-area power system, where four PV farms are connected and the operating parameters of the grids at the areas are fairly different.

    Original languageEnglish
    Pages (from-to)77-99
    Number of pages23
    JournalControl Engineering Practice
    Volume59
    DOIs
    Publication statusPublished - 2017 Feb 1

    Fingerprint

    Level control
    Farms
    Fuzzy Logic
    Fuzzy logic
    Control Strategy
    Grid
    Controllers
    Controller
    Coordinated Control
    Power Electronics
    Solar Radiation
    Transient State
    Solar radiation
    Fuzzy Logic Controller
    Power electronics
    Emergency
    Converter
    Weather
    Battery
    Power System

    Keywords

    • Battery state-of-charge control
    • Coordinated control strategy
    • Fuzzy logic controller
    • Grid frequency regulation
    • Large-scale PV farm
    • Multi-area power system

    ASJC Scopus subject areas

    • Control and Systems Engineering
    • Computer Science Applications
    • Applied Mathematics
    • Electrical and Electronic Engineering

    Cite this

    A two-level control strategy with fuzzy logic for large-scale photovoltaic farms to support grid frequency regulation. / Thao, Nguyen Gia Minh; Uchida, Kenko.

    In: Control Engineering Practice, Vol. 59, 01.02.2017, p. 77-99.

    Research output: Contribution to journalArticle

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