Conference Paper

Voltage and frequency control of inverter based weak LV network microgrid

VTT Processes, Vaasa, Finland
DOI: 10.1109/FPS.2005.204293 Conference: Future Power Systems, 2005 International Conference on
Source: IEEE Xplore

ABSTRACT

In this paper voltage and frequency control of islanded microgrid after intentional and unintentional switching events are investigated. The weak low voltage (LV) network based microgrid consists of two inverter based distributed generation (DG) units. One unit is a storage (battery) unit and the other is a photovoltaic (PV) cell. In this case the battery inverter with rapid response is considered to act as a master and it has the main responsibility to control the voltage and frequency in microgrid when islanded from the main distribution network. The studies are performed on a PSCAD simulation software package. Simulation studies show the voltage - active power and frequency - reactive power dependency in weak LV network. The studies also show that in order to maintain frequency balance in islanded microgrid, there is need for a reference sine wave generator inside master unit which imitates the main network phase voltages and gives the input for master units' (battery storage) PLL (phase locked loop) during islanding

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Available from: Hannu Laaksonen, Dec 31, 2014
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    • "In low voltage microgrids, the well-known P/f droop control requires much more complexity than P/V, as active power link with voltage and reactive power with frequency, because predominated resistive (higher R/X value) network line[13],[14]. Therefore, the active power/terminal voltage (P/V) droop strategy is applied to control the voltage and frequency in the low voltage microgrid[15]. The increased allotment of renewable intermittent energy sources in a microgrid need to be reconsidered instead of straightforward P/V control implementation. "
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    Full-text · Dataset · Jan 2016
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    • "In low voltage microgrids, the well-known P/f droop control requires much more complexity than P/V, as active power link with voltage and reactive power with frequency, because predominated resistive (higher R/X value) network line[13],[14]. Therefore, the active power/terminal voltage (P/V) droop strategy is applied to control the voltage and frequency in the low voltage microgrid[15]. The increased allotment of renewable intermittent energy sources in a microgrid need to be reconsidered instead of straightforward P/V control implementation. "
    Dataset: Active

    Full-text · Dataset · Jan 2016
    • "In low voltage microgrids, the well-known P/f droop control requires much more complexity than P/V, as active power link with voltage and reactive power with frequency, because predominated resistive (higher R/X value) network line [13], [14]. Therefore, the active power/terminal voltage (P/V) droop strategy is applied to control the voltage and frequency in the low voltage microgrid [15]. The increased allotment of renewable intermittent energy sources in a microgrid need to be reconsidered instead of straightforward P/V control implementation. "
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    ABSTRACT: This paper proposes a power balancing strategy for dispatchable and non-dispatchable sources in an islanded microgrid. This control method enables energy storage system that employs a voltage-band at the dc busbar to maintain grid voltage stability for short period disturbances in a network. This voltage-band, applied to obtain maximum benefit from the storage system, depends on a storage capacity feature to avoid voltage limit violation. In addition, a linear quadratic regulator is employed as a voltage controller to track the reference grid voltage that is obtained from the proposed P/V droop control strategy. In the proposed control method, a long-term energy storage element, such as a battery, also can be used to regulate voltage and deliver insufficient power in a microgrid. It is concluded that the proposed control method exhibits an effective result in voltage and power issue during transient.
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