Performance Enhancement of Low Voltage Distribution Network by Optimal Inverter Control of Solar PV System
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IOE Pulchowk Campus
Abstract
The thesis highlights the increasing contribution and impact of grid-connected
photovoltaic (GCPV) systems, a type of renewable energy source, in electrical
distribution systems. GCPV systems offer several advantages to customers and
distribution network utilities. They enable consumers to fulfill their own electricity
demand, reduce electricity bills, and even feed surplus power back into the grid.
Additionally, GCPV systems can act as backup systems when there is insufficient or no
PV generation. The increasing number of network-connected PV inverters also allows
for their usage as Volt Ampere Reactive Compensators, which can regulate distribution
network voltage and eliminate the need for expensive compensation devices like
capacitor banks. However, introducing a large number of small-scale rooftop gridconnected PV systems with varying ratings into the distribution network can lead to
technical challenges. One major problem is the voltage rise along the distribution
network, causing reverse power flow, especially during low power demand and high
PV generation conditions. This voltage rise limits the network's ability to accommodate
more PV connections. Another issue is the possibility of voltage drop along the network
during periods of no PV generation, particularly when there is high power demand and
no PV generation.
Description
To address these technical problems, the thesis proposes a new PV operational
optimization strategy to enhance the performance of Low Voltage Distribution Systems
(LVDS) with rooftop PVs. The strategy involves optimizing the reactive power control
of PV inverters and implementing real power cut-off if necessary. The study focuses on
the Butwal Distribution Centre, Kalika Feeder, Shiva Mandir Chowk Distribution
Network, using bus data of load and solar PV generation patterns obtained from the
allocated area. Three scenarios of PV penetration levels are considered: low PV
generation with respect to consumer load (LPVCL), high PV generation with respect to
consumer load (HPVCL), and medium PV generation with respect to consumer load
(MPVCL). The programming for the proposed algorithms is implemented using
MATLAB.