A Real-time Control Approach to Maximise the Utilisation of Rooftop PV Using Dynamic Export Limits

Abstract: The soaring intake of rooftop solar photovoltaic (PV) in low voltage (LV) distribution networks has resulted in significant over-voltage issues due to reverse power flows. Although the current practice followed by distribution network operators (DNOs) to tackle this issue is to impose fixed export limits, this results in under-utilisation of export capabilities of consumer-owned distributed energy resources (DERs). This paper presents a LV feeder-level real-time control approach to maximise the utilisation of rooftop PV by assigning 5-min active power export limits for households. The proposed approach consists of two stages. In the first stage, the feeder-level controller performs a snapshot load flow based on 5-min predicted household demand and generation to check for voltage constraint violations. If voltage violations exist, in the next stage, a single-period AC optimal power flow (AC-OPF) problem embedded with voltage constraints is solved to assign 5-min export limits for households. The simulation results validated on a real LV network using realistic household demand and PV generation profiles suggest that the proposed approach has the potential to effectively utilise household PV generation while ensuring the operation of the network within preferred limits. Furthermore, the results represent a further step towards developing computationally inexpensive and scalable control schemes to assign time-varying household export limits.

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