۱- Introduction

۲- Modelling methodology

۳- Case study

۴- Discussion

۵- Conclusions

References

Abstract

Exploiting the diversity between different renewable resources is regarded as a significant tool to managing their grid integration. Hybrid combinations of resources provide the potential to smooth output and so overcome limits on the export of power, but their network wide impact is not well understood. This paper examines whether combinations of renewable distributed generation can make more effective use of distribution network capacity. A multi-period, multi-resource optimal power flow approach is used to optimally configure wind and solar photovoltaic capacity to maximise energy production whilst complying with network physical limits. The effectiveness of hybrid distributed generation and the optimization method was examined through comparison with cases using single types of renewable distributed generation. This study demonstrates that by capturing the complementarity between renewables through hybrid design, the network can host more renewable generation capacity and increase total energy export. In addition, smart grid techniques, such as active network management, further boosts the value of resource diversity by allowing connection of more generation capacity of all considered renewables through isolating the infrequent co-occurrence of high outputs during periods of low electricity demand.

Introduction

Renewable generation from wind, solar photovoltaics (PV) and hydro is growing rapidly to meet ambitious targets for carbon emissions reduction [1]. Connecting renewable generators into power grids typically occurs in the distribution network, as distributed generation (DG). This can be a challenging exercise as these grids were generally designed to supply power from the transmission network via a grid supply point (GSP) to customers at medium and low voltages. Distribution network operators are concerned with a range of technical criteria that can be affected by the connection of DG: voltage rise, reverse power flows, increased fault levels, power quality and system stability [2]. The strict technical limits on these factors serve to limit the capacity of DG that may be connected to the network or necessitates expensive network reinforcement in order to raise capacity. Reverse power flows and voltage rise are generally the major issue [3]. These arise due to the changes in power flows following DG connection. Without DG, power flows through lines and transformers towards the load with flows following the pattern of demand. Voltage reduces in the direction of power flows through the network and more significant voltage drops are seen under high demand conditions. Once DG is connected, lower levels of DG output may be sufficient to supply local loads, reducing the power flows through the network.