Active distribution network with efficient utilisation of distributed generation ancillaryservices

Abstract

This study introduces an active distribution network with high penetration of inverter-based distributed generations (IBDGs) to improve the steady state, dynamic and transient performance of the distribution network. The size and location of the IBDGs, capacitor bank, on-load tap changers position and voltage regulator set points have been optimised to minimise the system losses, improve voltage profile and maximise the dynamic reactive power reserve. In addition to that, the adaptive master/slave roles are deployed in planning the active distribution network to achieve the best utilisation of each device based on its capability and response time in steady state, dynamic and transient operation. Indeed, the optimisation algorithm allows the IBDGs to operate in an inductive mode of operation during steady state resulted in maximising the dynamic reactive power reserve. Consequently, the IBDGs react with large dynamic margin in response to grid fault leading to enhanced voltage recovery and improved transient response. A comprehensive system optimisation and transient analysis are carried out to demonstrate the performance of the distribution network for enhancing the voltage profile, increasing the penetration level of renewable energy distributed generation, IBDGs, and improving the transient recovery in response to severe grid fault. Nomenclature V i , δ i voltage magnitude and the angle at the ith bus T tap setting of the on-load tap changers (OLTC) and VR Q DGi , P DGi reactive and active power of DG at the ith bus PF DG power factor of DG P lossi , Q lossi active and reactive power loss of the ith branch G i j , B i j i jth element of the Y-bus matrix P Di , Q Di active and reactive load demand at the ith bus P Gi , Q Gi active and reactive power generated at the ith bus P i j , Q i j active and reactive power flows on the i jth line S DGi MVA rating of DG at the ith bus S i j max thermal limit of the i jth line Q c reactive power supplied by CAPs' bank

Autonomous adaptive Q(U) control for distributed generation in weak medium‐voltage distribution grids

“…Even though, most medium-voltage networks are equipped voltage-control devices such as OLTC and VR, the interactions between DG and these devices are not considered in this work. This is because even if they are considered, they will be operated in different time scales as implemented in works such as [26][27][28], because DGs have a faster response because of its power electronic interface as compared to mechanically switched OLTC or capacitor banks.…”

Rebound behaviour of uncoordinated EMS and their impact minimisation

“…The conventional power system has undergone a substantial change in last decades which has led to a fundamental shift in the traditional generation and management of electrical energy [1][2][3]. In recent years, small-scale renewable energy generators supersede the bulky large-scale generators.…”

“…Various centralised and decentralised control approaches are used to manage these distributed and nondispatchable renewable generators. As renewable energy sources are intermittent, the uninterrupted power supply by regulating voltage and frequency remains a major challenge [1][2][3].…”

“…It stores excess energy from the renewables during off‐peak hours in the middle of a day, and discharges during peak hours or in the absence of renewable energy generation. Another form of battery storage is the electric vehicle (EV) that is becoming popular due to its bidirectional vehicle‐to‐grid (V2G) energy transfer mechanism [1, 2]. The charging–discharging mechanisms of the battery in an EV are similar to that of a stationary battery; however, the mobility makes these significantly complex.…”

Optimal planning in active distribution networks considering nonlinear loads using the MOPSO algorithm in the TOPSIS framework

“…Integer second‐order cone programming (ISOCP) model is proposed based on a distribution network forward backward–sweep power flow and constraint relaxation. In Ampofo et al, a comprehensive system optimization and transient analysis was performed to demonstrate the performance of the distribution network for enhancing the voltage profile, increasing the penetration level of renewable energy DG and inverter‐based DGs and improving the transient recovery in response to severe grid fault. In Kayalvizhi and Kumar, the DGs location and size and the power factor of diesel generator were optimized using the proposed algorithm.…”