Stand-alone power system

About: Stand-alone power system is a research topic. Over the lifetime, 8650 publications have been published within this topic receiving 192397 citations. The topic is also known as: Stand-alone photovoltaic power system.

Optimal Sizing and Control of Energy Storage in Wind Power-Rich Distribution Networks

Abstract: This paper presents a planning framework to find the minimum storage sizes (power and energy) at multiple locations in distribution networks to reduce curtailment from renewable distributed generation (DG), specifically wind farms, while managing congestion and voltages. A two-stage iterative process is adopted in this framework. The first stage uses a multi-period AC optimal power flow (OPF) across the studied horizon to obtain initial storage sizes considering hourly wind and load profiles. The second stage adopts a high granularity minute-by-minute control driven by a mono-period bi-level AC OPF to tune the first-stage storage sizes according to the actual curtailment. Congestion and voltages are managed through the optimal control of storage (active and reactive power), on-load tap changers (OLTCs), DG power factor, and DG curtailment as last resort. The proposed storage planning framework is applied to a real 33-kV network from the North West of England over one week. The results highlight that by embedding high granularity control aspects into planning, it is possible to more accurately size storage facilities. Moreover, intelligent management of further flexibility (i.e., OLTCs, storage, and DG power factor control) can lead to much smaller storage capacities. This, however, depends on the required level of curtailment.

Inverter-Less Hybrid Voltage/Var Control for Distribution Circuits With Photovoltaic Generators

Abstract: This paper proposes a hybrid voltage/var control (VVC) architecture for distribution systems with a high PV penetration. The architecture consists of two control loops: coordinated normal control loop and uncoordinated transient cloud movement control loop. In the first loop, hourly dispatches are scheduled for on-load tap changer (OLTC), capacitor banks (CBs), and static var compensators (SVCs) based on forecasted load and PV power output so as to minimize power losses and voltage deviations. The second loop is triggered when large variations of PV power output caused by rapid cloud movement happen. All SVCs and CBs become self-controlled based on local voltage measurements with the single control objective to minimize voltage deviations. SVCs will operate firstly to flatten the voltage profile. If SVCs fail, CBs will switch to provide reactive power support. A time-adaptive delay is applied to each CB to avoid overcompensation. Case studies show the proposed method can optimize the system operation and is effective in voltage regulation with PV generators.

Development of vanadium redox flow battery for electricity storage

Abstract: There is serious demand today for superior technology for load levelling placed on power generation and transmission facilities. The vanadium battery, developed by Kashima-Kita, uses vanadium compounds as an electrolyte, recovered from boiler soot in Orimulsion-fired power stations to provide a solution to this problem. This battery is eminently suitable for load levelling, being operable at room temperature and normal pressure, easily convertible to a large scale and is environmentally friendly. In September 1997, Kashima-Kita built a 200 kW/spl times/4 hour-rate battery after having built both 2 kW and 10 kW prototype units. The battery is interconnected to the company's power plant grid system and has to date achieved 650 cycle continuous operation at the rated efficiency. This success has proved that a high-efficiency heat power station system equipped with such an electricity storage battery reusing byproducts of the power plant can be commercially viable.