No abstract

The frequency stability of the power system is challenged by the high penetration of power electronic interfaced renewable energy sources (RES). Energy storage systems (ESS) are used to supply extra power injection to enhance the frequency stability during a disturbance. This paper presents a novel approach for improving the frequency dynamics by incorporating a designed ultracapacitor (UC) with a fully decoupled wind power generation (FDWG) unit. To this aim, a suitable model implementation of UC for real-time simulations is presented. The model constitutes a parallel RC branch, which is appropriate for illustrating the relevant fast UC dynamics that occur within the first milliseconds of the time period of action for fast active-power frequency control services. The frequency performance achieved by the support of the FDWG equipped with UC is compared against the performance achieved by using electrical batteries. The comparison includes the application of droop-derivative frequency control.

Fault currents may result in cascading failures and even system collapse if not detected and cleared on time. To account for the possibility of failure of primary protection under stressed system conditions, an extra layer of protection is commonly employed, referred to as backup protection. This paper introduces an effective formulation for realizing remote backup protection using available data from PMUs and Intelligent Electronic Devices (IEDs). The proposed method is split into three main stages. The first stage deals with the zoning detection of the fault. The second stage is aimed at faulted line detection, and finally, the third stage determines the fault distance on the faulted line. The method is designed to take full advantage of measurements provided by PMUs and IEDs. The challenges associated with different reporting rates are resolved thanks to the dynamic decimator employed to this end. The proposed method has been implemented in real-time by applying co-simulation with MATLAB and validated using the New England IEEE 39 bus system with several fault events.

This paper concerns the feasibility of Fast Active Power Regulation (FAPR) in renewable energy hubs. Selected state-of-the-art FAPR strategies are applied to various controllable devices within a hub, such as a solar photovoltaic (PV) farm and an electrolyzer acting as a responsive load. Among the selected strategies are droop-based FAPR, droop derivative-based FAPR, and virtual synchronous power (VSP)-based FAPR. The FAPR-supported hub is interconnected with a test transmission network, modeled and simulated in a real-time simulation electromagnetic transient (EMT) environment to study a futuristic operating condition of the high-voltage infrastructure covering the north of the Netherlands. The real-time EMT simulations show that the FAPR strategies (especially the VSP-based FAPR) can successfully help to significantly and promptly limit undesirable large instantaneous frequency deviations.