Conference Agenda

This paper proposes a new resonance-type FCL, which is designed specifically for DFIG-based wind turbines. The proposed topology overcomes the well-documented drawbacks associated with conventional resonance-based FCLs while preserving the advantages of this topology. The proposed circuit limits the fault current for the entire fault period independently of the reactor’s charging state and significantly reduces the wind turbine’s torque oscillations during a fault. The proposed FCL is simulated as part of a power system that includes a wind turbine, synchronous generator, and two step-up transformers. The results show that during a three-phase to-ground fault, the proposed FCL significantly improves the system’s stability, and leads to improved fault current, voltage, active power, reactive power, and torque transients.

The rapid proliferation of wind power plants has generated an increasing demand to modify the series-compensated network sections in Sweden. Moreover, the network planning must consider factors such as the expected load increase and series-capacitor refurbishments or renewal. This work discusses the Swedish transmission system operator’s perspective on planning series-compensated network sections containing wind power plants, providing in-depth summaries of essential studies conducted using frequency domain- and electromagnetic transient tools. Such studies include transient overvoltages, temporary overvoltages, and subsynchronous oscillation studies. However, the initial planning that determines the series capacitor’s design parameters is also covered to capture the entire system design chain. The initial planning consists of steady-state calculations, phasor-based transient simulations, and relay protection considerations, such as current inversion. Finally, this work thoroughly discusses how the study results are incorporated into the series capacitor design specification to achieve the best possible system solution.

This paper presents a model for photovoltaic (PV) distributed generators that operates in abnormal electrical voltage scenarios - Voltage Ride Through (VRT), following the Brazilian standard NBR 16149 of 2013. The model includes various modes of operation, such as interruption of energy supply, disconnection, and reconnection of the PV system to the grid. Two types of simulations were performed to test the model’s performance: the first involved using a ramp function to test
the activation of different operating modes, while the second connected the PV model to a distribution feeder and tested its response to a short circuit. The results showed that the model met
the requirements established by the standard and was efficient in representing the behavior of the PV system in real-world scenarios.

Fault signatures of doubly fed induction generator (DFIG) based wind turbine generators (WTGs) are different and more complex than that of synchronous generators (SGs). This paper proposes a new approach to elaborate the formation of the fault signatures of DFIG-based WTGs under asymmetrical faults and various fault ride through control. The proposed internal voltage vectors and equivalent circuit enable reorganizing the control schemes, electric and magnetic circuits of DFIG in terms of transient, positive- and negative-sequence components. This way, the characteristics of DFIG-based WTGs and SGs can be compared in a similar frame through their internal voltage
vectors. The differences and similarities are summarized in support of protection and control designs.