On capability of different FACTS devices to mitigate a range of power quality phenomena

Abstract

This paper investigates the impact of different FACTS devices on critical power quality (PQ) phenomena including voltage sags, harmonics and unbalance from the perspective of both mitigation effect and potential negative impact. The FACTS devices, including SVC, STATCOM and DVR, are modeled in commercially available software PowerFactory/DIgSILENT to study their impacts on the critical PQ phenomena. Two control strategies, voltage regulation and reactive power compensation, are considered for STATCOM. For DVR, a PI-controller is developed for the purpose of voltage sag mitigation. The merit of the proposed controller is presented by the dynamic response of during-fault voltage and the capability of post-fault voltage recovery. The study is carried out on a large-scale generic distribution network. The impact of various devices on PQ phenomena is assessed using appropriate evaluation methodologies, and the results obtained with and without mitigation are presented and compared using heatmaps.

Providing Fault Ride-Through Capability of Turbo-Expander in a Thermal Power Plant

“…As shown in Figure 9c-d, no voltage sag occurs at t = 0.5 in the load side voltage for both fault conditions (balanced and unbalanced), and in the scenarios (13)(14)(15)(16), voltage swell never occurs at the fault clearing moment (t = 1.5 s). All in all, the amplitudes and durations of voltage sag and swell are related to the fault voltage level, the type of the fault, and the location and type of the compensator.…”

“…Moreover, the output reactive power of STATCOM is more than SVC in voltage sag conditions [29]. Additionally, for compensation at this high-level voltage sag, post-fault voltage oscillations of SVC are greater than STATCOM [16]. The control system of STATCOM is the same as the one presented in the previous study [6].…”

“…Unlike other compensating devices, the existence of different compensation strategies and various topologies are among the other benefits of this compensator. Moreover, the application of DVR in the distribution network helps in achieving power factor (PF) correction, harmonic filtering, neutral current compensation, load balancing, enhancement of low voltage ride-through (LVRT) capability, and also compensation of voltage sag/swell/flicker [13][14][15][16].…”

“…In this section, all common types of DVR topologies, and the disadvantages and benefits of each of them are reviewed, and the proposed solutions for optimizing them will be presented. Based on [15][16][17][18][19], prevalent DVR topologies are divided into two categories: Energy-storage-based topologies and non-energy-storage-based topologies.…”

Effect of Distributed Wind Generation on the Voltage Sag of Distribution Networks

“…Among the devices used effectively for voltage sag mitigation is the dynamic voltage restorer (DVR). DVR is one of the Flexible AC Transmission Systems (FACTS) devices which is used to preserve sensitive loads from disturbances [10]. In essence, DVR is a power-electronic converter-based, custom power device that provides partial compensation during voltage sag to protect critical loads from supply-side voltage disturbances [11].…”