SSR Damping in Fixed-Speed Wind Farms Using Series FACTS Controllers

Abstract

Sub-synchronous resonance (SSR) damping in fixedspeed wind turbine generator systems (FSWTGS) by using two series flexible AC transmission system (FACTS) devices, the thyristor-controlled series capacitor (TCSC) and gate-controlled series capacitor (GCSC), is studied in this paper. The former is a commercially available series FACTS device, and the latter is the second generation of series FACTS devices uses gate turn-off (GTO) or other gate commuted switches. The GCSC is characterized by a fixed-capacitor in parallel with a pair of anti-parallel gate-commuted switches enabling rapid control of series impedance of a transmission line. It is shown that the SSR damping with a GCSC is limited to changing the resonance frequency, in comparison with a fixed capacitor, which may not be adequate to damp out the SSR. Therefore, a supplementary SSR damping controller (SSRDC) is designed for the GCSC. Moreover, it is proven that the GCSC equipped with a welldesigned SSRDC can effectively damp the SSR in FSWTGS. In order to verify the effectiveness of the GCSC in SSR damping, its performance is compared with the TCSC, which is an existing series FACTS device. In addition, time-frequency analysis (TFA) is employed in order to evaluate and compare the SSR timevarying frequency characteristics of the GCSC and TCSC. The IEEE first benchmark model on SSR is adapted with an integrated FSWTGS to perform studies, and the extensive simulations are carried out using PSCAD/EMTDC to validate the result.

Mitigation of sub‐synchronous control interaction of a power system with DFIG‐based wind farm under multi‐operating points

“…PSS's gain is determined by PSI of residue index (RI) [23]. For the washout, T w is equivalent to 10 s so as to allow oscillatory signals in the input to pass through without changing [34]. The initial time settings are estimated by phase compensation principle [26].…”

A New Perspective of Wind Power Grid Codes Under Unbalanced and Distorted Grid Conditions

“…All WPPs must provide a real-time SCADA point that will communicate to ERCOT and provide number of wind turbine generators (WTGs) that are available for active and/or reactive power injection into the ERCOT transmission grid. Also, there must be two other real-time SCADA points to provide the number of WTGs that are not able to communicate and out of service [25]. 4.…”

“…In addition, ERCOT requires all WPPs shall be available to deliver reactive power at all MW output levels at or above 10% of their nameplate capacity. If MW output of a WPP is less than 10% of its nameplate capacity and it is unable to provide voltage support, ERCOT may require WPP to disconnect from the system to protect system reliability [25], [27].…”

“…10(c 3 ) and exceeds the required reactive power limit. Under this condition, ERCOT may require the WPP to disconnect from the grid [25]. Fig.…”

Sub‐synchronous interactions in power systems with wind turbines: a review

“…The ability of GCSC for damping SSR has been verified in [116]. Meanwhile, with a well-designed SSR damping controller, GCSC can suppress SSI in wind farms [27,101,102]. 4.…”