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Adding a damping unit to a shunt capacitor is an effective way to mitigate capacitor-caused resonance. However, damping units suffer from power loss issues. This shortcoming is amplified further in cases where resonance has a low possibility of occurring. In view of this, an adaptive damping method is proposed to improve the existing scheme. The damping unit is capable of mitigating resonance and eliminating the power loss under the non-resonance condition. The core idea of the proposed approach is to add a breaker so that the damping unit can be switched on or off depending on whether resonance occurs. The design of and control mechanism for the proposed switchable damping unit are presented. The performances of the new resonance mitigation scheme in terms of harmonic mitigation, loading, switching transient and cost are verified for an actual capacitor application case.

Configuring a shunt capacitor as a detuned C-type filter is an effective way to mitigate the capacitor caused harmonic resonance. A design method has been developed recently that can guarantee the damping performance of the filter even if the system impedance data is not available. This article further improves the design method by considering the case where the system impedance data is available. It also answers the question if cost can be reduced by utilizing known system impedance data. For this purpose, the cost and power loss characteristics of the filter are investigated and included in the design. The performance of various design methods is compared from the perspectives of resonance-mitigation, power loss, cost, and robustness. The results have shown that the system independent design leads to superior performance except for the power loss. A guide on how to design the detuned C-type filter is recommended.

In conventional HVDC systems where the harmonic filters and shunt capacitors are installed at the ac grid side, the converter transformers inevitably suffer the detrimental impacts caused by harmonic penetration. In this paper, combined with an inductive filtering method, a parallel delta-connected filtering-winding scheme for 12-pulse converter transformer units is proposed to reduce the harmonic currents flowing through the transformers and, thus, to attenuate the harmonic effects on them. This paper describes the presented transformer configuration in terms of the wiring scheme of the 12-pulse converter transformer unit and corresponding flowing paths of different harmonic currents with the orders of $3,6n\pm 1\left(\mathrm{n}=1,3,5,\ldots \right)$ , 11 and 13 in the filtering winding circuit. Then, the mechanism of the proposed scheme on harmonic suppression to the converter transformers is explained theoretically. In an attempt to validate the theoretical analysis, simulations based on PSCAD/EMTDC and experiments in a laboratory prototype system are performed to evaluate the harmonic eliminating performance of the proposed scheme.

The increase of harmonic current circulation in electric system affects the shunt capacitor banks protection arrangement, causing false alarms and trips and leading to a reduction of the relay sensitivity. This paper analyzes the behavior of the protection system on a reduced-scale model, which reproduces the main features of grounded wye shunt capacitor banks. In such experiments, high levels of current harmonic distortion, voltage unbalance, and bank inherent unbalance were considered. This paper brings experimental analyses for protection arrangements considering robustness and sensitivity.

Summary form only given, as follows. This paper highlights results of a design study to optimize CAPS (CAPacitor bank series group Shorting) as applied to EHV and HV shunt capacitor banks. The study concluded that CAPS can be built from standard, commercially available components, and can have economic advantage over conventional shunt capacitor banks in certain applications. While technically viable, the challenge is finding applications where the benefits are great enough to overcome the reluctance to try something new. Described are application considerations and possible applications evaluated at Bonneville Power Administration (USA).

The authors carried out shunt capacitor switching tests on 24 kV model vacuum interrupters with contact materials CuW and CuCr. The restriking probability of the contact material CuW is lower than that of CuCr. The contact material CuW is also an excellent candidate for shunt capacitor switching except for its high current interruption ability. The restriking probability of a 24 kV, 25 kA vacuum interrupter with contact material CuW is calculated as 10/sup -5/, which is practically zero. >

A substation capacitor bank incorporating a number of innovations was installed at the Poston Station (Columbus Southern Power Company) and commissioned July 1988. A description is given of the installation, including a discussion of the various innovations, comments on the operating experience through mid-January 1989, and observations from a staged fault test on November 10, 1988. >

J.H. Nelson comments on the paper by D.P. Brown et al. (see ibid., vol.16, no.1, p.24-32, 2001) and asks for clarification on some areas. The original authors reply to the comments.