Reduced Harmonics Generated and Reactive Volt-Ampere absorption of HVDC Converter Using By-Pass Switch

Abstract

Control of a conventional converter station which uses a three-phase controlled bridge for converting AC to DC and vice-versa is achieved by fast-acting control of the valve firing angles. Tap-changers which are fitted on the converter transformer provide a near constant AC voltage input to the bridge to correct relatively slow changes of AC voltage. This paper describe a modification of the conventional bridge circuit, using by-pass valves connected to tapping points on the secondary winding of the transformer. This scheme permits a wide range of voltage control with a reduction in both the harmonic generation and the reactive voltampere absorption, and possibly eliminates the need for an on-load tap-changer on the converter transformer. Experimental results on a laboratory model compare well with the predicted values.

Performance analysis of multi-level high voltage direct current converter

“…In practical systems perfect conditions for analysis of characteristic harmonics of a converter are never met, and as a result, harmonics of uncharacteristic orders are produced. Unbalanced operation is studied in [33]- [35]. The transient state is studied in [36], fast and continuous control of a modified HVDC converter [37].…”

Issues and Challenges for HVDC Extruded Cable Systems

“…In more recent times, as VSC HVDC cable systems came, many simulations were done to calculate the overvoltagesespecially long Temporary Overvoltages (TOVs)-superimposed onto DC voltage in such systems. A lot of computational efforts were devoted to converters [116,117], especially in the presence of anomalous or faulty events-contingencies-either in the HVDC cable line, or in the converter itself, or even in the AC grid (see e.g., [118,119]); these simulations were particularly focused on transient voltages superimposed onto the DC voltage (Section 12) [96,[120][121][122][123][124]. Many other simulations were devoted to the issues of HVDC cable systems connecting non-programmable RES to the grid (see e.g., [125,126]).…”