Patent ID: 9093921
Filing Date: 2015-07-28
Classification: H02M

Abstract:
1. A substation of a power transmission system having a converter for conversion between AC and DC, said converter comprising: a first set of series connected converter valve elements provided together in a phase leg between a first and a second potential, where the absolute value of the second potential is higher than the absolute value of the first potential, and a second set of converter valve elements provided in the same phase leg between the second and a third potential, where the absolute value of the third potential is higher than the absolute value of the second potential, said second set comprising at least one converter valve element, wherein the converter valve elements of the first set of converter valve elements are placed in a common enclosure in the form of a valve hall provided at the first potential, converter valve elements of the first set are connected to the converter valve elements of the second set via a bushing designed for withstanding voltages having potentials at the second potential, all converter valve elements of the second set are provided inside one or more casings placed on elongated post-like insulation, where the potential of the end of the post-like insulation on which said casings are placed is in a range between the second potential and the third potential, while the other end of said post-like insulation has ground potential, and the casing of at least one converter valve element in the second set is connected to the second potential.