Abstract: A grid interactive uninterruptible power supply (UPS) is provided. The grid interactive UPS includes a first path including a rectifier, an inverter coupled in series with the rectifier, and a battery coupled in parallel with the inverter. The grid interactive UPS further includes a second path in parallel with the first path, wherein the grid interactive UPS is operable to supply power from the battery to a grid coupled to an input of the grid interactive UPS.

Abstract: Systems and methods are provided for controlling an uninterruptible power supply (UPS) to transition between three- or higher-level operation and two-level operation in a neutral-point-clamped (NPC) inverter. In an example, a UPS system includes an NPC inverter and a controller. The NPC inverter may supply power to a load. The controller may control the inverter to operate in a three-level mode or higher when the load is substantially balanced and to operate in a two-level mode when the load is substantially unbalanced.

Abstract: A grid interactive uninterruptible power supply (UPS) is provided. The grid interactive UPS includes a first path including a rectifier, an inverter coupled in series with the rectifier, and a battery coupled in parallel with the inverter. The grid interactive UPS further includes a second path in parallel with the first path, wherein the grid interactive UPS is operable to supply power from the battery to a grid coupled to an input of the grid interactive UPS.

Abstract: Systems and methods are provided for controlling an uninterruptible power supply (UPS) to transition between three- or higher-level operation and two-level operation in a neutral-point-clamped (NPC) inverter. In an example, a UPS system includes an NPC inverter and a controller. The NPC inverter may supply power to a load. The controller may control the inverter to operate in a three-level mode or higher when the load is substantially balanced and to operate in a two-level mode when the load is substantially unbalanced.

Abstract: Systems and methods for balancing current from an AC source. The method includes determining a difference between a DC voltage output by a rectifier in an uninterruptible power supply (UPS) to a DC reference voltage. The method also includes determining an error between the DC voltage and the DC reference voltage based at least in part on the difference. After determining the error, the method includes filtering a second order harmonic from the error thereby generating a filtered error. The method may then include determining one or more switching signals for one or more switching components in the rectifier based at least in part on the filtered error and sending the switching signals to the rectifier.

Abstract: The electrical insulator has an insulator body 3 which is fitted between an electrical conductor 1 and a grounded holder 2. The surface of the insulator is at least partially formed by a protective body 6. The material of the protective body has a low dielectric constant in comparison to that of the material of the insulator body 3. The protective body 6 prevents an electrically conductive particle 12 from coming to rest directly on the surface of the insulator body 3, in particular in the region of the triple points T, or causing a considerable increase in the field due to immediate proximity to the insulator body 3. The breakdown voltage of a gas-insulated system which contains such insulators provided with a protective body is increased. Gas-insulated systems can thus be made more compactly and more cheaply, and their life can be extended.

Abstract: The invention relates to a post insulator (4) whose surface (41, 51) is geometrically configured, in at least one area (4a) between an inner conductor (2) and encapsulation (3) for a gas-insulated switchgear assembly (1) such that surface discharge paths (6b) are provided between the inner conductor (2) and the encapsulation (3) and have a subsection in the opposite direction to the bridging direction (7). In consequence, surface discharges (6a) can be diverted in the opposite direction to an original propagation direction (7), and come to rest by self-blocking. Exemplary embodiments relate to: an indentation (4b) which is concave and is open toward the inner conductor (2) and/or toward the encapsulation (3) and is formed between a cup shaped barrier (5) and the base body (40) of the post insulator (4); diversion of surface discharges (6a) through up to 180° for efficient self blocking; and adhesive bonding (45) of the barrier (5) on a conventional post insulator (4).

Abstract: The invention relates to a post insulator (4) whose surface (41, 51) is geometrically configured, in at least one area (4a) between an inner conductor (2) and encapsulation (3) for a gas-insulated switchgear assembly (1) such that surface discharge paths (6b) are provided between the inner conductor (2) and the encapsulation (3) and have a subsection in the opposite direction to the bridging direction (7). In consequence, surface discharges (6a) can be diverted in the opposite direction to an original propagation direction (7), and come to rest by self-blocking. Exemplary embodiments relate to: an indentation (4b) which is concave and is open toward the inner conductor (2) and/or toward the encapsulation (3) and is formed between a cup shaped barrier (5) and the base body (40) of the post insulator (4); diversion of surface discharges (6a) through up to 180° for efficient self blocking; and adhesive bonding (45) of the barrier (5) on a conventional post insulator (4).

Abstract: The disconnector essentially comprises two isolating contacts (2), which are arranged in electrically conductive encapsulation (1) filled with insulating gas, and an isolating contact finger (3) arranged such that it can be moved between them. An insulation coating (7) is applied to the inside of the encapsulation (1) and has projections (8) pointing inward. The insulation coating prevents a disconnector spark (5), whose production cannot be avoided when the disconnector is opened, from flashing over onto the encapsulation (1). Furthermore, additional projections (9) prevent the spark from propagating in the direction of the isolating contacts (2).

Abstract: The disconnector essentially comprises two isolating contacts (2), which are arranged in electrically conductive encapsulation (1) filled with insulating gas, and an isolating contact finger (3) arranged such that it can be moved between them. An insulation coating (7) is applied to the inside of the encapsulation (1) and has projections (8) pointing inward.