STATCOM arrangement without phase reactors

A phase electricity and reactance technology, applied in circuit devices, output power conversion devices, electrical components, etc., can solve the problem of phase reactor maintenance gap occupying additional space, etc., to reduce complexity, reduce construction and maintenance costs, design small effect

CN113056854AActive Publication Date: 2021-06-29HITACHI ENERGY SWITZERLAND AG
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2021-06-29

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Abstract

The present disclosure relates to a STATCOM arrangement (1) comprising an MMC (2) and a transformer arrangement (3) arranged to be an interface between the MMC (2) and an AC grid. The MMC (2) is connected in a Y topology with a plurality of converter arms (5), one for each phase of the AC grid, each arm comprising a plurality of chain-linked converter cells. The transformer arrangement (3) is arranged to interface each of the arms of the MMC (2) with a respective phase of the grid, and arranged to for each of the converter arms produce leakage reactance resulting in reactance in series with the arm which obviates the need for a phase reactor connected in series with the arm.
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Description

technical field

[0001] The present disclosure relates to a static synchronous compensator (STATCOM) comprising a modular multilevel chain-link converter (MMC) connected to an alternating current (AC) grid via a transformer. Background technique

[0002] MMC STATCOMs now typically have a delta (Δ) topology, where each leg (also sometimes called a leg or branch) comprises a number of series-connected (also called chain-linked or cascaded) converter cells. Each unit typically has a full bridge (FB), also known as a bipolar or bidirectional topology. For each of the arms, a phase reactor (sometimes called a converter reactor) is connected in series with the unit to provide the required impedance. Charging circuits including resistors and disconnect switches are also commonly used.

[0003] For STATCOM to operate, phase reactors are required to create a voltage difference between the chain-link converter and the grid. The generation of reactive power is governed by the followi...

Examples

Embodiment Construction

[0020] Embodiments will now be described more fully with reference to the accompanying drawings in which certain embodiments are shown. However, other embodiments in many different forms are possible within the scope of this disclosure. Rather, the following embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Throughout the specification, like reference numerals indicate like elements.

[0021] According to the invention, a Y-connection topology device STATCOM is used. Instead of using phase reactors to provide impedance to the necessary voltage difference between the grid and the MMC, transformer leakage reactance is used. Overall, this reduces component count and footprint while simplifying the overall circuit. This does not exclude the use of (smaller) filter reactors in series with any of the converter arms. A filter reactor is a reactor whose purpose ...