US-12627148-B2 - Multi-level converter-type STATCOM system and operation method

US12627148B2US 12627148 B2US12627148 B2US 12627148B2US-12627148-B2

Abstract

A system including a multi-level converter including a plurality of valve sections including a plurality of sub modules, a plurality of VCU controllers connected to each of the plurality of valve sections, and an upper controller connected to the plurality of VCU controllers, wherein the VCU controller is configured to receive status information from each of the plurality of sub modules to transmit the state information to the upper controller, receive a specific sub module control command information from the upper controller, and transmit the control command information to a specific sub module among the plurality of sub modules.

Inventors

Jin Hee Lee

Assignees

LS ELECTRIC CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20220114
Priority Date: 20210127

Claims (8)

1 . A system including a multi-level converter including a plurality of valve sections including a plurality of sub modules, a plurality of Valve Connection Unit (VCU) controllers connected to each of the plurality of valve sections, and an upper controller connected to the plurality of VCU controllers, wherein each VCU controller of the plurality of VCU controllers is configured to: receive status information from each of the plurality of sub modules to transmit the status information to the upper controller, receive control command information for a specific sub module of the plurality of sub modules from the upper controller, transmit the control command information to the specific sub module among the plurality of sub modules, check whether a software upgrade is required for the plurality of sub modules included in a corresponding valve section, and transmit a program required for the software upgrade to each sub module in the corresponding valve section through a sub module controller disposed between the plurality of sub modules and the VCU controller.
2 . The system of claim 1 , wherein the plurality of valve sections including the plurality of sub modules performs power on/off operation of the specific sub module in response to the control command information when the control command information is received through the VCU controller.
3 . The system of claim 1 , wherein the upper controller receives the status information of each of the plurality of sub modules from the VCU controller and generates the control command information for the specific sub module to transmit the control command information to the VCU controller.
4 . The system of claim 1 , wherein a space is formed between each of the plurality of valve sections and a ground, wherein the VCU controller is disposed in the space.
5 . The system of claim 1 , wherein the VCU controller is disposed on one side of a valve section.
6 . A Valve Connection Unit (VCU) controller connected to a multi-level converter including a plurality of valve sections including a plurality of sub modules, and each of the plurality of valve sections, wherein the VCU controller is configured to: receive status information from each of the plurality of sub modules to transmit the status information to an upper controller, in communication with the VCU controller, receive control command information for a specific sub module of the plurality of sub modules from the upper controller, transmit the control command information to the specific sub module among the plurality of sub modules, check whether a software upgrade is required for the plurality of sub modules included in a corresponding valve section of the plurality of valve sections, and transmit a program required for the software upgrade to each of the sub modules through a sub module controller disposed between the plurality of sub modules and the VCU controller.
7 . The VCU controller of claim 6 , wherein a space is formed between each of the plurality of valve sections and a ground, wherein the VCU controller is disposed in the space.
8 . The VCU controller of claim 6 , wherein the VCU controller is disposed on one side of a valve section.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a National Stage of International Application No. PCT/KR2022/000728, filed on Jan. 14, 2022, which claims priority to and the benefit of Korean Patent Application No. 10-2021-0011703, filed on Jan. 27, 2021, the disclosure of which is incorporated herein by reference in its entirety. FIELD The present disclosure relates to an MMC-type STATCOM system and an operating method thereof. BACKGROUND A flexible power transmission system or new power transmission system (FACTS, Flexible AC Transmission System) is an operating technology that increases the flexibility of a power system by introducing a power electronic control technology to an AC power system. Specifically, the flexible power transmission system may control transmitted power using a power semiconductor switching device. Such a flexible power transmission system can maximize facility utilization of transmission lines, increase transmission capacity, and minimize voltage fluctuation. Among FACTS devices, STATCOM (Static Synchronous Compensator) is a facility that has the function of improving voltage stability and increasing power transmission capacity by compensating for reactive power connected in parallel to the line. Initially, STATCOM's converters were developed based on 2-level or 3-level converters, but had problems such as the limitation of large-capacity power transmission and high switching loss. Since then, the development of large-capacity IGBT device and the introduction of modular multi-level converters (MMCs) have made it possible to transmit large-capacity power. The MMC forms a step-shaped sinusoidal voltage by connecting modular half-bridge or full-bridge inverters in series. Accordingly, large-capacity power transmission is possible by adjusting the number of sub modules connected in series. Meanwhile, in the case of the MMC-STATCOM system, an optical cable must be connected from VBE (Valve Base Electronic) corresponding to the upper controller to a valve configured to N serially connected sub modules. In this case, if the number of optical cables increases and the distance from VBE increases, a product with high optic-power or a cable with low optical loss should be selected. Accordingly, there is a disadvantage in that cost and installation and manufacturing time are increased. In addition, when upgrading the software of each SMI (Sub module Interface) of the existing valve, there is an inconvenience in that each sub module must be downloaded. In this case, there is a problem that increases the physical time that occurs during software upgrade and greatly affects the safety of workers. SUMMARY The purpose of the present disclosure is to simplify the existing control system structure with an intermediate controller linked to the sub module controller (SMI) of the valve of the MMC-STATCOM system, and is to implement addition/enhance the functions of the converter power converter. According to an embodiment of the present disclosure, a system including a multi-level converter including a plurality of valve sections including a plurality of sub modules, a plurality of VCU controllers connected to each of the plurality of valve sections, and an upper controller connected to the plurality of VCU controllers, wherein the VCU controller is configured to receive status information from each of the plurality of sub modules to transmit the state information to the upper controller, receive a specific sub module control command information from the upper controller, and transmit the control command information to a specific sub module among the plurality of sub modules. Wherein the upper controller may receive state information of each of a plurality of sub modules from the VCU controller and generate specific sub module control command information to transmit the specific sub module control command information to the VCU controller. Wherein a space may be formed between each of the plurality of valve sections and a ground, the VCU controller may be disposed in the space. Wherein the VCU controller may be disposed on one side of a valve section. According to an embodiment of the present disclosure, a cable connection structure can be simplified by separately operating VCU controllers for each phase. According to an embodiment of the present disclosure, by separately operating a VCU controller for each phase, it is possible to reduce data processing load and perform protection function through quick response. According to an embodiment of the present disclosure, efficiency in inspection and maintenance can be improved by separately operating the VCU controller for each phase. According to the embodiment of the present disclosure, by separately operating the VCU controller for each phase, when an event occurs during MMC-STATCOM system operation, it is possible to analyze the cause of the event situation because the status/data/information before and after the accident can be stored in th