HVDC
(High Voltage Direct Current transmission)

Hyosung Heavy Industries was the first company in Korea to develop a HVDC system using Modular Multilevel Converter (MMC), the latest technology in voltage source converters. The performance and reliability of converter and control system constituting MMC HVDC system have been verified through 25MVA MMC type HVDC system installed in Jeju Island. Hyosung Heavy Industries is currently developing 200MW MMC type HVDC.

Features and Benefits

MMC(Modular Multilevel Converter): System capacity and voltage level can be expanded easily, enabling design that reflects various needs of customers.; The technical characteristics of the modular multilevel converters enable the use of industry standard components for high reliability and low maintenance costs.; Even if a certain number of sub-modules fail, it is possible to increase the availability by bypassing the failed sub-module.; It is possible to use standard AC transformer, which is advantageous for reliability and high efficiency operation.
VSC(Voltage Source Converter) HVDC: Multi-terminal DC grid configuration allows for the integration of multiple power systems.; Independent control of reactive power is possible, enabling stable connection of weak system (Weak AC grid).; High efficiency power transmission is possible with little loss.
Various Solutions: It is possible to install converters on a small area, and thus it is possible to connect the metropolitan area and offshore wind power system which require a lot of land.; The Black Start function e+G298nables blackout recovery.
Reference: We have a large number of domestic delivery results through the development of flexible transmission system with 3-level converter.
20 years of continuous product innovation: Hyosung Heavy Industries Co., Ltd. is constantly competing with global companies through the development of innovative products in the fields of heavy electric equipment (Flexible transmission system, High Voltage DC transmission).

Specifications

HVDC(High Voltage Direct Current transmission)
Contents		Level
Converter Station	Size	50m x 50m
Converter Station	Capacity, Voltage	20MW, ±12KV_DC
Converter Station		25MVA, 22.9kV
Sub-Module	DC Voltage	2.4KV_DC
	Topology	Half-Bridge
	Num./Arm	12(2 for Redundancy)

Applications

Grid Connection

BTB (Back to Back) Connects different power systems using high voltage DC transmission system.
PTP (Point to Point) Connects a system with a long distance using a high voltage DC transmission system.

Long-distance transmission(OHL)

Higher power transmission is possible by utilizing the pylon of the existing AC machining cable.

Long-distance transmission(Cable)

This can be an alternative to overcome the difficulties of constructing a new transmission line.
The generated power of the offshore wind farm can be transmitted onshore.
It can be economical in long distance transmission of about 80km for submarine cable and 120km for underground cable.

Multi-Terminal

Inter-country or inter-regional grid connections are possible.

Offshore Power System Grid Connectivity

We have achieved many domestic deployments through the development of a flexible 3-level converter-based transmission system.

Reference

Key Delivery Performance

Hyosung Heavy Industries develops a 25MVA HVDC system for Jeju Energy Corporation's Hangwon Wind Farm (2017)

HVDC (High Voltage Direct Current transmission)