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As global leader of transmission and distribution equipment, we realize reliable and resilient power grids around the world.

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Power Systems Maintenance

We offer comprehensive engineering and service solutions based on our extensive knowledge of power infrastructure.

In addition to engineering, construction, and supervision of power equipment, we also offer maintenance, condition monitoring, failure recovery, and on-site renovation.


Learn about the comprehensive solutions provided by power equipment experts.

Maintenance and diagnosis solutions for power equipment

When power equipment is operated for an extended period of time after installation or thorough inspection, moving and consumable parts degrade and become stuck. As a result, periodic inspections are necessary to ensure operational reliability and blackout prevention. Hyosung Heavy Industries prevents accidents by offering maintenance and diagnosis solutions for power equipment, based on vast data and extensive experience with existing power equipment.

Features and Anticipated Effects

Lowered Risk of Accidents (Ensuring quality due to new replacement)

  • Utilizing a special dust-proof room to maintain the cleanliness of the workplace.
  • Replacement of all device-degrading components (e.g. spacers, solenoid valves) with new ones.

Lifespan Management and Diagnosis

  • Assuring operational dependability and extending lifespan by inspecting and replacing components during scheduled blackouts.
  • Precise lifespan diagnosis provided based on expertise unique to power equipment manufacturers.
  • Identification of internal abnormalities using cutting-edge equipment such as X-ray diagnosis and UHF PD diagnosis.

Uninterrupted Preventive Diagnosis

  • Predictive maintenance and stable power operation are made possible by uninterrupted preventive diagnosis, and equipment deterioration is avoided by performing repairs and part replacements as needed.

Live Wire Diagnosis

  • Removal of abnormal gases and moisture from transformer oil via filtration during operation.
  • Maintenance of production load continuity and extension of the lifespan of transformers.
  • Hyosung Heavy Industries offers live wire filtration equipment (HS-100) developed in-house.
Construction-capable Types
Circuit Breakers
(800kV, 362kV, 170kV)
  • Circuit breaker capacity expansion work
  • Circuit breaker structure improvement work
  • Circuit breaker solid insulation replacement work
(765kV, 345kV, 154kV, 22.9kV, 6.6kV)
  • Transformer capacity expansion work
  • Transformer structure improvement work
  • Transformer performance improvement work (lifespan extension)
CGIS, Electric Field, and Panels
  • Opening improvement work
  • PMA eco-friendly CGIS replacement work
  • Protective relay replacement work

Remodeling Solution

To prepare for potential accidents, expansions, and alterations in customer load, power equipment remodeling is necessary. Hyosung Heavy Industries offers solutions for extending the lifespan of power equipment via its structure, extensive interior design experience, skilled supervisors, and commitment to quality.

Features and Anticipated Effects

Site Remodeling

  • Elimination of failure factors by enhancing the appearance, operation, and functionality of long-term power equipment through the application of lifespan extension techniques.
  • Replacement of aging consumables such as external parts, relays, OLTC drive boxes, and LCP with structural enhancements to achieve the same service life as new products.

Quality Guarantee

  • Applied with the same warranty period of three years and six months as that of factory remodeling.
  • Quality assurance through the optimization of testing and remodeling procedures for the site remodeling process.

Simplified Work Procedures

  • Reduced work time by ensuring the most efficient renovation procedure (within 15 days for GIS 2CCT, 5 days for GCB 1CCT).

Possible to operate a diverse portfolio of the entire power equipment.

  • Minimized risk of accidents through the application of various solutions (e.g. new replacement, factory warehousing, site renovation) by introducing on-site renovation.

No compatibility issues with the substation's existing facilities.

  • Conducting quality assurance through electrical/structural compatibility review and testing via a process change note (PCN) for each major discontinued part applicable to all products delivered by Hyosung Heavy Industries.

Parts Management

In the case of power equipment, a specific replacement period is established due to the deterioration of each component; consequently, periodic replacement is necessary to enhance product quality and ensure performance reliability. Hyosung Heavy Industries provides materials such as bushings, gaskets, spacer insulators, and instruments that meet the requested specifications based on our manufacturing expertise and track record of timely delivery. Our products can be used with confidence as we offer delivery and after-sales service guarantees.

Types and Characteristics of Parts


We manufacture and sell the following bushings as devices that connect and insulate the inner conductors (windings) of transformers and circuit breakers through enclosures or supports (structures):

By shed material

  • Composite Type
  • Porcelain Type

By condenser manufacturing method

  • RIP(Resin-Impregnated Paper) Type
  • OIP(Oil-Impregnated Paper) Type

We manufacture in-house and sell composite type

EPOXY Insulators

As devices that support the conductor within the circuit breaker and establish the separation of the insulation gas (SF6), we manufacture in-house and sell the following products:

  • Spacer
  • Post
  • Support Insulator
  • Bushing-type insulator for ES
  • Insulation shaft and plate
  • Insulation rod
  • Other


We provide the following components that monitor the normal operation of transformers and circuit breakers and report their status:

  • Oil thermometer
  • Winding thermometer
  • Oil gauge
  • Protective relay
  • Pressure relief device (PRD)
  • Shock pressure relay
  • Gas detection relay
  • Buchholz relay
  • Gas pressure gauge
  • UHF sensor
  • Other

Other parts

We provide the following components that monitor the normal operation of transformers and circuit breakers and report their status:

  • O-Ring
  • Packing
  • Solenoid valve
  • Gasket
  • Valves
  • Coil
  • Contact
  • Mechanism kit
  • Washer
  • Springs

Operator Training and Support for Supervisors

Based on our manufacturing knowledge and data, Hyosung Heavy Industries provides professional training for an accurate understanding of power equipment. Based on this, customers will be able to utilize and manage their facilities more efficiently. In addition, customers can receive stable technical support as we support supervisors through our certification process.

Details of Support

Roadshow for Civilian Customers

  • We invite customers to present business and technological trends for new products and services by region, and we promptly share and communicate regarding matters related to the operation of customer power equipment.

Korea Electric Power Corporation (KEPCO) and Power Generation Operator Consignment Training

  • KEPCO operators receive annual operator training about stable facility operation at the Changwon Plant by exchanging information on the manufacturer's newest products and technologies.

Support for Supervisors

  • It is possible to identify and diagnose the exact cause of symptoms based on data accumulated as a developer.
  • We provide tour programs for the manufacturing and assembly processes, and over 50 supervisors and 20 field managers offer precise solutions.
  • Customers can enhance their capabilities in operation/maintenance and construction/management.


Our track records speak for ourselves.

  • Republic of Korea

    Standard 154kV M.Tr 1st Side OIP -> RIP Bushing Remodeling Project

    • Korea Electric Power Corporation
  • Republic of Korea

    362kV GIS 40/50 kA -> 63 kA Capacity Expansion Project of Korea Electric Power Corporation

    • Korea Electric Power Corporation
  • Republic of Korea

    800/362kV GIB Section Radiation and PD Diagnosis Project

    • Korea Hydro & Nuclear Power
  • Republic of Korea

    Replacement of electric power equipment components and precision inspection for steel companies

    • POSCO, Hyundai Steel, etc.
  • Republic of Korea

    Replacement of electric power equipment components and precision inspection for private companies

    • Major subsidiaries of such companies as SK and LG
  • Republic of Korea

    Uninterrupted maintenance of facilities (transformer live wire filtration project)


We adhere to global standards and maintain an environment of the highest quality.

View all certifications
  • ISO9001


  • ISO14001


  • ISO45001