Reactive power compensation installation in Korea covers installing voltage-control equipment — reactors, power capacitors and static var compensators (SVC) — to improve transient stability and damp power swings and low-frequency oscillation. As load size and character change, power factor shifts and receiving-end voltage moves with it; the farther from generation, the more reactive power has to be compensated locally. This guide covers three stages: reactors, power capacitors and SVCs.
Contents
- Common Pre-Work Review
- 1. Reactor Installation
- 2. Power Capacitor Installation
- 3. SVC Installation
- Types of Compensation and Installation Points
- FAQ
- Reference Standards
- Summary
Common Pre-Work Review
Review the regulations, manufacturer installation drawings, design and specifications, and the safety and quality plans. Static compensation usually runs: foundation check → steel and equipment stands → cable trays → panels and equipment → power cables → earthing → control cables → terminations → tests and cleanup → energization. Prepare a capacitance meter, multimeter and insulation tester, and hire a mobile crane. Workers wear insulating gloves, hard hats, vests, safety glasses and dust masks.
1. Reactor Installation
- Insulate joints between foundation rebars to prevent overheating from stray load losses.
- Inspect the tank and fittings for damage, and check gas pressure gauges and the impact recorder for transit problems.
- For oil-filled reactors, connect filtration hoses and run a crackle test for moisture before filling.
- Connect the gas-oil sealed tank (GOST) to the top flange and fit the breather after oil filling.
- Wire bushing CTs, dial thermometer, oil level gauge, Buchholz relay and pressure relief device leads to the marshalling box for alarm and control circuits.
Before opening the tank, release internal pressure slowly through a valve until it reaches zero. Prepare carefully for vacuum work and monitor it with a vacuum gauge.
2. Power Capacitor Installation
- Check foundations, stands and earth leads against the drawings, and prepare materials, tools and test equipment.
- Install steel stands level to suit indoor or outdoor conditions.
- Bond the stand earth and capacitor enclosures together.
- Study the cable list, then connect capacitors, series reactors and discharge coils, terminate and seal against fire and moisture.
- Wire protective relays using the capacitors and discharge coils.
A power capacitor (static condenser) is a sealed, oil-filled tank of aluminum foil and paper elements, built up from series reactors and discharge coils. It switches in steps rather than continuously, but it is easy to run, easy to maintain and cheap, which is why it is widely used.
3. SVC Installation
- Check foundations, stands and earth leads against the drawings, and prepare materials, tools and test equipment.
- Level foundations and steel stands to suit indoor or outdoor conditions.
- Install control panels and switches for cooling and ventilation as designed.
- Configure thyristor-controlled reactors (TCR) and thyristor-switched capacitors (TSC) in series and parallel, and connect gate conductors to the transmission control unit (TCU) without reversing polarity.
- Confirm forward and reverse voltages and leakage current are normal.
- Connect thyristor valves, with their protection, to control cables.
- Terminate control and power cables at the master control panel (MCP) and HMI.
Before energizing, clean off contamination with suitable chemicals or water at the right pressure and let everything dry thoroughly.
Types of Compensation and Installation Points
| Type | Characteristic | Installation point |
|---|---|---|
| Shunt reactor | Absorbs reactive power, switched in steps | No closed rebar loops; impact recorder and crackle test |
| Power capacitor | Supplies reactive power, static | Wire capacitors, series reactors and discharge coils; bond enclosures |
| SVC | Continuous thyristor control, fast response | TCR/TSC configuration, gate polarity, leakage current |
| TCR | Reactor with continuous firing-angle control | Check thyristor valve protection |
| TSC | Capacitor bank on/off control only (no harmonics) | Allow for switching surges |
To prevent cracking from circulating currents, the NCS says reactor foundation rebar must not form a closed electrical loop in any direction, using insulating material and tubes so that voltage between bars stays at 5 V or less.
FAQ
Why insulate reactor foundation rebar?
A reactor’s magnetic field can drive circulating currents in rebar, causing stray-loss heating and foundation cracks. Insulating the bars stops them forming closed loops.
How does a power capacitor differ from an SVC?
Capacitors switch in steps and cannot adjust continuously; an SVC controls continuously with thyristors and reduces voltage swings faster.
What is a crackle test?
A quick check for moisture in insulating oil, done before filling an oil-filled reactor.
Reference Standards
- Electricity Business Act (전기사업법) — law.go.kr
- Electrical Safety Management Act (전기안전관리법) — law.go.kr
- Electric Technology Management Act (전력기술관리법) — law.go.kr
- Electrical Construction Business Act (전기공사업법) — law.go.kr
- Occupational Safety and Health Act (산업안전보건법) — law.go.kr
- Korea Electro-technical Code (KEC, 한국전기설비규정) — law.go.kr
- Technical Standards for Electrical Equipment (전기설비기술기준) — law.go.kr
- KEPCO design standards and substation construction practice; Korean Industrial Standards (KS)
- NCS competency unit Reactive Power Compensation Equipment Installation (무효전력 보상장치 설치공사, 1901070312_22v2; NCS is Korea’s National Competency Standards) — ncs.go.kr
Summary
The most common mistakes are tying reactor foundation rebar like an ordinary foundation so it forms closed loops, and reversing SVC gate conductor polarity. Reactors depend on rebar insulation and transit checks; capacitors on bonding and discharge coil wiring; and SVCs on TCR/TSC configuration, polarity and leakage current. Related guides: Substation Structure Installation, Substation Cable Installation, HVDC Converter Station Construction. A Korean version of this guide is available here.
This article restructures the Korean NCS competency unit ‘Reactive Power Compensation Equipment Installation’ (무효전력 보상장치 설치공사, code 1901070312_22v2) as a practical reference. Actual work must follow applicable standards and the judgment of qualified professionals; always confirm specific values, deadlines and criteria against the latest regulations and client standards.
Written/reviewed by VOLT · Last updated 2026-10-26