Oil-Immersed Three-Phase Core Shunt Reactor

The oil-immersed three-phase core shunt reactor is a fixed-reactance device connected in parallel with high-voltage transmission systems. It is produced by Jiangshan Yulan Transformer Co., Ltd., a manufacturer of transformers and reactors since 1999. The reactor absorbs capacitive reactive power from long overhead lines and cable networks, limiting light-load overvoltage and supporting voltage stability.

Product Overview

This oil-immersed three-phase core shunt reactor uses a three-phase common core and transformer oil for insulation and cooling. It is a static reactive power absorption device. Unlike an MCR, its reactance and capacity are fixed at design. It is selected for a specific system condition and operates continuously without a regulating control loop.

Working Principle

Overhead lines and cables have phase-to-ground and phase-to-phase capacitance. Under light-load or no-load conditions, this capacitance produces capacitive reactive power and raises voltage. The shunt reactor windings are connected in parallel to the line or bus. The iron-core inductance draws inductive reactive power, which offsets the line capacitance effect and limits voltage rise at the receiving end.

Product Structure

Technical Specifications

Features

Three-phase common core; compact footprint compared with three separate single-phase units.

Oil insulation and cooling; suitable for high-voltage and large-capacity service.

Fixed reactance; continuous absorption of capacitive reactive power without switching.

Low loss, low vibration, low noise.

Gas relay, pressure relief, oil level, oil temperature, and overcurrent protection.

Established maintenance practice for oil-immersed equipment.

Limitations and Site Requirements

Reactance and capacity are fixed. Reactive power cannot be continuously adjusted.

Oil leakage risk requires an accident oil pit, fire protection, and oil containment.

Periodic oil tests are required, including dielectric strength, moisture, DGA, and acid value.

Site should avoid corrosive gas and conductive dust. Outdoor installation needs weather protection.

Typical Applications

Long-distance overhead transmission lines

220 kV and 500 kV hub substations

Cable-dense urban networks where charging current is high

Hydropower and thermal power outgoing lines

Light-load or no-load conditions where voltage rise must be limited

FAQ

Q: What is the difference between this reactor and an MCR?

A: This reactor has fixed reactance. An MCR adjusts reactive power continuously by DC excitation. This reactor is a static compensation device; an MCR is a dynamic compensation device.

Q: Can the reactor capacity be adjusted?

A: No. The reactance and reactive power are fixed at design. Selection is based on system voltage, line capacitance, and required compensation.

Q: Is it suitable for cable networks?

A: Yes. It is used to compensate capacitive charging current in cable-dense urban networks.

Q: What oil maintenance is required?

A: Regular tests for dielectric strength, moisture, dissolved gas analysis, and acid value. Oil level, oil temperature, and leakage should be checked during routine inspection.

Q: Is an accident oil pit required?

A: Yes. Oil-immersed three-phase core shunt reactors require an accident oil pit, fire protection, and oil containment according to local codes.

Q: What information is needed for a quotation?

A: System voltage, frequency, required reactive power, reactance rate, connection type, neutral grounding method, indoor or outdoor installation, altitude, pollution level, noise limit, protection requirements, and project schedule.

Q: Are 50 Hz and 60 Hz designs available?

A: Yes.

Q: What is the typical lead time?

A: Lead time depends on capacity, configuration, and project schedule. Please contact us with project details.

Manufacturing Evidence

Jiangshan Yulan Transformer Co., Ltd. has manufactured transformers and reactors since 1999. For oil-immersed reactors, the production process covers silicon steel cutting, core stacking, winding, vacuum drying, oil filling, and routine and type tests.

Certifications: ISO 9001:2015, ISO 14001:2015, ISO 45001:2018. Products are tested by the National Transformer Product Testing Center of China.

Relevant equipment includes 400kW kerosene vapor phase vacuum drying system, 1200kV impulse test equipment, 400kV partial discharge free power frequency withstand voltage test transformer, 300kV induction test generator set, 1200 core slitting line, 400 and 800 core cross-cutting lines, 1500-ton hydraulic press, and foil winding machine.

Certificate images: ISO 9001:2015, ISO 14001:2015, ISO 45001:2018.
Factory and test equipment photos are available in the product gallery.