WST linear type De-Energized Tap Changer (OCTC)

The immersed off-load tap changer is a core voltage regulation device specifically engineered for oil-immersed power transformers. It must be operated exclusively under conditions where the transformer is fully de-energized and completely disconnected from the electrical load. The entire assembly is hermetically submerged in the transformer’s insulating oil, utilizing a precision mechanical transmission mechanism to actuate the internal contact assembly and shift between tap positions. This operation alters the effective number of turns of the transformer’s high-voltage winding, thereby enabling accurate adjustment of the transformer’s transformation ratio.

Its primary purpose is to compensate for seasonal and load-induced fluctuations in the grid input voltage. By switching between pre-calibrated tap positions, it maintains the transformer’s output voltage within the standard permissible range, ensuring stable and reliable operation of downstream electrical equipment. Renowned for its compact design, robust performance, and minimal maintenance requirements, this device is universally deployed in medium and low voltage oil-immersed power transformers worldwide.

Product Detail

1. Company introduction

Founded in 2001 with a registered capital of RMB 5 million, Liaoning Jinli Electric Power Electrical Appliance Co., Ltd. is a prominent national high-tech enterprise in China exclusively focused on the research, development, manufacturing and sales of transformer tap changers. The company holds the prestigious title of National Intellectual Property Advantage Enterprise and operates a provincial-level enterprise technology center, demonstrating its robust independent innovation capabilities and solid technical foundation.

Boasting a far-reaching global footprint, its high-quality products have been successfully marketed to over 20 countries and regions across Asia, Europe, Oceania and the Americas, including South Korea, Russia, Switzerland, Australia, Thailand, India and Peru. Its primary export offerings include no-excitation linear tap changers, disc-type tap changers and plate-type tap changers, as well as 10~35kV on-load tap changers, delivering reliable voltage regulation solutions for power systems worldwide.

2. Product parameters

3. Product feature and application

Tap changers are core components for voltage regulation of oil-immersed transformers with a voltage class below 35kV, widely used in medium and low voltage power distribution systems.

Structurally, this type of tap changer features a compact design, simple mechanism and reliable performance. It is mostly designed for off-circuit tap changing, requiring the transformer to be fully powered off before gear adjustment. Made of high-strength insulating materials and wear-resistant conductive parts, it adapts well to the oil-immersed operating environment, with strong resistance to aging, vibration and temperature changes. Its operation is easy, needing only manual rotation to switch taps, and the maintenance workload is low during long-term operation.

In terms of application scenarios, it is mainly deployed in urban and rural distribution networks, industrial parks, residential communities and small power stations. It stabilizes output voltage by adjusting transformation ratio, effectively solving voltage deviation caused by load changes and line loss.

Due to low manufacturing cost, convenient installation and stable operation, these tap changers perfectly match the operational demands of 35kV and below distribution transformers. They have become the mainstream choice for voltage regulation in medium and low voltage power systems, guaranteeing safe and stable power supply for daily production and living.

4. Production details

Our company is a specialized manufacturer of general-purpose transformer tap changers, with a strong focus on precision production, rigorous processing, and comprehensive quality control. We implement standardized, traceable workflows across every stage—from raw material incoming inspection, CNC machining, and assembly to final performance testing.

Our dedicated production team follows strict operational protocols to ensure each component meets dimensional accuracy and material stability requirements. Key processes include automated assembly lines, precision welding, and tap changer voltage withstand testing, all verified by our in-house laboratory. Every finished product undergoes full functional testing, including product appearance, contact pressure, contact resistance and mechanical endurance checks, before leaving the factory.