Introduction
In the power transmission and distribution system, the stability of voltage directly affects the normal operation of electrical equipment. As a key component of power transformers, the tap changer is responsible for adjusting the output voltage. Among them, the on-load tap changer (OLTC) stands out for its ability to adjust voltage without interrupting the load, which is widely used in 35kv distribution transformer and regulation transformer. JINSHANMEN TECHNOLOGY CO., LTD, as a professional manufacturer of power transmission and distribution equipment, integrates this core component into its high-quality transformers to ensure stable and reliable power supply for various industries.
1. Classification of Transformer Tap Changers
Transformer tap changers are mainly divided into two types: off-load tap changers and on-load tap changers. The off-load tap changer requires power interruption before adjusting the tap position, which is only suitable for scenarios with low voltage stability requirements. In contrast, the on-load tap changer can adjust the tap position while the transformer is in normal operation with load, making it an indispensable part of 35kv distribution transformer that requires continuous and stable power supply. For regulation transformer, the on-load tap changer further optimizes the voltage regulation precision, ensuring that the output voltage meets the strict requirements of high-end electrical equipment.
2. Composition and Functions of On-Load Tap Changers
A standard on-load tap changer consists of five core components, each playing an irreplaceable role in voltage regulation:
Selector Switch: Responsible for selecting the target tap position in the absence of load current, providing a stable foundation for subsequent switching. It is composed of gear mechanisms and contact systems, ensuring accurate positioning.
Transfer Switch: Completes the load current switching under the condition of continuous power supply. Equipped with main contacts, transition contacts and transition resistors, it prevents short circuits and arc generation during switching.
Transition Resistor: Connected in series between adjacent taps to limit circulating current, avoiding arc pollution and short-circuit faults. Its resistance value is designed according to the parameters of 35kv distribution transformer and regulation transformer.
Operating Mechanism: Provides power for the switch, including motors, gear transmission systems and safety interlocks, ensuring safe and precise operation.
Insulating Oil System: Achieves insulation, arc extinction, cooling and lubrication. Regular maintenance of insulating oil is crucial to the service life of the switch.
3. Working Principle of On-Load Tap Changers
The core principle of the on-load tap changer lies in the "make-before-break" switching logic and the application of transition circuits. Multiple taps are drawn from the transformer winding. When voltage adjustment is needed, the selector switch first pre-selects the target tap without load. Then the transfer switch connects the transition circuit (with transition resistor limiting the current between two taps) before disconnecting the original tap, ensuring continuous load current. After the main contact is completely switched to the new tap, the transition circuit is disconnected, and the voltage regulation is completed. This process takes only tens of milliseconds, which effectively ensures the stable operation of 35kv distribution transformer and regulation transformer without power interruption.
4. Basic Requirements and Switching Sequence
4.1 Basic Requirements
Ensure continuous current during the switching process to avoid power interruption;
Prevent short circuits between taps during switching to protect the transformer and electrical equipment.
4.2 Switching Sequence (Taking M-Type Switch as Example)
Pre-selection by the selector switch: Connect the adjacent tap without load to prepare for current transfer;
Action of the transfer switch: Disconnect the main contact from the original tap and connect the transition contact to the new tap to form a parallel path;
Operation of the transition resistor: Limit the current change rate and reduce arc interference;
Completion of main contact switching: The transition contact disconnects after the main contact is stably connected to the new tap, and the switching is completed.
About JINSHANMEN TECHNOLOGY CO., LTD
JINSHANMEN TECHNOLOGY CO., LTD mainly produces oil immersed power transformers, dry-type power transformers, oil immersed three-dimensional coiled power transformers, dry-type three-dimensional coiled power transformers, mining explosion-proof dry-type transformers, mining explosion-proof mobile substations, amorphous alloy power transformers, on load capacity regulating power transformers, locomotive dry-type transformers, as well as prefabricated substations, modular substations, wind energy box type substations, high and low voltage switchgear and other transmission and distribution equipment. With advanced production technology and strict quality control, the company integrates high-performance on-load tap changers into 35kv distribution transformer and regulation transformer, providing reliable power solutions for power grids, industrial and mining enterprises, renewable energy projects and other fields.
Conclusion
The on-load tap changer is a key component to ensure the stable operation of power transformers, especially for 35kv distribution transformer and regulation transformer that require high voltage stability. By mastering its composition, working principle and application characteristics, we can better understand the operation mechanism of power transformers and select suitable transmission and distribution equipment. JINSHANMEN TECHNOLOGY CO., LTD is committed to providing high-quality, high-performance transformers and supporting components, contributing to the safe and efficient operation of the global power system.