What are the differences and relationships between on-load tap changers and off-load tap changers in transformers?
Release date:
2020-07-22
In actual industrial production, many power utilities and departments use on‑load tap changers testers to measure and analyze the electrical performance parameters of on‑load tap changers in power transformers and special‑purpose transformers.
In actual industrial production, many power utilities and departments use on‑load tap changers testers to measure and analyze the electrical performance parameters of power transformers and special‑purpose transformers. The device that switches and connects the transformer’s tap leads is called a tap changer; it is also known as a voltage regulator. Tap changers are broadly classified into on‑load tap changers and off‑load tap changers. So what exactly are the differences between the two? Today, drawing on our many years of experience in transformer research, we will explain these distinctions.
1. The difference between on-load tap changers and off-load tap changers
① Transformer voltage regulation method
On-load tap changers, unlike off‑load tap changers, do not require the transformer to be disconnected from the power grid; they enable voltage regulation at any time, offer highly flexible adjustment, operate with very rapid response, and provide a much wider voltage‑regulation range. On‑load tap changer testers are equipped with functions for analyzing, storing, and printing measured data.
② Application Areas
No‑load tap changers, with their limited voltage‑regulation range and the requirement of a power outage for adjustment, are suitable only for industrial settings where power‑quality requirements are modest and where switching to a different tap can be performed during outages. By contrast, on‑load tap changers incorporate specially designed measurement and processing circuits that enable timely detection of latent faults during preventive testing of electrical equipment and major transformer overhauls, thereby playing a crucial role in enhancing the reliability of power‑system operation.
2. The relationship between on-load tap changers and no-load tap changers in transformers
When switching tap positions, an on‑load tap changer must disconnect the transformer from the power grid; therefore, on‑load voltage regulation involves switching under load without interrupting the circuit. However, its adjustment range is relatively limited, it cannot be used for frequent voltage adjustments, and it requires a power outage, which often results in extended downtime. By contrast, an on‑load tap changer represents an advanced evolution of the no‑load tap changer and belongs to the category of stepped voltage regulation.
Previous page
Previous page:
Share to
Telephone
Email box
Address
No. 3 Fengming Road, Hairun Subdistrict, Sanmen County, Taizhou City, Zhejiang Province
Website Development:China Enterprise Dynamics Nantong|Tag