English
RFQ

Download the app

Resistance and Reactance of the Transformer

Edwiin

05/28/2025

Transformer Resistance and Reactance Representation
Resistance Definition

The resistance of a transformer refers to the internal resistance of its primary and secondary windings, denoted as

R 1

and

R 2

. Corresponding reactances are

X 1

and

X 2

, with

K

representing the transformation ratio. To simplify calculations, impedances can be referred to either winding—either primary terms referred to the secondary side or vice versa.

Voltage Drops in Windings

Resistive and reactive voltage drops in primary and secondary windings are:

Secondary resistive drop: $I 2 R 2$
Secondary reactive drop: $I 2 X 2$
Primary resistive drop: $I 1 R 1$
Primary reactive drop: $I 1 X 1$

Primary-to-Secondary Referencing

When referring primary drops to the secondary side using transformation ratio

K

:

Primary resistive/reactive drops become K⋅I₁R₁ and K⋅I₁X.
Substituting $I 1 = KI 2$ , the referenced drops become:
- Resistive: K²I₂R₁
- Reactive: K²I₂X₁

Therefore this will be the load voltage.

Topics

Basic Physics Articles

Edwiin

Hello，I'm Wdwiin. A decade of hands-on experience in electrical engineering, specializing in high-voltage systems, smart grids, and renewable energy technologies. Passionate about technical exchange and knowledge sharing, committed to interpreting industry trends with professional insights to empower peers. Connection creates value—let’s explore the boundless possibilities of the electrical world together!

Working Voltage in Power System

Working Voltage in Power System

Working VoltageThe term "working voltage" refers to the maximum voltage that a device can withstand without sustaining damage or burning out, while ensuring the reliability, safety, and proper operation of both the device and associated circuits.For long-distance power transmission, the use of high voltage is advantageous. In AC systems, maintaining a load power factor as close to unity as possible is also economically necessary. Practically, heavy currents are more challenging to handle than hi

Frequency division method for measuring grid-to-ground insulation parameters

Frequency division method for measuring grid-to-ground insulation parameters

The frequency division method enables the measurement of grid-to-ground parameters by injecting a current signal of a different frequency into the open delta side of the potential transformer (PT).This method is applicable to ungrounded systems; however, when measuring the grid-to-ground parameters of a system where the neutral point is grounded via an arc suppression coil, the arc suppression coil must be disconnected from operation beforehand. Its measurement principle is shown in Figure 1.As

The insulation parameters of the power grid to ground are measured by the tuning method

The insulation parameters of the power grid to ground are measured by the tuning method

The tuning method is suitable for measuring the ground parameters of systems where the neutral point is grounded via an arc suppression coil, but not applicable to ungrounded neutral point systems. Its measurement principle involves injecting a current signal with continuously varying frequency from the secondary side of the Potential Transformer (PT), measuring the returned voltage signal, and identifying the system's resonant frequency.During the frequency sweeping process, each injected heter

Effect of Transition Resistance at the Grounding Point on the Rising Speed of Zero - sequence Voltage

Effect of Transition Resistance at the Grounding Point on the Rising Speed of Zero - sequence Voltage

In an arc - suppression coil grounding system, the rising speed of the zero - sequence voltage is greatly affected by the value of the transition resistance at the grounding point. The larger the transition resistance at the grounding point, the slower the rising speed of the zero - sequence voltage.In an ungrounded system, the transition resistance at the grounding point has basically no impact on the rising speed of the zero - sequence voltage.Simulation Analysis: Arc - suppression Coil Ground

Source professional electrical partners, experts, and explore smart grid & energy solutions.