Detecting insulation failures is crucial to ensure early assurance of dielectric integrity in equipment such as cables, transformers, generators, and motors, as well as the need for preventive maintenance of these devices.

These equipment are essential for electrical system operations, playing roles in power transmission, distribution, and robust industrial equipment operation. Therefore, understanding their characteristics and conducting tests using instruments that ensure reliability and safety of the process is critical.

In today's complex electrical systems, such as those powering major cities or supporting vital industrial infrastructures, transformers, cables, generators, and motors are fundamental:

 enable efficient energy transmission by adjusting voltage levels for different stages of transmission and distribution.

 ensure safe electricity transport, connecting generating units to small and large consumer centers.

 convert various forms of energy into electricity, ensuring continuous and reliable supply.

 convert electrical energy into motion, driving industries and equipment.

Together, these components promote stable, efficient, and reliable operation of electrical networks, supporting everything from urban infrastructures to industrial complexes. To understand the importance of the integrity of these elements in the electrical system, it is essential to first understand some variables involved in their operation and the available methods for detecting their potential failures.

Dielectric materials are substances with high resistance to electric current flow, characterized by low conductivity. When subjected to an electric field, they polarize and create an electric field opposite to the original field. Dielectrics are essential in various applications, including:

 Dielectric materials are commonly used to insulate conductors, cables, and electrical components, preventing short circuits and ensuring the safety of electrical circuits.

 In capacitors, dielectric materials are used to separate conducting plates, allowing the capacitor to store electric charges.

In electrical transformers, dielectric materials are used to insulate conducting coils, preventing electric current from passing between them.

 They are used in a variety of electronic components such as transistors, integrated circuits, resistors, and inductors to provide electrical insulation and other specific electrical properties.

Common examples of dielectric materials include glass, plastics, ceramics, and paper. Each dielectric material has unique electrical properties that make it suitable for different applications.

Withstanding Voltage and Dielectric Strength Testing

Once understanding what dielectric materials are present in transformers, cables, and motors, it is necessary to understand how they are tested. Notably, withstand voltage and dielectric strength tests are highlighted, aiming to evaluate the insulation capacity of equipment, promoting and ensuring safety and quality of objects that may be subjected to testing conditions.

In greater detail, this is a test aimed at assessing the maximum voltage levels that the tested equipment can withstand without the dielectric breaking down.

In the power system, for example, these voltage levels are grouped into voltage classes, and for each class, a basic insulation level (BIL) is also defined, providing the voltage limits that equipment should withstand to be safely integrated into the electrical system.

It is known that when conducting withstand voltage tests using conventional methods on large generators, motors, and cables, a high-capacity test transformer associated with a high-power source is required. These equipment are not only heavy and expensive, but also very inconvenient to use due to the space they occupy, often making the testing process impractical.

VLF HVEX: Ensuring Performance in Withstanding Voltage Tests

An alternative technology used to perform applied voltage tests, ensuring greater portability, agility, simplified operation, and assembly, are tests performed using VLF HVEX, also known as Very Low Frequency. It combines advanced digital frequency conversion technology using microcomputer control, complete automation of increase, decrease, measurement, and protection.

Operated through a control case and an elevator circuit, the tester provides high voltages at a very low frequency, ensuring that the injected power for capacitive loads remains low.

This device is specifically designed to detect and diagnose potential dielectric failures in high-voltage equipment, overcoming the difficulties of conventional methods, thereby enhancing safety and operational efficiency of the electrical system, while offering practicality and agility in conducting tests.

Furthermore, with VLF HVEX, real-time data visualization is possible; the meter includes multiple protection functions and test requirement versatility, making it indispensable in applied voltage tests.

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Very Low Frequency (VLF) Hipot Test Set for testing Cables and Generators

VLF is an advanced voltage tester that utilizes digital technology to ensure precise and safe testing on high capacitance loads such as high voltage cables, large motors, and generators. With direct sampling of current, voltage, and waveform data from the high voltage side, it provides increased accuracy and features overvoltage protection for quick interruption. Operated by a contro

Applied Low-Frequency Voltage Testing: Definitions and Tests with VLF HVEX

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VLF Hipot Test Set

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