Specialists of the Electrotechnical Laboratory of Novosibirsk State Technical University (NSTU) have developed and handed over to the customer a specialized testing complex designed to monitor manufactured varistors and surge protection devices (SPD). The complex is designed to test the pulsed electrical load of varistors and ultrasonic sensors used to protect electronic equipment, power supply systems, and telecommunications systems from pulsed voltage surges to verify their technical characteristics and compliance with regulatory requirements.
Varistors are key elements in protecting electronic devices and networks from surge surges caused by lightning discharges, switching processes, or electromagnetic interference. Their nonlinear volt-ampere characteristic (VAC) makes it possible to effectively limit overvoltages, absorbing excess energy and preventing damage to equipment.Due to the high response rate and stability of the parameters under repeated exposure, varistors are widely used in household, industrial, and telecommunication equipment, as well as in vehicle systems and generator sets.
"Representatives of Hakel JSC contacted us. Their main activity is the manufacture of surge protectors. Now they are opening a new direction of radioelectronic production in Russia—their own production of varistors. This requires both a production base and testing equipment that will allow us to confirm the characteristics of varistors—the compliance of devices with the norms established by state standards. We have manufactured a complex for testing the pulsed electrical load of varistors to confirm the technical characteristics," said Alexander Mulbayer, head of the Electrotechnical laboratory at NSTU-NETI.
The complex consists of three generators and an external operating voltage source—a separate unit is connected to the generators, which allows testing at operating voltages. The test complex is designed for a range of varistors manufactured by JSC Hakel (with a classification voltage from 18 to 1800 volts). It allows the creation of test current pulses with preset parameters (amplitude, duration, pulse shape) in accordance with the requirements of the standards (GOST 30265-95), namely: a rectangular current pulse with a duration of 2000 microseconds and an adjustable amplitude from 1 to 500 A; an aperiodic current pulse of 8/20 microseconds (8 microseconds is the duration of the pulse front, 20 microseconds — pulse duration) with an amplitude from 1 to 10000 A.
As Alexander Mulbayer notes, the main advantages of the developed test complex include the ability to control the complex both directly from the generator panel and remotely using a personal computer; a wide range of operating voltages that allow testing varistors with a classification voltage from 18 to 1800 V and sizes from 5 to 32 mm; and a locking system that protects the operator from electric shock. In addition, the design of the generator test chamber protects the operator from flying fragments of the varistors and ultrasonic sensors in case of their destruction.
The development of the test complex was carried out with the involvement of students from the design bureau, which allowed them to acquire practical skills in the design, configuration and operation of high-voltage equipment. This contributes to the training of qualified personnel for the domestic electrical industry.
Other developments of the NSTU-NETI electrotechnical laboratory can be found on the website.