Non-demountable periodic inspection – solution to the problem of operating worn-out electrical equipme

Since 1991, SKB EP (Special Design Bureau of Electric Instrument Engineering), LLC at the Melentiev Energy Systems Institute of the Russian Academy of Sciences has been developing and manufacturing instruments for inspection of high-voltage circuit breakers of all types and voltage classes without disassembling them. Throughout the years of its existence, the company has invented 40 different instruments.

Despite a relatively small number of developments, SKB EP confidently holds its position in the instrumentation market. The formula for the company's success is a constant struggle, first of all, for the quality of its products and their adaptability to the user needs. According to the analysis made by the SKB EP service center, only 1% of the produced instruments are submitted for repair. The average service life of the instruments is about 10 years, which also confirms the quality of our products. Released in 1994, the PKV/V1 test instrument for high-voltage air circuit breakers is still used by customers for diagnostics of high-voltage devices. The instruments are made of high-quality components produced in Russia and abroad (Maxwell, Hardigg Industries, Bolymin Inc., Texas Instruments, Vishay and many others).

A distinctive feature of the SKB EP instruments is the ability to diagnose a circuit breaker without disassembling it (you need only to turn off the voltage and ground the circuit breaker), without draining the oil and disconnecting the shunt resistors, etc. They inspect all the mechanical parts and components of the circuit breaker at once, as well as check several characteristics of the assembly (parameters related to time, speed, travel) simultaneously.

"The method of diagnosing (monitoring) the condition of high-voltage circuit breakers without disassembly developed and implemented by your company is an effective means of detecting defects and malfunctions of high-voltage circuit breakers, thus reducing the cost of equipment repair and maintenance."

V.V. Kostin, chief engineer of Tulenergo JSC

Thanks to the early detection of circuit breaker defects, you can detect faults at the early stage of their development, as well as detect even small deviations in the circuit breaker operation based on data obtained using a device for graphical display of process parameters.

"The method is simple, reliable, and clear. It saves time and is planned for further use in our company."

S.V. Melnikov, head of electrical laboratory Vologda Heat and Power Plant, RAO UES, branch of Vologdaenergo OJSC.

The devices listed below allow you to monitor and evaluate the technical condition of the following circuit breaker components: the drive, the mechanism for transmitting motion from the drive to the movable contacts, damping devices, the contact system, drive power circuits, and control circuits.

PKV/M7 instrument measures all the rated parameters: time, speed, travel, currents and voltages of electromagnets inside oil, vacuum, and SF6 circuit breakers. PKV/U3.0 and PKV/U3.1 cross functional instruments can also test all air circuit breakers (in addition to the above-listed). Monitoring the speed characteristics of oil circuit breakers is especially important, since, for example, a low speed during disconnection increases the duration of arc that emits gas and oil-gas mixture from the circuit breaker. When a short circuit is cleared, the emissions increase, causing an explosion of the circuit breaker.

"Based on our experience, the PKV/M7 instrument is currently the most convenient, reliable, and cross functional device for studying the characteristics of high-voltage circuit breakers of various types and rated voltages. It can be recommended for use not only during repairs, acceptance, standard, and endurance tests during operation, but also in the framework of specialized studies of processes happening when circuit breakers are switched."


SKB EP develops the MIKO series of instruments for measuring resistances in various circuits. The MIKO-1 microohmmeter is designed to measure the contacts resistances, and has become very popular in recent years due to its self-contained power supply and portability at a current of up to 50A, accuracy, and ease of maintenance. The MIKO-2.3 micromillikiloohmmeter is designed to measure contact resistance at a current of up to 700A, active resistance of transformer windings, electromagnets, etc., their temperature and resistance of shunt, ballast and other resistors in the presence of induced voltages up to several kilovolts.

A new PKR-2 instrument is released to test the on-load tap changers (OLTC) of the transformers. The device allows you to check the main parameters of OLTC specified in regulatory documents for both reactor type and fast-acting OLTCs.

The instruments are supplied with mounting hardware for installation of transducers to all types of Russian circuit breakers, and equipped with fast-acting high-precision incremental movement transducer. This allows to obtain a virtually instantaneous values of speed of the moving parts of the circuit breakers and, respectively, to quickly check their performances. Of course, the instruments are delivered with detailed instructions for connection and carrying out measurements on the circuit breakers. In addition, all instruments come with software for maintaining a database and analyzing measurements on a computer.

Our products have high frost resistance and small size and weight, which is very convenient for carrying out repairs in the field.

But most importantly, SKB EP devices allow you to switch from scheduled repairs of circuit breakers to repairs when necessary, which significantly (1.5 times!) reduces the cost of maintenance of high-voltage circuit breakers.

The calibration laboratory of SKB EP is accredited by Rosstandart for the right to calibrate products and issue calibration certificates. Our service department provides technical support and maintenance of all instruments manufactured from the company's inception.

In-house production of SKB EP boasts a complete production cycle, using a reasonable combination of domestic and imported components. The production capacity allows us to meet the demand of all companies in Russia and the CIS for these instruments.

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