Milli-ohmmeter MIKO-7M(A) new version

Currently, MIKO-7MA milli-ohmmeter is used in the electrotechnical laboratory of the equipment repair shop of VCEG, JSC.

This device has been used since May 2021 for testing power transformers with a capacity of 6-10 kV 25-630 kVA. The use of this device made it possible to reduce the time spent on measuring the ohmic resistance of the transformer windings compared to previously used devices.

The use of digital measurement indication allows you to reduce the number of errors when taking readings. Low weight, compactness and absence of fragile parts is an undoubted advantage of the device. During the short period of MIKO-7MA operation, no failures and malfunctions were detected.

In 2015, Siemens purchased a device for measuring electrical resistance, MIKO-7 milli-ohmmeter, which is currently successfully operated by our specialists. With the help of this device, the parameters of traction electric motor windings are monitored, as well as all kinds of equipment diagnostics for high-speed electric trains ESl "Lastochka".

According to the MIKO-7 device operation experience, we can note that this device is easy to use, it has a clear and simple interface. The best function is the ability to automatically select the resistance range.

Regard must be paid to the plug connectors of the device test cable and mains cable, which are easy to confuse. This can damage the contact pins and damage the device.

There is a positive moment, that the device can operated not only from mains, but also from the car battery. However, we would recommend your company to add a built-in battery to the device, since it is not always convenient to work from mains or an external power source.

MIKO-7M milli-ohmmeter has been operated at the Krasnoyarsk Power and Mechanical Plant since May, 2019.

The device has a clear software, a user-friendly interface, the device itself is easy to use in work.

The declared characteristics of the device are fully confirmed in practice.

The advantages of the device are its compact size, light weight and the ability to work from the network.

In addition, the device demonstrated good repeatability of the result, a wide range of resistance measurements, the possibility of manual adjustment of the test current.

We recommend this device for use in specialized enterprises.

The device was recommended to be purchased by the employees of electro technical laboratory of Tomskneftekhim, LLC.

MIKO-7M milliohmmeter that we received in December, 2020 corresponds to the description and the declared technical parameters. With this device we check the windings of power and measurement transformers, electric motors, generators, circuit breaker contactors, busbars and other circuits.

MIKO-7M is very convenient to be used and carried, as it has a protective case. The measurement settings menu is clear, the functionality of the device is more than convenient: there are user-friendly interface, automatic measurement mode selection, high speed and accuracy of measurements. Moreover, test cables remain flexible at subzero temperatures. MIKO-7M milliohmmeter fully meets our needs and requirements.

In August 2019, our company purchased MIKO-7 milliohmmeter for the needs of the electrotechnical laboratory. This device was purchased to replace the DC bridge R333.

During the use, the device has proven itself on the positive side.

The main advantage that was noted when working with MIKO-7 is the high measurement speed that significantly reduced the time required to check the resistance of the transformer windings.

I would also like to mention the strong robust and shockproof case of MIKO-7 that allows you to transport the device without fear of damaging it.

The only inconvenience is the lack of a built-in battery for the possibility of autonomous operation. As far as we know, this flaw is taken into account and corrected in the new modification of the device MIKO-7M(A).

[Manufacturer note]: You are absolutely right. Modified milliohmmeter MIKO-7M(A) is equipped with a built-in battery. You can learn more about its characteristics on the corresponding page of our website.

During the entire operation of the device, there were no failures in its operation.

We look forward to further cooperation and recommend SKB EP as a reliable and competent partner.

To date, the following devices are in operation in the electrotechnical laboratory of the Yaroslavl Power Supply Distance of the Northern Energy Supply Directorate: MIKO-2.3, MIKO-7, PKR-1 and PKV/M7.

These devices are used in conducting a comprehensive survey of electrical equipment of substations, such as power and converter transformers, high-voltage circuit breakers, and disconnectors. During the tests, SKB EP devices gave a good account of their reliability, stability of operation, and ease of use. When using the above-mentioned devices, total measurement time was reduced.

The use of PKR-1 OLTC analyzer made it possible to more accurately determine the defects of the power transformer and tap changing device during a comprehensive check-up. The most frequently diagnosed damages are burning and adjustment of the contactor contacts of the tap changing device. The second most common defect is the burning of circuit breaker contacts. One of these defects was confirmed by the visual inspection.

The use of MIKO-2.3 and MIKO-7 devices that are dedicated to the resistance measurement in inductive circuits gave the greatest reduce of measurement time. When using an AC bridge, one resistance measurement of the 110 kV transformer winding lasted about 1.5 minutes. When using MIKO-2.3 or MIKO-7 devices, the time spent on one measurement was reduced to 30 seconds.

PKV/M7 circuit breaker analyzer is used for a comprehensive assessment of the state of high-voltage circuit breakers. As the main direction was chosen the assessment of SF6 circuit breakers of MKP-110 type. There is a big survey conducted of SF6 circuit breakers installed instead of oil circuit breakers. The use of PKV/M7 circuit breaker analyzer has reduced the time spent on the diagnostics of circuit breakers, and increased the accuracy of the data obtained. Previously, the measurements of the moving parts movement and compression were controlled by a ruler with oil drained from the circuit breaker tank. PKV/M7 circuit breaker analyzer is, first of all, more comfortable to use and has better accuracy comparing to the previously used methods.

Having experience in the operation of SKB EP devices since 2016, we can definitely recommend the use of these devices for diagnostics of energy facilities.

Specialists of Irkutsk HPP (hydro power plant) have been using the SKB EP instruments for several years. The PKV/M7 instruments were used for measuring time characteristics of moving parts of such circuit breakers as ABB HGI-3 (13.8 kV), AREVA HGF-1012 (110 kV), SIEMENS 3AP1DT-145 (110 kV, 220 kV), and 3AP1DT-245 (220 kV); the MIKO-2.3 and MIKO-7 instruments are used on electric motors (0.4 kV) and disconnecting devices RVR(Z)-20/2000 M-U3, RGNP-110/2000-50UHL1, RDZ-1-110-2000UHL1, and RNDZ-220/2000U1 (13.8/110/220 kV).

The PKV/M7 instrument meets all our needs in HV circuit breaker diagnosis. It provides convenient control of poles time difference using the PC software that shows defects in a circuit breaker long before they may cause a heavy failure.

The MIKO-2.3 low / high resistance meter provides quick output of the results of measurements; it is a universal instrument that integrates four modes in one. The instrument is rather convenient and mobile.

MIKO-7 milli-ohmmeter in the course of operation proved to be rather efficient. The instrument has a robust shock-proof housing that “saved” the instrument many times.

The updated software of the milli-ohmmeter allowed us to save time and eliminate personnel’s mistakes. When we used a voltampermetre we had to carry several instruments, and a battery; their assembly took time, and measurements on a transformer took two hours minimum. Time of measurements using the MIKO-7 is halved or even makes one third of that.

Benefits of the PKV/M7 include: information on the results of measurements and ability to operate the circuit breaker from the instrument. The MIKO-2.3 is rather mobile and operative; the MIKO-7 has a large set of functions and automatic mode of operation.

During the SKB EP instruments operation on the main electric equipment of the plant we did not face any problems, the instruments worked properly, without failures. On the auxiliary equipment the problems with electric motors were timely revealed (inter-winding short circuit, break of windings end).

Specialists of Irkutsk HPP recommend the PKV/M7, MIKO-2.3 and MIKO-7 to all the companies as they are cost-effective analogues of the instruments of foreign manufacture.

On October 21, 2019, SKB Electrotechnical Instrument Making LLC, in a classroom at the Novo-Sverdlovsk Thermal Power Plant, conducted a demonstration and demonstration measurements for MIKO and PKV instruments to employees of the electrotechnical laboratories of several stations of the PJSC T Plus Sverdlovsk branch of "Novo-Sverdlovsk CHP.

The measurements were performed on the VGM-20 circuit breaker in conjunction with representatives of SKB EP: Konstantin Muravin, Gennady Kurov, Natalia Korneeva. The following devices were demonstrated: the MIKO-21 microohmmeter (transition resistance of the contacts was measured) and the control device for the high-voltage circuit breakers PKV / M7 (the characteristics of the stroke, speed, time, and also the timing of the contacts were taken).

On 6 kV 5DV-A motors, designed to measure the active resistance of DC windings, the operation of millimeters MIKO-7M (A) and MIKO-9A have been shown.

Instruments have proven themselves on the good side in terms of operation and accuracy, as well as measurement speed. We recommend them for purchase and operation.