High precision micro-ohmmeter MIKO-21

Certificates

  • Safety Test Certificate IEC 61010-1:2001
  • Conformity certificate with safety requirements EC/EU
  • Russian State Register Certificates
  • Declaration of Conformity of the Customs Union
  • Russian Register of Innovative Products
  • Recommended for use in JSC Russian Railways electric installations
  • PJSC ROSSETI Register of Innovative Solutions

Wide functionality and high accuracy ±0.05%

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Adjustable test current up to 200 A

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Special algorithms for measuring contact resistance of HV circuit breakers with built-in current transformers (CT)

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4 ways of resistance measurement start-up

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Automatic storage of measurement results

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Automatic indication of measured resistance thresholds

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Color graphic touch-screen display, intuitive interface

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Battery-operated power supply, light weight and size

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Variable instrument complete set

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MIKO-21 is designed for high precision measurements of DC electrical resistance in the range from 0.1 µΩ to 2 Ω with an accuracy of ±0.05% and can test:

  • contacts of high-voltage circuit breakers of all types and voltage classes;
  • contactors, relays, busbars, various bolted connections, welded joints, brazed joints;
  • elements of equipment for open and closed switchgears in extreme electric and magnetic field conditions;
  • in research laboratories and industrial workshops.

MIKO-21 is ahead of similar devices represented on the market due to a number of functional and technical features. For example, special measuring technologies ensure MIKO-21 compliance with the most stringent accuracy requirements. MIKO-21 is ideally applicable for high precision resistance tests in the µΩ range.

Please watch detailed video-reviews about MIKO-21 micro-ohmmeter up above or on our YouTube. Watch videos and subscribe.

One of the problems during contact resistance measurement with permissible error is availability of oxide films between contact surfaces.

According to international standard IEC 60694: General Specifications for High-Voltage Switch Gears (International Electrotechnical Commission), to control this type of error test current amperage during testing the electric resistance in the main circuit of a HV circuit breaker shall be between 50 A and its rated value.

Test current in circuit breakers is often limited by specific values: 100 A and 200 A.

The amperage in MIKO-21 can be set in several ways:

  • By selecting from a number of specified values: 10 A, 50 A, 100 A, and 200 A;
  • By setting the automatic mode for selecting test current;
  • By setting test current manually in the range from 1 A to 200 A at a step of 1 A.

SKB EP micro-ohmmeters are the only instruments enabling to measure contact resistance of live tank and dead tank circuit breakers using separate automatic modes optimized for those circuit breakers.

  • Mode 1 makes it possible to carry out measurements in the circuits without CT;
  • ­Mode 2 enables to operate measurements in the circuits with CT with minimal battery power consumption;
  • Mode 3 enables to operate measurement in the circuits with CT using 100 A or 200 A test current (set by a user) without saving battery power.

Current transformers of dead tank circuit breakers form an extended transition process when test current is applied. Due to that measurement time is determined by the parameters of CTs, their number, and test current. For example, for HV oil-blast circuit breakers measurement time may be up to 30 seconds.

MIKO-21 special algorithms with automatic measurement stop prevent subjective errors and increase number of measurements per one battery charge.

Four ways are programmed in the instrument to start resistance measurement:

  • Single is started once the cable clamps are contacted to the tested object and followed by pressing the START button.
  • Auto single circuit is initiated by pressing the START button. The instrument will start measurement when the electric contact between the tested circuit and the test cable contacts is set. The test can be repeated by pressing the START button again.
  • Periodic is used in pre-specified time intervals when both hands are occupied with cable probes pressing against the test points. The user can choose time interval between the tests. The instrument will work continuously until the user stops the mode.
  • Auto periodic circuit is initiated by pressing the START button and used for continuous measurements. The user connects the current cable, and as soon as the potential contacts are connected, the measurement will start automatically. To repeat a test, simply break contact with potential probes and reconnect.

The instrument contains a built-in database that contains nominal values of high-voltage circuit breakers indicating the maximum and/or minimum permissible values ​​of contact resistance. There are also the nominal values for rejected resistors indicating the acceptable values ​​of the upper and lower thresholds of resistance.

The user can add / edit / delete the nominal values ​​of the exact measured object.

Availability of a built-in archive of nominal values of electric resistances (main circuit resistance of HV circuit breakers) facilitates automatic detection, and once the measured value exceeds the nominal value it is highlighted with red colour.

This mechanism works due to either the built-in database of nominal values or the ability to add / edit / delete the nominal data of the measured object independently.

Color graphic display of high brightness ensures easy reading on a sunny day, whereas intuitively understandable interface with a multi-sensor display simplifies the instrument use.

The Instrument can be manipulated either from the keyboard or from the multi-sensor display, as suits.

Communication with PC via USB or a flash card facilitates data transfer from the Instrument to the company data base. The device can be integrated into measuring systems under PC control of diagnostic laboratories and companies producing electric equipment.

Battery power, low weight and small dimensions ensure complete independence and high mobility of the device in the vast territory of the substation or workshop, and the built-in memory for 2,000 measurements greatly simplifies the process of diagnostics and data transfer from the substation into the company office.

For convenient connection to the object, there are special test cables of different lengths and different types of clamps:

  • Test cables with Kelvin clamps for high voltage circuit breakers up to 110 kV 2 m long (standard complete set);
  • Test cables with Kelvin double hand spikes 1.5 m long for measurement in pipelines and interrupting chambers (recommended when the device is placed near the circuit breaker);
  • Test cables with Kelvin C-clamps for circuit breakers from 10 kV to 220 kV 4.5 m and 6 m long (recommended when the device is placed near the circuit breaker);
  • Test cables that consist of a cable with Kelvin clamp and Kelvin C-clamp for circuit breakers from 220 kV to 750 kV 3m / 6m or 9m long (recommended when the device is places in a cradle of a lift);
  • Test cable for precise measurements and measurements on sections of the electric circuit, to the end points of which the test current is applied.
Specifications Value
Resistance range, Ohm 0.1 µΩ - 2 Ω
Current range, A 1 - 200
Number of digits in the output of the measurement result 5
Accuracy ±0.05 %
Time of measurement in Mode 1, sec not more than 2
Time of measurement in Mode 2 on a dead tank circuit breaker with a built-in CT (energy saving), sec 10 - 30
Time of measurement in Mode 3 on a dead tank circuit breaker with a built-in CT (without energy saving), sec 5 - 15
Mains voltage 90-264 V AC, 47-63 Hz
127-370 V DC
Consumed power does not exceed, W 60
Battery type Li-Ion
Battery lifetime (in continuous operation), hrs more than 8
Battery recharge time, hrs less than 2
Built-in memory 2,000 measurements
Number of tests (max. current, I=200A) more than 500
PC communication USB / USB Flash
Display Color graphic display,
touch-screen, 480 x 272 pix
Interface, User manual language English
Environmental protection with closed cover IP 67
Environmental protection with open cover IP 40
Storage temperature, ºС -20 - +60
Operating temperature, ºС -20 - +50
Relative humidity, % (non condensing) 95
Dimensions, mm 270 х 246 х 124
Test block weight, kg (lbs) 3.3 (7.28)
Testing period, years 3
Calibration period, years 3
Warranty period, years 3

Standard complete set

Photo Item, Index Application
Main instrument<br>MIKO-21
  • Main instrument
    MIKO-21
  • 039.00.00.000
  • Main instrument
    MIKO-21
  • 039.00.00.000

Instrument and additional documents: Calibration Certificate, User Manual, Log Book.

Test cables<br>Set #2
  • Test cables
    Set #2
  • 039.27.00.000
  • Test cables
    Set #2
  • 039.27.00.000

200 A Kelvin clamp test cable 2 x 2 m (1.12 kg) with jaw up to
50 mm, for circuit breakers of up to 10kV.

Mains cable
  • Mains cable
  • 018.09.00.000
  • Mains cable
  • 018.09.00.000

Mains cable 1 x 2 m (0.24 kg). For instrument connection to the mains. Operating temperature range -25°С - +120°С. Rubber insulation.

Ground cable
  • Ground cable
  • 010.01.00.000
  • Ground cable
  • 010.01.00.000

Ground cable 1 x 2 m (0.07 kg) for instrument grounding. The cable is equipped with a C-clamp and a screw end cap. Rated current is 50 А.

Shunt
  • Shunt
  • Shunt

Type: 75ShSM M3 (75ШСМ М3). For checking MIKO-21 operability.

Fuses
  • Fuses
  • Fuses

Type: VP2B-1V-2A (ВП2Б-1В-2А) (2 pcs). For the power source protection.

Tool bag
  • Tool bag
  • 126.06.00.000
  • Tool bag
  • 126.06.00.000

Convenient, robust, wear proof bag for transportation of cables, documentation and other accessories to MIKO-21.
Weight 0.6 kg.

Test cables, if the instrument is placed near the circuit breaker (on order)

Photo Item, Index Application
Test cables<br>Set #1
  • Test cables
    Set #1
  • 039.19.00.000
    039.19.00.000-01
  • Test cables
    Set #1
  • 039.19.00.000
    039.19.00.000-01

200 A Kelvin double hand spike test cable 2 x 1.5 m (0.9 kg) for measurements in busbars or in arc extinguish chambers.

Test cables<br>Set #3
  • Test cables
    Set #3
  • 039.25.00.000
  • Test cables
    Set #3
  • 039.25.00.000

200 A Kelvin С-clamp test cable 2 x 4.5 m (3.8 kg) with jaw up to
80 mm, for all the circuit breakers of up to 35 kV, and for some circuit breakers of up to 110 kV.

Test cables<br>Set #4
  • Test cables
    Set #4
  • 039.26.00.000
  • Test cables
    Set #4
  • 039.26.00.000

200 A Kelvin С-clamp test cable 2 x 6 m (5.6 kg) with jaw up to
80 mm, for all the circuit breakers of up to 110 kV and some circuit breakers of up to 220 kV.

Test cable
  • Test cable
  • 039.24.00.000
    039.24.00.000-01
    039.24.00.000-02
  • Test cable
  • 039.24.00.000
    039.24.00.000-01
    039.24.00.000-02

Optional potential test cable with crocodile clips A25C (2 pcs) and probes (2 pcs) for precise measurements and for measurements on the sections of the electric circuit, to the end points of which the test current is applied.

  • To be used together with Set #2 - Length 2 m (39.24.00.000)
  • To be used together with Set #3 - Length 4.5 m (39.24.00.000-01)
  • To be used together with Set #4 - Length 6 m (39.24.00.000-02)

In particular, the cable can be used in case of measurement of cables resistivity.

Test cables
  • Test cables
  • 041.28.00.000
  • Test cables
  • 041.28.00.000

10A Kelvin test cable 2 x 2.5 m with spring-loaded probes. To be used for electrical resistance measurement in hard-to-reach places.

Test cables, if the instrument is placed in the lift cradle (on order)

Photo Item, Index Application
Test cables<br>Set #5
  • Test cables
    Set #5
  • 039.20.00.000
    039.21.00.000
  • Test cables
    Set #5
  • 039.20.00.000
    039.21.00.000

Test cable kit for circuit breakers of up to 220 kV.

  • 200 A Kelvin clamp test cable 1 x 1 m (0.5 kg) with jaw up to 50 mm.
  • 200 A Kelvin C-clamp test cable 1 x 3 m (1.3 kg) with jaw up to 80 mm.

Test cables<br>Set #6
  • Test cables
    Set #6
  • 039.20.00.000
    039.21.00.000-01
  • Test cables
    Set #6
  • 039.20.00.000
    039.21.00.000-01

Test cable kit for circuit breakers of up to 330 kV, and some of up to 500 kV.

  • 200 A Kelvin clamp test cable 1 x 1 m (0.5 kg) with jaw up to 50 mm.
  • 200 A Kelvin C-clamp test cable 1 x 6 m (2 kg) with jaw up to 80 mm.

Test cables<br>Set #7
  • Test cables
    Set #7
  • 039.20.00.000
    039.21.00.000-02
  • Test cables
    Set #7
  • 039.20.00.000
    039.21.00.000-02

Test cable kit for circuit breakers of up to 750 kV.

  • 200 A Kelvin clamp test cable 1 x 1 m (0.5 kg) with jaw up to 50 mm.
  • 200 A Kelvin C-clamp test cable 1 x 9 m (4 kg) with jaw up to 80 mm.

Additional accessories (on order)

Photo Item, Index Application
Potential spring-loaded contact (2 pcs.)
  • Potential spring-loaded contact (2 pcs.)
  • 023.21.00.000
  • Potential spring-loaded contact (2 pcs.)
  • 023.21.00.000

To be used together with sets ##2-7 for avoiding high contact resistances between an input pin and a clamp of the device.

Potential probe (2 pcs.)
  • Potential probe (2 pcs.)
  • 023.22.00.000
  • Potential probe (2 pcs.)
  • 023.22.00.000

To be used together with sets ##2-7 for avoiding high contact resistances between an input pin and a clamp of the device.

USB 2.0 A-B Cable
  • USB 2.0 A-B Cable
  • USB 2.0 A-B Cable

USB cable 1 x 1.8 m. For computer connection and data transfer.

Manipulating rod
  • Manipulating rod
  • 010.41.00.000
    010.41.00.000-01
    010.41.00.000-02
  • Manipulating rod
  • 010.41.00.000
    010.41.00.000-01
    010.41.00.000-02

Manipulating rod is designed for test cables connection from the ground or from the tank cover to the bushings of high-voltage circuit breakers, and to the structural elements of high-voltage disconnecting switches and earthing devices, without the use of ladders or elevated platforms.

The manipulating rod is completed with special extension cables. There is a Kelvin clamp with current and potential contacts to connect to the object on one side, and a contact pad on the other side. The device test cable is connected to the contact pad from the ground or a tank cover.

Manipulating rod extension cable is made according to a four-wire (Kelvin) scheme with the test current capacity of 100 A in the presence of a good contact.

Modern microohmmeter MIKO-21
  • Open Original

    TSU Rus, LLC

    To date, one MIKO-21 device is used in the laboratory of TSU Rus, LLC.

    This device is used in field tests to check the resistance of the equipment protective grounding as a part of the process of obtaining CE marking. During the tests, MIKO-21 showed high reliability, accuracy in severe conditions of exposure to electromagnetic interference in production.

    The main advantage of this device within the framework of the carried out tasks are the ability to work from a rechargeable battery, a strong case that is durable to mechanical influences during transportation of the device, as well as the stability of the device to climatic external factors.

    The main faults detected by MIKO-21 are non-compliance of the protective grounding resistance of the equipment with the harmonized EU standards.

    The use of the above device helped to automate and speed up the testing of equipment as part of the process of obtaining CE marking.

    During the operation of the device since July 2020, there have been no serious shortcomings and malfunctions. It is possible to recommend the use of MIKO-21 micro-ohmmeter for use in electrical laboratories.

  • Open Original

    Yamalo-Nenets enterprise of the main power networks the branch of FGC UES, PJSC

    Yamalo-Nenets enterprise of the main power networks the branch of FGC UES, PJSC thanks your company SKB EP, LLC for the fruitful cooperation in the supply of measuring instruments for the diagnostic of high-voltage equipment. We also thank you for prompt, professional work and individual approach, as well as for the high quality of instruments and its components.

    Our company operates such instruments as MIKO (10 pcs.), and PKV (10 pcs.) manufactured by SKB EP, LLC.

    These instruments are used to determine repair quality of high-voltage circuit breakers and disconnecting switches. The contact resistance of the current-carrying circuit, the time and speed characteristics of HV circuit breakers are checked with a help of them.

    The instruments are very convenient, they give an opportunity to identify the worsened condition of contact connectors on HV circuit breakers and of disconnecting switches. They reduce the time for detecting a defect and prevent accidents and technological disturbances. The defects are periodically identified. That fact allows us to schedule a necessary repair work on time and maintain the equipment in a good working condition.

    We recommend these instruments for use in organizations, which operate high-voltage equipment.

    Thank you for your help in solving our production tasks and sincerely hope for further mutually beneficial cooperation.

    S.I.Kandiano
    Acting Chief Engineer-Deputy Director

  • Open Original

    Urengoy branch of Gazprom Energo, LLC

    Since 2017 Electrotechnical laboratory of the Urengoy branch of Gazprom Energo, LLC has been operating MIKO-10 and MIKO-21 micro-ohmmeters and also MIKO-8M(A) milli-ohmmeter. These devices are used to measure the resistance of switching devices, power and measuring transformers, and electric motors.

    The advantages of the operated devices include small dimensions and weight, the presence of built-in power sources in MIKO-10 and MIKO-21 micro-ohmmeters, a simple and intuitive interface.

    [Manufacturer note]: MIKO-8M(A) milli-ohmmeter also has a built-in power supply. It can be supplied both without a battery: MIKO-8M version, and with it: MIKO-8MA version.

    During the operation, all devices have proven themselves on the good side, there are no malfunctions or failures. In comparison with the previous versions of measuring devices, MIKO-10, MIKO-21 and MIKO-8M(A) have become more efficient, which allows, in addition to the high accuracy of the measurements obtained, to reduce the work time due to the simpler assembly of the measurement circuit.

  • Open Original

    Altyntau Kokshetau, Ltd.

    Since 2017, we have been measuring resistance of the main circuits of high-voltage column and tank circuit breakers with the help of MIKO-21 microohmmeter.

    Advantages of the device: intuitive and easy-to-use interface, touch-screen color display, small dimensions and weight, a wide range of manually set values of the test current, the ability to transfer measurement results to the computer. MIKO-21 works both from the 230V network and from the built-in power supply. The complete set of the device assumes the possibility of choosing different test cable options.

    During the operation, there were no failures or malfunctions in the operation of the microohmmeter.

  • Open Original

    Kuban MEN the branch of FGC UES, PJSC

    I would like to inform you that in the branch of FGC UES, PJSC - Kuban CMEN uses MIKO-1, MIKO-2.3, MIKO-10, and MIKO-21 microohmmeters.

    During the operation, MIKO-group devices have proven themselves to be the best in terms of reliability, ease of use and accuracy of the results obtained on the state of the switching equipment (circuit breakers, disconnectors). The devices are also good at resistance measurement of pressed connections, resistance measurement of transformer windings. The devices are easy to transport (there is a special carrying bag), they are convenient to use due to the small size and built-in power supply.

    Among the disadvantages there is the lack of crocodile clips (or clamps) in the standard complete set for connecting to a large-section busbar (rigid busbar, hollow wires).

    [Manufacturer note]: Device complete set includes those cables that are most often used on various types of objects. Cables that help to measure resistance on large-section busbars are unfortunately used not as often, so they are included to the additional complete set of the devices and are available by request.

    Devices manufactured by SKB EP, LLC gave a good account of themselves and can be recommended to the companies performing adjustment or repair works, testings and measurements.

  • Open Original

    Kent

    Our electrical equipment commissioning team has been operating MIKO-21 micro-ohmmeters in the amount of 3 pieces since 2020. These instruments are used to measure resistance of automatic circuit breakers contact connections the contact resistance of bolted connections and welded joints.

    The instrument MIKO-21 has a small weight and is assembled in a convenient, durable case. The instrument menu is simple and user-friendly. When operating 200 A Kelvin double hand spike test cables and 200 A Kelvin С-clamp test cables has been additionally purchased, which expanded the possibilities for instrument connection.

    The instrument MIKO-21 has shown itself advantage and can be recommended to organizations to perform tests, measurements, commissioning and repair of electrical equipment.

    Tishkov I.V.
    Chief engineer for electrical equipment commissioning


  • Open Original

    Kamchatskenergo, PJSC

    Kamchatskenergo, PJSC has been operating instruments manufactured by SKB EP, LLC: PKV/M5, PKV/M7, MIKO-1, MIKO-2.3, MIKO-21 since 2005.

    The advantages of PKV/M5, PKV/ M7 are: the ease of operation, an ability to determine a necessary number of controlled parameters with the required accuracy, the identification of defects without disassembling a circuit breaker, an opportunity to view the results of measurements and graphs of dynamic characteristics, a choice between local and remote triggering and usage of instruments on almost all types of switching equipment. I would also like to note the compact size of the instruments and the presence of a protected case, which is important when transporting and working at a substation.

    MIKO-1, MIKO-2.3, MIKO-21 instruments are used to measure the transient resistance of contact connections of switching devices with a voltage of 6-10-35-110-220 kV. The advantages of these instruments include light weight and dimensions, a durable case, sufficient current for carrying out necessary measurements, autonomous power supply (MIKO-1), the ease of use.

    Basing on our own operational experience, Kamchatskenergo, PJSC recommends these instruments to all energy organizations and enterprises.

    V.V. Skvortsov
    The first deputy of General Director – chief engineer

  • Open Original

    Udokan copper, LLC

    Nowadays, specialists of an electrical laboratory of Udokan copper, LLC operate the following instruments, which are manufactured by SKB EP, LLC: MIKO-9A, MIKO-21 and PKV/M7.

    These instruments have been used since 2020 when conducting a comprehensive diagnostic of power and measuring transformers, high-voltage circuit breakers and disconnectors.

    We would like to note the universality of MIKO-21, extensive functionality when measuring parameters on electrical installations of 4-220 kV: for example, measuring the contact resistance of metallic bounding equipment with an earthing system, measuring the contact resistance of a contact system of circuit breakers with a voltage class of 6-10 -35-220 kV, measuring the contact resistance of bolted joints of 4-220 kV. Speaking about a specified functionality of the instrument, advantages are revealed both in terms of the cost (instead of several instruments we use one) and in terms of labor costs reducing for carrying out work.

    While using MIKO-9A, the following advantages were found: the ability to measure contact resistances of circuit breakers contact system 6-220 kV, measure the ohmic resistance of windings of power and measuring transformers of 6-220 kV with an AUTO 3Ph mode. These advantages can significantly reduce the time for preparing and performing measurements in comparison with instruments of previous generations and produced by other manufacturers.

    The instrument PKV/M7 is a reliable device for measuring parameters of circuit breaker VEB-UETM-220 of 10-35 kV manufactured by Elmash, LLC from Yekaterinburg.

    Having gained experience in the operation of instruments manufactured by SKB EP, LLC, we can confidently recommend these products for conducting a comprehensive diagnostic of power equipment.

    A.V. Sevostyanov
    Chief power engineer

  • Open Original

    COMPANY LIMITED DIMITROVGRADSKY METALLURGICAL PLANT

    On July 1-2 Dimitrovgradsky metallurgical plant, LLC was testing the MIKO-21 microohmmeter. The instrument was used for measuring the electric resistance of copper items.

    MIKO-21 is a convenient multi-functional instrument with user-friendly menu. One of its merits is a large range of manually set values of test current and an option of data downloading to PC. Touch color display, an archive of passport values of tested equipment, independent power supply and small size are also worth mentioning. The instrument demonstrated proper operation, there were no failures.

  • Open Original

    ELMASH (UETM), LLC

    In the first quarter of 2017,  ELMASH (UETM), LLC (Yekaterinburg City), a research and testing division of BBA Production Complex performed pilot operation of MIKO-21 microohmmeter manufactured by SKB EP, LLC.

    The microohmmeter was used for measuring the transient resistance of the main circuits of high-voltage column-type and bulk-oil circuit breakers of ВГБ-УЭТМ®-35, ВГТ-УЭТМ®-110, ВЭБ-УЭТМ®-220 types.

    We should like to note the following merits of the microohmmeter: simple and user-friendly interface, touch display, small size and light weight, availability of the option of connecting the device to PC. Microohmmeter can be powered both from the 230V network and from an in-built battery that is a big advantage since devices are often used far from the available power sources.

    The device’s kit allows a large variety of options. During pilot operation the microohmmeter proved to be a reliable and convenient device. There were no failures observed.

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