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OLTC maintenance check
OLTC in-place check mode (DRM method)
Radial diagram measurement of the resistor and reactor type OLTCs
Resistor type OLTC contactor switchover oscillography
OLTC check in static mode
Automatic self-adjustment to OLTC
Ergonomic calipers or alligator clip cable
Self-contained power supply, storage, transfer and analysis of measurement results in the instrument and PC
The instrument is represented in two modifications

Control instrument of OLTC transformers PKR-2M

Certificates
  • Safety Test Certificate IEC 61010-1:2001
  • EMC Compatibility IEC 61326-1:2005
  • Russian Register of Innovative Products
  • Recommended for use in JSC Russian Railways electric installations
  • PJSC ROSSETI Register of Innovative Solutions
  • Russian State Register Certificates
  • Declaration of Conformity of the Customs Union
OLTC maintenance check

PKR-2M is intended for demountable diagnostics of OLTC all type (both resistor and reactor type), as well as for in-place check, which enables to diagnose OLTCs with current-limiting resistors without removing the contactor tank cover.

OLTC in-place check mode (DRM method)

OLTC in-place check enables to conduct express diagnostics of the OLTC technical condition without opening the tank or OLTC removing. This check enables to obtain the contactor switchover diagrams for a wide range of switching devices (except reactor type ones) and conduct the OLTC condition evaluation based on the obtained diagrams, that gives the reasons to denote a defect nature and grounds for decisions related to repair of these on-load tap changers.

For example, for type RS, RNOA, etc., on-load tap changers the correctness of operation of the main and arcing contactor contacts, their condition (burned or not burned contact), current-limiting resistor integrity may be determined. For type RNTA – 35/320 on-load tap changers and in the analogous on-load tap changers, in which the contactor and selector are changed for a fine control circuit breaker, the main and arcing contacts, current-limiting resistor condition, as well as condition of surface of all fixed contacts of the circuit breaker, through which the moving contacts move, may be checked.

The application of in-place check mode based on the DRM method doesn’t require:

  • Opening of the tank or hatch of the fault-free/faulty OLTC and oil drain;
  • Additional money and labor costs for the OLTC diagnostics;
  • Connection of additional elements or knowledge of resistances of current-limiting resistors of the checked on-load tap changer, since all fine adjustments to a certain OLTC are conducted automatically in the instrument.
Radial diagram measurement of the resistor and reactor type OLTCs

The instrument is completed with a special transducer for the radial diagram measurement. Its interface with shafts of different drives is provided with a set of axes and bushings, which are installed without any tools by simply putting on the shaft extension.

All characteristics are measured simultaneously based on three phases for OLTCs located in the neutral conductor of "star-connected" windings, and single phase for OLTCs located in the line of "star-" or "delta-connected windings".

Resistor type OLTC contactor switchover oscillography

The switchover oscillography enables to detect the actuation delay, non-simultaneity of in phase actuation and bouncing during switchover.

All characteristics are measured simultaneously based on three phases for the OLTCs located in the neutral conductor of "star-connected" windings, and single phase for the OLTCs located in the line of "star-" or "delta-connected windings".

OLTC check in static mode

Check conducted during the drive shaft slow rotation using a handle with simultaneous display of contact closures/openings in degrees and voltage and current values.

Automatic self-adjustment to OLTC

No additional elements (for example, resistors) or knowledge of resistances of current-limiting resistors of the checked on-load tap changer are required to measure the OLTC parameters. All adjustments to a specific OLTC are performed automatically in the instrument.

Ergonomic calipers or alligator clip cable

The instrument is completed with special long calipers to be conveniently connected to some OLTCs (in this case, it is not necessary to drain oil from the contactor tank)..

The instrument may be connected to the on-load tap changer with measuring cables provided with alligator clips without contact calipers with oil being partially drained from the contactor tank or removal of the on-load tap changer from the transformer tank.

Self-contained power supply, storage, transfer and analysis of measurement results in the instrument and PC

PKR-2М is equipped with inbuilt battery, which makes it more mobile and easy to use. The inbuilt battery enables to use the instrument during the entire workday without recharge on the vast territory of substation or workshop, which does not require the use of the power supply cable, mains socket extension cord and grounding.

The instrument is equipped with a large color high-brightness and high-contrast display facilitating the graph processing to present information in graphical or tabular form.

The measurement results are stored in the non-volatile memory of the instrument, on the external flesh memory, and they may be transferred to the computer.

Therefore, the instrument may be controlled by the PC. It enables to measure diagrams being inside a car with the computer, which is important in winter.

The instrument is represented in two modifications
  PKR-2 PKR-2M
OLTC check mode
demountable
demountable and in-place *
Inbuilt battery supply
none
available
(operation time from 2 to 16 h)

* In-place check mode enables to conduct the in-place diagnostics of OLTCs with current-limiting resistors with the contactor tank cover in place. This mode is based on the DRM method (see above) and consists in measurement of current intensity through the winding, in which the OLTC is switched on.

Specifications Value
Time interval measuring range, sec 0.01 ÷ 1200
Maximum permissible intrinsic absolute error of time interval measurement, sec ±(3+tx)×10-4
Time interval measurement resolution ability, ms ±0.1
Angular movement measuring range, degrees 2 ÷ 360
Maximum permissible intrinsic absolute error of angular movement measurement, degrees ±0.56
Direct current intensity measuring range, А 1 ÷ 4
Maximum permissible intrinsic relative error of direct current intensity measurement, % ±2
Direct current electric voltage measuring range, V 1 ÷ 20
Maximum permissible intrinsic relative error of direct current electric voltage measurement, % ±5
Direct current electric voltage measurement range, Ohm 1 ÷ 20
Maximum permissible intrinsic relative error of direct current electric resistance, % ±5
Resistance measurement sampling rate per channel, kHz 10 ±0.1
Maximum recording time (radial diagram measurement), min 20
Maximum recording time (oscillography using the DRM method), min 20
Number of computer communication channels, pcs. 2 (USB, USB host)
Time of inbuilt battery operation in mixed mode (operation/standby), h 2 ÷ 16
Battery charge time from complete discharge till complete charge, h 2.5
Maximum consumed power in start standby mode, W 15
Maximum consumed power in measurement mode, W 210
Operation temperature range, ºС -20 ÷ +50
IP for transportation IP64
IP rating in operating state IP20
Maximum measuring unit weight, kg 6.1
Dimensions, mm 360×290×165
Interface language English
User manuals language English
Calibration period, year 3
Standard complete set
Photo Item, Index Application
PKR-2М measuring unit PKR-2М measuring unit СКБ035.00.00.000-1 Instrument and accompanying documents: inbuilt OLTC in-place diagnostics mode (DRM-test), calibration certificate, operation manual, record book, measurement procedure, software (SW) for PC.
Measuring cable with a connector<br>A, B, C poles cables Measuring cable with a connector
A, B, C poles cables
СКБ035.24.00.000
СКБ035.24.00.000-01
СКБ035.24.00.000-02
СКБ035.29.00.000
Intrusive method of diagnosis. For connection to transformer LTC terminals inside the tank.
Non-destructive method of diagnosis (DRM-test). For connection to transformer terminals up to 200 kV (inclusive).
Short-circuiting cable with ground clamp Short-circuiting cable with ground clamp СКБ032.13.00.000 For in-place check of the transformer OLTCs (DRM-test).
Secondary circuit shorting - G50 (ground clamp jaw opening – 45 mm).
Angular movement transducer DP22 Angular movement transducer DP22 СКБ035.26.00.000 The transducer enables to measure the angle and speed of the OLTC shaft rotation (complete with data sheet and calibration certificate). Angle measuring range – 0 - 360º (it is necessary to select the appropriate axis from the additional complete set).
Ground clamp Ground clamp СКБ035.30.00.000 To fix the DP22 transducer on the OLTC drive.
Handle Handle СКБ028.25.00.000 To fix the magnetic clamp. Handle for the OLTC shaft rotation. It is used together with axes from the additional complete set.
Axis No. 10 together with a bushing Axis No. 10 together with a bushing КБ035.25.00.000
СКБ028.25.01.008
Axis No. 10 is intended for the OLTC drives of MZ-4.1; M3.2; M3-4 types. It is used for the drive PDP-4U together with bushing SKB035.25.05.000.
Mains cable Mains cable СКБ018.09.00.0000 For connecting the instrument to the power line. Temperature range -15 ÷ +45 ºС (length – 1.5 m).
Ground wire Ground wire СКБ010.01.00.000 For instrument case grounding. Equipped with a ground clamp and screw end cap. Rated current – 50А (length – 1.8 m).
VP2B-1V-2А cut-out (2 pcs.) VP2B-1V-2А cut-out (2 pcs.) For power source protection.
Cable and ancillary equipment carrying case Cable and ancillary equipment carrying case СКБ126.06.00.000
Additional complete set (on order)
Photo Item, Index Application
DRM test lead DRM test lead СКБ035.28.00.000 To be used together with the standard СКБ035.29.00.000 test lead at non-destructive diagnosis (DRM-method) for connection to transformer and to auto transformer terminals above 200 kV. Length - 6 m.
Short-circuiting cable with ground clamp Short-circuiting cable with ground clamp СКБ032.13.00.000-01/-02 For in-place check of the transformer OLTCs (DRM-test).
Secondary circuit shorting - G75 (ground clamp jaw opening – 70 mm) and G100 (ground clamp jaw opening – 85 mm) at option. In standard complete set - G50 (ground clamp jaw opening – 45 mm).
A short-circuit cable A short-circuit cable СКБ035.31.00.000 For in-place check of the transformer OLTCs (DRM-test).
Secondary circuit shorting - alligator type clamps with the jaw of up to 50 mm. To be used for LTCs of power transformers and auto transformers (Length - 12 m).
Contact caliper set in a special case Contact caliper set in a special case СКБ035.27.00.000 Contact calipers (7 pcs.) for connection to the OLTC contacts without oil discharge. They are supplied in the convenient lockable carrying case.
Axises for setting a measuring sensor DP22 at the output shaft Axises for setting a measuring sensor DP22 at the output shaft

Select the axis for setting a measuring sensor DP22 at the output shaft:

  • Axis No. 1 - for OLTC drives of BUL type (СКБ035.25.01.000);
  • Axis No. 2 - for OLTC drives of PDP; МА-1; МAK-1 types (СКБ035.25.02.000);
  • Axis No. 3 - for OLTC drives of PDP; МА-1; MAK-1 types (СКБ035.25.03.000);
  • Axis No. 4 - for OLTC drives of PDP; МА-1; MAK-1 types (СКБ035.25.04.000);
  • Axis No. 6 - for OLTC drives of PDP-4U type (when a manual drive is used) (СКБ035.25.06.000);
  • Axis No. 9 - for OLTC drives of PDP-4U type (when an electric drive is used) (СКБ035.25.09.000);
  • Axis No. 7 - for OLTC drives of MZ-4.1, MZ-4.4 types (when the electric drive is used) (СКБ035.25.07.000);
  • Axis No. 8 - for OLTC drives of MZ-4.1, MZ-4.4 types (when the manual drive is used) (СКБ035.25.08.000);
  • Axis No. 11 - for OLTC drives of SMA-7 (SMS-China), ED 100/200 S, ED 100/200 S types (MR-Germany) (when the manual drive is used) (СКБ035.25.11.000);
  • Axis No. 12 - for OLTC drives of SMA-7 (SMS-China), ED 100/200 S, ED 100/200 S types (MR-Germany) (when the electric drive is used) (СКБ035.25.12.000);
  • Axis No. 13 - for OLTC drives of VAKUTAP type manufactured by MR (СКБ035.25.13.000);
USB 2.0 A-B cable USB 2.0 A-B cable For the instrument connection to PC (length – 1.8 m).
Manipulating rod Manipulating rod СКБ010.41.00.000
СКБ010.41.00.000-01
СКБ010.41.00.000-02
The rod is designed to ensure convenient connection to contacts of a transformer inputs.

The rod is completed with a clamp with current and potential contacts connected by wires with the measurement platform. Test cables are connected to the measurement platform from the ground.

  • Manipulating rod for equipment of up to 35kV (2.2 m);
  • Manipulating rod for equipment of up to 110kV (3.7 m);
  • Manipulating rod for equipment of up to 220kV (5.1 m);
Safety Test Certificate IEC 61010-1:2001 on the PKR-2
EMC Compatibility IEC 61326-1:2005 on the PKR-2
PKR-2 and PKR-2M is included in Russian Register of Innovative Products under #230, valid until 07.04.2018.
PKR-2 and PKR-2M is included in Russian State Register under #59602-15, valid until 16.01.2020.
PKR-2M - № EAC RU Д-RU.ME97.B.00023; valid until 11.09.2019
Testimonials about Milliohmmeter MIKO-8, PKR-2, PKR-2M
Irkutsk State Technical University

In the period between August 9-11 the Research Laboratory for Electric Equipment Testing of the Irkutsk State Technical University performed diagnosis of a block-type TDTNG 75000/110 transformer at a thermal power plant TPP-9 of OJSC Irkutskenergo using your instruments. Resistances of transformer windings were measured using the MIKO-8 microohmmeter. Circular diagrams of LTC transformer were obtained using PKR-2 instrument.

It should be noted that the instruments are of high quality, they are compact and have a number of advantages over similar instruments of other firms (particularly, user-friendly interface, ability to review curves of the instrument signal on site).

On the whole the instruments were highly appraised by our specialists.

Testimonials about PKR-2, PKR-2M, Micromillikilloohmmeter MIKO-2.3
OJSC RUSSIAN RAILWAYS BRANCH NORTHERN RAILWAY STRUCTURAL SUBDIVISION ELECTROTECHNICAL LABORATORY

In 2011 the elctrotechnical laboratory performed trial operation of PKR-1 (an instrument for transformer testing), PKV/M7 (an instrument for high-voltage circuit breaker testing), MIKO-2.3 (micromillikiloohmmeter) instruments manufactured by SKB EP. The instruments demonstrated high efficiency and are of great practical value.

The MIKO-2.3 instrument replaces the whole set of diverse devices for measuring both low (e.g., transient resistances of contacts, DC resistance of transformer windings) and high (e.g., shunt resistances of circuit breakers) resistances. Despite that the instrument is simple in operation, compact and has low weight. Its advantage is ability to be powered both from a battery and from a 220 V network. Rapid saturation of windings during DC resistance measurements drastically reduces the period of measurements.

PKR-1 device for transformer testing is worth special mentioning. Northern Railways currently has no specialized instruments for LTC diagnosis and for recording the circular diagram, therefore, this equipment is of special value. The instrument is easy to operate, has a friendly interface, is rather compact and convenient for transportation, measurements do not take much time. Defects were detected in six out of nine tested transformers and their presence was confirmed during repair.

Testimonials about PKR-2, PKR-2M
Branch of OJSC OGK-3 "Kostromskaya GRES"

PKR-1 Instrument has been successfully used by our Company since 2008 for controlling the operation of LTC transformers of TRDNG-32000/220, TRDNS-32000, 40000, 63000/35, TRDN-25000/35 type, and of autotransformers of ADOTsTN-267000/500/220 type. The instrument is robust, reliable, convenient in operation, and is of practical value.

Unlike other instruments, the instrument allows taking the oscillograms of contacts operation and circular diagram of three phases simultaneously without installing additional external elements, such as connections or external resistors. It also allows cursor measurements of contacts oscillograms parameters. The interface is user-friendly. Graphs can be viewed on the monitor. Under the lack of power supply the instrument can make measurements both from the electric drive and from the manual LTC drive.

Articles (3)
Peculiarities of Checking the State of the RNTA 35/320 OLTC Closing Switch
Peculiarities of Checking the State of the RNTA 35/320 OLTC Closing Switch
Parameters of the closing switch change-over oscillogram are among the indicators reflecting the state of high-speed OLTC devices.
Detection of faults in the transformer LTS devices. Enhanced DRM method
Detection of faults in the transformer LTS devices. Enhanced DRM method
For revealing the causes of LTC failures and for automation of the diagnosis the SKB EP Company entered the instrumentation market with the PKR-2 and PKR-2M instruments for the transformer LTS testing. Their main function is recording the oscillograms of contators operation and the circular diagram across all the phases at a time.
Reviews (3)
The PKR-2M testing at OJSC ZAVOD RETO Company
The PKR-2M testing at OJSC ZAVOD RETO Company
Early in December the SKB EP specialists together with specialists of  OJSC ZAVOD RETO conducted multi-disciplinary tests of new software of the PKR-2M instrument for the transformer LTC diagnosis. Tests were performed on the maintained transformer with LTC device of RS-9 type.
Testing of PKR-2M in OJSHC "ELEKTROZAVOD"
Testing of PKR-2M in OJSHC "ELEKTROZAVOD"
At the end of June, tests of the new control instrument for PKR-2М OLTCs VACUTAP MR on TRDTSN-200 MBA 220/11 kV power transformer with OLTC have been carried out.