Routine test of SKB EP devices on oil circuit breaker of U-220 type

In order to keep up with the times and to manufacture devices that meet all current customer needs, SKB EP constantly carries out device testings at various facilities.

Recently SKB EP engineers have visited the substation of Southern Electric Networks the branch of IESK, JSC and worked on an oil circuit breaker of U-220 type using universal HV circuit breaker analyzer PKV/U3.0 and multipurpose low / high resistance meter MIKO-2.3.

This exact circuit breaker is old and it has been in operation for quite a long time, so soon it will be replaced with the modern one. However, thus far it requires diagnostic.

SKB EP engineer measured the main contact resistance of the circuit breaker with the help of MIKO-2.3 low / high resistance meter. The measurement results were satisfactorily.

MIKO-2.3 is a portable mini-laboratory allowing to perform all tasks connected with resistance measurement in electrical equipment as this instrument operates in four modes: micro-ohmmeter, milli-ohmmeter, kilo-ohmmeter and thermometer. At the same time, its weight is only 2.7 kg, which ensures the best mobility at the substation.

Hereafter, the time, travel and speed parameters of the high-voltage circuit breaker moving parts were measured with the use of PKV/U3. Universal circuit breaker analyzer PKV/U3 provides control of main parameters of the circuit breaker as well as of voltages and currents of electromagnets and solenoids.

During the diagnostic a big time delay was found in contact switching. With this information we provided the employees responsible for planning and performing further works on the circuit breaker.

PKV/U3 is represented in two modifications: PKV/U3.1 and PKV/U3.0, which have some differences:

Voltage class of tested circuit breakers

from 6kV to 1150kV
from 6KkV to 500kV
Circuit breakers subject to testing
all, except for air-blast circuit breakers of VO-750, VO-1150, VNV-1150 types
Number of variable-resistance transducer channels
12 2
Number of movement transducer channels
3 1

One of the main PKV/U3 advantages is its ability to check travel and speed parameters by three phases simultaneously. It is possible with the use of additional transducers. For example, while performing measurement with one transducer, you have to measure travel parameters of each pole by switching from one pole to another performing three Close/Open operations. However, applying three transducers simultaneously, which can be done with PKV/U3, you will be able to perform measurement process much quicker as only 1 Close/Open operation will be needed.

PKV/U3 allows to reduce diagnostic time, and, what is more, it allows an early defect detection in HV circuit breaker mechanisms through digital data and graph analysis. It helps to increase the lifespan of switching equipment.

If you have any questions about PKV/U3 or MIKO-2.3, feel free to contact us via phone +7 (812) 500-25-48 or via e-mail

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