SKB PKV / M7 回路遮断器の状態の診断

Maintenance check of switches of Soviet-, Russian- and foreign-manufactured (ABB, AREVA, ALSTOM, SIEMENS, etc.) circuit breakers:

• Checkout of speed and travel parameters of oil, vacuum and SF6 high-voltage circuit breakers with 4 poles;
• Checkout of time characteristics of high-voltage disconnecting, isolating and short-circuiting switches;
• Measuring of electromagnet currents and voltages and solenoid heavy currents with the help of clamp meters;
• Built-in remote control for setting of ordinary operations and compound cycles for circuit breakers with the current of up to 14A for DC/AC drives.

PKV/M7 instrument is complete with attachment devices for the installation of measuring transducers on all types of Russian- and foreign-manufactured (ABB, AREVA, ALSTOM, SIEMENS, etc.) high-voltage circuit breakers. Adaptability of the instrument involves designing of transducer attachments to the circuit breakers and receiving of transfer function of movement from the shaft to the cross-arm. Transfer functions of kinematic chains of all circuit breakers are stored in the memory of the instrument. Adaptation work began with the first produced model of the instrument (PKV/М1) in 1995 and continues to this day.

Wide ranges of measurement by time (up to 5.1 sec), speed (up to 20 m/sec) and travel (up to 900 mm), covering the needs for monitoring of all existing high-voltage circuit breakers. For instance, the smaller time range of similar instruments does not allow for monitoring the operation of circuit breakers in compound cycles.

There are a number of nuances at measurement performance. For example, while registering of time characteristics of any high-voltage circuit breaker is quite a simple process, receiving of travel and speed characteristics can be performed only with the use of special linear and angular movement transducers.

PKV/M7 is supplied with incremental (discrete) transducers for measurement of speed characteristics and travel parameters which do not require adjustment or correction of conversion factors; these transducers provide accurate results and are convenient in service.

Instruments with wire rope transducers, for instance, have a limited upper value for speed. Pull-back spring of these transducers does not have enough time to reel the wire rope onto the drum in case of rapid change of speed and measurement results become less accurate. It is not recommended to use laser movement transducers as there is a risk of eye damaging by the laser beam in case of mishandling. Moreover, laser transducer is installed by sight without any fixing devices which contributes to bigger measurement errors.

High measurement accuracy when measuring time characteristics (±0.1 ms), as well as travel and speed characteristics is ensured by digital angular and linear movement transducers with the accuracy grade of 0.09° and 0.5 mm. Potentiometer-based transducers usually used in other instruments similar to PKV/M7 have poor accuracy (of up to 1%) even in normal conditions. With the maximum travel of 900 mm. it gives measurement uncertainty of ±9 mm.

The expanded set of time, travel and speed characteristics both for drive shaft and contacts as well as of voltages and currents of electromagnets and solenoid of the drive: time diversity, bounce durability, delay, rebound and transfer, medium velocities at various sections of travel, etc.

Along with the tables of digital values of parameters more detailed information on the circuit breaker condition can be obtained from the following registered graphs of processes:

• relation between speed and time, speed and travel;
• relation between electromagnet currents and voltages, and time and travel;
• diagrams of contact opening-closing.

The type of graphs is defined by the state of all parts (levers, springs, drafts, axes, cross-arms, damper, etc.) of the kinematic chain of the mechanism regulating opening-closing of circuit breaker contacts. Malfunction of any part of the mechanism (play increase, spring slackening, excessive friction, damper failure, etc.) immediately changes the type of graph from the normal type meant for properly functioning circuit breaker. SKB EP has developed a special method of graph analyzing which when applied provide for early in-place diagnostics of the state of the circuit breaker.

PKV/M7 switch allows for monitoring of circuit breakers both in simple and compound cycles of switching with electromagnet currents of up to 14А (direct and alternate) with setting of the required duration of impulses of switching close/open and pause/delay of switching open.

It is often required to check circuit breakers by performing their switching on not from the drive but, for instance, from a jack. For this purpose PKV/M7 has a mode “ruler/angle meter”, in which the instrument shows real-time value of circuit breaker travel (shaft turn angle) or the status of contacts (close/open).

If you have to carry out diagnostics in difficult weather conditions you can be sure that PKV/M7 will provide you with the most accurate results as it operates properly in the temperature range from -15 to +50°С.