ვაკუუმის პირობების ზომება ვაკუუმის ინტერრუპტორში მექანიკური წნევის მონიტორინგის მეთოდით

Vakuumis Sistemi Monitoresi Vakuumi Peretadlebisshi

Vakuumi peretadleebi (VP) xarjisxva da matanatvis sasaqleblad mis gamoqenebit medium voltage energiis sistemebis saxelze. VP-si gavrdzenili arsebobs sxvadasxva, mediumda da high-voltage sistemebis dros. VP-sia efektivobis ganxilasheba romelic unda daami internaluri dazgveulis naxazi 10 hPa-s danatsa (1 hPa = 100 Pa da 0.75 torr). Fabrikas chvenjere, VP-sia testirebt, romelic unda daami internaluri dazgveulis naxazi ≤10^-3 hPa.
VP-sia efektivobis ganxilasheba korelirebulia vakumis naxazze; amma, ar aris proporcionaluri internaluri dazgveulze. Dazgveuli VP-sshi mitxebs vamowmebuli tri grupis:

•    Naxazi: 10^-6 hPa-dan zemo
•    Mid-Range Dazgveuli: 10^-3 hPa-tan Paschen minimum dazgveulis naxaziwde
•    Dideba Dazgveuli: Isina shegzlia failuris, romelic airze davxilavs

Naxazi dazgveulis naxazi, VP-si efektivs funqirebat. Mid-Range dazgveulis naxazi, dielectric strength da interruption capabilities degregradirebat, romelic procesi nadavzavebs "up-to-air" naxez. Interesuli, romelic mid-range dazgveulis naxazi, dielectric performance aris ena zemo, amma up-to-air naxez aris davxilebuli parcxveneba, amma ar aris naxazi naxazi.
Ganxilasheba romelic monitores metodebi ar aris cvlilebeli VP-sia dazgveulis naxazi, naxazi "up-to-air" naxez. Mag adgil metodi aris konkretuli naxazi, romelic textshi da Table 1-s daagidebit. Asaki, metodebis efektivobis ganxilasheba variebreba VP-sia dizainze, da mag outputs ar isina influencira gasi, romelic potencialurad davxilavs VP-sshi, tamashi atmospheric air da GIS switchgear-is SF6 gasi.

VP-sia shiirebi medium voltage switchgear-is unda daamatas unda daami problemi, romelic vakumis integrity field-s ver moqmede, amali 20 wels daamatas sxvadasxvas. VP-sia inspekcioebi 20 wels daamatas sxvadasxvas aris mixed results. Ganxilasheba romelic VP-sia aris komponenti didi sistemebs, mekhanizmi, control circuitry, circuit design da other elements-i efektivobis VP-sia operaciebis unda daami kritikulia.

Table 1 provides a summary of the general applications of these monitoring techniques in SF6 environments, along with practical considerations for their use with GIS switchgear. This table also outlines the outcomes of various test methods, highlighting the complexities involved in ensuring the long-term reliability of VIs in diverse operational contexts. Understanding these nuances is essential for optimizing the performance and longevity of electrical systems reliant on vacuum interrupter technology.

Vakuumi Peretadlebis Sistemis Monitoresi Mekhanikuri Dazgveulebis Metodebi

Atmospheric pressure exerts a substantial closing force on the moving terminal of vacuum interrupters (VIs). For VIs used in circuit breakers, this force typically amounts to several hundred newtons. When the vacuum inside the VI is completely lost, the internal pressure equalizes with the external atmospheric pressure, significantly reducing the closing force and altering the mechanical behavior of the VI. Diagnostic methods based on detecting this change can only identify when the VI has fully lost its vacuum, i.e., it has become "up-to-air." Notably, even at pressures as high as those near the Paschen minimum, sufficient pressure remains inside the VI to maintain full closing force.

Mekhanikuri Dazgveulebis Metodebis Prangisi

Mekhanikuri dazgveulebis metodebis prangisi aris additional movable component-is gadakvevi VI-s da bellows da similar mechanism-is gamoyeneba (refer to Figure 1). Vakumi archeuldeba, additional part-is movment occurs due to the equalization of internal and external pressures. Unlike the moving contact, which is constrained by the circuit breaker mechanism, this additional part is free to move. A detection system monitors the position changes of this additional component and reacts accordingly. Depending on the detection system used, this setup allows for continuous monitoring of the VI. The motion of the additional part is determined by its own design rather than the overall VI design, making this method applicable to low, medium, and high-voltage VIs.
Practical Considerations

While theoretically possible, using the closing force on the VI's moving terminal to detect vacuum loss presents challenges. Atmospheric pressure normally applies a force of several hundred newtons to the VI’s moving terminal, whereas the circuit breaker itself applies a closing force of several thousand newtons. Therefore, identifying a reduction in the VI’s closing force through the breaker's mechanical behavior is difficult due to the relatively small magnitude of the VI closing force compared to that of the circuit breaker. In vacuum contactors, however, where the applied force from the contactor mechanism is lower, diagnosing complete vacuum loss through mechanical behavior may be more feasible.

By employing an additional moving part and a detection system, mechanical pressure monitoring offers a practical solution for continuously assessing the vacuum condition of VIs. This technique provides a reliable means to detect total vacuum loss, although it cannot identify partial pressure increases within the VI. Nonetheless, it represents a valuable tool for ensuring the integrity and functionality of VIs across various voltage levels and applications.

This method ensures that any significant vacuum loss is promptly detected, allowing for timely maintenance or replacement actions, thereby enhancing the reliability and safety of electrical systems relying on VIs.

Vacuum Interrupter Monitoring Using Mechanical Pressure Monitoring Method Background

The mechanical pressure monitoring technique assesses the vacuum integrity of a Vacuum Interrupter (VI) by detecting changes in mechanical behavior due to the loss of closing force caused by atmospheric pressure on the moving terminal. This method provides a binary, pass/fail measurement indicating whether the VI has lost its vacuum and is "up-to-air." Pressures around the Paschen minimum and other critical points where VI performance begins to degrade are too low to cause any detectable mechanical change using this method.

Advantages and Disadvantages of the Mechanical Pressure Monitoring Method

Advantages:
•    Compatibility: The method is generally compatible with various insulation types, including SF6, oil, and solid insulation, provided that practical issues such as space constraints and guiding light to detection equipment can be managed.
•    Optical Technique Benefits: Utilizing an optical technique allows for relocating non-optical components into the low-voltage compartment of the switchgear, which can enhance safety and ease of maintenance.
Disadvantages:
•    Installation Requirement: The moving part necessary for pressure monitoring must be installed during the initial manufacturing of the VI. It cannot be retrofitted to already built VIs. While it might be theoretically possible to integrate VIs equipped with this feature into existing circuit breakers along with the required monitoring equipment, practical challenges related to fitting the extension for the extra part into existing installations often make this impractical.
•    Reliability Concerns: The reliability of the measurement equipment compared to the VI itself poses a significant risk. Additional brazed parts added to the VI introduce potential new leak paths and may be more susceptible to damage during installation, potentially leading to vacuum loss.

Fragility of Components:

• Optical Techniques: Fiber optics used in the detection system are vulnerable to misalignment, damage during installation, and blockages from condensation or dust.

• Electrical Contact Method: Motion detection via electrical contacts requires a powered microcircuit near the VI, which must also be electrically isolated. This introduces several potential failure modes, including issues with microcircuit reliability, successful signal transmission, powering the circuit, and maintaining electrical isolation.

In summary, while the mechanical pressure monitoring method offers a straightforward way to confirm if a VI has completely lost its vacuum, it comes with notable limitations. These include the inability to retrofit existing VIs, potential reliability concerns with additional components, and practical challenges related to installation and operation. Careful consideration of these factors is essential when deciding on the suitability of this method for specific applications. Ensuring robust design and implementation can help mitigate some of these risks, thereby enhancing the overall reliability and effectiveness of vacuum interrupter monitoring systems.