Wata Tstsa Da Turanci Da Yawan AIS Current Transformer Ya Zama Da Koyar?

Sannu da duka, ina ni Oliver, mai 10 shekaru a matsayin mutanen tushen karkarun jirgin gida. Yanzu zan iya hada kan abu mai yiwuwa — yadda za a sani cewa current transformer (CT) wanda ake amfani da shi a Air Insulated Switchgear (AIS) ya fi shahara? Wannan ba na biyan haruffa kawai bane, yana arewacin hankali ga dalilin kyakkyawan abubuwa, kudaden gwamnati, da kuma adadin inganci mai daidai.Za mu ci gaba — ta hanyar ilimin kaɗansu.

Bayani

A substations ko kuma tushen kawalawa, current transformers suna da muhimmanci mai yawa. Suna haɓaka currents mai yawa don kayayyakin da suka da kayayyaki, hukumomin, da kuma kawalwar.

Don hakan da su yi da tabbataccen hankali, ana bukatar wurare da za a yi — daga wurare masu ƙungiyar zuwa wurare masu ƙarin samun da take da tattaunawa.

Duk da wannan, wadannan wurare mahaifi ne?

Ina bayar ku da su kadan-kadan.

Babu 1: Wurare Masu Kayayyakin Da Ake Yi A Ƙungiyar Tsakiyar Samun Da Take Da Tattaunawa
(1) Wuraren Dukkiyar Dabbobi

Wannan ita ce mafi muhimmanci — amma mafi muhimmanci — daga cikin wurare.

• Dalili: Don duba cewa dukkiyar daban-daban, daban-daban uku, da kuma kayayyakin da suka da kayayyaki an sauya.

• Tarihi: Amfani da megohmmeter (dabbobin dukkiya) don adadin resistance.

• Ma'adini: Tana da tsari a ƙarin da 500 MΩ, amma irin abubuwa ke na ƙarin da ma'adinta masu ƙungiyar ko kamar IEC ko IEEE.

Adadin da ya ƙara yana nuna cewa an samu ruwan da suka da rukan, dukkiya ta daɗe, ko kuma abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da abin da suka da ab......

(2) Wuraren Dukkiyar Voltage A Tsarin Kwallon Kirkiya (Wuraren Dielectric)

Ana kiran wannan da "hi-pot" test.

• Dalili: Don tabbatar cewa CT ya fi shahara wajen haɗa voltage mai yawa bane ta hanyar karshen gwamnati ko transient overvoltages.

• Tarihi: Amfani da voltage da yake ƙara da rated (misali, 3 kV don 1 kV-rated CT), gaba daya da shekara.

• Me Yadda Ka Duba: Duk abu da ya samu arcing, flashover, ko dukkiya ta daɗe.

Wannan tana ba da shi wajen haɗa stress mai tsabta daga elektrik.

(3) Wuraren Ratio Error

Muhimmancin CT shine duba currents daidai.

• Dalili: Don tabbatar cewa actual current ratio ya danganta da nameplate value.

• Yadda An Yi:

• Adadin primary da secondary currents a farkon loads.

• Lalace error percentage.

• Tsari Mai Daɗe:

• Don metering CTs: ±0.5%

• Don protection CTs: ±1% ko ƙarin, na ƙarin da takarda.

Za mu iya daidai — musamman idan adadin inganci ko logic mai hukuma ke da ita.

(4) Wuraren Polarity Check

Abubuwa da suka da polarity errors suna iya ƙara abubuwa mai yawa, musamman a circuits masu differential protection.

• Dalili: Don tabbatar cewa direction da ta daɗe ya danganta da primary da secondary windings.

• Tarihi:

• DC method: Apply DC voltage da ƙarin lokaci da kuma duba deflection a voltmeter.

• AC method: Amfani da standard CT don compare phase angles.

• Best Practice: Duba da ƙarin bayan samun da take da tattaunawa.

Ba a yi wannan — yana da kyau a yi amma babu ƙananan a lura.

Babu 2: Wurare Masu Kayayyakin Bayan Samun Da Take Da Tattaunawa
（1）Wuraren Grounding Resistance

Grounding mai daɗe yana da muhimmanci don hankalin da kuma kayayyaki.

• Aikata: Ground resistance tester.

• Target: Gaba ƙarin da 4 ohms, amma ma'adinta mai ƙarin za a iya zama a cikin takardun mai daɗe.

• Me Yadda Ya Muhimmi: Grounding mai daɗe zai iya ƙara electric shock risks, damage to equipment, ko kuma false tripping.

Yana da muhimmanci a AIS setups masu gida da take da takardun al'umma da tattalin arziki.

(2) Wuraren Secondary Loop Continuity

Yana tabbatar cewa ba a kan open circuits ko loose connections a wiring uku.

• Tarihi: Amfani da multimeter don check for continuity across terminals.

• Muhimmanci:

• Open circuit zai iya ƙara dangerously high voltages.

• Loose connections zai iya ƙara signal loss ko overheating.

Ba a energize CT da open secondary ba!

(3) Wuraren Temperature Rise

Overheating zai iya ƙara dukkiya ta daɗe da kuma ƙasa ƙasa CT.

• Tarihi: Run the CT at rated current for a set time and monitor temperature rise.

• Limits: Must stay within specified thermal limits (e.g., 55K rise for Class B insulation).

• Tools: Infrared thermography or embedded temperature sensors.

Helps identify poor contact points or inadequate cooling.

(4) Dynamic Response Test

Checks how well the CT responds to sudden changes in current, such as short circuits.

• Method: Inject a simulated fault current and observe secondary output behavior.

• Goal: Ensure fast, stable response for reliable protection triggering.

Crucial for applications involving relay protection systems.

Babu 3: Wurare Masu Kayayyakin A Cikin Ƙarin Samun Da Take Da Tattaunawa
(1) Partial Discharge Detection

Early signs of insulation degradation often appear as partial discharges.

• Technique: Use ultrasonic or ultra-high frequency (UHF) sensors to detect discharge activity.

• Frequency: At least once a year for critical systems.

• Benefits: Early warning before major insulation failures occur.

Especially useful for aging equipment or units operating in harsh conditions.

(2) Accuracy Calibration

Over time, due to aging or environmental effects, CT accuracy may drift.

• Approach: Remove key CTs periodically and recalibrate in a lab setting.

• Interval: Varies by usage, but typically every 3–5 years for metering CTs.

Ensures continued compliance with standards and avoids billing disputes.

(3) Visual Inspection & Cleaning

Simple but effective.

• Checklist:

• Cracks or discoloration on housing

• Corrosion on terminals

• Dust buildup or blockage in ventilation

• Action: Clean with dry cloth, tighten connections, replace damaged parts.

Combine with regular patrols for early detection of issues.

Final Thoughts

Testing a current transformer in air insulated switchgear isn’t something you can afford to take lightly. From basic factory checks to field commissioning and long-term monitoring — every step plays a vital role in ensuring safe, stable, and accurate operation.

Here’s a quick recap of the key tests:

If you're working with AIS CTs and have questions about any of these tests — or need help interpreting results — feel free to reach out anytime. I’d be happy to share more hands-on tips and troubleshooting techniques.

Let’s keep our CTs running strong — silently guarding our power systems behind the scenes.

— Oliver