Ko da zaune da kusa da muhimmanci na gwamnati masu aiki a makarantun takardun gida daga cikin mafarin kwakwalwa na tsari

A cikin 15 shekara a kimiyyar kula

Sannu duka, ina ni Felix, wanda na yi aiki a cikin kimiyyar kula ne 15 shekara.

Daga harkokin yakin da na faruwa a substation masu tarihi zuwa yanzu na gudanar da aikinsu a kan abubuwan photovoltaic da kuma kula mai haruffaci, wanda mafi yawan da na sani shi a kan abubuwan da na yi shi shine Electromagnetic Voltage Transformer (PT).

Yau, wanda ya bincike ma'a muni a kan sabbin kula:

“Tana da PT da yake da tsirrai, tana koyarwa, kuma yana iya haifar da malamai. Wani abu ya faru?”

Wannan shine matsalolin da ya fi girma, musamman a kan sabbin kula. Idan PT ya faru, zai iya haifar da duk daidai daga ba da cewa bayanai ba da kasa ta da kuma kafuwarsa.

Yanzu, na son ci gaba:

Wadannan su ne matsalolin da aka fi sani game da electromagnetic voltage transformers? Me ya faru? Da kuma me muna gudanar da su?

Babu kalmar da aka fuskantar - kawai halayen da na samu a shekarun da na yi. Bana da neman waɗanda ya faru da wannan "hadin".

1. Me ke Electromagnetic Voltage Transformer?

Muna biyo da takarda da take aiki.

Electromagnetic voltage transformer, wanda ake kira VT ko PT, shine transformer mai kawo da take kawo kula mai yawa zuwa kula mai hankali (sauran 100V ko 110V), wanda ake amfani da shi a kan bayanan bayanai da kuma systems of relay protection.

Kasashensa ya fi yawa: primary winding ya fi yawa da many turns da wire mai karfi, wanda ake kawo zuwa kulan kula mai yawa; secondary winding ya fi yawa da fewer turns da wire mai yawa, wanda ake kawo zuwa control circuit.

Amma, saboda wannan kasashen yadda, ana iya kasancewa da operating conditions, load changes, da resonance phenomena.

2. Matsalolin da Aka Fi Sani Da Kuma Tabbacin Abubuwa

Ta hanyar 15 shekarun da na yi a field, wadannan su ne matsalolin da aka fi sani:

Fault 1: Tsirrai Mai Yawa Ko Kuma Koyarwa/Burnout

Wannan shine wata matsala mai yawa - zai iya haifar da insulation degradation ko kuma fire.

Abubuwan Da Ya Faru:

• Secondary short circuit ko overload (misali, multiple protection devices connected in parallel without checking capacity);

• Core saturation (musamman a ferroresonance);

• Insulation aging ko moisture ingress;

• Loose terminals causing high contact resistance and localized heating.

Halayen Gida:

Yau, na sami PT da yake da tsirrai mai yawa a PV step-up station - infrared thermography ta bayyana temperatures over 120°C. Idan an rufe shi, na sami cewa secondary winding insulation ta koyarwa. Sabucin da ya faru shine open circuit condition caused by a disconnected secondary breaker while still connected to a high-impedance meter.

Tips:

• Babu da PT secondary don rufo - although not as dangerous as CTs, it can still cause voltage distortion and measurement errors;

• Use infrared thermography regularly to check terminal and enclosure temperatures;

• If abnormal heating is detected, shut down immediately for inspection.

Fault 2: Ferroresonance Causing Voltage Fluctuations

Wannan shine wata matsala mai fi sani amma mai yawa a sabbin kula.

Symptoms:

• Unbalanced three-phase voltage;

• Voltage fluctuating up and down with buzzing noise;

• Protection misoperations or false trips;

• Sometimes even false ground signals appear.

Root Cause:

• In ungrounded or arc suppression coil grounded systems, when line-to-ground capacitance combines with PT excitation inductance under certain conditions, ferroresonance can occur;

• It often gets triggered during breaker switching, sudden loss of voltage, or single-phase grounding.

Halayen Gida:

A wind farm, kuli lokacin da main transformer ya zama, PT ta koyarwa, bus voltage ta zama mai yawa, kuma ya haifar da standby auto-switch incorrectly. Ba da neman, an sami cewa shine ferroresonance. An zaɓe damping resistor a open delta don haifar da wannan.

Prevention Suggestions:

• Install anti-resonance devices (such as open-delta resistors or microprocessor-based suppressors);

• Use anti-resonant type PTs (like JDZXW series);

• Optimize operation mode to avoid long-term non-full-phase operation;

• During outage maintenance, perform magnetizing curve tests to assess core saturation tendency.

Fault 3: Low or No Secondary Voltage Output

Wadannan su ne matsalolin da su iya haifar da bayanai da kuma logic of protection, kuma babu wani lokaci na iya haifar da failure of other devices.

Possible Causes:

• Primary fuse blown (often after lightning strikes or overvoltage events);

• Secondary fuse blown or air switch tripped;

• Incorrect polarity or ratio setting;

• Inter-turn short circuits in internal windings;

• Oxidized or loose terminal connections.

Halayen Gida:
A PV station, SCADA ta bayyana abubuwa mai yawa bus voltage. A cikin bayanin, an sami cewa PT primary fuse ta koyarwa. Bayan an sa shi, an zama da shiga. Bayan neman, an sami cewa shine lightning strike da ya haifar da wannan.

Troubleshooting Steps:

• Check fuses and breakers first;

• Measure primary and secondary voltages for consistency;

• Verify wiring and polarity;

• Perform ratio test and insulation resistance test if necessary.

Fault 4: Internal Discharge or Insulation Breakdown

Wannan yana faru a cikin wurare da suka da ƙaramin ruwa ko jirgin lura, musamman a cikin wurare da suka da tsakiyar ruwa ko wurare mai yammacin.

Symptoms:

• Smell of burning or visible discharge marks on housing;

• Crackling sounds during operation;

• Reduced insulation resistance;

• In severe cases, explosion or tripping occurs.

Possible Causes:

• Moisture ingress causing insulation deterioration;

• Surface dirt or dust buildup reducing creepage distance;

• Long-term overloading or harmonic effects;

• Manufacturing defects or transport damage.

Halayen Gida:

PT installed near the coast repeatedly tripped during the rainy season. Inspection revealed clear signs of internal discharge — the root cause was poor sealing allowing moisture to enter.

Countermeasures:

• Increase protection rating (IP54 or higher);

• Install dehumidifiers or space heaters;

• Regular cleaning and drying;

• Conduct insulation and partial discharge tests before commissioning.

Fault 5: Human Error or Wiring Mistakes

Human error remains a major cause of many incidents.

Common Mistakes Include:

• Switching isolators under secondary load;

• Reversed polarity causing incorrect metering or protection misjudgment;

• Accidental removal of grounding wires leading to floating potentials;

• Performing live work without proper safety measures.

Halayen Gida:

A new technician replaced a PT secondary fuse without disconnecting the power, causing a short circuit — the fuse holder burned out and nearly caused injury.

Key Takeaways:

• Strengthen training and standardize procedures;

• Clearly label wiring to prevent mistakes;

• Enforce lockout/tagout procedures to eliminate live work;

• Ensure one-point grounding of all PT secondary circuits.

3. My Suggestions and Field Experience Summary

As a 15-year veteran in the electrical field, I always say:

“Though small, the electromagnetic voltage transformer plays a critical role in measurement, metering, and protection.”

It may not be as noticeable as a circuit breaker or as large as a transformer, but once it fails, it can trigger a chain reaction.

So here are my recommendations:

For Daily Operation & Maintenance:

Regular inspections — listen for unusual sounds, smell for burning, and measure temperature;

• Check fuses, breakers, and grounding integrity;

• Record operational data and compare with historical trends;

• Increase inspection frequency before and after thunderstorm seasons.

For Fault Diagnosis:

• Prioritize checks on secondary circuits and fuses;

• Use multimeters to verify voltage levels;

• Conduct insulation resistance, ratio, and magnetizing characteristic tests when needed;

• Take immediate action to suppress resonance if suspected.

For Equipment Selection:

• Consider environmental factors (humidity, altitude, salt fog);

• Prefer anti-resonant PTs;

• Choose appropriate rated capacity to avoid long-term overloading;

• Leave room for redundancy to support future expansion.

4. Final Thoughts

Although structurally simple, electromagnetic voltage transformers play a vital role in new energy power plants.

They act like the "eyes" of the power system, telling us exactly how "high" the voltage is.

After 15 years in the field, I firmly believe:

“Details determine success or failure. Safety comes above everything.”

If you're dealing with tricky PT issues on site, feel free to reach out — I'm happy to share more hands-on experiences and troubleshooting methods.

May every PT operate stably, keeping our grid safe and intelligent!

— Felix