Cad é a chuirpí bunúsach fóiléirí volaithe féirmeagmha i stáisiúin forbartha nua-aoise?

Ag Felix, 15 Bliain sa Tionscal Leictreach

Dia duit go léir, is mise Felix, agus táim ag obair sa tionscal leictreach le 15 bliain.

Ó mo chuid rannpháirtíochta i bhfeidhmiú agus údarású stáisiún tréithe tradiciúla go dtí anois, nuair a bhíonn mé ina bhainisteoir ar oibriú córais leictreacha do roinnt tionscadail ghlaisghine agus fuinneamh ghaoithe, is é an comhartha is coitianta a bhíonn orm ná an Trasnachóir Voltáige Eilemhithe (PT).

An lá eile, d'fhiafraigh oibrí seifti in ionad fhuinnimh nua de:

“Tá trasnachóir voltáige eilemhithe againn atá tar éis a bheith trína chion agus a dhéanamh torrach, agus uaireanta cuireann sé isteach ar na scéimeanna cosaint. Cén fáth?”

Is í seo ceist an-choitianta, go háirithe i n-ionaid fhuinnimh nua. Mar chomhartha mearaithe agus cosaint ríthábhachtach, más faoi bhréag a tharlaíonn PT, is féidir leo aon rud ó mhéideadh míchruinn go dtreoil nó go dtugtar isteach ar tháirgeadh.

Inniu, ba mhaith liom labhairt faoina:

Céard iad na feabhsuithe coitianta ar trasnachóirí voltáige eilemhithe? Cén fáth a ndéantar siad? Agus conas déantar a réiteach?

Gan téarmaíocht casta — ach cásanna beatha a bhíonn agam le 15 bliain anuas. Fág linn féachaint ar an mbunús a bhíonn sínte amach leis an "seanchara" seo.

1. Cad é Trasnachóir Voltáige Eilemhithe?

Briofa ar a fheidhm bunúsach a thosú.

Is é trasnachóir voltáige eilemhithe, a bhfuil VT nó PT air freisin, ná trasnachóir laghdaithe atá ag aistriú voltáigh ard go voltáigh íseal caighdeánach (gnáth 100V nó 110V), a úsáidtear ag imeachtaí mearaithe agus córais cosaint relay.

Tá a struchtúr go leor simplí: tá go leor tuairiscí agus dráidín bog ag an bhfreagrúlach príomhshocheach, atá ceangailte lena lárnach ard-voltáighe; tá tuairiscí níos lú agus dráidín níos crua ag an bhfreagrúlach socheach, atá ceangailte lena chiorcal rialúch.

Mar gheall ar a chomhartha struchtúrach seo, is é a chur chun cinn saraíochta, athruithe laiste agus réimsí foinsithe.

2. Feabhsuithe Coitianta agus Anailís Ró-fhondúil

Bunaithe ar mo cheannaireacht 15 bliain san áit, is iad na feabhsuithe is coitianta a leanas:

Feabhas 1: Teaspach Neamhchodladh nó Dóiteach/Dóiteach

Is é seo ceann de na ceisteanna is ngairid — is féidir leis an gcúlscéal a chur ar ais nó fiú teine a chruthú.

Fágbháil Féideartha:

• Comhshracaimh nó buafás socheach (mar shampla, roinnt scéimeanna cosaint ceangailte i bpárlálach gan a chur i gcoinne a chumas);

• Lárú croí (go háirithe le linn ferroresonance);

• Aoisú insiltáin nó teacht isteach anama;

• Termínneolaí folamh a chuir isteach résistance cothrom agus teaspach áitiúil.

Cás Beatha:

Ar deireadh, aimsíodh PT ag teaspach go minic ag stáisiún ardú PV — léirigh thermography infrarghoirm teorainneanna os cionn 120°C. Nuair a díolradh, aimsíomar gur briseadh trí insiltáin socheach. Ba ea an chúlscéal comhshracaimh oscailte mar gheall ar briseadh socheach agus fós ceangailte lena mhéadar íseal-impedance.

Consae:

• Niamh a lig do PT socheach a rith oscailte — cé nach raibh sé chomh ngairid le CTs, is féidir leis an gcúlscéal a chur ar ais agus mearaithe míchruinn a dhéanamh;

• Úsáid thermography infrarghoirm go rialta chun teorainneacha agus teorainneacha teoranta a shocraíodh;

• Má aimsítear teaspach neamhchodladh, stopaigh go dian don scrúdú.

Feabhas 2: Ferroresonance a chur ar ais Oscillations Voltáige

Is é seo ceann de na fadhbanna is mó a chur ar ais ach is é an ceann is ngairid i n-ionaid fhuinnimh nua.

Symptóim:

• Voltáige trí-phás neamhchomhordaithe;

• Voltáige oscillating suas agus síos le torrach;

• Scéimeanna cosaint míchruinn nó triopaiseanna míchruinn;

• Uaireanta, tosaíonn sínnals talún míchruinn.

Príomhchúlscéal:

• I gcórais neamhlonnaithe nó coil smachtú lonna, nuair a chuirtear capacitance line-to-ground le PT excitation inductance faoi chónraí, is féidir ferroresonance a tharla;

• Is minic a tharla sé le linn switching briseadh, suíochán voltage go dian, nó grounding phearsantach.

Cás Beatha:

Ag wind farm, gach uair a bhíonn an transformála príomha energised, bhí PT ag emit a humming noise, agus bus voltage ag oscillate go hard, fiú a trigger the standby auto-switch incorrectly. Tar éis an scrúdú, aimsíodh gur ferroresonance a chuir isteach. Chuir an instaláid resistor damping san open delta an fadhb ar ceal.

Forbairt Mionsonais:

• Socrú anti-resonance devices (mar shampla, open-delta resistors nó microprocessor-based suppressors);

• Úsáid anti-resonant type PTs (cosúil le JDZXW series);

• Optimize modh oibriú chun a sheachaint oibriú neamhfull-phase fadtéarmach;

• Le linn oiriúint, déan tests magnetizing curve chun meastachán a dhéanamh ar threoch lárú croí.

Feabhas 3: Voltáige Socheach Íseal nó Gan Aon Isteach

Is minic a bhíonn na fadhbanna seo ag tionchar ar mheastachán agus logaic cosaint, agus is minic a bhíonn siad mídhleathan mar fadhbanna eile.

Fágbháil Féideartha:

• Primary fuse blown (go minic tar éis lightning strikes nó overvoltage events);

• Secondary fuse blown nó air switch tripped;

• Polarity míchruinn nó ratio setting;

• Inter-turn short circuits in internal windings;

• Oxidized nó loose terminal connections.

Cás Beatha:
In one PV station, SCADA showed abnormally low bus voltage. On-site inspection revealed that the PT primary fuse had blown. Replacing it restored normal operation. Further analysis showed it was caused by a voltage surge from nearby lightning.

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

This usually occurs in humid or heavily polluted environments, especially in coastal or high-altitude areas.

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.

Real Case:

A 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.

Real Case:

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