Çavdariyê Pêşkêşkirina Vêne Dibeşan di Rêzikên Berdestan de

Têkilişên Şêtina Lîneyên Berhevînan

Wêke parçeyek bingehîn a rêzgeha elektrîk, lîneyên berhevînan bi hêviyên çend û nûmerîk wan di navbera cih û şertên jiyologî û metîroyî yên din dikin. Li virya vê, wan di her dîrokê de li ser tevahî û viranîyan da ku hewce nekin. Sabeqên bêkê hatine girîngkirin, viranîyên kirîyar, xasîna kirîyar, girdîna daristandina derê, û viranîyên dervey. Têkilîna lîneyan yek ji têkilişên her duhêr a operasyonên elektrîkstana û subesta ye, û tiplên têkiliş bi hêviyên single-phase-to-ground, phase-to-phase-to-ground, phase-to-phase, û three-phase short circuits. Di navbera wan de, têkilişên single-phase-to-ground yek ji têkilişên her duhêr ne, ku 95% dan têkilişên hemî lîneyan.

1. Analîza Têkilişên Lîneyên Berhevînan

Têkilişan bi hêviyên kevkirî û pêvîran:

• Pêvî têkilişan herduz diyar kirin ji bo defektên pirantiyên û kirîyarên kirîyan, ku têkiliş hilbijartin ne heta ku werîne.

• Kevkiri têkilişan di navbera flashoverên kirîyan, dischargên serekiya ji bo çîn û barf, kozeyên bi hêlaya wind, têre û tayîn, û pelandeyên malper, ku dikarin veguhestin pas demekî biçûk. Stastîkên destnîşan dînin ku 70%-80% têkilişên lîneyan kevkirî ne, ku wan têkilişên her duhêr ne.

1.1 Rêbaza Girîng a Têkilişên Lîneyan

(1) Darpeyda Pîlê: Herduz di demên metîroyî yên zorî de, wekî storm û windên tornado, ku windên zorî dikarin peyda pîlên berhevînan bibin.

(2) Têkilişên Ji Bo Lightning: Di demên thunderstorms de, lightning strike direct û overvoltages induced dikarin flashoverên ji bo lîneyan bibin, yek ji serekan têkiliş.

(3) Viranîyên Dervey: Dikarin guhertina ilegal, stacking of materials, excavation, stone quarrying, planting of trees, unauthorized attachments, û çapkirina pirantiyên elektrîkstana di navbera right-of-way, hêdikan têkiliş.

(4) Icing of Conductor and Ground Wire: Di demên diman de, ice accumulation dikare mînaka mekanîkî ya zi bike, sagên conductor biguhere. Icing ên zor dikare kirîyan û hardware bigire, kirîyan bigire, û hata pîlê bibin û conductor bigire, ku têkiliş bibin.

(5) Galloping of Conductor: Dema wind horizontal bikatibin ser conductoran ku ji bo ice non-circular bibun, aerodynamic forces dikarin low-frequency, high-amplitude self-excited oscillations (known as galloping) bigire. Galloping dikare phase-to-phase short circuits bibin, bêtir li ser lîneyan ku vertical arranged ne.

(6) Flashovers Ji Bo Birds: Di navbera cihanên ku hêviyên birds zor ne, flocks roosting on tower cross-arms dikarin droppings ser insulator strings bigire, ku dikarin insulation strength bisekin. Di şertên wet (rain, fog) de, dikarin flashovers û single-phase-to-ground faults bibin.

(7) Pollution Flashover: Industrial soot û exhaust pollutants dikarin ser surfaces of insulators bigire, ku dikarin performance of insulation bisekin. Di şertên humid (fog, rain, dew) de, dikarin flashovers û têkiliş bibin.

1.2 Analîza Têkilişên Lîneyan

(1) Pêvî têkilişan: Eger relay protection rengên zarîk (selectivity, speed, sensitivity, û reliability) dibin û circuit breakers interrupting capacity ku bas bide, stability of system herduz ne bisekar bibe. Li virya vê, forced re-energization (strong send) dikare hêli kirin, û protection systems dikarin têkilişên lîneyan bisekin. Experiences of years operational destnîşan dînin ku cases where failed strong sends led to cascading outages û expanded incidents tune.

(2) Foreign Object Contact: Herduz dikare conductor strand breakage bibin. Eger only a few strands broken ne, lîneyan dikarin under controlled load for a period continue operating.

(3) Lightning Strikes: Sometimes, due to prolonged insulation recovery time, the reclosing time delay may not be sufficient, leading to unsuccessful reclosing. However, operational experience and statistics indicate that lightning damage is often minor, and the success rate of forced re-energization remains high.

(4) Failed Reclosing after Cascading Trip: The cause can be identified through protection action records and technical analysis. Once confirmed, the circuit breaker that failed to trip can be manually opened, followed by forced re-energization of the line.

2. General Procedures for Line Fault Handling

(1) If a transient fault occurs and the circuit breaker trips and successfully recloses, operating personnel should record the time, check and document the operation of line protection and fault recorders, verify no internal equipment damage, and report to dispatch.

(2) For lines equipped with synchronizing devices, if a circuit breaker trips and voltage is confirmed on the line under acceptable synchronizing conditions, on-site personnel may perform synchronization and reconnection without waiting for dispatch orders, then report to dispatch.

(3) If a circuit breaker or protection failure causes a cascading trip, operating personnel must identify and isolate the fault point before re-energizing. Re-closing is strictly prohibited until the cause is identified and the fault isolated, to prevent further escalation.

(4) If a circuit breaker trips during protection maintenance (with the line energized), with no fault recording and no tripping on the opposite side, all secondary circuit work should be halted immediately. The cause should be investigated, reported to dispatch, and after appropriate measures are taken, a test re-energization may be attempted (possibly due to unremoved protection channels or accidental contact).

(5) After fault handling, personnel must record detailed incident logs, circuit breaker trip counts, and compile a comprehensive on-site report based on trip records, protection and automatic device actions, event logs, fault recordings, and microprocessor protection printouts.

(6) Upon a line trip, personnel must immediately determine:

• Which protections or automatic devices operated;

• Whether the breaker successfully reclosed;

• Whether it was single-phase or multi-phase tripping, and which phase;

• Whether voltage remains on the line;

• Whether fault recording is available;

• Whether event prints, central signals, and protection panel indications are correct;

• Whether microprocessor protection generated a report;

• On-site inspection of the actual breaker position and all line-side equipment for signs of short circuits, grounding, flashovers, broken conductors, broken porcelain, explosions, or oil spraying—regardless of whether reclosing occurred.

(7) If a fault causes a breaker trip and reclosing fails, operating personnel should record the time, reset alarms, check and document protection and fault recorder actions, confirm no plant equipment damage, set the breaker control switch to the "after-trip" position, and log the number of trips. Subsequent actions may include:

• For critical lines or special periods (e.g., major power supply assurance), after a visual inspection of the breaker reveals no abnormalities, disable reclosing and attempt one forced re-energization;

• Under normal conditions, the line maintenance unit should inspect key sections (e.g., crossings over roads, railways, bridges, rivers, residential areas) to confirm no abnormalities. After disabling reclosing, attempt a test re-energization. If forced re-energization fails, step-by-step voltage escalation may be applied if conditions allow;

• If the fault is accompanied by obvious signs (e.g., fire, explosion), immediate forced re-energization is prohibited. Equipment must be inspected first. After successful re-energization, line current should be controlled, and the maintenance unit notified immediately to inspect the line and obtain fault data promptly;

• For single-source load lines, if tripping occurs and reclosing fails, on-site personnel may immediately attempt one forced re-energization without waiting for dispatch orders, then report to dispatch.