Alltengi viðmiðuð varnarskipan fyrir stór kraftavirkjar með notkun mikrosporar

1. Yfirlit

Með orkukerfum sem fara í átt að hærri stöðum, stærri kapasíti og flóknari netstöðu, er örugg og örlygð staða virkja einnig mikilvæg fyrir allsherjar öryggis netsins. Sérstök reyndar vörður tengjast viðfangsefnum eins og blindra svæði og ekki nógu mikið ofbeldi þegar um fer að flóknum innri villum við gervivél. Þetta lausn notar framleidd mikrospjaldsbundin vörðartækni, með samþættingu af fleiri upplýsingum og snertilegum reikniritum til að veita hratt, örugg og almennt vörðarkerfi fyrir stór gerðar (til dæmis, hitakerfi, kjarnorku- og vatnarverk). Mál er að losna úr öllum vörðarbliksvæðum og tryggja öruggu virkja.

2. Kernefn

Stórar gerðar standa frammi fyrir mörgum innri villuhætti í keyrslu, þar á meðal:

• ​Villur í stötur spennuband: Phase-to-phase short circuits, inter-turn short circuits, and ground faults. Inter-turn short circuits, in particular, exhibit low initial fault currents, making them difficult to detect with traditional transverse differential protection due to inherent blind zones.
• ​Rotor Circuit Faults: Single-point ground faults, double-point ground faults, and open or short circuits in the excitation circuit. While a single-point ground fault may allow continued operation, its progression to a double-point ground fault can cause magnetic asymmetry and severe unit vibration.
• ​Abnormal Operating Conditions: Reverse power, loss of excitation, over-excitation, overvoltage, and frequency abnormalities. Although not instantaneous faults, these conditions can severely damage the generator or threaten grid stability.

3. Nánar um Lausn

Okkar mikrospjaldsbundið vörðarkerfi notar hierarkisk dreifð skipulag. Kjarnavörðurvirkjan er sameinadur sterkt verktakaflöt með fullorðnum vörðaraðferðum, eins og lýst er hér fyrir neðan:

3.1 Fyrir inter-turn short circuits í stötur: Samþætt vörð með margföldum markmælum

Til að takast á móti óþarfleika sérstakrar vörðar við inter-turn short circuits í sama phase, notar þessi lausn margföldum markmælum samþætta ákvörðunaraðferð, sem markarlega bætir yfirbeldi og ofbeldi.

• ​Teknileg grunnvallar:
• Negative-Sequence Power Direction Criterion: Monitors negative-sequence current and voltage at the generator terminals to calculate the direction of negative-sequence power. Internal asymmetric faults (e.g., inter-turn short circuits) generate a negative-sequence source, with power direction flowing from the generator to the system, enabling accurate internal fault detection.
• Third Harmonic Voltage Variation Criterion: Tracks the amplitude ratio and phase difference between the neutral and terminal third harmonic voltages. Inter-turn short circuits disrupt the inherent distribution pattern of third harmonic voltages, to which this criterion is highly sensitive.
• Neutral Point Displacement Voltage Criterion: Serves as an auxiliary enhancement to improve reliability.
• ​Performance Advantages:
• High Sensitivity: Capable of detecting minor inter-turn short circuits as low as 0.5%.
• Rapid Operation: Full operation time under 20 ms, significantly limiting fault damage.
• High Reliability: Multiple criteria interlock or operate in parallel to prevent maloperation and avoid failure to operate.
• ​Case Study: After implementation in a 500MW coal-fired generator, the solution achieved 98% sensitivity in detecting inter-turn short circuits, successfully preventing major burn-out accidents caused by minor insulation defects.

3.2 Fyrir 100% stötur ground fault protection: Tvívís tækni samþætting

Sérstök grunnvalla zero-sequence voltage protection sýnir blindra svæði nálægt neutral point. Þetta lausn sameinar tvær fullorðnar tækni til að ná 100% protection coverage frá endapunktum til neutral point.

• ​Teknileg grunnvallar:
• Conventional Zone (85–95%): Uses the third harmonic voltage ratio method to protect most of the stator winding from the neutral point toward the terminals.
• Blind Zone Compensation (Near Neutral Point, 5–15%): Employs injection-based stator ground fault protection. A low-frequency (20Hz or 12.5Hz) voltage signal is injected into the rotor circuit, and changes in the injection current are monitored to accurately calculate insulation resistance and fault location, completely eliminating blind zones near the neutral point.
• ​Performance Advantages:
• 100% Coverage: No blind zones, ensuring full stator winding protection.
• Precise Localization: Accurately pinpoints ground fault locations for targeted maintenance.
• ​Case Study: At a nuclear power plant, the solution successfully located a ground fault at only 3% from the neutral point, with less than 1% error, enabling planned maintenance and avoiding unplanned outages.

3.3 Fyrir rotor circuit health: Dynamic Monitoring and Early Warning

Rotor circuit faults, particularly open rotating diodes, are common hidden dangers. This solution shifts from "post-fault protection" to "pre-fault warning" through real-time monitoring.

• ​Teknileg grunnvallar:
• High-frequency current transformers (CTs) or dedicated monitoring modules installed at slip rings collect real-time excitation current waveforms.
• Built-in algorithms perform Fast Fourier Transform (FFT) harmonic analysis on the current.
• Open rotating diodes cause severe distortion of the excitation current waveform, significantly increasing characteristic harmonics (e.g., the fifth harmonic).
• ​Performance Advantages:
• Early Warning: Issues alerts based on harmonic content exceeding thresholds (e.g., fifth harmonic exceeding 8%), prompting maintenance checks on the rotating rectifier bridge before faults occur.
• Prevention of Escalation: Timely warnings prevent serious accidents such as insulation damage due to excitation current loss and rotor overheating.
• Condition-Based Maintenance: Provides critical data for predictive maintenance.

4. Samantekt og Gildi

Þetta mikrospjaldsbundið vörðarkerfi sameinar framleidd sönugreiningartækni, merkiþróunarreiknirit og margföldum markmælum intelligent ákvörðun til að takast á móti sérstökum vandamálum við vörður gervivéla:

• Losnar úr öllum vörðarbliksvæðum, nálgast 100% coverage fyrir stötur inter-turn short circuits og ground faults.
• Breytir eftir-villu vörð í á undan-villu varning, efni villur með dynamic rotor monitoring.
• Staðfest af raunverulegum tilvikum, býður upp á hátt ofbeldi, hraða og öruggu, uppfyllir öruggu kröfur stórra og mega gerða (500MW og meira).