الحماية الكهربائية
- 1. المحتويات: المقدمة .......................................................................................................................................... 1 المصطلحات المستعملة في مجال حماية النظم الكهربية ............................................................................... 2 دور أجهزة الحماية )المرحلات( ............................................................................................................ 5 وظيفة وأسلوب عمل أجهزة الحماية ....................................................................................................... 7 المبادئ الأساسية لعمل دائرة الحماية ..................................................................................................... 8 المتطلبات العامة لأجهزة الحماية ......................................................................................................... 10 الحماية الرئيسية والحماية الاحتياطية ................................................................................................... 15
- 2. ٢ - 1 - א אא א א אאאאא א אא א K אא א א אאא אא א אא א אא א K אא אאאאא א אא א אאאאאאאא א א א אא KE א א אF א א א א א אאא א אאא א א א אא K אא אאאאא א אאאאאאא א אאא K אאא אאאא K א
- 3. ٢ - 2 - א א א א • Norma F l E אא אאאא א א K א • ERelays F א א א אאא אאא،אאאאא אא FAbnormal אאא KE • א Normally Open Contact (NOC) אא אא K אאא א אא K אאא אא אאאא א אא K א • Normally Closed Contact (NCC ) אא אא K א אא K א F אא E א F א E K אא א א א K א א א K א אא K א • א Primary Relay s א א א אא K
- 4. ٢ - 3 - א Secondary R א elays א א אאאא K א א • א Electromagnetic Rel ays א א א א א K א • א Stati א c Relays א א א (semi-conductors) אא אא אא K אאא אא (slave devices) אאאא K • אא Main Relays א א K א א • א א Back-Up Relays א א אאא א אא K • א Selectivity א E אF א אאאא א אא،אאא א אא אאא K
- 5. ٢ - 4 - א Sensitivity א אא א אא K C • א onsistency א K א א א • א Operating Time אאאאא אאא אא K א • א Instantaneous Relays א אא א א F E א ٠١ K • אא Time-delay Relay אא K Over Current Relays א • א א אאאא א א W א א K١ אא Definite time-Current Relay א א א אאא K א K٢ אאא Inverse-time-Current Relays א א אאא א א א ( I . t = k) א K
- 6. ٢ - 5 - K٣ אאאאא Inverse-definite time Relay אאא א K א א א E אF א אא א F א E אאאאאאאא אאא K א ، אא אאאאאא K א אאא K אאא אאא א אא אא K א א אא E ٢ W١F ٪ אא K א אאאאאא א אאא אאא “Electric Brain” K אא א א E אF אאאאא א אאא א א K א א אאאאאאאא אא א א K אאאאאא א אאא אא K אאאא אאא K אאאא א אאא א א אא א K W
- 7. ٢ - 6 - K١ אא א א K א K٢ א K K٣ אאאאאאא K K٤ אאא אא K K٥ א אאאאא K א Fu א • א ses • אאא Circuit Breakers • א Relays • אא Lightning Arrestors א אאאאאאא אאאאאאאא א K א א אאא א א א אא אא K אאאאאא אא K אF E א אא א אאא אאאאאא א F א KE א אאאא אאא אא א א K
- 8. ٢ -7 - א אאאא אא אא،אא א א F א KE אאא (Distance Relay type reactance) אאאאאאא אאאא אאא (Cos Φ) אא ) Sin φ I V ( ٪٢ א א א K א א אאאא אא א א א א (Potential Transformer) א (Current Transformer) א W K١ אאא א K א K٢ אאאאאא א א א K א א א א K٣ א א K אאאאאא א אאא א K אא אאא א אא אא אא אאא א אא K ( Sensing element) א K ( Control element) אאא א אאאאאא אא א K א א אאאא K אאאאאא
- 9. ٢ -8 - א אא א א K א א א א א (Protective Relays) אאאא אאאאאאא אא אא אא א F E אא א F K א אE א א א א א א אE١F א K אאא (Bus-Bars) א (Feeders) א א אא א K אאא א K אאאאא א אא אאאא F א E אאאא אא K ،אאאא אאא אא אאאא (Trip Coil t.c.) אא (auxiliary switch) K א אאאאא אא K אא אאא W א אאאאאאא אאא אאאאא K אאאא א א א א א אא אא א א א אא אאאא א K אאא (L/R) א אאא،אא א K א א
- 10. ٢ -9 - אאאא (a) אא א א K (rest) אא א א א אא א K א אE١F א محول الجهد P.T رايتلا ول حم CT دائرة لا طع اق ةيمحملا رة ئادلا اتجاه لتشغيل ا يع زوتلا قضيب قضيب توزيع لثانوي ا الجهد شغيل ت لف م مرحل رية اطب a b c
- 11. ٢ -1 0- א א א אאאא א אא אא K אאא א ،אאאאא א א א אא א K אא א K א W אא W א אK א א א א Selectivity א א א אאאאא אא אאאא א K א א א א אאאאאא א א K E٢F א ، K א אא א אE٢F א G G אא א
- 12. ٢ -1 1- אאאאאא א א אאאא K א אאאאאא K אא F א א Eא אא אאא K א ، K אא ( over lapping) א K א אא אאא א א E٣F א Kא א א א א E٣F א KE٢F א א א א א אאא אאא Metal clad type א א א אאאאאאא E٤F אKא א אאא K אא אא K א אאאאאאאא K א א ١ אאאא ٢ אא ٣ ٤ א ٥ Kא
- 13. ٢ -1 2- א א א אE٣F א א אE٤F
- 14. ٢ -1 3- Speed of operation א אאאא ،א אא אאאא א א א א K אא א אא אאא אא אא K אאא א אאאא א אא אא א ،אא ، ،אא א K א א א אא א א אאא אאאא ٠{١F E ٠{١٢ א K אאאא ٠{١٥ ٠{٣ אאאא א ١{٥ ٣ א K אאאאאאא אאא א אאאא،אא א אאא،א ، E٠{١٥٠{٠٦F א ٠ א {٢ א ٠{١٤٠{٠٥ א אא ٠{١٢ א ٠{٠٨ א ٠{٠٤ א א ٠{١ ٠{٢ א אא ٠{٠٢ א ٠{٠٤ K אאאא אאאא K
- 15. ٢ -1 4- Sensitivity א אאא א K אאא א F א E אאא א K א אא א אא א אא אא K אא אא אאאא (Back – up protection) K Reliability א א א אא אא א K אאאא K א אאא אאאאא אאאא אאאא א K א א א אאא א K אא אאאאא א K Stability א א אאאא EF א א א א K א א א א א K
- 16. ٢ -1 5- Main and Back-up Protection א א א א א א א א אאאא אאא אאאאאאאא E٤FK א א א א K א א אא אא א אאא ،אאא אאאא W א K١ אאאא K א K٢ אא K K٣ אאאא K א K٤ א א אא K K٥ א א א א K אא