1 / 46

Protection Schemes and Different Types of Relays SVS Sathyanarayana Dy.Manager POWERGRID, Kadapa 400 KV S/S Phone :91-

Welcome. Protection Schemes and Different Types of Relays SVS Sathyanarayana Dy.Manager POWERGRID, Kadapa 400 KV S/S Phone :91-8562-231256, Cell:9440002222 Email: svssai@sancharnet.in. PHILOSOPHY OF PROTECTION.

Faraday
Télécharger la présentation

Protection Schemes and Different Types of Relays SVS Sathyanarayana Dy.Manager POWERGRID, Kadapa 400 KV S/S Phone :91-

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Welcome... Protection Schemes and Different Types of Relays SVS Sathyanarayana Dy.Manager POWERGRID, Kadapa 400 KV S/S Phone :91-8562-231256, Cell:9440002222 Email: svssai@sancharnet.in POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  2. PHILOSOPHY OF PROTECTION A. To maintain proper operation in electrical power system we must hold together the various areas of the power system. Due to geographic location of generating stations practically all produced electric energy is transmitted over transmission & sub- transmission lines and this is the reason why operational reliability of the transmission networks is of vital importance. POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  3. Simultaneous faults • Interline faults T R T R R S R S S T S T Phase selective tripping ? PHILOSOPHY OF PROTECTION The transmission lines are the most widely spread part of the power system and overhead lines are the least protected from environmental influences. The number of line faults is consequently very high compared to the number of faults on the other elements of the power system. The reliability & security of power transmission line largely depends on protection system. POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  4. FUNDAMENTAL PRINCIPLES OF PROTECTIVE RELAYING 1.Two groups of relaying is necessary a. Primary relaying – First line of defense b. back up relaying – functions only when primary relaying fails. 2. Primary relaying may fail because of failure in any of the following: a. Current or voltage supply to the relays b. DC Supply c. Protective relaying d. Tripping circuit e. Circuit breaker POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  5. PRIMARY RELAYING Generator Protection Low voltage SG Protection Power Trans. Protection High voltage SG Protection Transmission line Prot. High voltage SG Protection POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  6. REQUIREMENTS OF PROTECTIVE RELAYS • Any relaying equipment must be sufficiently sensitive so that it will operate reliably when required under actual condition that produce the least operating tendency. • SENSITIVITY : The relay shall be sensitive to operate for minimum quantity of operating parameter. • SELECTIVITY: The relay/scheme should be able to select the faulty section and isolate. • SPEED : The relay should operate faster so that fault is isolated as fast as possible. • STABILITY : The Relay should be stable. • RELIABILITY: The relay/scheme should operate for all types of faults with repeatability and reliability. • COST: The relay/scheme should be economical . POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  7. B VALUE PRICE / UNIT COST A RELIABILITY REQUIREMENTS OF PROTECTIVE RELAYS POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  8. ELEMENTS OF PROTECTION • Fault Clearance: CBs • Fault Sensing: Relays • Inputs to Relays • CT: For sensing Currents • VT: For sensing voltages • DC supply: For functioning of relays & CB • Diagnostic Equipment: DRs, EL, FL POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  9. ELEMENTS OF PROTECTION Bus Trip Ckt CB CT Current DC SOURCE Voltage CVT Relay Feeder POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  10. Types of Relays and Their Characteristics What is a Relay? • A device which has an electrical / non-electrical quantity as input • Output is in form of a switch called “Contacts”, which either close or open depending on the input quantity POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  11. A Simple Relay Solenoid Input Armature Normally Open Contact Normally Close Contact POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  12. Basis of Classifications • Quantity of response: Voltage, current, frequency, power etc. • Function: Detection, time-delay, tripping, alarm, signaling, flag, contact multiplication etc • Construction: Electromagnetic, Static or Numerical POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  13. Basic Types Based on Operating Principle • Attracted Armature • Moving Coil • Induction • Thermal • Motor-Operated • Mechanical • Static • Numerical POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  14. Limitations of Electro-Mechanical relays • Requiring high aux power • High burden on CTs / PTs • Bulky • Difficult to obtain complex characteristics • Prone to drift in characteristics • No facility for monitoring • Limited range of settings POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  15. Application based classifications • Directional O/C & E/F relays • Distance relays • Differential relays • Over-flux relays • Pilot-wire relays • Phase comparison relays etc.. POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  16. Directional O/C & E/F relays IDMT Characteristics PSM x Current TMS x Time POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  17. Directional O/C & E/F relays • Direction sensing is achieved by giving voltage input from PT / CVT • Widely used as back-up protection for power transformers POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  18. Distance relays • Basically measure impedance with voltage and current inputs • Most widely used as primary / back-up protection for transmission lines as well as back up protection for shunt reactors POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  19. DISTANCE RELAY ZONES Z3 Z2 Z1 X X X X X X BASIC SETTING PHILOSOPHY ZONE –1 : 80 % OF PROTECTED LINE ZONE –2 : 100 % OF PROTECTED LINE + 20 % OF SHORTEST ADJ LINE SECTION OR 100% + 50% OF TR IMP ZONE –3 : 100% OF PROTECTED LINE + 100 % OF LONGEST ADJ LINE SECTION or 100% OF TR IMP CHECK SHOULD BE MADE FOR REACH TO TRANSFORMER ADJ TO PROTECTED LINE. POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  20. Differential Relays I1 I2 i1 i2 id=(i1-i2) POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  21. Differential Relays Stabilization is achieved by: • Biasing • High Impedance in Diff ckt POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  22. Over-flux relay • Used to protect transformers against over-fluxing condition • Measures V/f POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  23. Pilot-wire relays • Used for protection of feeders • Works on differential relay principle • Current information of other end is carried by pilot wires • Economical only for very short lines POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  24. Phase comparison relay • Makes use of carrier (PLCC or others) • Sends phase information of current to other end • At each end phase information of both the ends is compared. • If both ends indicate current flow to the line, an in-zone fault is inferred POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  25. Phase Comparison Relay(Through fault) A B A B B A No Trip A+B A+B No Trip POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  26. Phase Comparison Relay (In-Zone fault) A B A B B A Trip A+B A+B Trip POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  27. Phase Comparison Protection Un-Affected by : • Heavy load transfer • Power swings • CT saturation • CT Phase errors POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  28. Phase Comparison Protection Limitations: • Cannot be used on long lines • Affected by Capacitive currents POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  29. TYPES OF TRANSMISSION LINE PROTECTIVE RELAYS • IMPEDENCE BASED RELAYS (Distance protection) • Electromagnetic : MM3T Scheme-(YTG 31 based) • Static : Michromho, Quadromho,RAZFE,LZ96,THR • Numerical :REL100, REL 316, REL521, EPAC, MiCOM, SIPROTEC,SEL • PHASE COMPARISION RELAY • P-10, P-40 • VOLTAGE BASED RELAYS • RXEG21,VTU21 POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  30. POWER TRANSFORMER PROTECTION The Power Transformer is one of the most important links in a power transmission and distribution system. A Transformer fault will cause a large interruption in power supplies and the impact is more serious than a transmission line outage and also cause damage to power system stability. POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  31. Transformer protection falls under two major categories : • Protection of the system against the effects of faults arising inside the transformer. • Protection of the transformer against the effect of faults occurring on any part of the system (external). POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  32. TRANSFORMER FAULTS HV LV MV LV CB R Y B N MAIN TRANSFORMER POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  33. FAULTS INTERNAL TO THE TRANSFORMER • Earth faults • Phase to Phase faults • Inter turn faults • Core faults • Tank faults POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  34. EXTERNAL SYSTEM CONDITIONS: • Over-load • System faults (phase to phase/ phase to earth) • Over voltage • Reduced system frequency. POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  35. NORMAL PROTECTIONS FOR TRANSFORMER • Differential Protection : DTH31,RADSB,RADHA • Ground Fault Protection : CAG14, RADHD • Over Current Protection : CDD,RXIG • Over Load Protection : VTU,RXEG • Over Fluxing Protection : GTT,RATUB • Buchholz Relay (OLTC & Main Tank) • Pressure Relief Device • Oil and Winding temp alarms and trips • Oil Level Monitoring (MOLG) POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  36. Transformer Differential R Y B Differential relay BIASWinding Main CTs R Second Harmonic Restraint Y B Aux CT POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  37. Transformer Differential Bias 3.0 Operate 2.0 Differential Operate Current Non-Operate 1.0 0.2 1.0 2.0 3.0 4.0 Through Bias Current POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  38. Restricted earth fault protection 64 POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  39. EVOLUTION -GRAPH ELECTRO MAGNETIC STATIC EFFECTIVE COST DIGITAL NUMERICAL FUNCTIONS POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  40. EVOLUTION OF NUMERICAL RELAYS ELECTRO MAGNETIC E/M MICRO PROCESSORS ANALOG Static Analog A to D Converter Digital Static Digital Trip Coil Micro Processor A to D Converter Static Numeric Software POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  41. Technology comparison for Protective Relays … continued POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  42. Technology comparison for Protective Relays POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  43. Technology comparison for Protective Relays … continued POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  44. Technology comparison for Protective Relays … continued POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  45. Technology comparison for Protective Relays … continued POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

  46. Thank You POWER GRID CORPORATION OF INDIA LTD – SECUNDERABAD

More Related