1 / 81

SWITCHYARD OF A 500MW POWER PLANT

SWITCHYARD OF A 500MW POWER PLANT. 3 NOS.GEN TRF 1  BANK 400 / 21 kV 200 MVA. ISOLATED PHASE BUSDUCT FOR GENERATOR AND TRFS. LA VT 4. GCB. UNIT TRF 21 / 11.5 KV 50 MVA. A. UT - B. SC VT 1,2,3. LINE CT’s. 11 kV 1 BB SWGR. 11 kV 1 BA SWGR. EARTH SWITCH OF GENERATOR.

chongd
Download Presentation

SWITCHYARD OF A 500MW POWER PLANT

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. SWITCHYARD OF A 500MW POWER PLANT

  2. 3 NOS.GEN TRF 1  BANK 400 / 21 kV 200 MVA ISOLATED PHASE BUSDUCT FOR GENERATOR AND TRFS. LA VT 4 GCB UNIT TRF 21 / 11.5 KV 50 MVA A UT - B SC VT 1,2,3 LINE CT’s 11 kV 1 BB SWGR 11 kV 1 BA SWGR EARTH SWITCH OF GENERATOR GENERATOR NEUTRAL CT’s 400 KV NGT & NGR 21KV / 220 V 175 KVA 0.212 OHMS 800 A 21 KV CT 11 KV EARTH

  3. Salient Features of the Project • Total Capacity - 500MW • Generating Voltage - 21kV • Transmission Voltage - - 400kV & 220kV • 400kV Switchyard - One & Half Breaker Scheme • 220kV Switchyard - Two Main one Transfer Bus Scheme

  4. What is a Switchyard ? It is a switching station which has the following credits : (i) Main link between Generating plant and Transmission system, which has a large influence on the security of the supply. (ii) Step-up and/or Step-down the voltage levels depending upon the Network Node. (iii) Switching ON/OFF Reactive Power Control devices, which has effect on Quality of power.

  5. Switchyard Type • Conventional Air Insulated Type. • Gas Insulated type. • Outdoor Gas Insulated type.

  6. Switchyard layout Objective: Substation layout consists essentially in arranging a number of switchgear components in an orderly pattern governed by their function and rules of spatial separation as described in electrical single line diagram. Pre-requisites: 1) single line diagram 2) general layout plan of power plant 3) orientation of line evacuation 4) control room building

  7. LAYOUT CONTD… • Options / Alternatives The layout will vary for the following: • Switching schemes • Type of insulation - Air Insulated/Gas Insulated.

  8. SWITCHYARD EQUIPMENTS Equipments commonly found in switchyard : • Lightening arrestor • Current transformer • Voltage transformer • Power transformers / I.C.T. • Bus bar and clamp fittings • Support structure • Isolators • Circuit Breaker • Wave traps • Earthing switch

  9. Functions of various equipment : * Transformers : - Transforms the voltage levels from higher to lower level or vice versa, keeping the power constant. * Circuit breakers : - Makes or automatically breaks the electrical circuits under Loaded condition. * Isolators : - Opens or closes the electrical circuits under No-load conditions. * Instrument transformers : - For stepping-down the electrical parameter (Voltage or Current) to a lower and safe value for Metering and Protection logics. * Earth switch : - Used to connect the charged body to ground to discharge the trapped charge to have a safe maintenance zone.

  10. * Lightning arrestors : - Safe guards the equipment by discharging the high currents due to Lightning. * Overhead earth wire : - Protects the O/H transmission line from Lightning strokes. * Bus bar : - Conductors to which a number of circuits are connected. * Wave Traps/Line traps : - Used in PLCC circuits for Communication and telemetering. * Reactive Power control devices : - Controls the reactive power imbalance in the grid by switching ON/OFF the Shunt Reactors, Shunt Capacitors etc., * Current Limiting Reactors : - Limits the Short circuit currents in case of faulty conditions.

  11. EXECUTION SEQUENCE:- • Execution sequence for a substation • Tower foundation • Equipment foundation • Laying of Cable trench • Laying of Earthmat • Support structure installation • High level stringing • Equipment installation • Equipment interconnection • Cabling layout • Commissioning

  12. TABLE I: INSULATION LEVELS & CLEARANCE REQUIREMENTS AT DIFFERENT VOLTAGE LEVELS

  13. Clearance contd… 5) Equipment spacing a) Ease of maintenance/removal of equipment. b) Equipment foundation & their cable trenches. c) Distance between LA and equipment based on the protection reach of LA. d) The spacings are generally kept in order to achieve various clearances specified at Table-I.

  14. Clearance contd… 6) Bus bars: The bus bars of 400 kV switchyard are generally made up 4 “IPS aluminum tube or Quad Moose rated for 3000 A”. The bus bars of 220/132kV switchyard are generally made up of 3 “IPS aluminum tube or quad/ twin moose conductor”. Bus bars are placed at right angles to the feeders for tapping the power. 7) Equipment Interconnection 8) Spacer spans and locations 9) Connection Level 10) Land & Road Layout 11) Sequence and mounting of line traps

  15. Clearance contd…. 12) Control Room Layout 13) Lighting System 14) Cabling Philosophy 15) Gravel Filling 16) Earthing System 17) Lightning Protection System

  16. Selection of Bus Switching Scheme • PRE-REQUISITES 1)System security 2)Operational flexibility 3)Simplicity of protection arrangements 4)Ability to limit short circuit levels (ease of sectionalizing) 5)Maintenance – Its effect on system security 6)Ease of extension 7)Total land area 8)cost

  17. EVOLVING A SUBSTATION LAYOUT LAYING OUT A SUBSTATION INVOLVES STEP-BY-STEP PROCEDURE. MOST IMPORTANT POINTS TO BE CONSIDERED ARE BRIEFLY DESCRIBED BELOW: THE IMPORTANT ELECTRICAL PARAMETERS ARE ESTABLISHED BY THE SYSTEM DESIGN. THE MAIN PARAMETERS ARE: 1) THE VOLTAGE AND BASIC INSULATION LEVEL OR SWITCHING SURGE LEVEL., THE SITE AND CLIMATIC CONDITIONS, THE METHOD OF CIRCUIT CONNECTION, AND SWITCHING OVER-VOLTAGE CONDITIONS. 2) THE BUS BAR SYSTEM DIAGRAM, THE NUMBER OF CIRCUITS AND THEIR PURPOSE I.E. THE CONTROL OF GENERATORS, TRANSFORMERS, FEEDERS, ETC. THE DIAGRAM SHOULD INCLUDE DETAILS OF EXTENSIONS AND FUTURE CONVERSION TO A DIFFERENT BUS BAR SYSTEM, IF INTENDED.

  18. EVOLVING A SUBSTATION LAYOUT • THE CONTINUOUS CURRENT RATING OF THE BUS BARS AND CIRCUITS. • THE SHORT CIRCUIT RATING OF BUS BARS AND EQUIPMENTS. • PARTICULARS OF REACTORS, NEUTRAL EARTHING EQUIPMENT AND REACTING, Interconnecting Transformers REQUIRED. • METHOD OF CONNECTION OF CIRCUITS, WHETHER BY OVERHEAD LINES OR BY CABLES. • DETAILS OF LIGHTNING PROTECTION EQUIPMENT. • DETAILS OF PROTECTIVE EQUIPMENT, DETERMINING THE INSTRUMENT TRANSFORMERS REQUIREMENTS, CARRIER CURRENT EQUIPMENT ETC.

  19. EVOLVING A SUBSTATION LAYOUT THE EXTENT TO WHICH CIRCUIT AND BUSBAR OUTAGES FOR MAINTENANCE WILL BE POSSIBLE. SOME PARAMETERS WHICH INFLUENCE THE FORM OF THE LAYOUT ARE DETERMINED BY THE LOCAL CONDITIONS. THESE ARE: • THE AVAILABLE LAND AREA, SITE AND CLIMATE CONDITIONS, PLANNING AUTHORITY REQUIREMENTS AND AESTHETIC CONSIDERATIONS DETERMINE THE TYPE OF SUBSTATION. • THE DIRECTION OF OVERHEAD LINE ENTIRES POSITION AVAILABLE FOR TERMINAL TOWERS, LOCATION OF TRANSFORMERS AND REACTORS, ETC. • THE AVAILABILITY OF MATERIALS AND THE TRANSPORT AND ACCESS FACILITIES. • THE CAPABILITY AND SKILL OF THE MAINTENANCE STAFF DETERMINES THE IMPORTANCE OF CLARITY OF LAYOUT AND SIMPLICITY OF MAINTENANCE ZONING.

  20. GUIDELINES FOR MAINTENANCE OF OIL PIT FOR TRANSFORMERS AND REACTORS • 1.0 INTRODUCTION: • The layout for a transformer or reactor is planned in such away that there is adequate oil drainage facilities from underneath the equipment. This is essential in order to prevent catastrophic damage to nearby building/ equipments, if the transformer fire takes place and the oil is accumulated below the equipment due to explosion of the transformer/ reactor tank. The oil pit needs to be cleaned at a regular interval so that the oil drainage path is not blocked and in case of explosion, the oil is freely drained to the main oil pit. This regular cleaning is essential because at one of the site, although the oil pit was there below the transformer tank, its drainage was chocked and the transformer fire was accelerated since the accumulated oil in the pit also caught fire. • 2.0 TYPES OF OIL PIT: • There are two types of oil pits in practice which are made below transformers/ reactors depending upon location, size and oil quantity etc. These are: • Soak Oil pit. • Drain and Retention Oil Pit. • SOAK OIL PIT: • If the oil pit provided below the transformer/reactor is not connected with the oil pit of any other equipment or main oil pit. it is classified as soak oil pit. The total volume of this individual soak oil pit is designed in such a way that volume of soak oil pit up to gravel filling level minus the volume of gravels should at least be equal to the oil volume in the transformer. The details of this type of soak oil pit are shown in figure-1.

  21. SOAK OIL PIT

  22. DRAIN AND RETENTION OIL PIT: • For the transformer or reactors located in the transformer yard i. e. unit aux. transformers/station aux. transformers/generator transformers and other transformers of 25 MVA and above rating, individual oil drain pits are provided and these individual oil pits are connected to one common retention oil pit for oil/water separation as these transformers are provided with mulsifire system and in case of fire, the mulsifire system will spray water, which will occupy the empty volume available in retention oil pi t. Also the transformers separated by fire walls and having oil quantity of more than 5000 liters are provided with individual oil drain pits which in turn are connected to one common retention oil pit. The drain oil pit is shown in figure-2.

More Related